不同遮荫棚下农田人参叶片光合特性的生育期变化

Seasonal Changes of Photosynthetic Characteristics in Farmland Ginseng Leaves under Different Shades

为了确定农田人参的最佳遮荫方式,以3年生人参为材料,设4种遮荫棚处理(P1M1.拱形棚覆盖蓝色棚膜;P1M2.拱形棚覆盖黄色棚膜;P2M1.梯形棚覆盖蓝色棚膜;P2M2.梯形棚覆盖黄色棚膜),利用Li-6400便携式光合测定系统测定人参叶片不同生育期的光合相关参数,研究了不同遮荫棚下农田人参净光合速率和水分利用效率。结果表明:农田人参叶片在全生育期内净光合速率呈现双峰曲线,在展叶期和绿果期出现峰值,开花期略低,红果期后逐渐降低,黄叶期最低。不同遮荫棚下农田人参叶片净光合速率具有显著差异,表现为P1M1处理叶片净光合速率最高,P2M1处理的次之,P2M2处理的最低。生育期内,P1M1处理叶片净光合速率平均分别比P2M1、P1M2和P2M2处理的高15.02%、48.99%和81.97%;P2M1处理的净光合速率分别比P1M2和P2M2处理的净光合速率高29.53%和58.20%。蒸腾速率、水分利用率效率和表观叶肉导度变化趋势与净光合速率相同。这说明在拱形棚覆盖蓝色棚膜下,农田人参叶片光合代谢较强,水分利用最好,有利于其生长,为农田人参最佳遮荫方式。

In order to determine the optimum farmland ginseng shading mode,with 3-year-old ginseng as materials,setting four shade treatments（ P1M1. arch shed covered with blue film; P1M2.arch shed covered with yellow film; P2M1.trapezoidal shed covered with blue film; P2M2.trapezoidal shed covered with yellow film）,using Li-6400 portable photosynthesis system to measure photosynthetic parameters of ginseng leaves at different growth stages,we studied changes of photosynthetic characteristics of farmland ginseng under different shades. The results showed that net photosynthetic rate of the farmland ginseng leaves presented a two-peak curve in the whole growth period,with the peaks appearing at full unfolding stage and green fruit stage,respectively. At floweringstage,the curve slightly declined,after red fruit stage,it fell steadily,and the lowest appeared at yellow leaf stage. Farmland ginseng net photosynthetic rate was also significantly different under different shades,showing that P1M1 was the highest,followed by P2M1 treatment,and the lowest was P2M2 treatment. Net photosynthetic rate throughout P1M1 treatment was respectively 15. 02%,48. 99% and 81. 97% higher than the average of P2M1,P1M2 and P2M2 treatments in growth stage; net photosynthetic rate throughout P2M1 treatment was respectively 29. 53% and 58. 20%higher than P1M2 and P2M2 treatments. Transpiration rate,water use efficiency and Pn / Ci were the same as net photosynthetic rate. The conclusion is that arched awning covered with blue film is of strong photosynthesis and metabolism,thus is the optimum way for cultivation.