桑树/大豆间作对其生长及光合作用对光强响应的影响

摘要

为了提高桑树与大豆间作模式下地上部分的光能利用率,优化桑树与大豆复合经营的空间配置,研究了在这一间作模式下大豆结荚期桑树和大豆生长特点及光合作用光响应的特点.结果表明:在桑树和大豆间作共生期间,间作桑树的株高、叶绿素含量、根干重、地上生物量分别比单作桑树增加了15.3％、21.6％、30.7％、43.3％,而大豆呈现相反的趋势.间作桑树的净光合速率(Pn)、蒸腾速率(Tt)、气孔导度(Gs)比单作桑树增加了26.7％、100.3％、19.4％,间作桑树的水分利用率(RWEU)比单作桑树降低了37.2％,但大豆呈现相反的趋势.桑树/大豆间作显著提高了桑树的光饱和点(VLSP)、光补偿点(VLCP)和最大净光合速率(Pmax),降低了大豆光饱和点(VLSP)、光补偿点(VLCP)和最大净光合速率(Pmax),但都提高了桑树和大豆的表观量子效率(yAQY).表明桑树/大豆间作提高了桑树对强光和大豆对弱光的利用能力,从而对桑树和大豆的生长产生影响.%In order to improve the solar energy utilization efficiency in mulberry and soybean intercropping and optimize the spatial allocation, the growth and the light response of photosynthesis characteristics of soybean and mulberry during soybean podding period in the intercropping system were investigated. The results show that the plant height, content of chlorophyll, root dry weight, above-ground biomass of intercropped mulberry increased by 15.3%, 21.6%, 30.7%, 43.3% respectively, during the co-growth stage in mulberry/soybean intercropping system, but that of intercropped soybean emerged a reverse trend.. The net photosynthetic rate (/"?), transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2 (Ci) of intercropped mulberry increased 26.7%,100.3%,19.4% respectively, compared with sole mulberry, and the water use efficiency(RWEU) of intercropped mulberry decreased by 37.2%, compared with sole mulberry, but that of intercropped soybean presented a increased trend. The mulberry and soybean intercropping remarkably enhanced the light saturated point (VLSP), light compensation points (VLCP) and photosynthetic rate at light saturation (Pmax) of intercropped mulberry, and mulberry and the soybean intercropping reduced the light saturated point (VLSP) light compensation points (VLCP) and photosynthetic rate at light saturation (Pmax) of intercropped soybean, but the mulberry and soybean intercropping enhanced apparent quantum yield (YAQY) of mulberry and soybean. The findings indicate that the mulberry and soybean intercropping can enhance the utilization efficiency of strong light by mulberry and that of weak light by soybean, and thus the intercropping mode can affect the growth of mulberry and soybean.