Exam 2 Flashcards
liverworts
In some, these gametangia are borne on stalked structures called archegoniophores, which bear archegonia, & antheridiophores, which bear antheridia.
o Their life cycle is basically the same as that of mosses, although some of the structures look quite different.
o The resulting zygote develops into a multicellular embryo that becomes a mature sporophyte.
o The liverwort sporophyte is attached to the gametophyte, as in mosses. Sporogenous cells in the capsule of the sporophyte undergo meiosis, producing haploid spores. Each spore has the potential to develop into a green gametophyte, & the cycle continues.
signal transduction
A process in which a cell converts and amplifies an extracellular signal into an intracellular signal that affects some function in the cell. Also see cell signaling.
vascular tissue system (embedded to the ground tissue)
The tissues specialized for translocation of materials throughout the plant body, i.e., the xylem and phloem (cont. throughout body).
responsible also for dissolving minerals/sugars, also helps strengthen/support plant.
caryopses or grains
Other simple, dry fruits, such as caryopses (sing., caryopsis), or grains, do not split open at maturity. Each caryopsis contains a single seed. Because the seed coat is fused to the fruit wall, a caryopsis looks like a seed rather than a fruit. Kernels of corn and wheat are fruits of this type.
conifers
Any of a large phylum of gymnosperms that are woody trees and shrubs with needlelike, mostly evergreen leaves and with seeds in cones. ex pines, redwoods
parenchyma
perform important functions,→ photosynthesis, storage, and secretion, store starch grains, oil droplets, water, and salts, which are sometimes visible as crystal in the cells.
cells that function in photosynthesis contain green chloroplasts, whereas nonphotosynthetics lack chloroplasts and are often colorless.
Materialss. Resins, tannins, hormones, enzymes, and sugary nectar are examples of substances that may be secreted by parenchyma cells.
functions require that cells be alive and metabolically active.
ability to differentiate into other kinds of cells, particularly when a plant has been injured. If xylem (water-conducting) cells are severed, for example, adjacent parenchyma cells may divide and differentiate into new xylem cells within a few days.
thin primary cell walls contain predominantly cellulose, although they also contain hemicelluloses and pectin.
Sori (sing., sorus)
In ferns, a cluster of spore-producingsporangia.
What is a Plant?
A plant is a complex multicellular eu- karyote that has cellulose cell walls, chlorophylls a and b in plastids, starch as a storage product, and may have cells with two anterior flagella. In addition, all plants develop from multicellular embryos that are enclosed in maternal tissues; this last character is one that distinguishes plants from green algae.
coevolution
The reciprocal adaptation of two or more species that occurs as a result of their close interactions over a long period.
vascular cambium
a layer of meristematic cells that forms a long, thin, continuous cylinder within the stem and root.
It is located between the wood and bark of a woody plant. Division of cells of the vascular cambium adds more cells to the wood (secondary xylem) and inner bark (secondary phloem).
Sepals
One of the outermost/lowest parts of a flower (on the whorl), usually leaflike in appearance, that protect the flower as a bud.
cutin
The cuticle, which consists primarily of the waxy substance cutin, varies in thickness in different plants, in part as a result of environ- mental conditions.
epedermis
An outer layer of cells that covers the body of plants and functions primarily for protection.
Tissue in a typical leaf blade
The leaf blade had an upper and lower surfaces, each consisting of a layer of epidermis. The upper epidermis covers the upper surface, and the lower epidermis covers the lower surface. Most cells in these layers lack chloroplasts and are relatively transparent. One interesting feature of leaf epidermal cells is that the cell wall facing toward the outside environment is somewhat thicker than the cell wall facing inward. This extra thickness may provide the plant with additional protection against injury or water loss.
karyogamy,
two haploid nuclei fuse.
xylem
The vascular tissue that conducts water and dissolved minerals in plants.
How is the plant body of flowering plants (& other vasculars) usually organized?
The plant body of flowering plants (and other vascular plants) is usually organized into a root system and a shoot system. The root system is generally underground. The aerial portion, the shoot system, usually consists of a vertical stem that bears leaves and, in flowering plants, flowers and fruits that contain seeds.
phloem fiber cap
In sunflowers and certain other herbaceous eudicot stems, phloem contains a cluster of fibers toward the outside of the vascular bundle, called a phloem fiber cap, that helps strengthen the stem.
not present in all herbaceous eudicot stems.
root pressure
The pressure in xylem sap that occurs as a result of the active absorption of mineral ions followed by the osmotic uptake of water into roots from the soil.
cortex
The tissue between the epidermis and vascular tissue in the stems and roots of many herbaceous plants.
a cylinder of ground tissue that may contain parenchyma, collenchyma, and sclerenchyma cell.
from the various types of cells that it contains, in herbaceous eudicot stems can have several functions, such as photosynthesis, storage, and support. If a stem is green, photosynthesis occurs in chloroplasts of cortical parenchyma cells.
Parenchyma in the cortex also stores starch (in amyloplasts) and crystals (in vacuoles).
Collenchyma and sclerenchyma in the cortex confer strength and structural support for the stem.
simple fruit
Most fruits are simple fruits.
develops from a single ovary, which may consist of a single carpel or several fused carpels. At maturity, simple fruits may be fleshy or dry. 2 examples of simple, fleshy fruits are berries and drupes.
apoptosis
programmed cell death
Bryophytes
Phylum Hepatophyta
Liverworts
Liverworts are so named because the lobes of their thalli superficially resemble the lobes of the human liver; wort is derived from the Old English word wyrt, meaning, “plant.”
dominant gametophyte generation, but the gametophytes of some liverworts are quite different from those of mosses.
o Their body form is often a flattened, lobed structure called a thallus (pl., thalli) that is not differentiated into leaves, stems, or roots.
o The common liverwort, Marchantia polymorpha, is thalloid (FIGS. 27-9a & b).
o On the underside of the liverwort thallus are hairlike rhizoids that anchor the plant to the soil.
o Other known as leafy liverworts, superficially resemble mosses, w/ leaflike blades, “stems,” & rhizoids rather than a lobed thallus (FIG. 27-9c).
o As in the mosses, leafy liverwort “leaves” consist of a single layer of undifferentiated cells.
o small, generally inconspicuous plants that are largely restricted to damp environments.
o Lack stomata, although some liverworts have surface pores thought to be analogous to stomata.
Liverworts reproduce both sexually & asexually (see Figs. 27-9a & 27-9b). Their sexual reproduction involves production of archegonia & antheridia on the haploid gametophyte.
Fruit types
basal cell
large, located toward outside of ovule typically develops into a suspensor, an embryonic tissue that anchors the developing embryo & aids in nutrient uptake from the endosperm.
pith
a ground tissue at the center of the herbaceous eudicot stem that consists of large, thin-walled parenchyma cells that function primarily in storage.
Because of the arrangement of the vascular tissues in bundles, there is no distinct separation of cortex and pith between the vascular bundles.
