不同灌溉量条件下乔木状沙拐枣蒸腾耗水特性的研究

利用Flow32热平衡式茎流计,对塔克拉玛干沙漠腹地不同灌溉量条件下(每次每株灌水17.5、 28和35 kg)乔木状沙拐枣(Calligonum arborescens)的水分生理进行研究,结果表明:茎干液流日变化随着灌溉量的不同而有所不同,灌溉量每株每次35和28 kg,其日变化曲线呈"单峰型",液流速率较高;灌溉量每株每次17.5 kg,日变化曲线为"双峰型",且液流速率较低,其生长受到胁迫。相同时间不同灌溉量条件下,随着灌溉量的减少,其清晨和午后水势逐渐降低,且气候条件越严酷灌溉量越少,水势降低更显著;整个生长季7月水势最低。相同时间不同灌溉量条件下,单株日耗水量也随灌溉量的减少而减少,整个生长季7月各处理单株日耗水量均最高。可以看出,在塔克拉玛干沙漠腹地乔木沙拐枣可通过协调水分平衡来适应其环境,但从防护林的稳定及水资源的角度考虑,应降低塔里木沙漠公路防护林现行的灌溉量,但不能低于每次每株17.5 kg,这既满足了沙拐枣对水分的需求,同时也维护了防护林稳定性。

Research on Water-Consumption Characteristics of Calligonum arborescens under Different Irrigation Amounts

As a primary limiting factor affecting survival and growth of plants,moisture has important effects on water physiological characteristics.We studied water-consumption characteristics in the Tarim Dersert Highway Protection Forest to provide some references for local irrigative management.The heat-balance stem flow gauge was used to measure water physiological characteristics of Calligonum arborescens under different irrigation amounts(17.5,28 and 35 kg·plant-1 once a time).The results showed that: the diurnal variation curve of stem sap flow of C.arborescens varied with irrigation amounts,when irrigating 35 and 28 kg·plant once a time,the diurnal variation of stem sap flow presented unimodal curve and the sap flow rate were higher;as for irrigating 17.5 kg·plant-1 once a time,the diurnal variation changed in two-peak curve and the sap flow rate was small,which caused stress.With irrigation amounts reduced,the predawn and midday water potential of C.arborescens all gradually decreased at the same time and the more severe climatic conditions and the less irrigation,the more significant water potential decrease.The water potential of July was the least under different irrigation amounts during the growing season.The daily water consumption was decreased with reducing irrigation amounts at the same time;the daily water consumption of July was the most under different water treatments.It can be seen that the C.arborescens adapts to the environment by coordinating water balance.Considering the stabilization of protection forest and water resources,the current irrigation volume of protection forest in the Tarim Desert Highway should be reduced,but it can not be lower than 17.5 kg·plant-1 once a time,this will satisfy the water demand of C.arborescens,and also maintain the stabilization of protection forest.