Biochar application improves the yield, lodging resistance, and lignin synthesis mechanism in rice

Abstract

AbstractBiochar application elicits positive environmental and agricultural impacts owing to its physicochemical properties; however, the mechanism of biochar in regulating the lodging resistance in rice remains unclear. The present study was conducted to investigate the effects of biochar application on rice yield, lodging‐related traits, and enzymes activity and gene expression related to lignin biosynthesis in two rice (Oryza sativa L.) cultivars, that is, Shennong 265 and Akihikari. The biochar treatments were: 0 (B1), 5 (B2), 10 (B3), 20 (B4), and 40 (B5) t/ha. Results depicted that compared with B1, the B2 and B3 treatments improved the rice yield by 8.36%–27.62% and decreased the lodging index by 7.72%–24.14% for both rice cultivars, respectively. The increase in rice yield was mainly due to an increase in chlorophyll content, net photosynthesis, and dry matter at the heading stage. The reduced lodging index in B2 and B3 was mainly owing to an increase in stem lignin and silicon content by 28.55%–62.80% and 16.27%–50.09%, respectively, that was possibly linked to an increase in lignin synthase activity and its gene expression, that is, phenylalanine ammonia lyase, caffeic acid 3‐O‐methyltransferase, 4CL3 (where 4CL is 4‐coumarate: CoA ligase), and CCR20 (where CCR is cinnamyl coenzyme A reductase). Furthermore, the numbers of large and small vascular bundles were the highest in B2 and B3 treatment for both rice cultivars. However, excess biochar applications had an inhibitory effect on rice yield. Overall, biochar application at 5–10 t/ha is an appropriate dosage to improve lodging resistance and rice yield.