人工模拟降雨变化对白刺(Nitraria tangutorum)生理生态特征的影响

Effect of Artificial Simulated Rainfall on Physiological and Ecological Characteristics of Nitraria tangutorum

为研究气候变化背景下降水格局改变对荒漠植物生长的影响,以甘肃民勤典型荒漠植物白刺(Nitraria tangutorum)作为对象,通过4年连续人工模拟增雨试验(+0%、+25%、+50%、+75%和+100%多年平均降水量),于2011年7月对不同增雨处理的白刺土壤水分、叶片性状和枝条形态特征进行测定,研究不同増雨处理影响白刺生理生态特征变化的累积效应。结果表明:75%和100%增雨处理能够显著改善白刺灌丛10cm土层的含水量。白刺叶水势、净光合速率、蒸腾速率、气孔导度、比叶面积、单位重量叶氮含量,以及枝条长度和基部直径的增长量均随降水量的增加而增加。100%增雨处理的叶水势和叶片功能性状指标在增雨后第1天显著大于0%处理(P<0.05);比叶面积和叶氮含量在各増雨处理下均未达到显著差异(P>0.05);75%、100%增雨处理的枝条长度和基部直径的增长量比0%处理的分别增加64.57%、66.63%和48.71%、67.54%,且达到显著差异水平(P<0.05),这说明在降水增加的情景下,白刺通过采取内在生理和外在形态方面的适应策略来促进其生长发育。

Under the background of global change,the variation of precipitation pattern might affect vegetation dynamics in arid zone.Nitraria tangutorumshrub land,which is one of the typical desert vegetation in Minqin County,Gansu Province,was chose to study the effect of precipitation variation on vegetation dynamics.Through the successive four years of artificial rain enrichment scenario,soil moisture of the N.tangutorumshrub land,leaf traits index and morphological characteristics of branches of N.tangutorum were measured in 2011 under different simulated rainfall gradients（increased 0%,25%,50%,75% and 100%of mean annual precipitation,respectively）.The cumulative effects of different treatments on the physiological and ecological characteristics of N.tangutorum were studied.The results showed that soil moisture of the N.tangutorumshrub land shallow layer was obvious improved,soil moisture of 10 cm layer in the increased 75% and 100% rainfall treatment was significantly increased;leaf water potential,net photosynthetic rate（Pn）,transpiration rate（Tr）,stomatal conductance（Gs）,specific leaf area（SLA）,mass-based leaf nitrogen（Nmass）,and the growth of the length and basal diameter of N.tangutorum branch were increased with increasing rainfall,leaf water potential and indexes of leaf functional traits on the first day after the 100% rainfall treatment were significantly greater than that in the increased 0% rainfall treatment;SLA and Nmass were increased with increasing rainfall,and not reached significant level;The growth of the length and basal diameter of N.tangutorum branch were increased with increasing rainfall,and in the increased 75% and 100% rainfall treatment was significantly greater than that in the increased 0% rainfall treatment,their differences were 64.57%、66.63% and 48.71%、67.54%,respectively.It was suggest that N.tangutorum through adaptive strategies of internal physiological and external forms to promote its growth.