生草对干旱荒漠区苹果光合特性与叶片质量的影响

为探究干旱荒漠区生草覆盖对果园苹果光合特性和叶片质量的影响，选用富士苹果，设置清耕和生草覆盖处理，研究不同处理对苹果叶片光合特性日变化及叶片质量的影响。结果表明，生草覆盖与清耕处理的果园空气相对湿度（RH）及苹果叶片的净光合速率（P_n）、气孔导度（G_s）、水分利用率(WUE)及光能利用率（LUE）的日变化趋势相似，生草覆盖提高了苹果叶片的P_n、G_s、RH、WUE、LUE，降低了叶片胞间CO2浓度(C_i)、蒸腾速率(T_r)及空气温度（T_a）。通径分析发现，清耕处理的T_a对P_n有限制作用，G_s、C_i、T_r和RH是P_n的主要决定因子；生草覆盖处理的T_a和RH对P_n有限制作用，G_s、C_i和T_r是P_n的主要决定因子。果园生草覆盖增加了叶片的鲜重、干重、比叶重、叶绿素含量及K元素含量。研究表明果园生草覆盖适合在干旱荒漠区推广使用，为干旱荒漠区果园生草覆盖提供理论依据。

Impacts of Orchard Herbage-mulching on Photosynthetic Characteristics and Leaf Quality of Apples in Arid Desert Area

In order to explore the effect of natural herbage-mulching on photosynthetic characteristics and leaf quality of apple in arid desert area, apple variety Fuji was selected, the effects of different treatments on diurnal variation of photosynthetic characteristics and leaf quality of apple were studied by setting up clear tillage and herbage-mulching treatments. The results showed that the diurnal changes of relative humidity (RH) and net photosynthetic rate (P_n), stomatal conductance (G_s), water use efficiency (WUE) and light energy use efficiency (LUE) of apple leaves in herbage-mulching treatment were similar to those in clean tillage treatment. Herbage-mulching increased the levels of P_n, G_s, RH, WUE and LUE of apple leaves, and decreased those of C_i, T_r and air temperature (T_a). Path analysis showed that T_a had a limiting effect on P_n in clean tillage treatment, and G_s, C_i,T_r and RH were the main determinants of P_n. T_a and RH had a limiting effect on P_n in herbage-mulching treatment, G_s,C_i,and T_r were the main determinants of P_n. Fresh weight, dry weight, specific leaf weight, chlorophyll content and K+ content of leaves increased in herbage-mulching treatment, compared to clean tillage treatment. The present research demonstrated that herbage-mulching in orchard was suitable for popularization and application in arid desert areas, and provided basis reference for herbage-mulching of orchard in arid desert area.