植物生理学总复习讲解

Chapter 1 Water Relationship in Plant 26+3

一、Term translation and definition：

1.Water potential (Ψw)水势

每偏摩尔体积水的化学势差。水势反应了植物系统中化学反应以及运动的能力。

Water potential is defined as the difference in free energy per unit volume, between metrically-bound, pressurized, or osmotically-constrained water and pure water.Ψw reflects the capacity for chemical reaction and movement in plant system

2.Apoplast and symplast 质外体和共质体

质外体是指原生质之外的结构部分及空间，包括细胞壁、细胞间隙和木质部的导管等无生活物质的各个部分。

共质体是指活细胞内的原生质体通过细胞与细胞间的胞间连丝互相连接成的一个连续的结构。

A continuous system consists of cell wall, cell space(interplace) and vessel of xylem, except protoplast, considered as a non-life part in the plant.

A continuous system consists of protoplast, plasmodesma and plasmic membrane, considered as

a life part except apolast.

3.Free water and bound water 自由水和束缚水

靠近胶粒而被胶粒吸附不易移动的水分称为束缚水；距离胶粒较远而可以自由移动的水分称为自由水。其实这两种水分状态的划分是相对的，它们之间没有绝对的界限，只是物理性质有所不同。自由水参与各种代谢作用，作为溶剂易凝固，而束缚水则不参与。【定义+相对+作用】

Free water: It does not bind to components of cell tightly and moves freely in the plant. Special characters: participate in metabolism, take as solvent and easily freeze 。

bound water：It binds to components of cell tightly and does not move freely in the plant. Special characters: do not participate in metabolism, do not take as solvent and do not easily freeze 。

4.Bleeding and guttation 伤流和吐水

吐水：没有受伤的植物如果处于土壤水分充足、大气温度和湿度较高的环境中，在蒸腾作用大为减弱以至停止的环境中，叶尖或叶缘分泌液体的现象。

伤流：如将生长旺盛的植物，从地面切断，可见到有汁液从残茎的切口溢出，这种现象。Bleeding: a phenomena that the sap flows out from the wounded part. It is caused by root pressure.

Guttation: when soil has enough water and atmosphere is warm and higher RH, often in the early mourning, unwounded leaf can secret sap from tip or margin of leaf. It is an index for health seedlings.

5.Root pressure 根压

由于根系的生理活动使液流从根部沿木质部的导管上升的压力。根压的大小取决于跟生理活动的强弱。

Root pressure is a power which pushed water to mount along vessel, depending on physiological activity of root.0.1-0.2MPa, much or less depending on stronger or weaker physiological activities of the root.

6.Soil available water土壤可利用水分

指土壤中可以直接被植物吸收利用的水分，即土壤中高于永久萎焉系数值的含水量部分。

It is referred as the water that can directly be taken up and utilized by plants, which water content is higher than wilting coefficient in the soil.

7.Temporary wilting and permanent wilting 暂时萎焉和永久萎焉

水分亏缺严重时，植物细胞因失水而松弛，靠膨压维持挺立状态的叶片和茎的幼嫩部分下垂，这种现象叫萎焉。

暂时萎焉：当蒸腾作用强烈，根系吸水及转运水分的速度较慢，不足以弥补蒸腾失水时，发生暂时萎焉，当蒸腾速率降低时，根系吸水的水分足以弥补失水，消除水分亏缺，即使不浇水或者通过荫蔽能恢复，这种靠降低蒸腾就能消除的萎焉。

永久萎焉：如果土壤中缺少植物可利用的水，那么即使降低蒸腾，植物仍不能消除水分亏缺，也不能恢复原状，需要浇水才能得到缓解。【定义+症状+消除方法】

The wilting is caused by loss of equilibrium between water absorption and evaporation (main transpiration). Transpiration is larger than absorption. It can be recovered by shading or in the evening upon decreasing in transpiration, but not by watering.

The wilting is caused by no available soil water, plant can not absorb water from the soil. It can be recovered by watering or water spring, but not by decreasing in transpiration.

8.Transpiration pull蒸腾拉力

这种由于蒸腾作用产生的一系列水势梯度使水分沿着导管上升的力量称为蒸腾拉力。蒸腾拉力与根新陈代谢无关，并且是植物水分吸收的主要动力。

A power driving water upward along xylem vessel, and is decided by a gradient of water potentials due to transpiration. It is independent of root metabolism and is the main power for water absorption.

9.Transpiration coefficient (water requirement)蒸腾系数（需水量）

植物制造1克干物质所需水分的克数，大部分作物为500-100g。【定义+举例】

The water (unit: g) demanded by plants to produce 1 g dry weight.

10.Transpiration efficiency (ratio)蒸腾效率

蒸腾效率是指植物每消耗一千克水时所形成的干物质g。

The dry weight increased（unit: g）after consuming 1kg water by plants.

11.Transpiration rate 蒸腾速率

植物在一定时间内单位叶面积蒸腾的水量。

The water lost through transpiration by given size of the leaf in a given length of time (g/m2 s).

12.Critical period of water 水分临界期

水分临界期是植物对水分不足最敏感且最易因此受损伤的时期，但这一时期，植物的蓄水量并不是最大的。

A period during which plant is most sensitive to water deficiency and is most easily injured by water deficiency, but the water requirement is not always largest at that period

13.Transpiration-cohesion-tension theory蒸腾-内聚力-张力学说

水分具有较大的内聚力足以抵抗张力，保证由叶至根的水柱不断，从而使水分能够源源不断的从根部运至地上部分。Water can be transported in a continuous water column because water cohesion is larger than its tension.

14.Osmosis absorption渗透性吸水

渗透指溶剂分子通过半透膜依水势梯度移动的现象。

15.imbibition absorption 吸胀吸水

是未形成液泡的植物细胞戏水的主要方式，其大小与植物细胞内的物质种类有关。如蛋白质>糖类>脂肪