水分在植物茎叶中运动的热力学研究

Thermodynamics Research on Water Flow in Leaves and Stems of Plants

在热力学中,吉布斯自由能G,化学势μ和水势ψ是状态函数,化学势μ_i=(δG_i/δn_i)T、P、n具有强度性质,表示某组份物质起的反应或转移的本领;水势ψ_w=Δμ_w-/V_w,是每偏摩尔体积水的化学势差,其内容为化学势和自由能.本文从热力学角度解释了植物体内的水分由高水势向低水势方向运动的现象,解决了植物生理教学过程中,植物体内水分为何从低处向高处运动的教学难点.

In thermodynamics, Gibbs free energy G, chemical potential μ, and water potential ψare state functions. Chemical potential μi=（δGi/δni）T、P、n has the Character of intensity, which indicates the reactions of some composing substance or its ability of transference. The water potential ψW=△μW-/VW , is the difference of the chemical potential of per molar vlume of water, whose contents are chemical potential and free energy. This paper explains the reason in thermodynamics why the moving direction of water in plants is from high tissue water potential to low tissue water potential and the difficulty in the porcess of the teaching of plant physiology of why the water in plants moves from lower leaels to higher levels has been solved.