Raza A, Asghar M A, Hussain S, Bin C, Shafiq I, Ahmad I, Ghafoor A, Karim H, Iqbal T, Yang W, Weiguo L
Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture, Sichuan Agricultural University, Chengdu, 611130, China.
Institute of Ecological Agriculture, Sichuan Agricultural University, Chengdu, 611130, China.
Plant Biol (Stuttg). 2021 May;23(3):464-472. doi: 10.1111/plb.13219. Epub 2021 Jan 20.
In the maize-soybean intercropping system, shade is the major chronic restraint that affects normal growth of soybean. Different spatial patterns of this system affect the microclimate of soybean through shading from maize plants. However, the negative impacts of shading stress can be mitigated by providing optimal ratios of different fertilizers. Therefore, to test this hypothesis, soybean plants were grown under different light conditions (normal light or shade) to evaluate the response to varying NH /NO ratios. Seeds of soybean (Glycine max L. cv. Nan-99-6) were grown in nutrient solution with a total concentration of 5 mM N using different NH /NO ratios (T = 0:0, T = 0:100, T = 25:75, T = 50:50 and T = 75:25) for 40 days in a greenhouse at PPFD 320.95 μmol m s (low light) or 967.53 μmol m s (normal light). Under low light, growth and photosynthesis of soybean seedlings significantly decreased as compared to normal light conditions. However, the optimal ratios of NH / NO improved growth and photosynthesis of soybean seedlings under both light conditions. Our results indicated that soybean seedlings supplied with optimal NH /NO ratios (25:75 and 50:50) have maximum biomass yield, chlorophyll pigments, leaf gas exchange, photochemical activity and root growth as compared to low and high NH /NO ratios (T and T ). High ratios of NH /NO (T ) resulted in reduced plant growth due to nutrient accumulation in plant tissues; therefore, we suggest that optimal ratios of NH /NO (T and T ) can enhance the shade tolerance of soybean seedlings.
在玉米 - 大豆间作系统中，遮荫是影响大豆正常生长的主要长期限制因素。该系统不同的空间模式通过玉米植株的遮荫作用影响大豆的微气候。然而，通过提供不同肥料的最佳比例，可以减轻遮荫胁迫的负面影响。因此，为了验证这一假设，将大豆植株种植在不同光照条件下（正常光照或遮荫），以评估其对不同铵态氮/硝态氮比例的响应。大豆（Glycine max L. cv. Nan - 99 - 6）种子在总氮浓度为5 mM的营养液中，使用不同的铵态氮/硝态氮比例（T₁ = 0:0，T₂ = 0:100，T₃ = 25:75，T₄ = 50:50和T₅ = 75:25），在光合有效辐射为320.95 μmol m⁻² s⁻¹（弱光）或967.53 μmol m⁻² s⁻¹（正常光照）的温室中培养40天。在弱光条件下，与正常光照条件相比，大豆幼苗的生长和光合作用显著下降。然而，铵态氮/硝态氮的最佳比例在两种光照条件下均改善了大豆幼苗的生长和光合作用。我们的结果表明，与低铵态氮/硝态氮比例（T₁和T₅）相比，供应最佳铵态氮/硝态氮比例（25:75和50:50）的大豆幼苗具有最大的生物量产量、叶绿素色素含量、叶片气体交换、光化学活性和根系生长。高铵态氮/硝态氮比例（T₅）由于植物组织中养分积累导致植物生长减少；因此，我们建议最佳铵态氮/硝态氮比例（T₃和T₄）可以增强大豆幼苗的耐荫性。