Leaf arrangement on a stem
Leaves are arranged on a stem in one of three possible ways. Plants such as beeches and walnuts have an alternate leaf arrangement, with one leaf at each node. In an opposite leaf arrangement, as occurs in maples and ashes, two leaves grow at each node. In a whorled leaf arrangement, as in catalpa trees, three or more leaves grow at each node.
alternation of generations
A type of life cycle characteristic ofplants and a few algae and fungi in which they spend part of their life in a multicellular (n) gametophyte stage and part in a multicellular (2n) sporophyte stage.
pressure flow-model
proposed by (German) Ernst Munch
states that solutes (such as dissolved sugars) move in phloem by means of a pressure gradient—that is, a differ- ence in pressure. The pressure gradient exists between the source, where the sugar is loaded into phloem, & the sink, where the sugar is removed from phloem.
At the source, the dissolved sucrose is moved from a leaf’s mesophyll cells, where it was manufactured, into the companion cells, which load sucrose into the sieve tube elements of phloem. Sucrose loading occurs by active transport, a process that requires adenosine triphosphate (ATP). The ATP supplies energy to pump protons (H+) out of the sieve tube elements, producing a proton gradient that drives the uptake of sugar through specific channels by the cotransport of protons back into the sieve tube elements. (Recall the discussion of a cotransport system in Chapter 5.) In the cotransport system involved in phloem loading, sugar is moved from a region of low concentration to a region of high concentration by coupling its transport to the transport of protons down their concentration gradient.
The sugar therefore accumulates in the sieve tube element. The increase in dissolved sugars in the sieve tube element at the source—a concentration that is two to three times as great as in surrounding cells—decreases (makes more negative) the water potential of that cell. As a result, water moves by osmosis from nearby xylem cells into the sieve tubes, increasing the turgor pressure (hydrostatic pressure) inside them. Thus, phloem load- ing at the source occurs as follows:
proton pump moves H+ out of sieve tube element→sugar is actively transported into sieve tube element→water diffuses from xylem into sieve tube element→turgor pressure increases w/in sieve tube→ (unloading of sink) sugar is transported out of sieve tube element→water diffuses out of sieve tube element & into xylem→turgor pressure decreases w/in sieve tube
Primary growth
Primary growth is an increase in the length of a plant and occurs at apical meristems located at the tips of roots and shoots and also within the buds of stems.
all plants
Plants have alternation of generations in which they spend part of their lives in a multicellular haploid stage & part in a multicellular diploid stage.
What s the haploid portion of the lifecycle called/ describe?
The haploid portion of the life cycle is called the gametophyte generation because it gives rise to haploid gametes by mitosis
charophytes or stoneworts
land plants descended fromthis group of green algae
describe a eudicot leaf
usually composed of a broad, flattened blade and a petiole.
typically have netted venation.
In a cross section of a eudicot blade often shows veins in both cross-sectional and lengthwise views.
guard cells are shaped like kidney beans.
alternation of generations
A type of life cycle characteristic ofplants and a few algae and fungi in which they spend part of their life in a multicellular n gametophyte stage and part in a multicellular 2n sporophyte stage.
Bryophytes
Phylum Anthocerophyta
hornworts
thalloid plants (gametophytes)
live is disturbed habitats
single large chloroplast in ecah cell resembles certain algals cells more that plant cells
(Anthoceros natans), archegonia & antheridia are embedded in the gametophyte thallus rather than on archegoniophores & antheridiophores.
o After fertilization & development, the needlelike sporophyte projects out of the gametophyte thallus, forming a spike or “horn”—hence the name hornwort.
o A single gametophyte often produces multiple sporophytes (FIG. 27-10).
o Meiosis occurs, forming spores w/ in each sporangium (pl., sporangia), or spore case.
o The sporangium splits open from the top to release the spores; each spore can give rise to a new gametophyte thallus.
o A unique feature of hornworts is that the sporophytes, unlike those of mosses & liverworts, continue to grow from their bases for the remainder of the gametophyte’s life, a characteristic known as indeterminate growth. Some botanists think that indeterminate growth may indicate that hornworts evolved from plants w/ larger, more complex sporophytes.
filament
In flowering plants, the thin stalk of a stamen; the filament bears an anther at its tip.
Megaphylls
Type of leaf found in horsetails, ferns, gymnosperms, and angiosperms; contains multiple vascular strands (i.e., complex venation). Compare with microphyll.
double fertilization
A process in the flowering plant life cycle inwhich there are two fertilizations; one fertilization results in formation of a zygote, whereas the second results in formation of endosperm.
Bark
the outermost covering over woody stems and roots, consists of all plant tissues located outside the vascular cambium.
two regions, a living inner bark composed of second- ary phloem and a mostly dead outer bark composed of periderm.
bulb
Leaves may also be modified for storage of water or food. For example, a bulb is a short, underground stem to which large, fleshy leaves are attached.
Onions and tulips form bulbs.
Many plants adapted to arid conditions, such as jade plant, medicinal aloe, and string-of-beads, have succulent leaves for water storag. These leaves are usually green and function in photosynthesis.
Collenchyma tissue
Collenchyma tissue, a simple plant tissue composed of collenchyma cells, is an extremely flexible structural tissue that provides much of the support in soft, nonwoody plant organs.
individual cells, including collenchyma cells, support it.
Collenchyma cells, which are usually elongated, are alive at maturity. Their primary cell walls are unevenly thickened and are especially thick in the corners. Collenchyma is not found uniformly throughout the plant and often occurs as long strands near stem surfaces and along leaf veins. The “strings” in a celery stalk, for example, consist of collenchyma tissue.
collenchyma cells have primary cell walls, but their walls are chemically distinct because the thickened areas of collenchyma walls contain large quantities of pectin in addition to cellulose and hemicelluloses.
DNA microarray
A diagnostic test involving thousands of DNA
molecules placed on a glass slide or chip.
Liverworts (phylum Hepatophyta)
A phylum of spore-producing, nonvascular, thallose or leafy plants with a life cycle similar to that of mosses.
evergreen
Aplantthatshedsleavesoveralongperiod,sosome
leavesarealwayspresent.Comparewithdeciduous.
Stomata (sing. Stoma)
Small pores located in the epidermis of plants that provide for gas exchange for photosynthesis; each stoma is flanked by two guard cells, which are responsible for its opening and closing.
pistil
The female reproductive organ of a flower; consists of either a single carpel (simple)or two or more fused carpels (compound). See carpel.
Each pisti; generally has 3 sections: a stigma, a style, and an ovary.
soil erosion
The wearing away or removal of soil from the land; although soil erosion occurs naturally from precipitation and runoff, human activities (such as clearing the land) accelerate it.
Cuticle
1) A noncell, waxy covering over the epidermis of the aerial parts of plants that reduces water loss. (2) The outer covering of some animals, such as roundworms.
Microspores
The n spore in heterosporous plants that gives rise to a male gametophyte. Compare with megaspore.
rhizoids
tiny hairlike absorptive structures
illuviation
The deposition of material leached from the upper layers
of soil into the lower layers.
anthocyanins
red water-soluble pigments called anthocyanins may accumulate in the vacuoles of epidermal leaf cells in some species; anthocyanins may protect leaves against damage by ultraviolet radiation.
