How Do Plant Tissues and Organs Originate?

A) basal-apical axis: from shoot to root (upwards, downwards)
b) radial axis: concentric arrangement of tissue systems (outwards)

What: cluster of undifferentiated cells
where: root and shoot tipfunc.: 1) postembryonic development, 2) form organs throughout lifetime

1)dermal2)vascular3)ground

Charac.: small, round, small/no central vacuole
-can differentiate into 3 structures: -stomatal guard cells: form stomata (gas x-chng)
-trichomes: aka leaf hairs for protec.against leaf hairs and solar radiation
-root hairs: inc. root surface area--> greater uptake of water and minerals

-aboveground epi. cells secrete protective extracellular cuticle made of cutin
-limits water loss, reflects solar radiation, barrier against pathogens

-makes up most of plant body
-3 types of cells in ground tissue
-parenchyma
-collenchyma
-sclerenchyma

Large vaculoes
thin cell walls (only primary cell wall, share middle lamella)
roles: photosynthesis and storage

Resemble Parenchyma cells
provide flexible support
primary cell walls thick at corners (b/c of depositions of pectin)
flexible

Thickned 2ndry cell walls for support
programmed cell death (so start supporting when dead)2 types sclerenchyma:
a) fibers: rigid support, organized in bundles
b) sclereids: pack together densely

2 constituent tissues:
-xylem: distributes water and mineral ions from roots to shoot
-phloem: transport, support, and storage
-gets E by transporting carbohydrates from sources to sinks

= indeterminate
will continue to grow as long as plant lives

= lengthening of roots and shoots by production of new roots and shoots through branching

= increase in girth

Orchestrate primary growth = primary plant body
growth due to cell division, cell enlargement (verticle elongation)

Orchestrate secondary growth
2 types lat. meri.:
a) vascular cambium
b) cork cambium