Chloroplasts Cell walls Seedless, but vascular Monocots & dicots NonvascularGametangia, need water to reproduce Chloroplasts Cell walls Seedless, but vascular Monocots & dicots
Adaptations to Terrestrial Life Stomata(gas exchange) Cuticle(prevention water loss) Lignin(support) Gametangia & seeds (reproduction) Pollen(reproduction) Vascular tissue(support & transport)-xylem & phloem Roots(water acquisition, support) Seed dispersal mechanisms
General Structure
Plants- General Characteristics Terrestrial Photosynthetic Alternation of generations
charophyte
bryophytes
pteridophytes
gymnosperms
angiosperms
Plant Morphology Organs tissues cells Leaves dermal parenchyma Stems vascular collenchyma Roots ground sclerenchyma meristematic
Tissues Dermal Vascular Ground Outer covering Protective Epidermal cells (cuticle) Guard cells Root hairs Vascular Transport & support Xylem & phloem Ground Bulk of plant Photosynthesis, storage, support
4. Meristematic Embryonic tissue-grows throughout life of plant Roots, shoots, stem(lateral)
Cell Types Found in all 3 tissue types phloem Found in vascualr bundles Thicker cell walls Include Fibers-bundles, support Scleroids-nut shells, seeds Tracheids & vessels of xylem Heavy lignin
sclerenchyma collenchyma parenchyma
Stems Functions Transport between roots & leaves Storage support
Stems-basic structure Epidermis Cuticle, stoma, photosynthetic Body mostly parenchyma Support tissues-collenchyma & sclerenchyma Vascular tissues in bundles Scattered (monocots) or in rings (dicots) Can grow up or out
Monocot stems scattered
Epidermis______
Dicot Stems In ring, around pith
Secondary growth-woody dicots only Produce a new layer of xylem & phloem each year Vascular cambium divides & differentiates Epidermis becomes cork cells, part of bark, along w/ phloem
Vascular cambium- undifferentiated cells Pith & cortex parenchyma for storage Phloem & xylem rays Transport H2O & nutrients Laterally Primary xylem & phloem Non-functioning Cork cambium Produces cork cells which replace epidermis-secrete suberin & die Bark Phloem(living & dead), cork cambium & cork Periderm Cork cambium & cork
Xylem = oldest Dead cells & suberin
How does secondary growth happen? c=vascular cambium cell D=undifferentiated product of mitosis X=xylem P=phloem
Roots Differentiation complete 1st stage of differentiation Responsible for lengthening of root 1st stage of differentiation Protection/lubrication
Root Functions Anchoring Take up water & minerals 1st part to develop 2 types Taproot(dicot) Fibrous(monocot)
Basic Structure Epidermis(dermal)-covers entire surface, including hairs Absorption, protection No cuticle Cortex-mainly parenchyma No chloroplast, but has storage plastids Stele/vascular cylinder Surrounded by endodermis-cells are highly selective Xylem & phloem inside Casparian strip Pericycle Pith(monocots) Thru cell walls Thru cytoplasm
Lateral branch from pericycle
Differences between monocots & dicots
Monocots
__________endodermis ____________pericycle
Dicots ________ epidermis __________________ cortex Vascular Cylinder___ Endodermis___________ ________________xylem Pericycle________________ ________________phloem
Leaves Functions Photosynthesis Maximize sunlight exposure Gas exchange Water conservation
Special Leaf Adaptations Specialized photosynthetic cells Shape-most are broad & flat Stomata Pointed-water run off Needle-shaped-cold & wind Succulents-water storage
General Structure Outer leaf Cuticle(cutin) Epidermis(upper & lower) Stomata & guard cells Inner leaf Mesophyll Palisade parenchyma Densely packed, columnar, upper surface only Spongy parenchyma Irregular shapes, large spaces for gas diffusion Bundle-sheath cells(C4 plants) Vascular bundles/veins
Monocots vs Dicots Monocots Dicots Parallel veins No palisade layer Vascular bundles appear scattered under ‘scope Dicots One large central vein, smaller veins branching off (perpendicular) Palisade layer distinct
monocot monocot dicot
Palisade layer_______ _________spongy layer Main vein________
Leaf epidermis
General Structure cont…
fibers