摘要
【目的】通过分析不同光照强度下苗期大豆叶片气孔特征、光合作用及碳水化合物变化,揭示大豆叶片光合及气孔特性对荫蔽的响应机制。【方法】选用对荫蔽敏感性弱的南豆12和荫蔽敏感性强的桂夏豆7号为材料,在人工气候室进行盆栽实验,设置正常光照(CK)、轻度荫蔽(LS,遮光20%)、中度荫蔽(MS,遮光40%)和重度荫蔽处理(SS,遮光75%),分析不同荫蔽程度对大豆叶片上下表皮气孔特性、光合荧光参数、可溶性糖和淀粉含量的影响。【结果】荫蔽敏感性弱的南豆12叶片上、下表皮气孔数量在LS和MS处理下显著高于CK,上表皮气孔在LS、MS处理分别增加26.9%和18.5%,下表皮分别增加了13.9%和39.2%,差异显著,南豆12在SS处理和荫蔽敏感性强的桂夏豆7号在3个荫蔽处理下显著低于CK(P<0.5)。2个大豆品种光合速率在LS、MS处理显著高于CK,最大值出现在LS处理,平均为14.33μmol CO2·m-2·s-1,在CK和SS处理下南豆12显著高于桂夏豆7号;光强减弱,南豆12气孔导度和蒸腾速率均先减后增,桂夏豆7号逐渐减小,且南豆12和桂夏豆7号2个品种的气孔导度均在LS处理出现最大值,分别为0.57 mm·m-2·s-1和0.30 mm·m-2·s-1;南豆12胞间CO2浓度在LS和SS处理下显著高于CK,桂夏豆7号胞间CO2浓度随荫蔽程度增加而逐渐增大;荫蔽程度增加,2个品种的实际光量子产量和最大量子产额逐渐降低,且不同处理下南豆12的实际量子产量均大于桂夏豆7号。相反,南豆12和桂夏豆7号非光化学淬灭系数随荫蔽程度增加而增大。光强降低,南豆12淀粉含量分别显著下降了59.0%、77.8%、95.8%,桂夏豆7号则显著下降了47.5%、67.3%、87.8%;2个品种可溶性糖含量逐渐降低,南豆12在LS处理下增加了72.7%,显著高于南豆12的CK和桂夏豆7号的LS处理,桂夏豆7号的LS、MS处理和CK无显著差异(P>0.5)。【结论】荫蔽直接影响气孔性状和光合特性,适当的荫蔽会使叶片通过增加叶片气孔开放来提高净光合速率,增加碳水化合物积累量,进而增强大豆的耐荫性。
【Objective】To reveal the response mechanism of photosynthetic and stomatal characteristics of soybean leaves to shade,it analyzed the stomatal characteristics,photosynthesis and carbohydrate changes of soybean leaves in seedling stage under different light intensity.【Method】A pot experiment was conducted to analyze the impact of four light-intensity levels including CK(normal light),LS(light shading,20%shading),MS(medium shading,40%shading)and SS(severe shading treatment,75%shading)on stomata characteristics of upper and lower epidermis,photosynthetic fluorescence parameters,soluble sugar and starch content of two soybean varieties(Nandou-12,weak shade-sensitive and Guixiadou-7,high shade-sensitive).【Result】Results revealed that the maximum number of stomata on the upper and lower epidermis of soybean leaves was observed with Nandou-12.Among shading treatments,LS and MS treatments significantly increased the number of stomata on the upper(by 26.9%and 18.5%)and lower(by 13.9%and 39.2%)epidermis as compared with CK.And between soybean varieties,the highest rate of photosynthesis was measured under LS treatment,whose average was 14.33μmol CO2·m-2·s-1.In addition,the highest values of stomatal conductance in Nandou-12(0.57 mm·m-2·s-1)and Guixiadou-7(0.30 mm·m-2·s-1)were measured under LS treatment,and the maximum concentration of carbon dioxide under LS and SS treatments with Nandou-12 was significantly higher than that under CK.These results implied that increasing light intensity decreased the actual quantum yield,however,the actual quantum yield of Nandou-12 was significantly higher than that of Guixiadou-7.In contrast,the non-photochemical quenching coefficient of Nandou-12 and Guixiadou-7 was enhanced with a decline in light intensity.Moreover,the starch content of Nandou-12 and Guixiadou-7 was decreased by 59.0%,77.8%,and 95.8%,and 47.5%,67.3%,and 87.8%,respectively,under LS,MS,and SS treatments.Whereas,light shading(LS)significantly increased(72.7%)the soluble sugar content of Nandou-12 as compared with the corresponding values of Guixiadou-7.【Conclusion】Overall,our results confirmed that shading conditions directly affect the stomata and photosynthetic characteristics of soybean leaves.However,by maintaining appropriate shading,the net photosynthetic rate of soybean leaves could be increased by increasing the rate of stomatal opening,which was conducive to increase the accumulation of carbohydrates and thus enhance the shade resistance of soybeans.
作者
陈吉玉
冯铃洋
高静
时健祎
周雨晨
涂发涛
陈元凯
杨文钰
杨峰
CHEN JiYu;FENG LingYang;GAO Jing;SHI JianYi;ZHOU YuChen;TU FaTao;CHEN YuanKai;YANG WenYu;YANG Feng(College of Agronomy,Sichuan Agricultural University/Key Laboratory of Crop Ecophysiology and Farming System in Southwest China,Ministry of Agriculture/Sichuan Engineering Research Center for Crop Strip Intercropping System,Chengdu 611130)
出处
《中国农业科学》
CAS
CSCD
北大核心
2019年第21期3773-3781,共9页
Scientia Agricultura Sinica
基金
国家重点研发计划项目(2016YFD0300109)
大学生科研兴趣培养计划项目(2019053)
关键词
大豆
荫蔽
气孔特性
光合特性
碳水化合物
soybean
shade
stoma characteristics
photosynthetic characteristics
carbohydrate
