反光膜对桃树光合特性及根际温度的影响

Effect of reflective film on photosynthetic characteristics and rhizospheric temperature of juicy peach

为研究地面铺反光膜对桃树光合特性及根际温度变化的影响，以“浅间白桃”结果树为材料，于果实成熟期间进行地面铺反光膜的田间试验，测定了果树叶片的光合特性及不同土层根际温度的变化。结果表明，处理树叶净光合速率（Pn）、光能利用率（LUE）明显高于对照树。随着光强增加，处理和对照叶片的蒸腾速率（Tr）和水分利用率（WUE）均增加，且处理叶WUE明显高于对照。气孔限制值（Ls）和水蒸气压差（VpdL）与光强呈正相关，处理树叶片Ls显著高于对照，但VpdL和胞间CO2（Ci）却明显低于对照。处理树前期（7月22日-8月10日）不同深度土壤温度变化呈双峰曲线，土层越浅土壤温度越高且变化幅度越大；8月9日根际土壤温度值为20cm〉15cm〉10cm〉5cm；之后又恢复到前期水平。对照树前期（7月22日～8月12日）根际温度的变化与处理树相似，但8月15日后不同深度土壤温度值为10cm〉20cm〉15cm〉5cm。

Photosynthetic characteristics of four-year-old peach trees and soil temperatures at different depth,with and without reflective film mulch,were investigated during fruit maturation stage （June - Aug. , 2002 ）in selected peach orchard. Results show that Net Photosynthetic Rate（Pn） and Light Use Efficiency（ LUE ）are higher in the treatment（ with reflective film）than in the control（ without reflective film）. Additionally, there is increase in Limited Value of Stomata （ Ls）, Transpiration Rate （Tr） and Water Use Efficiency（WUE）with increase in light intensity in both the control and treatment. Leaf WUE in the treatment markedly outweighs that of the control,while Leaf Vapor Deficit（VpdL） and Intercellular CO2 Concentration （Ci） in the treatment are significantly lower than those of the control. Ls and VpdL have positive relation with light intensity. Soil temperature in different depths in the peach orchard under reflective film cover（from July 22 to Aug. 10）changes with two-peak curves. And the shallower the soil, the higher the soil temperature. The soil temperature on Aug. 9 follows the following sequence ：20 cm 〉 15 cm 〉 10 cm 〉 5 cm, after which period it rebounds to the initial level. CK soil temperature shows similar trend with the treatment from July 22 to Aug. 12 ,but follows the given order：10cm 〉20cm 〉 15cm 〉Scm after Aug. 15.