Chaper 25: Plant Form And Function Flashcards
Basic components and functions
- Root system- absorption and storage
2. Shoot system- stems and leaves
What do plants require?
- Light
- Water
- Carbon dioxide
- Oxygen
- Specific nutrients (N, Ca, K etc)
3 tissue types
- Vascular tissue
- Dermal
- Ground
Vascular tissue
Xylem, phloem, stele, pericycle and pith
Dermal tissue
Outer protective covering (epidermal)
Ground tissue
All cells that are not vascular or dermal. Storage and photosynthetic - viscera of the plant cortex and endodermis
Three organs of plants are?
Leaves, stems, and roots
What are the function of Roots?
Water uptake, anchor plant, store food (carrots, potatoes)
Root structure:
3 tissues arranged in circles: epidermis, cortex, and vascular tissue
Epidermis
Thin with root hairs
Root hairs
Soak up water. Pulled off easily. Transplant with soil
Cortex
Majority of root. Parenchyma walls for food storage. Loosely packed cells so water can move easily between
Endodermis
Innermost layer that contains the casparian strip in the cell walls forcing the water and minerals to pass through the membrane
Casparian strip
Protein that prevents water from flowing out and back to the cortex and leak out of the roots
Vascular cylinder
Areas with xylem and phloem also a layer of cells
Pericycle
Which produced branched roots (meristem)
Vascular tissue in plant:
Root- vascular cylinder
Stem- vascular bundle
Leaf- vein
Monocots have what in the center with a ring a xylem around it?
Pith
Have a star shaped vascular bundle
Eudicots
Root cap
Protects the apical meristem, gets worn away as root pushes through the soil. Lubricates and loosens the soil
Cell division
Occurs in meristem. Constantly produces new cells and new cap
Elongation
Cuboidal cells elongate. Root length 10x
Differentiation
Maturation. Cells mature and specialize into vascular, dermal or ground tissue
Adventitious
“Not coming from the root”. Example: Arial roots and prop roots of corn.
Haustoria
Root like stems that parasitize other close plants
Inside of stems:
Parenchyma, collenchyma, and scleremchyma
Parenchyma
Most common ground tissue for turgid pressure with large vacuoles. No secondary walls. Water had to flow back and forth between cells
Collenchyma
Walls contain pectin, thick primary walls. Strong but flexible and hard to cut or knock down
Sclerenchyma
Have lignin (hardens cellulose) in secondary walls for rigidity. Contains fibers or schlereids. Ex: Grit in pears
Meristem
A group of actively dividing cells, plant is growing
Tap root
One main root that grows straight down. Exp: carrot
Fibros roots
Roots grow same length as width
Vascular cylinder
Root system- xylem and phloem
Vascular bundle
Xylem and phloem in stems
Vein
Xylem and phloem in leaf
Dicots
Star shaped
Adventitious roots
Grow above ground
Haustoria
Act like parasites. Don’t photosynthesize. Roots can grow oh other plants and steal their nutrients
Mycorrhizae
Grow directly on root (fungus). Absorb glucose from root, provide nitrogen and excess water to plant
Herbaceous stem
Doesn’t have bark
Derma layer that has stomata and carries on photosynthesis
Woody stem
Bark, don’t carry on photosynthesis
In Angiosperms
Sieve tube members with sieve plates at ends with pores
Companion cells
Associated with non nucleated sieve tube offer chemical support- connected by plasmodesmata
Tracheids taper and overlap with pits inbetween
Gives support
Vessel elements
Short and wide tubes arranged in series
Dicots vascular tissue
Cylinder with xylem on the inside close to the pith and phloem on the outside close to the cortex
Shoot systems grow…
Like the root system, with the shoot apical meristem, cell elongation and differentiation
Develop above the nodes-
Auxiliary buds (become branches and flowers)
Branches develop only if
The terminal bud is absent- apical dominance
Internodes
Area between leaves
In grasses the meristem is
At the base of the leaves
Stolons
On surface, horizontal
Ex. Strawberry or spider plant
Rhizomes
Horizontal below the surface
Ex. Potatoes and iris
Grafting
Stem cut inserted into a cut in the rooted plant
Ex. Rose bushes
Stem cuts-
Hormones promote adventitious roots
Primary growth
The growth of stems , roots, and leaves. Up and down
Protoderm
Primary growth- Becomes the epidermis
Procambium
Primary growth- Becomes vessels
Ground meristem
Primary growth- Becomes cortex
Secondary growth
Involves thickness (elongation) growth never stops during the life span of the plant. Side to side
Indeterminate growth
Not determined, grow continuously through your life each year
Vascular cambium
Secondary growth- thin meristems between xylem and phloem that produces both- xylem to the inside and phloem to the outside
Rays
Secondary growth- lateral xylem vessels
Old phloem-
Secondary growth- splits and becomes party of bark
Old xylem
Secondary growth- gets clogged in older growth (heartwood )
Cork cambium
Produces cork to the outside and replaces the epidermis
Girdling
Removing a strip of bark all around the tree, cuts phloem and eventually kills the tree
Function of leaves
Position for maximum photosynthesis, conserve water, collect water for photosynthesis
Ground tissue of leaves
Mesophyll
Pallidsade parenchyma
Columnar cells for photosynthesis
Spongy parenchyma
Irregular fitting with spaces for water vapor, O2, and CO3
Leaves
Dermal-
Upper and lower epidermis are covered by a wavy cuticle
Vascular bundles in leaves
Veins
Petioles
Leaf stalks
Pinnate or palmate be nation
Dicots and veins arranged like a net or palm
Leaves
Monocots
Veins are parallel
Types of leaves-
Simple Compound Pinnately compound Palmately compound Double compound
Longevity of plants
- Annuals- lives only 1 season
- Biennials- live over 2 seasons
- Perennials- live for many seasons
