论文部分内容阅读
该文研究了多重复干旱循环对１年生北美短叶松和黑云杉苗木的气体交换速率及水分利用效率的影响．结果表明，多重复干旱循环对它们的气体交换（Ｃｓ，Ｐｎ，Ｔｒ）有显著影响（Ｐ＜０．５），而对其水分利用效率（ＷＵＥ）影响不大（Ｐ＞０．１）．尽管北美短叶松的气孔对轻度干旱胁迫不如黑云杉敏感，但是它对中度及严重干旱胁迫的敏感程度却高于黑云杉．在轻度及中度干旱胁迫下，北美短叶松的光合作用主要受非气孔因素的影响，而黑云杉则主要受气孔因素的影响．解除干旱胁迫后，黑云杉的气孔敏感性、光合能力及水分利用效率的恢复都要比北美短叶松更快．轻度的干旱胁迫锻炼可以帮助北美短叶松在更严重的干旱胁迫下保持固有而强劲的耐旱能力．然而，通过多重复干旱循环锻炼后，黑云杉在改善耐旱能力的强度方面大于北美短叶松．
The paper studied the effects of multiple cycles of drought on the gas exchange rate and water use efficiency of one-year-old Pinus nigra and black spruce seedlings. The results showed that the multiplicity of drought cycles had significant effects on the gas exchange (Cs, Pn, Tr) (P <0.5), but had little effect on the WUE (P> 0.1). Although the Pinus tabulaeformis stings are less sensitive to mild drought stress than black spruce, they are more susceptible to moderate and severe drought stress than black spruce. Under mild and moderate drought stress, the photosynthesis of Pinus thunbergii was mainly influenced by non-stomatal factors, whereas that of black spruce was mainly affected by stomatal factors. After drought stress was relieved, stomatal sensitivity, photosynthetic capacity and water use efficiency of black spruce were all recovered faster than N. nigra. Mild drought stress exercises can help Pinus thunbergii maintain an inherent and strong drought tolerance under more severe drought stress. However, after cycling through multiple replications of drought cycles, the black spruce was greater in strength than drought to improve drought tolerance.