Primary Plant Body Flashcards
What is the primary plant body?
Roots
Shoots-stems and leaves
Plants shoots are _____
Modular
-repetitive units
-photomere: internode, node, leaf, bud
Meristems
Clump of small, unspecialized cells
-dense cytoplasm
-large nuclei
-repeated cell divisions
Apical meristem
-near tips of stems and roots
-elongation of roots and shoots
-produce primary tissues to make plant body
-root apical meristem protected by a cap
-shoot apical meristem protected by leaf primordia or bent hypocotyl
Lateral meristems
Increase girth
Not present in all plants
Intercalary meristems
In stem internodes
Many monocots, horsetails
Primary growth
-result of cell division at the apical meristem
-elongation of organ (stem, root)
Secondary growth
-result of cell division at lateral meristem
-increase in girth
Lateral meristem types
Vascular cambium: secondary xylem and phloem
Cork cambium: cork cells of outer bark in woody species
Periderm is made up of
Cork=phellem
Cork cambium
Phelloderm
Part of the dermal tissue system
Phellogen is the same as
Cork cambium
Root functions
-anchorage
-absorption of water and minerals
Zones of roots
-zone of cell division
-Zone of elongation
-Zone of maturation
Root cap
-several layers of cells
-protects root apical meristem as root pushes through soil
-border cells: old cells sloughed off, replaced by new cells
-mucigel produced by outer layer
-new root cap produced when existing cap is removed
-gravitropism, hydrotropism
Zone of cell division
-cell divide every 12-36 hours
-apical meristem daughter cells divide into Protoderm, Procambium, and ground meristem tissues
Zone of Elongation
-roots lengthen because cells produced by primary meristems grow more on length than width
Zone of maturation
-cells differentiate into epidermal cells, some with a root hair
-cortex produced by parenchyma cells. Inner boundary differentiated into endodermis Surrounded by casparian strips composed of suberin
Endomyccorhizae and Ectomycorrhizae
Endo-thin mantle of hyphae that penetrate the root cortex
Ecto-thick mantle of hyphae that form a sheath outside the root
Quiescent Center
Dormant Center of meristem
How can plant elongate if it has a rigid cell wall?
Cell wall expands with use of enzymes to acidify walls of cellulose
Enzyme-expansins
Arbuscule
Invaginations to create more surface area with Plasmodesmata in mycorrhizae
What do fungi get from plants and what do plants get from fungi
P and N to plant root
Carbs to fungi
What do plants release to attract fungi
Hormones
Stele
All tissues interior to the endodermis
Pericycle
Cells immediately adjacent and interior to the endodermis
Monocot stele arrangement in roots
-primary xylem in discrete vascular bundles
-ring surrounds pith
-poem between bundles
Eudicots stele arrangement in roots
-Xylem x-shaped
-Phloem in discrete groups of cells between arms
Where do lateral roots originate
Pericycle
Casparian strip
Integral band-like portion of primary wall and middle lamella impregnated with suberin and lignin
Apoplasic, symplasitc and trans cellular roots
Between cell walls
Go through Plasmodesmata into cells and then transfer through cells following the outside portion of inner cell
Go through cells