The various combinations of carotenoids and anthocyanins are responsible for the brilliant colors found in autumn landscapes in temperate climates.
abscission
The normal (usually seasonal) fall of leaves or other plant parts, such as fruits or flowers.
generative cell
At first, each pollen grain consists of two cells surrounded by a tough outer wall. One cell, the generative cell, divides mitotically to form two nonflagellate male gametes, known as sperm cells. The other cell, the tube cell, produces a pollen tube, through which the sperm cells travel to reach the ovule.
root system
The underground portion of a plant that anchors it in the soil and absorbs water and dissolved minerals.
fiber
In plants, a type of sclerenchyma cell; fibers are long, tapered cells with thick walls.
often occur in patches or clusters
soil
a relatively thin layer of Earth’s crust that has been modified by the natural actions of weather, wind, water, and organisms.
cell signaling
Mechanisms of communication between cells. Cells
signal one another with secreted signaling molecules, or a signaling molecule on one cell combines with a receptor on another cell. See signal transduction.
Embryo
(1) A young organism before it emerges fromthe egg, seed, or body of its mother. (2) Developing human until the end of the second month, after which it is referred to as a fetus. (3) In plants, the young sporophyte produced following fertilization and subsequent development of the zygote.
Pollination, pollen tube growth & double fertilization
Primary growth
Two kinds of meristematic growth may occur in plants. Primary growth is an increase in stem and root length. All plants have primary growth, which produces the entire plant body in herbaceous plants and the young, soft shoots and roots in woody trees and shrubs.
springwood vs. summerwood
appearance of a ring in cross section is due to differences in cell size and cell wall thickness between secondary xylem formed at the end of the preceding year’s growth and that formed at the beginning of the following year’s growth.
In the spring, when water is plentiful, wood formed by vascular cambium has large-diameter conducting cells (tracheids and vessel elements) and few fibers and is appropriately called springwood or early wood.
As summer progresses and water becomes less plentiful, the wood formed, known as summerwood or late wood, has narrower conducting cells and many fibers. It is this difference in cell size between the summerwood of one year and the springwood of the following year that gives the appearance of rings.
megaspores
The n spore in heterosporous plants that gives rise to a female gametophyte. Compare with microspore.
perennial
A flowering plant (herbaceous/woody) that lives for many years.In temperate climates, the aerial (aboveground) stems of herbaceous perennials such
as iris, rhubarb, onion, and asparagus die back each winter. Their underground parts (roots and underground stems) become dormant during the winter and send out new growth each spring. in certain tropical climates with pronounced wet and dry seasons, the aerial parts of herbaceous perennials die back, and the underground parts become dormant during the unfavorable dry season. Other tropical plants, such as orchids, are herbaceous perennials that grow year-round.
follicle
a simple, dry fruit that develops from a single carpel and splits open along one suture to release its seeds.
apical meristem
An area of dividing tissue, locatedat the tip of a shoot or root, that gives rise to primary tissues; apical meristems cause an increase in the length of the plant body.Compare with lateral meristems.
Flowering plants
see angiosperms
photoperiodism
any response of a plant to the relative lengths of daylight and darkness.
Initiation of flowering at the shoot apical meristem is one of several physiological activities that are photoperiodic in many plants.
Plants are classified into four main groups— short-day, long-day, intermediate-day, and day-neutral—on the basis of how photoperiodism affects their transition from vegetative growth to flowering.
archegonia (sing., archegonium)
In plants,the multicellular female gametangium (sex organ) that contains an egg. Compare with antheridium.
signal transduction
A process in which a cell converts and amplifies an extracellular signal into an intracellular signal that affects some function in the cell.
Diversity of Life
The deposition of material leached from the upper layers
of soil into the lower layers.
Descibe the moss sporophyte.
Initially green & photosynthetic, the sporophyte becomes golden brown at maturity. It consists of three main parts:
- A foot, which anchors the sporophyte to the gametophyte & absorbs minerals & nutrients from it
- A seta, or stalk
- A capsule, which contains sporogenous cells (spore mother cells). The capsule of some species is covered by a caplike structure, the calyptra, which is derived from the archegonium
gravitropism
Growth in response to the direction of gravity
Most stem tips exhibit negative gravitropism by growing away from Earth’s center, whereas most root tips exhibit positive gravitropism.
The root cap is the site of gravity perception in roots; when the root cap is removed, the root continues to grow, but it loses any ability to perceive gravity.
Special cells in the root cap possess starch-containing amyloplasts that collect toward the bottom of the cells in response to gravity, and these amyloplasts may initiate at least some of the gravitropic response. If the root is put in a different position, as when a potted plant is laid on its side, the amyloplasts tumble to a new position, always settling in the direction of gravity. The gravitropic response (bending) occurs shortly thereafter and involves the hormone auxin.
ovules
The structure (i.e.,megasporangium) in the plant ovary that develops into the seed following fertilization.
apical meristem
An area of dividing tissue, located
at the tip of a shoot or root, that gives rise to primary tissues; apical meristems cause an increase in the length of the plant body.Compare with lateral meristems.
gametangia (sing., gametangium)
Special multicellular or unicellular structure of plants, protists, and fungi in which gametes are formed.
horsetails (phylum Pteridophyta)
G
dioecious
Having male and female reproductive structures on separate plants; compare with monoecious.
mycelium
As hyphae grow, they form a tangled mass or tissuelike network
internode
A segment of a plant stem between the points where leaves are attached.
dichotomous branching
In botany,a type of branching in which one part always divides into two more or less equal parts.
Hornworts (phylum Anthocerophyta)
A phylum of spore-producing, nonvascular, thallose plants with a life cycle similar to that of mosses.
thigmotropism
growth in response to a mechanical stimulus, such as contact with a solid object.
The twining or curling growth of tendrils or stems, which helps attach a climbing plant such as a vine to some type of support, is an example of thigmotropism.
Prothallus (pl., prothalli)
The free-living, n gametophyte in ferns and other seedless vascular plants.
plasmodesmata
Cytoplasmic channels connecting adjacent plant cells and allowing for the movement of
molecules and ions between cells.
Mechanism of stomata opening
blue light activates proton pumps → proton pump moves H+ out of guard cells → K+ and Cl- diffuse into guard cells through voltage–activated ion channels → water diffuses by osmosis into guard cells → guard cells change shape and stoma opens
To summarize, different mechanisms appear to regulate the opening and closing of stomata. The uptake of potassium and chloride ions is mainly associated with stomatal opening, and the declining concentration of sucrose is mainly associated with stomatal closing.
deciduous
fall off at maturity
What are flowers?
Flowers are reproductive shoots usually composed of four parts— sepals, petals, stamens, and carpels—arranged in whorls (circles) on the end of a flower stalk, or peduncle (FIG. 28-10). The pedun- cle may terminate in a single flower or a cluster of flowers known as an inflorescence. The tip of the flower stalk that bears the flower parts is known as the receptacle. All four floral parts are important in the reproductive pro- cess, but only the stamens (the “male” organs) and carpels (the
“female” organs) produce gametes.
