plant vascular tissues Flashcards
func of xylem
transports water & dissolved minseral salts from roots to other parts of plant, provide mechanical support
adv of long & hollow lumen (xylem)
reduced resistance to allow for continuous & incr rate of transport
adv of lignified walls (xylem)
provides mech support when xylem vessels are bundled together to allow for continuous & incr rate of transport
what are parenchyma cells (xylem)
typical plant cells which undergo specialisation to form xylem tissues
func of phloem
transports manufactured food (sucrose, amino acids) from leaves to other parts of plant
adv of sieve tubes elements which have little protoplasm & joined end to end (phloem)
reduced resistance to facilitate incr ease & rate of flow of subst through a continuous column
adv of pores in sieve plates (phloem)
allow for rapid flow through sieve tubes –> incr rate of flow of sucrose & amino acids
adv of numerous mitochondria in companion cells (phloem) FROM WHERE TO WHERE
release more energy through incr rate of cellular resp –> incr rate of AT to load sugars from mesophyll cells into sieve tube
what is a cambium
tissue btw xylem & phloem, can divide & differentiate to form new xylem & phloem tissues
func of pith in stem
contains regular plant cells, storage tissue
func of epidermis
covers stem, protected by waxy waterproof cuticle that reduces evaporation of water from stem
how are mineral salts absorbed into rhc when conc of ions in soil is higher than conc in rhc
diffusion
how are mineral salts absorbed into rhc when conc of ions in soil is lower than conc in rhc
active transport
func of rhc
absorb water molecules & dissolved mineral salts from surroundings into root
adv of long narrow protrusion (rhc)
greater sa:v ratio –> incr rate of absorp
adv of cell sap w lower w.p than surroundings (rhc)
maintain steep conc gradient –> allows h2o to continuously enter cell by osmosis down the w.p gradient
adv of uniformly thin cell wall (rhc)
less dist for movement of subst via diffusion/osmosis –> incr rate of absorp
adv of numerous mitochondria in rhc
release energy through cellular resp –> incr rate of AT for absorp of h2o & mineral salts
how does water enter the rhc and into xylem vessels
water enters rhc through osmosis (w.p in sap lower than w.p in soil solution).
inside rhc, water enters next cell through osmosis (now rhc sap has higher w.p than next cell sap’s w.p)
process continues until water reaches xylem vessels
