Chapter 32
Where do plants get stuff from?
Plants use Sunlight, carbon, oxygen, water, and photosynthesis to create sugars, which are a store of energy.
Plants must be able to move water from roots to leaves, and sugar from leaves to roots.
water ans Solutes are absorbed by root hairs, and move upwards via a variety of paths:
Notecard 1: Is the root cross section on the screen a monocot or dicot?
Casparian strip is a waxy layer within the root, that stops extracellular transport. Solutes moving inwards have to go through a cell to get into the Vascular Cylinder. This allows control over how much solute moves in.
Fluid in the Xylem is called Xylem sap - it contains a lot of dissolved inorganic nutrients.
Transpiration and Evaporation at the top of the plant create a pulling force to help raise xylem sap.
Root Pressure - Roots absorb a lot of water, creating pressure - this can push water up a meter or two.
Cohesion and Adhesion - molecules sticking together and to other things respectively. molecules stick together in chains, and adhesion lets them “crawl” up tiny pathways.
All of these forces help pull/push xylem sap up the plant.
Guard cells on leaves actively take up potassium from other cells. This causes a conentration gradient, water flows in, cells bend, stomata opens, allowing O2, Co2, water to be exchanged with the air.
At this point my laptop died