Parts of a leaf
ovary
In flowering plants, the base of the carpel that contains ovules; ovaries develop into fruits after fertilization.
Each young ovule contains a female G. phyte that form 1 f.male gamete (egg), 2 polar nuclei, & several other haploid cells. After fertilization ovule develops into a seed and the ovary into a fruit.
Pollination
In seed plants, the transfer of pollen from the male to the female part of the plant.
turgor pressure
Hydrostatic pressure that develops within a walled cell and presses outward against the plasma membrane.
cotyledon
The seed leaf of a plant embryo, which may contain food stored for germination.
monocots 1
eudicot 2
Magnoliids
One of the clades of flowering plants; magnoliids are core angiosperms that were traditionally classified as “dicots,” but molecular evidence indicates they are neither eudicots or monocots.
sporophyte generation
The 2n, spore-producingstage in the life cycle of a plant. Compare with gametophyte generation.
pneumatophores
Even though roots live in the soil, they still require oxygen for aerobic respiration. Flooded soils are depleted of oxygen, so these aerial “breathing” roots, known as pneumatophores, may assist in getting oxygen to the submerged roots.
help anchor the plant, have a well-developed system of internal air spaces that is continuous with the submerged parts of the root, presumably allowing gas exchange.
Polyploid
The condition of having more than twosets of chromosomes per-nucleus. Compare with diploid and haploid.
stipule
One of a pair of scalelike or leaflike structures found at the base of certain leaves.
drupe
a simple, fleshy or fibrous fruit that contains a hard stone (pit) surrounding a single seed.
Ex include peaches, plums, olives, and almonds. The almond shell is actually the stone, which remains after the rest of the fruit has been removed.
blade
(1) The thin, expanded part of a leaf. (2) The flat, leaflike structure of certain multicellular algae.
Bryophytes
Mosses (phylum Bryophyta)
Describe key characteristic
small, live in dense colonies/beds
tiny hairlike absorptive structrures called rhizoids
some have sugar/water conducting cells
may have both or seperate sex plants
Fertilization occurs when one of the sperm cells fuses w/ the egg w/ in the archegonium.
Sperm cells, which have flagella, are transported from antheridium to archegonium by flowing water, such as splashing rain droplets.
Alternatively, arthropods such as insects & mites may touch the sperm-laden fluid & inadvertently carry it for considerable distances.
Once in a film of water on the female moss, a sperm cell swims into the archegonium, which secretes chemicals to attract & guide the sperm cells, & fuses w/ the egg.
diploid zygote, formed by fertilization, grows by mitosis into a multicellular embryo that develops into a mature moss sporophyte.
This sporophyte grows out of the top of the female gametophyte & remains attached & nutritionally dependent on the gametophyte throughout its existence.
the sporogenous cells undergo meiosis to form haploid spores (see Fig. 27-7).
- When spores are mature, the capsule opens & releases the spores, which are then transported by wind or rain.
- If a moss spore lands in a suitable spot, it germinates & grows into a filament of cells called a protonema.
- The protonema, which superficially resembles a filamentous green alga, forms buds, each of which grows into a green gametophyte, & the life cycle continues.
sieve tube elements
Cells that conduct dissolved sugar in the
phloem of flowering plants.
Joined end to end to form long sieve tubes.
The cells’ end walls, called sieve plates, have a series of holes through which cytoplasm extends from one sieve tube element into the next. Sieve tube elements are living at maturity, but many of their organelles, including the nucleus, vacuole, mitochondria, and ribosomes, disintegrate or shrink as they mature.
among the few eukaryotic cells that can function without nuclei. (bout a yr, notable)
cuticle
Epidermal cells of aerial parts secrete a waxy cuticle over the surface of their exterior walls; this waxy layer greatly restricts water loss from plant surfaces.
slows diffusion of CO2
Mosses (phylum Bryophyta)
A phylum of spore-producing nonvascular plants with an alternation of generations in which the dominant n gametophyte alternates with a 2n sporophyte that remains attached to the gametophyte.
forest decline
the gradual deterioration, and often death, of trees
been observed in many European and North American forests in recent decades.
may be partly the result of soil changes, such as leaching of essential cations, caused by acid precipitation.
pollination
The transfer of pollen grains from anther to stigma
Leaf form simple compound
Leaves may be simple (having a single blade) or compound (having a blade divided into two or more leaflets). Sometimes it is difficult to tell whether a plant has formed one compound leaf or a small stem bearing several simple leaves. One easy way to determine if a plant has simple or compound leaves is to look for axillary buds, so-called because each develops in a leaf axil (the angle between the stem and petiole). Axillary buds form at the base of a leaf, whether it is simple or compound. However, axillary buds never develop at the base of leaflets. Also, the leaflets of a compound leaf lie in a single plane (you can lay a compound leaf flat on a table), whereas simple leaves usually are not arranged in one plane on a stem.
radicle
an embryonic shoot
Secondary growth
Secondary growth is an increase in the girth (thickness) of a plant. For the most part, only gymnosperms and woody eudicots have secondary growth. (Woody eudicots include trees and shrubs such as oak, sycamore, ash, cherry, apple, beech, and maple.)
megasporangia
x
ground tissue system
ground tissue system All tissues in the plant body other than the dermal tissue system and vascular tissue system; consists of 3 tissues parenchyma, collenchyma, and sclerenchyma.
Plant tissues that are neither vascular nor dermal, fulfilling a variety of functions, such as storage, photosynthesis, and support.
gymnosperms
Any of a group of seed plants in which the seeds are not enclosed in an ovary; gymnosperms frequently bear their seeds in cones. Includes four phyla: conifers, cycads, ginkgoes, and gnetophytes.
Antheridia (sing., antheridium)
antheridium (pl., antheridia) In plants, the multicellular male gametangium (sex organ) that produces sperm cells. Compare with archegonium.
suckers
aboveground shoots that develop from adventitious buds on roots. Each sucker grows additional roots and becomes an independent plant when the parent plant dies. Examples of plants that form suckers include black locust, pear, apple, cherry, blackberry, and aspen.
fibrous root system
A root system common to monocots consisting of a mat of thin roots spreading out below the soil surface.
taproot= better for deep water
fib root = better for absorbing water around plant
petiole
The part of a leaf that attaches to a stem.
seed coat
The outer protective covering of a seed.
microsporocytes
Pollen sacs within the anther contain numerous diploid cells called microsporocytes, each of which undergoes meiosis to produce 4 haploid cells called microspores. Each microspore divides mitotically to produce an immature male gametophyte, also called a pollen grain, that consists of two cells, the tube cell and the generative cell. The pollen grain becomes mature when its generative cell divides to form 2 nonmotile sperm cells.
preprophase band
preprophase band In plant cells, a dense array of microtubules just
inside of the plasma membrane that appears just prior to mitosis
and determines the plane in which the cell will divide.
