Ch2 Adaptations to the Physcial Environment - Water and Nutrients4.pdf

1 Page
53 Views
Unlock Document

Department
University College Courses
Course
UNI101Y1
Professor
Spencer Barrett
Semester
Winter

Description
 as soils dry, the remaining water is held tighter b/c a greater proportion lies close to the surfaces of soil particles  most crop plants can extract water from soils with water pot. down to -1.5MPa  drought-adapted species can from even drier soils  wilting coefficient wilting pointt) is a water potential of -1.5MPa  at lower water pot., plants wilt even if some water remains Osmotic Potential and Water Uptake by Plants  solutes are dissolved substances in water which influence the diffusion of water molecules  water tends to move from regions of low solute conc. to regions of high solute conc.  osmosis is the process whereby the fluid in a cell has a high conc. of ions and other solutes (thus a low water potential), water tends to move from the envmt into the cell  osmotic potential is the force with which an aqueous soln attracts water by osmosis  this potential in roots cause water to enter the roots from the soil against the attraction of soil particles and the downward pull of gravity  the problem is that ions and other solutes diffuse through water  from areas of high solute conc. to areas of low solute conc.  so, as water is coming into the cell, solutes tend to move out  eventually, conc. would come to equilibrium in and out of the cell  but there will be no net movement of water across cell membrane  cells prevent equalization in 2 ways: 1. a cell membrane cam be semipesemipermeablee small molecules and ions can diffuse across it, but larger ones can’t)  CHO and proteins too big, remain inside cell, maintain low water pot.
More Less

Related notes for UNI101Y1

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit