Vasculature: xylem and transpiration

Question 1

what are vasc tissues

Answer 1

specialized in rpid and efficient movement of solutes and solvents throughout the pnat

Question 2

what are xylem tissues

Answer 2

specialized in the movement of water throughout the plant

transport mineral elements
support

Question 3

what are he types of xylem cells

Answer 3

tracheary elements
fibers
perenchyma cells

Question 4

characteristics of the tracheary element cells

Answer 4

highly specialized unique cells
dead at maturity
lack of vacuoles, nucleus, cytoplasm

Question 5

role of tracheary elements

Answer 5

create xylem

it is the death and hardeing of parenchyma cells

Question 6

2 types of tracheary elemt cells

Answer 6

tracheids

vessel elements

Question 7

what are tracheids

Answer 7

long narrow cells with a large surface area/volume ratio
considered to be the first vasc tissue evolved
found in all vasc plants

Question 8

what are pit membranes

Answer 8

porous modified primary cell walls

allow water nut traps large molecules and gasses

Question 9

how does water flow in tracheids

Answer 9

between them and through thepit membranes

Question 10

when did vessel elemnts evolve

Answer 10

late in plant history

gnetidae have a form of vessel element that evolved differently

Question 11

what are vessel elements

Answer 11

shorter and wider than tracheids

have specialized divisions between adjacent vessel elements

Question 12

what are perforation plates

Answer 12

divides vessel elements

lacks primary and secondary cell wall

Question 13

how does water flow in vessel elements

Answer 13

rapidly

Question 14

what is a bad thing about vessels

Answer 14

they are more vulnerable to air embolisms

Question 15

what are air embolisms

Answer 15

when a gas inside vasculature obstructs water movement

Question 16

fiber cells are made of wghat

Answer 16

sclenrenchyma cells

Question 17

what processes allow for bulk flow of water through the xylem

Answer 17

transpiration

adhesion/cohesion theory

Question 18

where does all the water absorbed by the plant go

Answer 18

99% of the water is converted to water vapor and lost in the atmosphere aka transpiration

Question 19

what does photosynthesis require

Answer 19

• max light exposure : large surface area of leaves relative to low volume inside the cell
• gas exchange: pores or stomata open passage between atmosphere and internal plant space

Question 20

consequence of maximizing photosynthesis

Answer 20

maximizing water loss

Question 21

how is water mainly lost in transpiration

Answer 21

through the stomata

Question 22

what is a stomata

Answer 22

specialized dermal cells in the plant

Question 23

what are guard cells

Answer 23

open and close stomata

controlled by environmental signals and solute concentrations in the cell

Question 24

what is needed to open guard cells

Answer 24

increased turgor pressure in cells

Question 25

how is turgor pressure increased

Answer 25

by drawing water into the celle through increasing the concentration of solutes in the guard cells

Question 26

why is it important for plants to control the flow of water out of the plant

Answer 26

if it is unchecked, the plant will use up all the water inside it and not be able to replace it and wilt

Question 27

is water transport in the plant active or passive

Answer 27

passive

Question 28

how can bulk flow of watr be passive

Answer 28

thanks to water potential and natural chemical properties of water

Question 29

where is water potential lower and higher in plants

Answer 29

lower =in leaves | higher= in roots

Question 30

how does water flow

Answer 30

from cells with high water potential to low water potential

Question 31

what is cohesion

Answer 31

attraction of 2 similar molecules to each other

Question 32

what happens because of the slight polarity of water

Answer 32

+ charged at one and end - charged at the other molecules attract each other and drag along other water molecules

Question 33

what is adhesion in plants

Answer 33

water molcules are weakly attracted to the tracheary elements, adhere to them and pull other molecules along

Question 34

what creates difference in water potential in the plant

Answer 34

transpiration

Question 35

water moving through the xylem is a solution made of what

Answer 35

``` solutes = mineral elements solvent = water ```

Question 36

what happens to minerals when water evaporates

Answer 36

the minerals are left behind in the leaves and it creates an area of significant low water potential

Question 37

what is cohesion tension theory of water movement

Answer 37

combination of transpiration facilitating the movement of water in the plant and the cohesion/adhesion concept

Question 38

when does transpiration stop

Answer 38

- plant needs to conserve water and closes stomata | - air is so humid that little transpiration takes place

Question 39

what is root pressure

Answer 39

when roots actively import ions into the xylem and create a new gradient from roots to xylem water potential