(encircle nucleus like a belt)
pith rays
The areas of parenchyma between the vascular bundles are often referred to as pith rays.
whisk ferns (phylum Pteridophyta)
H
Short-day plants (also called long-night plants)
flower when the night length is equal to or greater than some critical period
two kinds of short-day plants: qualitative and quantitative. In qualitative short-day plants, flowering occurs only in short days; in quantitative short-day plants, flowering is accelerated by short days.
photosynthesis
The biological process that captures light energy and transforms it into the chemical energy of organic molecules (e.g., carbohydrates), which are manufactured from carbon dioxide and water.
adventious roots
Of plant organs, such as roots or buds, that arise in an unusual position on a plant.
The main roots of a fibrous root system do not arise from pre-existing roots but from the stem; such roots are called adventitious roots
gnetophytes
x
palisade mesophyll.
In many plants, the mesophyll is divided into two sublayers. Toward the upper epidermis, the columnar cells are stacked closely together in a layer called palisade mesophyll.
specialized for light capture and is the main site of photosynthesis in the leaf.
bracts
Some leaves associated with flower clusters (inflorescences) are modified as bracts. In flowering dogwood, the inconspicuous flowers are clustered in the center of each inflorescence, and what appears to be four white or pink petals are actually bracts. Similarly, the red “petals” of poinsettia are not petals at all but bracts
Microphyll
Type of leaf found in club mosses; contains one vascular strand (vein ) (i.e., simple venation). Compare with megaphyll.
buttress roots
roots of many tropical rainforest trees are shallow and concentrated near the surface in a mat only a few centimeters (an inch or so) thick. The root mat catches and absorbs almost all minerals released from leaves by decomposition. Swollen bases or braces called buttress roots hold the trees upright and aid in the extensive distribution of the shallow roots
Life cycle of a fern ?
Involves a clearly defined alternation of generations.
o The ferns grown as houseplants (EX: Boston fern, maiden-hair fern, & staghorn fern) represent the larger, more conspicuous sporophyte generation.
The fern sporophyte consists of a horizontal underground stem, or rhizome, that bears leaves, called fronds, & true roots.
o As each young frond first emerges from the ground, it is tightly coiled & resembles the top of a violin, hence the name fiddlehead (FIG. 27-15b).
o As fiddleheads grow, they unroll & expand to form fronds. Fern fronds are usually compound (the blade is divided into leaflets), w/ the leaflets forming beautifully complex leaves.
o Fronds, roots, & rhizomes all contain vascular tissues.
Spore production usually occurs in certain areas on the fronds, which develop sporangia.
o Many species bear the sporangia in clusters, called sori (sing., sorus) (FIGS. 27-15c & d).
o Within sporangia, sporogenous cells (spore mother cells) undergo meiosis to form haploid spores.
o The sporangia burst open & discharge spores that may germinate & grow by mitosis into gametophytes.
The mature fern gametophyte, which bears no resemblance to the sporophyte, is a tiny (less than half the size of one of your fingernails), green, often heart-shaped structure that grows flat against the ground.
o Called a prothallus (pl., prothalli), the fern gametophyte lacks vascular tissues & has tiny, hairlike absorptive rhizoids to anchor it (FIG. 27-15e).
o The prothallus usually produces both archegonia & antheridia on its underside.
o Each archegonium contains a single egg, whereas numerous sperm cells are produced in each antheridium.
Ferns use water as a transport medium.
o The flagellate sperm cells swim, usually from a nearby prothallus, to the neck of an archegonium through a thin film of water on the ground underneath the prothallus.
o After one of the sperm cells fertilizes the egg, a diploid zygote grows by mitosis into a multicellular embryo (an immature sporophyte).
o At this stage, the sporophyte embryo is attached to & dependent on the gametophyte; but as the embryo matures, the prothallus withers & dies, & the sporophyte becomes free-living.
The fern life cycle alternates between the dominant, diploid sporophyte w/ its rhizome, roots, & fronds, & the haploid gametophyte (prothallus) (FIG. 27-16).
o The sporophyte generation is dominant not only because it is larger than the gametophyte but also because it persists for an extended period (most fern sporophytes are perennials), whereas the gametophyte dies soon after reproducing.
patch–clamp technique
A method that allows researchers to study
the ion channels of a tiny patch of membrane by tightly sealing a micropipette to the patch and measuring the flow of ions through the channels.
Lifecycle of a flowering plant?
As a result of double fertilization and subsequent growth and de- velopment, each seed contains a young plant embryo and nutritive tissue (the endosperm), both of which are surrounded by a protec- tive seed coat. In monocots the endosperm persists and is the main source of food in the mature seed. In most eudicots the endosperm nourishes the developing embryo, which subsequently stores food in its cotyledons.
As a seed develops from an ovule following fertilization, the ovary wall surrounding it enlarges dramatically and develops into a fruit. In some instances, other tissues associated with the ovary also enlarge to form the fruit (see discussion of fruits in Chapter 37). Fruits serve two purposes: to protect the developing seeds from desiccation as they grow and mature and to aid in the dispersal of seeds. For example, dandelion fruits have feathery plumes that are lifted and carried by air currents. Animals often assist in dispersing seeds found in edible fruits. Once a seed lands in a suit- able place, it may germinate and develop into a mature sporophyte that produces flowers, and the life cycle continues as described.
cofactors
A nonprotein substance needed by an enzyme for normal activity; some cofactors are inorganic (usually metal ions); others are organic (coenzymes).
Zygote
F
indeterminate growth
ability of roots and stems to grow throughout a plant’s life is known as indeterminate growth
bundle sheath.
One or more layers of nonvascular cells surround the larger veins and make up the bundle sheath.
composed of parenchyma or sclerenchyma cells. Frequently, has support columns, called bundle sheath extensions,
sessile
Permanently attached to one location,e.g.,coral
animals.
bulb
a modified underground bud in which fleshy storage leaves are attached to a short stem. A bulb is globose (round) and covered by paperlike bulb scales, which are modified leaves. It frequently forms axillary buds that develop into small daughter bulbs (bulblets). These new bulbs are initially attached to the parent bulb, but when the parent bulb dies and rots away, each daughter bulb can become established as a separate plant. Lilies, tulips, onions, and daffodils are some plants that form bulbs.
osmosis
The net movement of water (the principal solvent in biological systems) by diffusion through a selectively permeable membrane from a region of higher concentration of water (a hypotonic solution) to a region of lower concentration of water (a hypertonic solution).
Prop roots
adventitious roots that develop from branches or a vertical stem and grow downward into the soil to help support the plant in an upright position. Prop roots are more common in monocots than in eudicots. Corn and sorghum, both monocots, are herbaceous plants that produce prop roots.
mesophyll
(from the Greek meso, “the middle of”; and phyll, “leaf”)
The photosynthetic ground tissue of the leaf, called the mesophyll is sandwiched between the upper epidermis and the lower epiderimis.
