降雨量变化对樟子松生理生态特性的影响

Effects of precipitation change on eco-physiological characteristics of Mongolian pine

全球气候变化背景下大气环流及水文循环的改变,可导致区域降雨格局变化,作用于区域陆地生态系统物质循环与能量流动过程,从而影响植物群落对降水量变化的生理生态响应。以科尔沁沙地樟子松(Pinus sylvestris var.mongolica)人工林为对象,设置野外降雨变化实验样地(天然降雨(CK)、降雨量减少30%(-30%)、降雨量增加30%(+30%)3种处理)、选择2个不同的生长季降雨格局(DRY-236mm、WET-357mm),研究生长季樟子松针叶的光合速率、蒸腾速率、水分利用效率、叶绿素、脯氨酸、可溶性蛋白、丙二醛(MDA)、SOD活性以及生长变化,分析降雨变化对樟子松人工林的影响。结果表明,樟子松针叶光合、蒸腾速率和水分利用效率与降雨量呈正相关,降雨量变化对樟子松生理生态特征产生显著影响,其中生长季水分胁迫对樟子松生长的影响存在滞后效应,樟子松针叶N含量的变化可反映不同水分变化与土壤养分有效性共同作用模式。

Global climate change has altered the atmospheric circulation and hydrologic cycle,and led to the changes of regional precipitation patterns,giving effects on the material cycling and energy flow of terrestrial ecosystems,and accordingly,on the eco-physiological response of plant communities to precipitation change.In this paper,a Mongolian pine（Pinus sylvestris var.mongolica） plantation in Horqin Sandy Land was selected as test object to study its eco-physiological responses to potential precipitation change.Three treatments（natural precipitation,30% reduced precipitation,and 30% increased precipitation） and two precipitation patterns in growth season（236 mm and 357 mm） were installed,and the tree growth status as well as the needle photosynthetic rate,transpiration rate,water use efficiency,chlorophyll,proline,soluble protein,and malondialdehyde（MDA） contents,and SOD activity in growth season were measured.The needle photosynthetic rate,transpiration rate,and water use efficiency were positively correlated with precipitation,and precipitation change had significant effects on the eco-physiological characteristics.The water stress in growth season had a lag effect on the growth of Mongolian pine.The changes of the needle N content could reflect the co-action patterns of soil nutrient availability and soil moisture change.