Effect of Shading on Leaf Anatomical Structure, Photosynthesis Characteristics and Chlorophyll Fluorescence of Soybean (Glycine max)

The present study aimed to investigate the effect of different shade treatments (0%, 35%, 50% and 75%) on physiological traits and yield attributes of two soybean genotypes namely JS 97-52 and JS 95-60. The results clearly showed that plants which were grown under control conditions exhibited the highest values for specific leaf weight, chlorophyll content, leaf thickness and stomatal density, whereas the lowest values were observed in plants subjected to 75% shading. Moreover, a significant reduction in photosynthetic rate, stomatal conductance and electron transport rate was observed with decreased solar radiation. Performance index, fluorescence area, Fv/Fo, Fo/fm, ABS/CSo, DIo/CSo, TRo/CSo and ETo/CSo were also reduced under heavy shade. Seed yield was reduced by 24%, 47% and 62% in JS 97-52 and by 51%, 82% and 92% in JS 95-60 under 35%, 50% and 75% shading, respectively, compared to the control conditions. Therefore, to enhance crop productivity under intercropping, the effects of shade should be taken into consideration.