Studies on the effects of salt tolerant mechanism and water table on growth of halophytes

研究了5000 ppm盐灌、6 mm/d（盐灌区）和3 mm/d（干盐灌区）以及清水（对照区）对白杨生长的影响。除根系生物量外，其它各处理的生长量和生物量均以盐灌处理最高，干灌处理最低，但各处理间根系生物量差异不显著。盐灌植物通过控制地上生物量与总生物量的平衡和能量消耗来维持其生命。与清水灌溉相比，咸水灌溉使白杨的光合量和蒸腾量降低，胸径生长量也下降。结果表明，该植物的水分利用效率提高，吸收的盐分沉淀在根系中，这可能是该植物的耐盐策略。白杨的原产地是中国，我们分析了该物种在日本（鸟取，北海道）和中国（内蒙古）不同环境下生长的生理特性。光合速率在调查地间差异不大，表明其在各生长地均保持了原有的遗传适应性。地下水位的高低及其变化影响着积盐土壤上植物的生长。研究了2000 ppm盐分灌溉对高耐盐植物柽柳（Tamarix chinensis）的水位效应，结果表明：盐分灌溉对柽柳的生长没有抑制作用，但可阻止根系向地下渗透。变水位处理的植株含盐量高于定水位处理。

We investigated the effects of salt irrigation with 5000ppm saline, 6mm/day (salt irrigated plot) and 3mm/day (dry-salt irrigated plot), and fresh water (control plot) on growth of Poplus alba. Growth and biomass except of root in salt irrigated plots were higher than in the others, especially lowest in dry-salt irrigated plot, but root biomass was not different among treatment plots. This plants under saline irrigation were maintained their lives to control the balance of their above ground biomass to the total one and energy consumption. Amounts of photosynthesis and transpiration for Poplus alba with salt irrigation were decreased, and their diameter growths also were declined, compared with those in fresh water irrigation. As a result water efficiency of this plant was become larger and absorbed salt was sunk in roots, and this mechanism seems to have the salt tolerant strategy for this species. The place of origin for Poplus alba is China and we analyzed physiological characteristics of this species grown under different environments, in Japan (Tottori, Hokkaido) and China (Inner Mongolia). Photosynthesis rate of this species was not different among investigated place, which shows that they keep original genetic adaptabilities in each grown place. Growth of plant on salt accumulated soil was affected by level of water table and its changes. We investigated the effect of water level on high salt tolerant plant (Tamarix chinensis) with salt irrigation of 2000ppm, and there was no growth decrease by salt irrigation, but penetration of their roots to deeper soil layer was prevented around logging water level. Salt contents of the plants in treatments changed water level were higher than those in fixed water level.