Mesophyll cells, which are parenchyma cells packed with chloroplasts, are loosely arranged, with many air spaces between them that facilitate gas exchange. These intercellular air spaces account for as much as 70% of the leaf ’s volume.
axillary bud
A structure that has the potential to form a lateral shoot, or branch. The bud appears in the angle formed between a leaf and a stem.
nuts
simple, dry fruits that have a stony wall and do not split open at maturity. usually large, single seeded, and often derived from a compound ovary.
Examples of nuts include chestnuts, acorns, and hazelnuts.
Many so called “nuts” do not fit the botanical definition.
Peanuts and Brazil nuts, for example, are seeds, not nuts.
hormone
an organic compound that acts as a chemical signal eliciting a variety of responses to growth & development.
tropism
a directional growth response that is elicited by an environmental stimulus.
positive or negative, depending on whether the plant grows toward the stimulus (a positive tropism) or away from it (a negative tropism).
electrochemical gradient
a charge and concentration differnece forms on the two sides of the guard cell plasma membrane.
pigment
a molecule that absorbs the light
monoecious
Having male and female reproductive parts in separate flowers or cones on the same plant; compare with dioecious.
Tension cohesion model
Henry Dixon proposed the tension– cohesion model to explain the ascent of water against the force of gravity.
water is pulled up the plant as a result of a tension produced at the top of the plant. This tension, which resembles that produced when drinking a liquid through a straw, is caused by the evaporative pull of transpiration.
The tension extends from leaves, where most transpiration occurs, down the stems and into the roots. It draws water up stem xylem to leaf cells that have lost water as a result of transpiration and pulls water from root xylem into stem xylem. As water is pulled upward, additional water from the soil is drawn into the roots. Thus, the pathway of water movement is as follows:
soil→root tissues (epedermis, cortex, etc)→root xylem→stem xylem→leaf xylem→leaf mesophyll→atmosphere
bryophytes
Nonvascular plants including mosses,liverworts, and hornworts.
Development of female/male gametophytes
endosperm
The 3n nutritive tissue that is formed at some point in the development of all angiosperm seeds.
tubers
Some rhizomes produce greatly thickened ends called tubers, which are fleshy underground stems enlarged for food storage. When the attachment between a tuber and its parent plant breaks, often as a result of the death of the parent plant, the tuber grows into a separate plant. Potatoes and elephant’s ear (Caladium) are examples of plants that produce tubers. The “eyes” of a potato are axillary buds, evidence that the tuber is an underground stem rather than a storage root such as a sweet potato or carrot.
terminal bud
Embryonic tissue at the tip of a shoot (stem) , made up of developing leaves and a compact series of nodes and internodes.
figs
Why does the primar eudicot root lack piths?
Because it has an inner core of vascular tissue, the primary eudicot root lacks pith, a ground tissue found in the centers of many stems and roots.
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abscission layer/zone
The area at the base of the petiole where the leaf will break away from the stem. Also known as abscission zone.
protective layer of cork cells develops on the stem side of the abscission zone.
Spores
A reproductive cell that gives rise to individual offspring in plants, fungi, and certain algae and protozoa.
dikaryotic
Hyphae that contain two genetically distinct, sexually compatible nuclei within each cell
guttation
The appearance of water droplets on leaves, forced out through leaf pores by root pressure.
microsporophyllsa
a
rhizobia
Certain nitrogen-fixing bacteria, collectively called rhizobia, form associations with the roots of leguminous plants—clover, peas, and soybeans, for EX. Nodules (swellings) that house millions of the rhizobia develop on the roots.
Bacteria receive photosynthetic products from plants while helping plants meet their nitrogen requirements by producing ammonia (NH3) from atmospheric nitrogen.
initial signal molecules produced by rhizobial bacteria are called nodulation factors, or nod factors. These nod factors help root-hair cells in the roots of leguminous plants recognize the presence of the bacteria; recognition is the first step in the infection by rhizobia and the development of root nodules.
The nod factor apparently attaches to a plant receptor on the root-hair plasma membrane. This attachment triggers a calcium-dependent signal transduction cascade within root cells that alters gene expression and metabolism, resulting in nodule formation.
The plant hormone cytokinin is involved in root nodule formation.
microgametophytes
male
What makes a rhizoid different than a rhizome?
Rhizoids are on gametophytes
Rhizomes are on sporophytes
node
the area of the stem where one or more leaves are attached.
gemmae (sing., gemma)
I
monokaryotic
Hyphae that contain only one nucleus per cell
phototropins
family of yellow pigments
light-activated kinases, enzymes that transfer phosphate groups.
polar nuclei
In flowering plants, one of two n cells in the embryo sac that fuse with a sperm during double fertilization to form the 3n endosperm.
Buds
Buds are dormant embryonic shoots that eventually develop into branches.
gnetophytes (phylum Gnetophyta)
consist of
about 70 species in three diverse
and obscure genera
(Gnetum, Ephedra, and Welwitschia).
The genus Gnetum contains tropical vines, shrubs, and trees with broad leaves. Species in the genus Ephedra include many shrubs and vines that grow in deserts and other dry temper- ate and tropical regions. Some Ephedra species resemble horsetails in that they have jointed green stems with tiny leaves. Commonly called joint fir, Ephedra has been used medicinally for centuries. An Asiatic Ephedra is the source of ephedrine, which stimulates the heart and raises blood pressure. At one time, ephedrine was commonly sold over the counter in weightcontrol medications and herbal energy boosters; several deaths were reported from chronic use or overdose of products containing ephedrine, so its use has been restricted.
Describe the diploid portion of the life cycle and what is it called?
When two gametes fuse, the diploid portion of the life cycle, called the sporophyte generation, begins.
The sporophyte generation produces haploid spores by the process of meiosis;
These spores represent the first stage in the gametophyte generation.
Haploid gametophytes produce male gametangia, known as antheridia (sing., antheridium), in which sperm cells form, and/or female gametangia, known as archegonia (sing., archegonium), each bearing a single egg
Sperm cells reach the female gametangium in a variety of ways, & one sperm cell fertilizes the egg to form a zygote, or fertilized egg.
The diploid zygote is the first stage in the sporophyte generation. The zygote divides by mitosis & develops into a multicellular embryo, the young sporophyte plant.
o Embryo development takes place w/ in the archegonium; thus, the embryo is protected as it develops.
o The embryo grows into a mature sporophyte plant.
veins
The veins, or vascular bundles, of a leaf extend through the mesophyll. Branching is extensive, and no mesophyll cell is more than two or three cells away from a vein. Therefore, the slow process of diffusion does not limit the movement of needed resources between mesophyll cells and veins. Each vein contains two types of vascular tissue: xylem and phloem.
humus
partly decayed organic portion of the soil is referred to as humus.
is not a single chemical compound but a mix of many organic compounds, binds mineral ions and holds water.
On average persists in agricultural soil for about 20 years.
Certain components may persist in the soil for 100s of years. Although its somewhat resistant to decay, a succession of microorganisms gradually reduces it to carbon dioxide, water, and minerals.
