BIO REVIEW CYC 6

BIO REVIEW CYC 6

ANATOMY OF ​A PLANT

​(Coverage: teacher created vids from C6)

​Plant Tissues

Plant Cell Types​

​Meristems

​PLANT TISSUE

​GROUND TISSUE

fills the spaces between more speciulized cell types inside roots, stems, leaves, fruits, and seeds

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​PLANT TISSUE

​DERMAL TISSUE

covers the plant - ​'skin'

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​Herbaceous plant: epidermis - single layer of packed, flat, transparent, parenchyma cells

​Woody plants - tough bark

​PLANT TISSUE

​DERMAL TISSUE

cuticle: waxy layer

​coats epidermis of leaves and stem

​mitigates transpiration (exhaling of water vapor through stoma)

​protects from predators/fungi

​oxygen, carbon dioxide, and water can't permeate (pass thhrough) the cuticle

​PLANT TISSUE

​DERMAL TISSUE

Stomata: since d cuticle is impermeable to O2 & CO2, stoma facilitate gas exchange

​Guard cells: control the opening/closing of stomata (which is signalled by its interaction with water.

​PLANT TISSUE

​VASCULAR TISSUE

xylem and phloem

​choochoo

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​PLANT CELL TYPES

​GROUND TISSUE CELLS

​makes up the majority of a herbaceous plant

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​ Herbaceous plant: non-woody

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​Consists of Parenchyma, Collenchyma, Sclerenchyma

​Parenchyma

​Most abundant ground tissue type

​Alive at maturity

​Thin cell walls

​Can divide

​ ^in response to injury/environment

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​FUNCTIONS: photosynthesis, respiration, gas exchange, storage

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​Paren = parent

Collenchyma

Uneven thickness of cell walls

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Elastic

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​FUNCTIONS: structure support

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​Collen = column (but elastic so more like a rubber column)

Sclerenchyma

Dead at maturity

​Thick cell walls

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Rigid (compact, sturdy)

​ ^contains lignin, a complex molecule that add strength to cell walls

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​FUNCTIONS: inelastic support to non-growing plant parts

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​scleren = scleleton (skeleton -> dead, hard bone)

​PLANT CELL TYPES

​VASCULAR TISSUE CELLS

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transport water, minerals, carbohydrates, & other dissolved compounds

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​similar to animal circulatory system

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​Consists of Xylem and Phloem.

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​XYLEM - TRACHEIDS

Long, narrow cells that overlap at their tapered ends

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​Water moves through pits in the tracheid

​ ^pits are thin areas of the cell wall

XYLEM - VESSEL ELEMENTS

Short, wide, barrel-shaped

Stacked end-to-end, forming long, continuous tubes

​Faster water movement

​Water moves through pits in the tracheid

​ ^pits are thin areas of the cell wall

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​looks like a blood vessel

PHLOEM - SIEVE TUBE ELEMENTS

Main conducting cells of phloem

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​Aligned end-to-end

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​Alive but no nucleus and little cytoplasm

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PHLOEM - SIEVE TUBE ELEMENTS

COMPANION CELL

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adjacent to sieve tube element

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​specialized parenchyma cell

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​transfers carbs

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​provides energy and protein

​transition time o

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DETERMINATE VS INDETERMINATE GROWTH

​determinate - plants that stop growing after they reach their mature size

^​genetic limitation

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​indeterminate: plants that continue to grow as long as environmental conditions allow it

​ ^environmental limitation

​MERISTEMS

​regions that undergo active mitotic cell division

​ ^mitotic = cell splits into copies of itself

​useful for repair, growth, and response to environmental changes

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​APICAL MERISTEMS

​for length/height/reach - elongates by absorbing water (turgid)

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​LATERAL MERISTEMS

​for girth/thiccness/w i d t h

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​*both of these are present in roots and shoots*

​MERISTEMS

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​ROOT APICAL MERISTEMS

AREA OF MATURATION

​AREA OF ELONGATION

​AREA OF CELL DIVISION

​MERISTEMS

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LATERAL​ MERISTEMS

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​Vascular cambium - produces thin layer between xylem and phloem

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​Cork cambium - densely packed, dead at maturity, forms waterproof and insulating layers

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​MERISTEMS

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LATERAL​ MERISTEMS

​(annual highlights)

How do rings form: vascular cambium cells are dormant during late summer/fall which gives it a darker hue

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​compared to the vc during spring/early summer where cells are active and are lighter in color

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​SUMMARY

• ​3 Plant tissues

• ​ground, dermal, vascular

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• ​parenchyma, collenchyma, sclerenchyma

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• ​cuticle, epidermis/bark

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• ​xylem, phloem (tracheids, vessel, sieve tube elements)

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• ​​determinate, indeterminate growth

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• ​Meristems - regenerative cells for growth/repair/adaptation

• ​area of maturation, elongation, cell division

• ​vascular cambium, cork cambium