华东师范大学：《植物生理学》课程教学资源（实验）植物组织水势的测定 Water potential in the plant

Water potential in the plant Course: Plant physiology lab Experimental Teaching Centre Of Life Sciences

Water potential in the plant Course: Plant Physiology Lab Experimental Teaching Centre Of Life Sciences

The way of water absorbed by plant Diffusion concentration gradient 简单扩散浓度梯度 a Mass flow- pressure gradient 集流 压力梯度 Osmosis- water potential gradient 渗透作用水势梯度

The way of water absorbed by plant ◼ Diffusion —— concentration gradient 简单扩散 浓度梯度 ◼ Mass flow —— pressure gradient 集流 压力梯度 ◼ Osmosis —— water potential gradient 渗透作用 水势梯度

Water potential ■ Chemical potential -free energy per mole of substance Water Potential the chemical potential of water divided by the partial molal volume of water n-0△

Water Potential ◼ Chemical Potential ——free energy per mole of substance ◼ Water Potential —— the chemical potential of water divided by the partial molal volume of water w w w w w V V w 0 ( )       = − =

ce‖ Water potentia a Factors: concentration, pressure and gravity yw=ys typtyg Water enters the cell along a water potential gradient yw=ystyp 适用于有液泡的细胞或细胞群

Cell Water Potential ◼ Factors: concentration, pressure and gravity ◼ Water enters the cell along a water potential gradient 适用于有液泡的细胞或细胞群  w = s + p + g  w = s + p

(A) Pure water (B)Solution containIng 0.1 M sucrose 0.1 M Sucrose solution Pure water n =0MPa Y =OMPa s=-0.244MPa OM was Yp+ =0-0.244MPa =0 MPa =-0.244MPa (C Flacdd cell dropped Into sucrose solution (D)Concentration of sucrose Increased Flaccid cell Yp=OMPa 88 MPa ye =-0.732 MPa 732 MPa W=-0732 MPa 244 MPa 0.3 M Sucrose solution Cell after equilibrium Cell after equilibrium w=-0.244MPa Ww=-0732 MPa Pp=0MPa 5=-0.732MP y5=-0732MPa s=-0.732MPa Pr u-s=0 MPa w=-0.732MPa Pp =Yw-t's=0. 488 MPa (E)Pressure applled to cell queeze out half the w thus doublin y from -0.732 to-1464 MPa ng 0.1 M Sucrose solution Cell in initial state Cell in final state W=-0 244 MPa Hw=-0.244MF Ys =-0.732 MPa 华s=-1.464MPa 甲p=w-s=0488MPa Pp=Yw-ts=1. 22 MPa

Experient ■质壁分离法—测定细胞渗透势 质壁分离和质壁分离复原现象可证明植物细胞是 渗透系统。 小液流法—测定细胞水势 要求:叶片在蔗糖溶液中浸没的时间内不时振荡? 蔗糖溶液配制过程中充分混匀?

◼ 质壁分离法——测定细胞渗透势 质壁分离和质壁分离复原现象可证明植物细胞是一 个渗透系统。 ◼ 小液流法——测定细胞水势 要求：叶片在蔗糖溶液中浸没的时间内不时振荡？ 蔗糖溶液配制过程中充分混匀？ Experient

Thinking a As the soil dries, how to adjust water potential of the plants

Thinking ◼ As the soil dries, how to adjust water potential of the plant?

■有人说:鲜切花放在含有茶叶水的花瓶中 可以保持更长的时间。请问:你是如何看 待这个现象背后的生物学原理?

◼ 有人说：鲜切花放在含有茶叶水的花瓶中， 可以保持更长的时间。请问：你是如何看 待这个现象背后的生物学原理？