Plant Tissues - CH23

what is the meristem?

permanent regions of active cell division

where are apical meristems found?

found at the tips of roots and shoots

apical meristems increase in _______ as it produces new cells

length 

the main function of meristems is:

primary growth of the plant

what are the different primary meristems that can come from an apical meristem?

protoderm, ground meristem, procambium 

what primary tissue does the protoderm become?

the epidermis or dermal tissue system

what primary tissue does the ground meristem become?

ground tissues (parenchyma, collenchyma and sclerenchyma) 

what primary tissue does the procambium become?

primary xylem and primary phloem (vascular tissue system)

what do the lateral meristems produce?

tissues that increase the width of roots and stems

• on her slides “width” was “girth” 

what are the different types of secondary growth associated with lateral meristems?

vascular cambium and cork cambium

what is the function of vascular cambium?

it produces secondary tissues that function primarily in support and conduction 

• thin cylindrical cells 

what secondary tissues does vascular cambium produce?

xylem and phloem 

where is cork cambium located?

lies outside the vascular cambium just inside the outer bark 

cork cambium gives rise to _____ cells

cork

T or F: cell division occurs at the protoderm, apical meristem, and procambium 

True 

Grasses and related plants do not have vascular cambium or cork cambium, but do have___________ in the vicinity of the nodes

apical meristems 

were do the intercalary meristems develop?

at intervals along stems where they add to stem length

the plant body has 3 tissue system:

• ground tissue system 

• vascular tissue system 

• dermal tissue system 

the xylem is a vascular tissue that functions primarily in the distribution of _______

water

the phloem is a vascular tissues that functions primarily in the distribution of _______ 

sugar/food 

simple tissues can be classified as:

tissues that are produced by meristems and composed of one cell type 

what are the three types of simple tissues?

parenchyma, collenchyma, and sclerenchyma

what is parenchyma?

composed of parenchyma cells. tends to have large vacuoles and many contain various secretions

parenchyma only has the primary cell wall. T or F?

True

what are the two subtypes of parenchyma?

Aerenchyma and Chlorenchyma

what is aerenchyma?

parenchyma tissue with extensive connected air spaces 

• these plants can float on the surface of water due to their air bubbles that give them 

what is chlorenchyma?

parenchyma cells containing chloroplasts

• ex: elodea cells 

the most basic and abundant simple tissue is:

parenchyma

what is collenchyma?

containing living cytoplasm and may live an extended time, elongated, with primary cell wall

collenchyma provides ________ for young organs

flexible support

collenchyma cells are characterized by their _________ at the corners of the cell

thickened walls

which cells are shown in the top half of this picture vs the bottom half?

Collenchyma; Parenchyma 

uneven cell wall is indicative of a __________ cell.

collenchyma 

what are sclerenchyma?

cells with thick, tough, secondary walls, normally impregnated with lignin.

what is the function of sclerenchyma cells?

it provides rigid support to the plant 

what are the two types of sclerenchyma?

sclereids- stone cells

fibers - contain lumen (tiny cavity) 

what is lignin?

an organic polymer 

what is this an image of?

stone cells of a pear 

what are complex tissues?

tissues made up of two or more cell types

what is the xylem?

the chief conducting tissue for water and minerals that is absorbed the roots 

what are the different tracheary elements?

vessel elements, tracheids, and fibers and parenchyma cells h

what are vessel elements?

long tubes open at each end/perforations, with secondary cell wall have pits

what are tracheids?

tapered at the ends with pits (cavities in the cell wall) that allow water passage between cells 

• stacked pits allow for movement of water and minerals horizontally b/w cells

T or F: perforation plates in vessel elements can have a single opening or can have ladderlike bars 

True 

what are pits?

cavities in the cell wall

what is the phloem?

conducts dissolved food minerals produced by photosynthesis throughout the plant

what are sieve elements?

sieve tube elements and companion cells

what are sieve tube elements?

large, cylindrical cells w/o secondary walls, no nuclei at maturity 

• sieve plates: porous regions

what are companion cells?

narrow, tapered cells with nuclei 

T or F: phloem is composed of sclereids, fibers, and parenchyma cells

True

the companion cells can be thought of as ________ for the cell

life support 

what is the xylem in gymnosperms?

tracheids

what is the xylem in angiosperms?

vessel elements

what is the phloem in gymnosperms?

sieve cells (w albuminous cells)

what is the phloem in angiosperms?

sieve-tube elements (w companion cells)

what is the epidermis?

complex tissue, outermost layer of cells

what is the function of the epidermis?

to provide protection for the plants

the epidermis is how many cells thick?

one

what are some characteristics of the epidermis?

• most secrete fatty substances, cutin, on the surface of the outer walls 

  • forms the cuticle 

• root epidermal cells produces root hairs 

• leaves have stomata bordered by pairs of guard cells 

what is this image depicting?

waxes that are produced by the epidermis on the stem of black raspberry 

what is this image depicting?

hairs on the surface of a mint plant (epidermis)

what is the periderm?

the outer bark of a plant

the periderm is primarily composed of _____ cells

cork

what does the cytoplasm of cork cells secrete into the walls?

suberin 

what are lenticels and what is their function?

part of the periderm that is composed of cork cambium thats formed into loosely arranged pockets of parenchyma cells that protrude thru the surface of the periderm

• function in gas exchange

what is a dicot stoma?

a microscopic pore on the surface of a dicotyledonous plant's leaf, surrounded by two kidney-shaped guard cells that regulate its opening and closing to control gas exchange for photosynthesis and prevent water loss