Blue-Light-Dependent Stomatal Density and Specific Leaf Weight Coordinate to Promote Gas Exchange of Soybean Leaves

Blue and red light are essential light signals used to regulate stomatal development and leaf structure. In the present study, stomatal and leaf traits that respond to blue and red light were studied at two light intensities (400 and 100 mu mol m(-2) s(-1)) in soybeans. The stomatal traits and leaf characteristics were determined. Furthermore, their contribution to the operational maximum stomatal conductance (g(opmax)) was evaluated using the rdacca.hp R package. With the light intensity significantly reduced, the stomatal size (SZ) under blue light did not change. Similarly, the decrease in light intensity did not influence the stomatal density (SD), specific leaf weight (SLW) or g(opmax) under red light. These results implied that the regulation of SD and SLW depended on blue light and that SZ was highly sensitive to red light. In addition, SLW was strongly correlated with SD. The SLW and SD had the highest contribution rates (19.43% and 19.5%, respectively) to g(opmax,) as compared with the other parameters. In conclusion, these results suggested that in long-term exposure to blue light, the enhancements in g(opmax) were primarily due to the synergistic promotion of SLW and SD.

Automated summary

Blue and red light are important light signals for regulating stomatal development and leaf structure. This study investigated the response of stomatal and leaf traits in soybeans to blue and red light at two light intensities. The results showed that stomatal size remained unchanged under blue light, while stomatal density, specific leaf weight, and maximum stomatal conductance were unaffected by the decrease in light intensity under red light. These findings suggest that stomatal density and specific leaf weight are regulated by blue light, while stomatal size is highly sensitive to red light. Furthermore, specific leaf weight and stomatal density had the highest contribution rates to maximum stomatal conductance. Overall, these results indicate that long-term exposure to blue light enhances maximum stomatal conductance through the synergistic promotion of specific leaf weight and stomatal density.