Effects of Multiple Planting Densities on Lignin Metabolism and Lodging Resistance of the Strip Intercropped Soybean Stem

Abstract

The shading of maize and self-shading are the key factors affecting the stem lignin biosynthesis and lodging resistance of soybean at middle and later growth stages in the strip intercropping system. A study was designed to explore the regulation mechanism of lignin metabolism and different planting densities; PD1, PD2, and PD3 were used having a total number of 17 plants m−2, 20 plants m−2, and 25 plants m−2, respectively, on the lodging resistance of strip intercropped soybean stem. Our results depicted that the lower planting density (PD1) appropriately promoted the leaf photosynthesis activities (Pn), increase the activity of lignin-related enzymes and the accumulation of carbohydrates in stems, and eventually enhanced the lodging resistance of the strip intercropped soybean stem. Correlation analysis also showed that the lodging resistance index of soybean stem was significantly correlated with the available light for soybean canopy and Pn strip intercropped soybean stem characteristics and activities of enzymes related to lignin synthesis among the different planting densities. The findings of our research will be useful in future studies to understand the relationship between different light environment, planting densities, and lodging resistance of intercropped soybean and also guide the optimum planting density in maize–soybean intercropping system.

Agro-Techniques for Lodging Stress Management in Maize-Soybean Intercropping System—A Review

“…Most specifically, the plant height was decreased by 6.2% and 9.4% at 17 and 20 plants/m 2 , respectively than that of 25 plants/m 2 planting density. In addition, decreasing the planting densities such as 17 and 20 plants/m 2 could decrease the lodging percentage by 50.3% and 19.3%, respectively as compared to 25 plants/m 2 planting density [ 134 ]. However, further field experiments to optimize the planting densities in the maize-soybean intercropping system Table 2 .…”

Overview of the advantages and limitations of maize-soybean intercropping in sustainable agriculture and future prospects: A review

“…These soybean-related restrictions are obviously linked to maize canopy development (Chui and Shibles, 1984;Liu et al, 2017a). In addition, maize shade affects the stem circumference of soybean and lowers its lodging susceptibility (Liu et al, 2016;Raza et al, 2019a;Cheng et al, 2020). Low PAR and the ratio of red light to far red light, which decreased because of the maize canopy, also produce soybean stem vining in maize-soybean relay strip intercropping.…”

Effects of Shading on the Internode Critical for Soybean (Glycine Max) Lodging

“…Hussain et al [8] argued that shading reduces the amount of lignin deposited in the cells of vascular bundles and sclerenchyma, rendering the stems slender and more fragile. Cheng et al [9] showed that when soybeans were intercropped, decreasing their planting density could increase the activity of lignin-related enzymes and the accumulation of carbohydrates, thereby enhancing the lodging resistance of soybean stems.…”