Biology 2601A/B Lecture Notes - Lecture 11: Water Potential, Apoplast, Leaf

• School: Western University
• Department: Biology
• Course: Biology 2601A/B
• Professor: Danielle A Way

Document Summary

Lecture 11 - water and fluid transport: moving fluids in plants. Xylem and phloem: xylem, translocates water and inorganic nutrients from the roots to the leaves. Source tissues create or generate material, sink tissue use this material: thinner ring. Figure: soil is fairly close to zero, as you move up the tree water potential becomes more negative, big jump from leaf --> air. Leaves: -1. 5 mpa: air spaces in leave: -7 mpa, outside air: - In leaves: water moves into leaf, into air spaces then out through stomata. Figure: close up cross section of a leaf cell, note these are living cells, cell walls are fully saturated with water. Is (cid:454)(cid:455)le(cid:373) (cid:449)as(cid:374)"t so st(cid:396)o(cid:374)g tha(cid:374) these tissues (cid:449)ould i(cid:373)plode due to st(cid:396)o(cid:374)g (cid:374)egati(cid:448)e p(cid:396)essu(cid:396)es: this is the (cid:396)easo(cid:374) that pla(cid:374)ts do(cid:374)"t (cid:373)o(cid:448)e. If xylem (cid:449)as fle(cid:454)i(cid:271)le the(cid:455) (cid:449)ould(cid:374)"t (cid:271)e a(cid:271)le to (cid:373)o(cid:448)e (cid:449)ate(cid:396: water must fill this fixed volume, so evaporating water must be replaced.