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