植物根系提水作用研究述评

Review on studies of hydraulic lift in root system

根系提水作用是植物在干旱生境下,通过根系将深层湿润土壤中的水分提升至浅层干燥土壤中的一种生理过程,不同植物具有不同的根系提水强度。这一研究的基本方式是分根法,而时域反射仪(TDR)法和中子水分仪法则是近年来较受重视的测定方法,并逐步由室内测定向大田测定过渡。研究的主要内容可归纳为五个方面,其中在根系提水作用与植物蒸腾作用、浅层土壤营养的有效性以及与植物遗传性的关系等方面,研究结果较为一致,但在提水的数量和发生提水作用时土壤水分状况等方面,研究结果不尽相同;对植物光合、呼吸等其他代谢的影响以及室内测定结果与大田条件一致性等问题的研究,报道较少,特别是作用机理的研究。因此,深入这方面的研究对于进一步提高植物水分利用率,促进旱地节水农业和畜牧业的发展具有重要的意义。

The hydraulic lift is a process in which water moves from moist deep soil to drier shallow soil layers through the plant root system in an arid habitat.There were the different hydraulic lift intensities in different plants.The major ways of studies is to divide the root system of plant into different regions and the major instruments used in the measure are Time Reflectometer (TDR) and Neutron Probe.At present the measure is developing from greenhouse to field.The contents of study may be sumed into five aspects,in which the results of studing on the relations of hydraulic lift in root system with the transpiretion,heredity,property of plant as well as the efficiency of soil nutrients are more idential,but the results of study on the moisture quantity lift to shallow soil layer by root system and the soil moisture content at that time which the hydraulic lift in root system was occuring is not idential.There were a few reprots in the studies of the effects of hydraulic lift in root system on other metabolism,such as photosynthesis and respiration etc.and the unity of results measured in greenhouse and the condition in field,specially mechanism on hydraulic lift.To make the thorough study is a work of very significance for raising water utilization efficiency (WUE) of plant and bring about a great advance in dryland farming and animal husbandry.