Reasons for abscission
During winter, the plant’s metabolism, including its photosynthetic machinery, slows down or halts temporarily.
related to a plant’s water requirements, which become critical during the physiological drought of winter. As the ground chills, absorption of water by the roots is inhibited. When the ground freezes, no absorption occurs. If the broad leaves were to stay on the plant during the winter, the plant would continue to lose water by transpiration but would be unable to replace it with water absorbed from the soil.
sieve tube elements
Cells that conduct dissolved sugar in thephloem of flowering plants.
coevolution ex
polinator table
LM of Monocot stem
As in herbaceous eudicot stems, the vascular tissues run in strands throughout the length of a stem. In cross section the vascular bundles contain xylem toward the inside and phloem toward the outside. In contrast with herbaceous eudicots, vascular bundles of monocots are not arranged in a circle but are scattered throughout the stem. Each vascular bundle is enclosed in a bundle sheath of supporting sclerenchyma cells.
does not have distinct areas of cortex and pith.
The ground tissue in which the vascular tissues are embedded performs the same functions as cortex and pith in herbaceous eudicot stems.
do not possess lateral meristems (vascular cambium and cork cambium) that give rise to secondary growth.
have primary growth only and do not produce wood and bark.
callus
Undifferentiated tissue formed on an explant (excised tissue or organ) in plant tissue culture.
angiosperms
The traditional name for flowering plants, a very large (more than 300,000 species), diverse phylum of plants that form flowers for sexual reproduction and produce seeds enclosed in fruits; include monocots and eudicots.
guard cells
Each stoma is flanked by two specialized epidermal guard cells, which are responsible for opening and closing the stoma. Guard cells are usually the only epidermal cells with chloroplasts.
describe conifer life cycle?
Pine tree = mature sporophyte → heterosporous= micro/megaspores (separate cones). Male [pollen] cones(near bottom part time) smaller(consist of sporophylls leaflike scales that bear sporangia on the underside.) female larger(various) (length)(upper,yr round, bear seeds after reproduction). At base of each sporophyll are 2 microsporangia, which contain numerous microsporocytes, aka microspore mother cells. → undergoes meiosis to form 4 haploid microspores. → develop into extremely reduced male gametophytes. Each immature male gametophyte, aka pollen grain, consists of 4 cells, 2 of which—a generative cell and a tube cell—are involved in reproduction. The other 2 cells soon degenerate. Two large air sacs on each pollen grain provide buoyancy for wind dissemination. Male cones shed pollen grains in great numbers, and wind currents carry some to the immature female cones.
female cones (aka seed cones) may be modified branch systems. Each cone scale bears 2 ovules, or megasporangia, on its upper surface. Within each megasporangium, meiosis of a megasporocyte, or megaspore mother cell, produces 4 haploid megaspores. One of these divides mitotically, developing into the female gametophyte, which produces an egg within each of several archegonia. The other three megaspores are nonfunctional & soon degenerate.
When the ovule is ready to receive pollen, it produces a sticky droplet at the opening where the pollen grains land. Pollination, the transfer of pollen to the female cones, occurs in the spring for a week or 10 days, after which the pollen cones wither and drop off the tree. One of the many pollen grains that adhere to the sticky female cone grows a pollen tube, an outgrowth that digests its way through the megasporangium to the egg within the archegonium. The germinated pollen grain with its pollen tube is the mature male gametophyte.
Ultimately, two nonmotile (nonflagellate) sperm cells form within the germinated pollen grain. When it reaches the female gametophyte, the pollen tube discharges the two sperm cells near the egg. One of these sperm cells fuses with the egg, in the process of fertilization, to form a zygote, or fertilized egg, which subse- quently grows into a young pine embryo in the seed. The other sperm cell degenerates.
The developing embryo consists of an embryonic root and an embryonic shoot with several cotyledons (embryonic leaves). Haploid female gametophyte tissue surrounds the embryo and becomes the nutritive tissue in the mature pine seed. A tough, protec- tive seed coat derived from the integuments encloses the embryo and nutritive tissue. The seed coat forms a thin, papery wing at one end that enables dispersal by air currents. Some seeds remain within the female cones for several years before being shed.
Monocots
One of two classes (large ones) of flowering plants; monocot seeds contain a single cotyledon, or embryonic seed leaf, endosperm (nutritive tissue) usually present in mature seed.
include palms, grasses, orchids, irises, onions, & lillies mostly herbaceous w/ long narrow leaves that have parallel veins. parts usually occur in 3’s. Compare with eudicot.
stolons or runners
Stolons, or runners, are horizontal, aboveground stems that grow along the surface and have long internodes. Buds develop along the stolon, and each bud gives rise to a new shoot that roots in the ground. When the stolon dies, the daughter plants live separately. The strawberry plant produces stolons.
evolution of flowering plants
Evidence indicates that several clades of basal (early-diverging) angiosperms evolved before the divergence of core angiosperms. The 170 species of basal angiosperms represent groups thought to be ancestral to all other flowering plants.
The oldest surviving clade of basal angiosperms is represented by a single extant species, Amborella trichopoda. A shrub native to New Caledonia, an island in the South Pacific, Amborella may be the nearest living relative to the ancestor of all flowering plants. The water lilies & related families compose the second clade of basal angiosperms. This clade, which contains about 70 species of aquatic or wetland herbs, may be the second- oldest surviving lineage. Star anise & relatives—the third clade of basal angiosperms—consist of about 100 species of vines, trees, & shrubs found mostly in warmer climates. Star anise is important economically because it is a source of spice used by confectioners & anise oil. Star anise is also used to make Tamiflu, one of the treatments for influenza.
The core angiosperms comprise magnoliids, monocots, & eudicots. Most angiosperm species belong to a clade of core angiosperms, which is divided into three subclades: magnoliids, monocots, & eudicots. Magnoliids include species in the magnolia, laurel, & black pepper families, as well as several related families. Although magnoliids were traditionally classified with the eudicots as “dicots,” molecular evidence such as DNA sequence comparisons indicates that the magnoliids are neither eudicots nor monocots. Native to tropical or warm temperate regions, magnoliids include sev- eral economically important plants, such as avocado, black pepper, nutmeg, and bay laurel.
apical cell
toward the inside of the ovule, develops into the plant embryo
Initially, the apical cell divides to form a small cluster of cells, called a proembryo. As cell division continues, a sphere of cells, often called a globular embryo, develops. Cells begin to develop into specialized tissues during this stage. When the eudicot embryo starts to develop its two cotyledons (seed leaves), it has two lobes and resembles a heart; this is often called the heart stage. During the torpedo stage, the embryo continues to grow as the cot- yledons elongate. As the embryo enlarges, it often curves back on itself and crushes the suspensor.
signal transduction
a receptor converts an extracellular signal into an intracellular signal that causes 1 or more cellular responses.
gnetophytes (phylum Gnetophyta)
consist of
about 70 species in three diverse
and obscure genera
(Gnetum, Ephedra, and Welwitschia).
