典型耐淹植物主茎死亡特征对水压的响应
Effect of High Hydrostatic Pressure on Main Stem Death of Three Typical Flooding-Tolerant Species

陆生植物遭受水淹胁迫，特别是大型水库修建导致的长时间、大深度的水淹，不仅导致光照、溶氧及CO₂浓度等环境因子发生显著变化，也导致植物所承受的压力发生明显变化，但是目前关于水压对陆生植物影响的研究鲜见报道.以长江三峡水库消落区典型陆生耐淹植物狗牙根、牛鞭草及瘦瘠野古草为研究对象，进行变量控制实验设计，探究了水压对典型耐淹植物主茎死亡特征的影响.结果表明：1）水压对典型耐淹植株主茎的死亡过程有着显著的促进作用（即表现为正效应）；2）不同种类（或耐淹能力不同）的植株在抵抗水压胁迫时，其主茎死亡过程表现出显著差异，并且随着水淹深度的增加继而水压亦增加，这种差异表现得越来越明显.通过本研究，有助于了解陆生植物对水淹环境下水压胁迫的响应机制，并且丰富和发展了关于陆生植物对水淹逆境的响应及适应机制研究的理论和方法.
The construction of large reservoirs often results in long-time and deep flooding of terrestrial plants in the riparian zones, and illumination, dissolved oxygen (DO) and CO₂ concentration undergo great changes. But the effects of such environmental stress on terrestrial plants are now poorly documented. In order to have a better understanding of the response and adaptation mechanism of flooding-tolerant terrestrial plants to flooding stress, a variable-controlling experiment was made with three typical riparian plant species (Cynodon dactylon, Hemarthria altissima and Arundinella anomala Steud.) to study the effects of flooding on the death of their main stem. Three submergence level treatments (2m, 5m and 10m water depth), and three flooding duration treatments (0, 25 and 50 days) were set. We measured total stem length and total stem biomass of the three plants before and after they were submerged. It was found in the experiment that high hydrostatic pressure significantly accelerated the death rate of the main stem of the three plant species, and that different plant species performed differently in main stem death process under submergence. At the early stage of submergence (0-25 d), main stem death rate of A. anomala was higher than that of C. dactylon and H. altissima and the reverse was true at the late stage of submergence (26-50 d)