白刺枝叶生长对人工模拟降雨的响应

Responses of Nitraria tangutorum Branch and Leaf Growth to Simulated Rainfall

为揭示未来降水增加对荒漠地区植物生长的影响,以甘肃民勤的典型荒漠优势植物白刺为对象,研究白刺枝叶形态在2010年和2011年不同人工模拟降雨处理(增雨量分别为多年平均降水量的+0%、+25%、+50%、+75%、+100%)的变化规律。结果表明:100%增雨处理能够显著促进2010年和2011年白刺当年生枝叶生长;75%增雨处理显著促进2011年白刺当年生枝叶生长,75%增雨处理对6月花枝长度、基部直径、新生叶片和营养枝长度、新生叶片,以及9月花枝成熟叶片和营养枝基部直径、成熟叶片增长量的影响均显著,其值分别为(1.20±0.35)cm、(0.012±0.004)cm、(4.35±2.51)片、(1.65±0.69)cm、(3.20±1.45)片、(2.15±0.69)片、(0.013±0.006)cm、(2.20±1.10)片。2011年白刺当年生花枝和营养枝的长度、基部直径、新生叶片和成熟叶片增长量出现显著差异的阈值均低于2010年,这表明白刺能够通过改变其枝叶形态特性及其数量来适应降雨的变化。

Precipitation is the primary water source of desert plants in arid regions.Nitraria tangutorum Bobr.,a typical desert plants in Minqin County of Gansu Province,was used to reveal the effect of precipitation enhancement on the growth of desert plants.The morphology of N.tangutorum Bobr.branch and leaf was analyzed under different simulated rainfall gradients（increased 0%,25%,50%,75% and 100% of mean annual precipitation respectively）.The results showed that the length,basal diameter and leaf number of N.tangutorum Bobr.branch were significantly promoted under 100% increased rainfall treatment in 2010 and 2011;the length,basal diameter and leaf number of N.tangutorum Bobr.branch was also promoted by the increased 75% rainfall treatment in 2011.The 75% increased rainfall had the most significant influences on the growth of absolute length of flower branch,the absolute basal diameter,the absolute number of new leaf and vegetative branch,the absolute number of new leave in June,and the growth of absolute number of mature leaf of flower branch,the absolute basal diameter and the absolute number of mature leaf of vegetative branch in September,the values were 1.20±0.35 cm,0.012±0.004 cm,4.35±2.51,1.65±0.69 cm,3.20±1.45,2.15±0.69,0.013±0.006 cm,and 2.20±1.10 respectively.The different morphological characteristics of N.tangutorum Bobr.branch,the absolute length of flower and vegetative branch growth,the absolute basal diameter growth and the absolute number of new and mature leaf growth significantly increased,and the threshold values in 2011 were lower than those in 2010.It was suggested that N.tangutorum Bobr.can adapt to different precipitation pattern by changing branch morphology.