风沙流持续吹袭对樟子松幼树光合蒸腾作用的影响

为了解风沙流持续吹袭对樟子松幼树光合蒸腾特征影响,2013年春季在内蒙古科尔沁沙地研究了0(CK)、6、9、12、15、18m/s等6个梯度风速处理30min持续风沙流吹袭下樟子松幼树光合蒸腾速率和水分利用效率等指标的变化规律。结果表明:随着风沙流吹袭强度的增加,光合速率、气孔导度和水分利用效率的日变化规律发生了明显改变,而蒸腾速率和胞间CO2浓度日变化曲线没有显著变化。和CK相比,6m/s和12m/s风沙流吹袭下其日均光合速率分别提高13.8%和38.9%,18m/s风沙流吹袭下则下降18.9%;6m/s和15m/s风沙流吹袭下其日均蒸腾速率分别提高16.9%和53.0%,18m/s风沙流吹袭下其日均蒸腾速率降低18.54%。和CK相比,其日均胞间CO2浓度在6—12m/s风沙流吹袭下没有显著变化,15m/s和18m/s风沙流吹袭下则分别提高16.2%和3.3%。6m/s和15m/s风沙流吹袭使其日均气孔导度较CK分别增加26.6%和45.2%,18m/s风沙流吹袭则使其降低13.7%。6、9、12、18m/s风沙流吹袭使其日均水分利用效率分别较CK增加7.3%、1.9%、18.2%和3.1%,而15m/s风沙流吹袭下其水分利用效率下降13.5%。

Effects of sustained wind-sand flow on photosynthesis and transpiration rates of Pinus sylvestris var. mongolica saplings

To understand the effects of sustained wind-sand flow on the photosynthesis and transpiration rates of Pinus sylvestris var. mongolica saplings, a field wind-sand flow experiment with a gradient of wind speed treatments (0 CK], 6, 9, 12, 15, 18 m/s) was conducted in the spring of 2013 in the Horqin Sand Land of Inner Mongolia. The results showed that:(1) wind-sand flow over 9 m/s can significantly change daily photosynthesis rate patterns, (2) wind-sand flow over 12 m/s can significantly change daily patterns of stomatal conductance, (3) wind-sand flow of 15 m/s and 18 m/s can significantly change the daily WUE pattern, and (4) different strengths of wind-sand flows had a lesser effect on daily transpiration rates and intercellular CO₂ concentrations compared to photosynthesis rate. Compared to the CK, the daily maximum and average photosynthetic rates increased by 12.35% and 13.8%, and 18.33% and 38.9%, at the 6 m/s and 12 m/s treatments, respectively, and decreased by 17.9% and 18.9% at the 18 m/s treatments, respectively. The daily maximum and average transpiration rates increased by 51.9% and 16.9%, and 58.6% and 53.0%, at the 6 m/s and 15 m/s treatments, respectively, and decreased by 22.5% and 18.5% at the 18 m/s treatment, respectively. The daily maximum and average intercellular CO₂ concentrations did not significantly differ with the 6-12 m/s treatments, as compared to those in the CK, but increased by 86.9% and 16.5%, and 44.5%, 3.28% with the 15 m/s and 18 m/s treatments, respectively. Compared to the CK, the daily maximum and average stomatal conductance increased by 14.1%,26.6%, and 27.6%,45.2%, at the 6 m/s and 15 m/s treatments, respectively, and decreased by 11.95% and 13.70% at the 18 m/s treatment, respectively. The daily average WUE increased by 7.33%, 1.93%, 18.15%, 3.09% at 6, 9, 12, and 18 m/s respectively, and decreased by 13.51% at 15 m/s.