Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Sichuan Agricultural University, Chengdu, 611130, China; Sichuan Engineering Research Center for Crop Strip Intercropping System, Sichuan Agricultural University, Chengdu, 611130, China; CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu, 610041, PR China; University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, PR China.
Agricultural Institute, Centre for Agricultural Research, ELKH, Martonvásár, 2462, Hungary.
Plant Physiol Biochem. 2023 Jun;199:107720. doi: 10.1016/j.plaphy.2023.107720. Epub 2023 May 4.
Excessive use of nitrogen fertilizers enhanced the stem lodging, leading to serious threats to environmental sustainability. As the maize-soybean intercropping system is eco-friendly, however, soybean micro-climate hinders soybean growth and caused lodging. Since the relationship between nitrogen and lodging resistance under the intercropping system is not widely studied. Therefore, a pot experiment was conducted with the application of different nitrogen concentrations referring to low nitrogen (LN) = 0 mg/kg, optimum nitrogen (OpN) = 100 mg/kg, and high nitrogen (HN) = 300 mg/kg. To evaluate the optimum nitrogen fertilization under the maize-soybean intercropping system, two soybean cultivars were selected Tianlong 1 (TL-1), (lodging resistant) and Chuandou 16 (CD-16), (lodging susceptible). The results revealed that under the intercropping system, the OpN concentration significantly improved the lodging resistance of soybean cultivars by reducing the plant height of TL-1 and CD-16 by 4 and 28% as compared to LN, respectively. Following OpN, the lodging resistance index for CD-16 was also increased by 67% and 59% under the respective cropping systems. In addition, we found that OpN concentration prompted the lignin biosynthesis by stimulating the enzymatic activities of lignin biosynthetic enzymes (PAL, 4CL, CAD, and POD), which was reflected at the transcriptional levels (GmPAL, GmPOD, GmCAD, Gm4CL), too. Henceforth, we proposed that optimum nitrogen fertilization boosts soybean stem lodging resistance by modulating the lignin metabolism in the maize-soybean intercropping system.
过量使用氮肥会增强茎秆倒伏，对环境可持续性造成严重威胁。然而，由于玉米-大豆间作系统是环保的，大豆的微气候会阻碍大豆生长并导致倒伏。由于间作系统中氮素与抗倒伏性的关系尚未广泛研究，因此进行了一项盆栽试验，应用不同氮浓度，低氮（LN）=0mg/kg、最佳氮（OpN）=100mg/kg 和高氮（HN）=300mg/kg。为了评估玉米-大豆间作系统中的最佳氮肥用量，选择了两个大豆品种天龙 1 号（TL-1）（抗倒伏）和川豆 16 号（CD-16）（易倒伏）。结果表明，在间作系统下，OpN 浓度通过降低 TL-1 和 CD-16 的株高分别比 LN 低 4%和 28%，显著提高了大豆品种的抗倒伏性。在 OpN 之后，CD-16 的抗倒伏指数在各自的间作系统中也分别增加了 67%和 59%。此外，我们发现 OpN 浓度通过刺激木质素生物合成酶（PAL、4CL、CAD 和 POD）的酶活性来促进木质素生物合成，这也反映在转录水平上（GmPAL、GmPOD、GmCAD、Gm4CL）。因此，我们提出最佳氮肥施肥通过调节玉米-大豆间作系统中的木质素代谢来提高大豆茎秆的抗倒伏性。
