Foliar Application of NH4 +/NO3 - Ratios Enhance the Lodging Resistance of Soybean Stem by Regulating the Physiological and Biochemical Mechanisms Under Shade Conditions

Ali Raza; Chunying Yin; Muhammad Ahsan Asghar; Muhammad Ihtisham; Iram Shafiq; Bin Cheng; Abuzar Ghafoor; Hafiz Hassan Javed; Tauseef Iqbal; Nawab Khan; Weiguo Liu; Wenyu Yang

doi:10.3389/fpls.2022.906537

Foliar Application of NH₄ ⁺/NO₃ ^- Ratios Enhance the Lodging Resistance of Soybean Stem by Regulating the Physiological and Biochemical Mechanisms Under Shade Conditions

Front Plant Sci. 2022 Jul 22:13:906537. doi: 10.3389/fpls.2022.906537. eCollection 2022.

Authors

Ali Raza^{1

2

3

4}, Chunying Yin^{3

4}, Muhammad Ahsan Asghar⁵, Muhammad Ihtisham⁶, Iram Shafiq^{1

2}, Bin Cheng⁷, Abuzar Ghafoor⁸, Hafiz Hassan Javed⁹, Tauseef Iqbal⁹, Nawab Khan¹⁰, Weiguo Liu^{1

2}, Wenyu Yang^{1

2}

Affiliations

¹ Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Sichuan Agricultural University, Chengdu, China.
² Sichuan Engineering Research Center for Crop Strip Intercropping System, Chengdu, China.
³ CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China.
⁴ Chengdu Institute of Biology, University of Chinese Academy of Sciences, Beijing, China.
⁵ Department of Biological Resources, Agricultural Institute, Centre for Agricultural Research, ELKH, Martonvásár, Hungary.
⁶ College of Landscape Architecture, Sichuan Agricultural University, Chengdu, China.
⁷ Chengdu Da Mei Seeds Co., Ltd., Chengdu, China.
⁸ College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
⁹ College of Agronomy, Sichuan Agricultural University, Chengdu, China.
¹⁰ College of Management, Sichuan Agricultural University, Chengdu, China.

Abstract

Shading is one of the most chronic restrains which can lead to the lodging of intercropped plants. In order to increase the soybean stem lodging resistance, a 2-year field trial was conducted to evaluate the impact of different ratios and concentrations of NH₄ ⁺/NO₃ ^- on the morpho-physiological and biochemical characteristics of soybean stem under shade conditions. The total 5 ratios of NH₄ ⁺/NO₃ ^- were applied as follows: T0 = 0/0 (control), T1 = 0/100 (higher ratio), T2 = 25/75 (optimum), T3 = 50/50 (optimum), and T4 = 75/25 (higher ratio) as a nitrogen source. Our findings displayed that the T2 (25/75) and T3 (50/50) treatments alleviated the shading stress by improving the photosynthetic activity, biomass accumulation, carbohydrates contents, and lignin related enzymes (POD, CAD, and 4Cl) which led to improvement in stem lodging resistance. The correlation analysis (p ≤ 0.05, p ≤ 0.01) revealed the strong relationship between lodging resistance index and stem diameter, stem strength, lignin content, photosynthesis, and lignin related enzymes (POD, CAD, and 4CL) evidencing the strong contribution of lignin and its related enzymes in the improvement of lodging resistance of soybean stem under shade conditions. Collectively, we concluded that optimum NH₄ ⁺/NO₃ ^- ratios (T2 and T3) can boost up the lodging resistance of soybean stem under shade stress.

Keywords: NH4+/NO3–; lignin enzymes; shade stress; soybean; stem lodging resistance.