Plant Tissue and Structure Flashcards
Ground Tissue
Parenchyma
Collenchyma
Scierenchyma
Parenchyma
Site of photosynthesis
Has thin cell walls
Collenchyma
Mechanical support and has thick cell walls, but flexible
Scierenchyma
Mechanical support
Thickest cell walls
Dermal Tissue
Epidermal cell (secrete waxy cuticle) Guard cells (around stomata) Specialized cells (i.e. hair, glandular...etc)
Vascular Bundle
Xylem + Phloem
Xylem
Used for water and mineral transport
Acts as mechanical support
Contains a secondary cell wall for added strength
Dead cells at maturity, consist of cell walls but lack the cellular components
2 types- tracheids, vessel elements
Pits
Where secondary cell wall is absent
Tracheids
Long and tapered
Water passes from one tracheid to another through pits on the overlapping tapered ends of cells
Vessel Elements
Shorter and wider than tracheids
Have less or no taper at their ends
Column of vessel members = vessel
Perforations in Vessel Elements
Holes between cells
Water passes from one vessel member to the next through areas devoid of both primary and secondary cell walls (perforations)
Water moves through better and more easily through perforations than tracheids (more evolutionary advanced)
Phloem
Transport sugars
Made up of sieve tube member cells
Sieve tube members
Form fluid conducting columns called sieve tubes
Are living at maturity (unlike xylem cells)
Lack nuclei and ribosomes, but contain other cell components
Pores on ends of cells form sieve plates
Each sieve tube member is connected with companion cells (parenchyma) by a plasmodesmata tube
Sieve plates
Junctions hat connect 2 cell cytoplasms
Gymnosperms
Conifer seeds
Angiosperms
Flowering plants seed
Can be dicots (2 seeds inside seed coat), or monocots (1 seed inside seed coat)
Seed
Embryo + seed coat + storage material
Storage material can be endosperm or cotyldons (formed by digesting/using storage material in endosperm
Parts of embryo
Epicotyl Plumule Hypocotyl Radicle Coleoptile
Epicotyl
Top part of seed
Becomes the shoot tip
Plumule
Young leaves attached to the epicotyl
Hypocotyl
Below the epicotyl
Attached to the cotyledons
Becomes the young shoot
Radicle
Develops into the root
Only forms in some plants
Coleoptile
A sheath that surrounds and protects the epicotyl
Germination
Seed reaches maturity and becomes dormant until certain cues are triggers for it to grow (water, temperature, light…etc)
Process of Germination
Absorption of water causes seed to swell, seed coat cracks
Radicle produces roots to anchor the seed (root cap protects apical meristem behind it)
Hypocotyl elongates, producing shoot
In young seedling, grows at apical meristems (tip of roots and shoots)
Meristematic
Areas of cells actively divididing
Forms zone of cell division
Zone of elongation
After division, newly formed cells absorb water and begin to elongate
(Growth)
Zone of maturation/differentiation
Cells mature into xylem, phloem, parenchyma, or epidermal cells
Primary growth
Mostly occurs for monocots
Actively dividing cells are only at the apical meristerms
Increases length of root or shoot
Primary tissues develop from this type of growth (primary xylem and primary phloem)
Secondary Growth
Occurs in conifers and woody dicots
Occurs in addition to primary growth
Increases the lateral dimensions of the plant (girth)
Occurs at 2 lateral meristerms (vascular cambium, cork cambium)
Vascular cambium
Produces secondary xylem and phloem
Cork cambium
Produces periderm (protective covering on outside)
Stamen
Male reproductive structure of angiosperms
Pistil
Female reproductive structure
Sepal
Part of a flower
Encloses petals
Peduncle
Stalk part of flower
Bears flower/fruit