The third gnetophyte genus, Welwitschia, contains a single species found in deserts of southwestern Africa. Most of Welwitschia’s body—a long taproot—grows underground. Its short, wide stem forms a shallow disc, up to 0.9 m (3 ft) in diameter, from which two ribbonlike leaves extend. These two leaves continue to grow from the stem throughout the plant’s life, but their ends are usually broken and torn by the wind, giving the ap- pearance of numerous leaves. Each leaf grows to about 2 m (6.5 ft) in length. When Welwitschia reproduces, cones form around the edge of its disclike stem.
protonema
h
rhizome
a horizontal underground stem that may or may not be fleshy. Fleshiness indicates that the rhizome is used for storing food materials, such as starch. Although resemble roots, they are really stems, as indicated by the presence of scalelike leaves, buds, nodes, and internodes. (Roots have none of these features.) Rhizomes frequently branch in different directions. Over time, the old portion of the rhizome dies, and the two branches eventually separate to become distinct plants. Irises, bamboos, ginger, and many grasses are examples of plants that reproduce asexually by forming rhizomes.
Xylem
Conducts water and dissolved minerals from the roots to the stems/leaves & provides structural support. In flowerng plants, is a complex tissue composed of 4 cell types: tracheids, vessel elements, parenchyma cells, & fibers. 2 of the 4 cell types ;the tracheids and vessel elements, conduct water & dissolved minerals. also contains fibers that provide support, & parenchyma cells, known as xylem parenchyma, that perform storage functions.
Development of 2ndary growth
LM of herbaceous Eudicot stem
buds
Bud scales cover the terminal bud and protect its delicate apical meristem during dormancy. When the bud resumes growth, the bud scales covering the terminal bud fall off, leaving bud scale scars on the stem where they were attached. Because temperate-zone woody plants form terminal buds at the end of each year’s growing season, the number of sets of bud scale scars on a twig indicates its age. A leaf scar shows where each leaf was attached on the stem; the pattern of leaf scars can be used to determine leaf arrangement on a stem—alternate, opposite, or whorled. The vascular (conducting) tissue that extends from the stem out into the leaf forms bundle scars within a leaf scar. Axillary buds may be found above the leaf scars. Also, the bark of a woody twig has lenticels, which look like tiny specks on the bark of a twig.
seed structure
Phloem
Conducts food materials (carbohydrates formed in photosynthesis) throughout the plant and provides structural support.
In flowering plants, is a complex tissue composed of four cell types: sieve tube elements, companion cells, fibers, and phloem parenchyma cells. Fibers, which are usually extensive in the phloem of herbaceous plants, provide additional structural support for the plant body.
coleoptile
A protective sheath that encloses the
young stem in certain monocots.
Venation patterns
Leaf blades may possess parallel venation, in which the primary veins—strands of vascular tissue—run approximately parallel to one another (generally characteristic of monocots), or netted venation, in which veins are branched in such a way that they resemble a net (generally characteristic of eudicots. Netted veins can be pinnately netted, with major veins branching off in succession along the entire length of the midvein (main or central vein of a leaf ), or palmately netted, with several major veins radiating out from one point.
lenticels
As a stem thickens from secondary growth, the epidermis, including stomata that exchange gases for the herbaceous stem, dies. Stomata are replaced by lenticels, which permit gas exchange through the periderm.
Are the sex organs, or gametangia (sing., gametangium), of most plants multicellular or unicellular?
How about for algae?
The sex organs, or gametangia (sing., gametangium), of most plants are multicellular, whereas the gametangia of algae are unicellular
accessory fruit
plant tissues in addition to ovary tissue make up the fruit. For ex, the edible portion of a strawberry is the red, fleshy receptacle. Apples and pears are also accessory fruits; the outer part of each of these fruits is an enlarged floral tube, consisting of receptacle tissue along with portions of the calyx, that surrounds the ovar.
coevolution
The reciproca ladaptation of two or more species that occurs as a result of their close interactions over a long period.
aggregate fruit
second main type of fruit. An aggregate fruit is formed from a single flower that contains several to many separate (free) carpels.
After fertilization, each ovary from each individual carpel enlarges. As they enlarge, the ovaries may fuse to form a single fruit. Raspberries, blackberries, and magnolia fruits are examples of aggregate fruits.
Eudicots
One of the two clades of flowering plants; eudicot seeds contain two cotyledons, or seed leaves. Compare with monocot.
include oaks, roses, mustards, cacti, blueberries, & sunflowers. Either herbaceous or woody (hickory tree). Leaves vary in shape but usually broader than monocots, have netted veins, parts usually occur in 4’s or 5’s or multiples thereof. Endosperm usually absent in mature seed, having being absorbed by the 2 cotyledons during seed development.
sclerenchyma tissue
specialized for structural support is sclerenchyma tissue, whose cells have both primary and secondary cell walls. The root of the word sclerenchyma is derived from the Greek word sclero, meaning “hard.” The secondary cell walls of sclerenchyma cells become strong and hard because of extreme thickening. Pits, which are thin areas where secondary walls did not develop, allow an exchange of substances between adjacent living sclerenchyma cells. Mature sclerenchyma cells are unable to stretch or elongate. At functional maturity, when sclerenchyma tissue is providing support for the plant body, its cells are often dead.
Sclerenchyma tissue may be located in several areas of the plant body. Two types of sclerenchyma cells are sclereids and fibers. Sclereids are cells of variable shape common in the shells of nuts and in the stones of fruits such as cherries and peaches. The slightly gritty texture of pears results from the presence of clusters of sclereids. Fibers, which are long, tapered cells that often occur in patches or clumps, are particularly abundant in the wood, inner bark, and leaf ribs (veins) of flowering plants
thick secondary walls of sclerenchyma cells are chemically different because they are rich in lignin, in addition to cellulose, hemicelluloses, and pectin.
macro vs. micronutrients
micro - An essential element that is required in trace amounts for normal growth.
macro - An essential element required in fairly large amounts for normal growth.
acidic precipitation
Precipitation that is acidic as a result of both sulfur and nitrogen oxides forming acids when they react with water
in the atmosphere.
Development of secondary vascular tissues in a primary root
root cap
Primary growth is evident when a root tip is examined A protective layer of cells called a root cap covers the root tip. Directly behind the root cap is the root apical meristem, which consists of meristematic cells.
parts of the flower
All 4 organs , normal order of whorls (circles) on the end of the flower stalk
seplas → petals → stamens → carpels
Embryonic development in shepards purse
Describe the pathway of water movement in plants.
conifers lifecycle?
epiphytes
Climbing plants and epiphytes, which are plants that grow attached to other plants, have aerial roots that anchor the plant to the bark, branch, or other surface on which they grow.
Some have aerial roots specialized for functions other than anchorage.
may absorb moisture as well.
Certain epiphytic orchids, for example, have photosynthetic roots.
corm
A corm is a short, erect underground stem that superficially resembles a bulb. Unlike the bulb, whose food is stored in underground leaves, the corm’s storage organ is a thickened underground stem covered by papery scales (modified leaves). Axillary buds frequently give rise to new corms; the death of the parent corm separates these daughter corms, which then become established as separate plants. Familiar garden plants that produce corms include crocus, gladiolus, and cyclamen.
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