植物水分生理中几个争议性问题的理论分析

Theoretical analysis on several controversial issues in plant water relations

本文对涉及王小菁教授主编的《植物生理学》(第8版)和慕课网关于植物水分生理的一些反馈意见进行了分析讨论。主要包括细胞衬质势的特性,衬质势被体相水溶液屏蔽,体相水含量低的细胞代谢不活跃的原因,无液泡细胞水势不应包含衬质势的原因,以及重力势造成的树冠细胞水势高反而缺水的问题并尝试提出了解释。同时也分析了"根压是根系的吸水动力"和根系"主动吸水"说法的误导性以及质外体途径在根部水分径向运输中比例很小的依据。

Several controversial issues arisen from the feedbacks of the users of the textbook Plant Physiology(8 th Ed) by Prof. Wang Xiaojing and of the MOOC audience were analysed and discussed. The main points included the features of matric potentials in plant cells and the shielding of matric potentials by bulk solutions, as well as the reasons why cell activity was low in cells lacking bulk water, together with the reasons why the water potential in young cells without vacuoles should not include the matric item. The analysis also included the dilemma why cells having higher gravitational potential will lack water with a tentative explanation. In response to feedbacks, the misconceptions "root pressure is the driving force of water absorption" and "active water absorption"were disproved. In addition, the reasons why radial apoplastic water transport in root was insignificant were deduced.