transport in plants Flashcards
state the need for transport in plants
metabolic demands - need to transport glucose and oxygen to places like roots where photosynthesis doesnt take place.
size - plants carry on growing all their life, they need an efficient transport system to move substances up and down the plant
SA:V - leaves adapted to have a large SA:V ratio but trunk, stems and roots are not making the plants have relatively small SA:V
describe the structure of the xylem
xylem is made up of several types of cells, most of which are dead.
no end walls between cells
contain a lignin structure for structure and strength
has pits where there is no lignin for water ions to move in or out
main function of xylem
transport water and minerals
structure of phloem
made up of sieve tube elements, sieve plates and companion cells
function of the phloem
transport sugars up and down the plant
what is meant by the apoplast and symplast pathways
apoplast pathway - water travels through cell walls to the xylem
symplast pathway - water travels through the cytoplasm of living cells to the xylem
what is transpiration
Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Transpiration is essentially evaporation of water from plant leaves.
what is translocation
Translocation is the movement of materials from leaves to other tissues throughout the plant. Plants produce carbohydrates (sugars) in their leaves by photosynthesis, but nonphotosynthetic parts of the plant also require carbohydrates and other organic and nonorganic materials.
