Lecture 7 Flashcards
how does the apical meristem aid in stem growth
it adds cells to primary plant body, produces leaf primordia and bud primordial, protect young leaves, phytomeres
how does the vegetative shoot apex help stem growth
tunica-corpus organization
what is tunica organization
outermost layer of cells, divide anticlinally
what is corpus organization
body of cells beneath tunica, divide periclinally
how is the vegetative shoot apex different than the root
can’t be divided into zones like the root
what happens to prevent the vegetative shoot apex from differentiating into zones
leaf primordia originate too quickly to distinguish nodes and internodes; elongation occurs primarily when internodes elongate
what is the intercalary meristem
a meristematic region between 2 more highly differentiated regions
what must happen before an internode can elongate
leaves need to finish differentiating
what causes stem thickness
periclinal division, cell enlargement, (in monocots meristematic cap)
what are the three basic organizations in the primary structure of the stem
vascular system is more or less continuous cylinder within ground tissue, primary vascular tissues develop as bundles separated by ground tissue, and more complex
what type of plants have continuous organization vascular systems
some conifers, magnoliids, and eudicots
what types of plants have bundle organization in their vascular system
eudicots
what types of plants have complex organizations in their vascular system
herbaceous eudicots and monocots
what are some of the relationships between the vascular tissues of the stem and leaf
procambial system of leaf is continuous with stem, bundles diverge at each node, leaf traces, leaf trace gaps
what are leaf traces
extensions in stem towards leaves
what are leaf trace gaps
gaps of ground tissue in vascular cylinder above leaf traces
what does the pattern of the vascular system in a stem reflect
the arrangement of leaves
what are the five different phyllotaxy of leaves
helical, distichous, opposite, decussate, and whorled
what is the difference between pinnately and palmately compound leaves
pinnately- leaflets arise from either side of an axis in one plane; palmately- leaflets arise from the end of the petiole in one plane
what are the two ways to distinguish leaflets from leaves
buds are in axils of leaves not of leaflets, leaves extend in various planes
what are the three ways you can characterize plants by water availability
mesophytes, hydrophytes, and xerophytes
what are mesophytes
plants that are exposed to moderate amount of water
what are hydrophytes
plants that grow in water
what are xerophytes
plants that have little to no water
what are the characteristics of epidermis on a leaf
compactly arranged, covered with cuticle, stomata may occur on one or both sides
what are the two arrangements the stomata may have on a leaf
scattered and rows
what type of plants have scattered stomata on their leaves
eudicots
what type of plants have stomata arranged in rows on their leaves
monocots
what are some characteristics of the epidermis on xerophytes
may have more stomata, sunken stomata on lower surface of leaves, epidermal hairs
what are some characteristics of the epidermis on mesophyll
ground tissue of leaf, large volume of intercellular spaces, numerous chloroplasts mesophytes
what is the differences between C3 and C4
bundle-sheath cells/leaf anatomy, inter veinal distances
what things are involved in leaf development
founder cells, leaf buttress, leaf primordium, intercalary growth, tips of leaf stop growing first, determinate growth
what is leaf primordium
side closest to apical meristem is often flatter than the opposite side
what is intercalary growth
different rates of cell division and enlargement, cell enlargement contributes most to expansion
what are some characteristics of mangled and eudicot leaf development
procambium differentiates to become mid vein, major veins develop upward/outward, minor veins initiate at leaf tip
which direction do minor veins grow
start growing at the edge and work their way backwards
what are some characteristics of monocot leaf development
growth spreads laterally and encircles shoot apex, then growth proceeds linearly from basal meristem
what are characteristics of sun leaves
smaller, thicker than shade leaves; more extensive vascular system; epidermal cell walls thicker; higher photosynthetic rates under high light
what is leaf abscission
separation of leaf from stem
what is the abscission zone
formed by structural and chemical changes near base of petiole (woody angiosperms)
what are characteristics of leaf abscission
abscission zone, retranslocation, and leaf scar
what is the sequence of development of the flower
flower parts develop in order of sepals, petals, stamens, and then carpels
what is the sequence of physiological and structural changes of the development of the flower
vegetative shoot apex becomes reproductive apex; often preceded by elongation of internodes; development of lateral buds below shoot apex; apex increases mitotic activity (becomes dome shaped)
what is homeotic mutation
mutations which result in the formation of the wrong floral organ in the wrong place
what are tendrils
aid in support, most modified leaves, some modified stems
what are cladophyll
modified stems that appear to be leaves, do not have buds in axils, (ex. asparagus and some cacti)
what are spines
modified leaves
what are thorns
modified branches in axils of leaves
what are prickles
outgrowth from cortex and epidermis (ex. rose “thorn”)
how are leaves modified on carnivorous plants
leaves modified to trap insects
what are tubers
modified underground stem, food storage
what is a bulb
large bud of a small stem with many modified leaves attached, food storage, adventitious roots from bottom of stem
how are corm leaves modified
thickened, fleshy stem tissue; thinner, smaller leaves than bulbs
how are petiole leaves modified
thick and fleshy (ex. celery)
how are succulent plant leaves modified
storage of water in stems or leaves
