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凝结水(隐匿降水)和降水是荒漠地区两种不同形式的水分来源,对荒漠生态系统极为重要。叶片毛尖(leaf hair points,LHPs)是很多荒漠藓类的重要外部形态结构特征,但它在藓类植物利用凝结水和降水中的作用尚不清楚。齿肋赤藓(Syntrichiacaninervis)是古尔班通古特沙漠藓类结皮的优势种,其叶片顶端具有较长的白色毛尖。采用自制微渗计(h=3.5 cm,d=5.7cm)研究了正常有毛尖和人工去除毛尖的齿肋赤藓结皮的凝结水特征及其在3种模拟降水梯度(1、3、6 mm)下的短期蒸发特征,结果表明:(1)在凝结阶段,有毛尖结皮每时段的凝结水量均大于无毛尖结皮,但日出后有毛尖结皮凝结水下降速度稍快;有毛尖结皮的日凝结水量均大于无毛尖结皮,且前者的总凝结水量比后者多10.26%,即毛尖能增加10.26%的凝结水量。(2)3种模拟降水梯度下,有毛尖结皮在各时段的累积蒸发率始终小于无毛尖结皮,以蒸发前期阶段最为明显,表明毛尖能显著减少和延缓结皮内的水分蒸发、延长植株水合时间,而且降水量越大减缓效果越明显。毛尖对这2种不同形式水分利用的差异是因为利用方式不同:对凝结水的利用主要归因于毛尖增大了结皮表面粗糙度,而减少对降水的蒸发主要是毛尖能反射阳光、形成内部毛细管及减小植株间隙的缘故。因此,毛尖的存在有利于齿肋赤藓结皮对凝结水和降水的利用,增强了藓类结皮对干旱环境的适应能力。
Condensation (Precipitation) and Precipitation are two different forms of water sources in the desert and are extremely important for desert ecosystems. Leaf hair points (LHPs) are important external morphological structural features of many desert moss, but its role in the utilization of condensate and precipitation by mosses is unclear. Syntrichiacaninervis is the dominant species of moss crust in the Gurbantunggut desert, with long white hair tips on the top of leaves. The self-made micro-osmotic meter (h = 3.5 cm, d = 5.7 cm) was used to study the condensed water characteristics of erythrocytic crusts with normal hairy hair and artificial hair removal tips and their effects on three simulated precipitation gradients mm). The results showed that: (1) In the condensation stage, the amount of condensation water in the hairy tip crust was higher than that of the hairless tip crust at each stage, but the hair sinking rate was slightly lower after sunrise The daily condensation water content of the fur tip was larger than that of the hairless tip skin, and the former had 10.26% more total condensed water than the latter, ie, the hair tip could increase the amount of condensate water by 10.26%. (2) Under the three kinds of simulated precipitation gradients, the accumulated evaporation rate of the hairy tip crust was always less than that of the hairless tip crust, which was the most obvious in the early stage of evaporation, indicating that the tip of the hair tip can significantly reduce and delay the evaporation of water in the skin crust and prolong the water evaporation Plant hydration time, and the greater the amount of precipitation mitigation effect more obvious. The difference in water use of these two different forms of hair tips is due to different ways of utilization: the utilization of the condensed water is mainly attributed to that the hair tips increase the surface roughness of the skin, while reducing the evaporation of precipitation is mainly that the hair tips can reflect sunlight and form the interior Capillary and reduce the gap between plants sake. Therefore, the existence of the hairy tip is beneficial to the utilization of condensation water and precipitation in the erythrocytic crust of the tooth, and enhances the adaptability of the moss crust to the arid environment.