不同种源沙柳(Salix psammophila)苗木蒸腾耗水特性的研究

于2004年生长季节利用BP3400精密天平等仪器,在人工模拟干旱的条件下,对5个种源沙柳苗木的连日耗水量和耗水速率日变化规律进行观测。结果表明:5个种源沙柳的连日耗水量呈现一致的波动递减趋势;耗水速率日变化均呈明显的"单峰型"曲线,峰值出现在12:00-14:00,随干旱胁迫的加剧,民勤和榆林种源提前到10:00-14:00。白天平均耗水速率和最大耗水速率均是适宜水分>中度干旱>严重干旱。民勤种源在整个干旱胁迫过程中总耗水量最小为1876.9g,其次是达拉特种源(1972.8g)和盐池种源(2001.8g),耗水量最大是乌审旗(2200.6g)和榆林种源(2112.9g)。沙柳各种源最大耗水速率与白天平均耗水速率的比值非常接近,平均为1.56,根据这一比例关系,在对沙柳的最大耗水速率进行测定后,可以推算出其白天的平均耗水速率,并进一步推算白天(或整天)的耗水量。

Characteristics of Transpiration Water Consumption of Salix psammophila Seedlings from 5 Source Regions

Diurnal variations of water consumption and water consumption rate in annual seedlings of Salix psammophila from 5 source regions were studied using BP3400 Precision Balance under the condition of simulated droughts in greenhouses in the growing season of 2004.The results showed that all 5 provenances tended to decrease accordantly with fluctuations in water consumption day after day;The daily curves of water consumption rates were of typical " unimodal type " with peak value occurred between 12:00 to 14:00.For the seedlings from Minqin and Yulin,peak values were found between 10:00 to 12:00 in severe water stress.The average diurnal water consumption rate and the maximum water consumption rate both were the highest in optimum water condition,then in moderate water stress,and the lowest in severe water stress.Water consumption amount during water stress of the seedlings from Minqin was the lowest with 1876.9g,and that Dalate <(1972.8 g)< Yanchi(2001.8 g)