野生和栽培大豆叶片形态与光合特性对荫蔽的响应

Response of leaf morphology and photosynthetic characteristics to shading in wild and cultivated soybeans

选育耐荫高光效的大豆品种是玉米大豆带状复合种植模式的重要研究内容之一,通过分析野生大豆和栽培大豆幼苗在正常及荫蔽环境下的叶片形态和光合生理响应差异,揭示其耐荫机制,可为培育耐荫高光效新大豆品种提供理论基础。本研究以两种栽培大豆(南豆12、天隆1号)和两种野生大豆(W1、W2)为试验材料,设置自然光和50%遮荫两种光环境,探究栽培大豆和野生大豆的叶片形态及光合特性对荫蔽的响应差异。结果表明,荫蔽胁迫下野生大豆和栽培大豆的比叶重、叶片厚度、栅栏组织厚度、净光合速率、气孔导度、Chlb含量均显著低于自然光照。在荫蔽下,栽培大豆的净光合速率、光合色素含量、海绵组织厚度和叶面积变化幅度高于野生大豆,而比叶重和栅海比显著低于野生大豆。野生大豆可以通过维持Chlb含量、增加叶绿素在光合色素中的比例和激发潜在最大光合活性等响应措施提高对弱光环境的适应性。野生大豆和栽培大豆对荫蔽环境的响应差异可以为今后培育耐荫大豆提供理论支撑。

The selection of shade-tolerant and high-light-efficient soybean varieties is one of the important re-search elements of the maize-soybean ribbon complex cropping model.By analyzing the differences in leaf morphol-ogy and photosynthetic physiological responses between wild and cultivated soybean seedlings under normal and shaded conditions,we can reveal their shade-tolerance mechanisms and response differences,which can provide a theoretical basis for the breeding of new shade-tolerant and high-light-efficient soybean varieties.In this study,two types of cultivated soybean(Nandou 12 and Tianlong No.1)and two types of wild soybean(W1 and W2)were used as experimental materials to investigate their response to shade under two light environments:natural light and 50%shade.The results showed that the specific leaf weight,leaf thickness,fenestrated tissue thickness,net photo-synthetic rate,stomatal conductance,and photosynthetic pigment content of wild and cultivated soybean were signif-icantly lower under shade stress than under natural light.In shade,cultivated soybean showed higher variation in net photosynthetic rate,photosynthetic pigment content,spongy tissue thickness,and leaf area than wild soybean,while specific leaf weight and ratio of fenestrated tissue to spongy tissue were significantly lower than wild soybean.Wild soybean can improve its adaptation to low light conditions by maintaining Chlb content,increasing the propor-tion of chlorophyll in photosynthetic pigments and stimulating potential maximum photosynthetic activity as a re-sponse.The differences in the response of wild and cultivated soybean to shade conditions could provide theoretical support for future breeding of shade-tolerant soybean.