Abstract

Mineral nutrient supplementation is a vital strategy to detoxify the lethal effects of salinity stress induced by sodium chloride. To explore the role of mineral nutrition (nitrogen), a hydroponic experiment was carried out for the whole growing season to find out the effects of different levels of nitrogen (0.25, 2.5, and 5 mmol·L⁻¹ N) on the growth and yield of upland cotton genotypes (salt-tolerant, ST, Z9807 and salt-sensitive, SS, Z0102) exposed to salt stress (200 mmol·L⁻¹ NaCl). Salt stressed cotton genotypes exhibited a marked reduction in growth traits and dry biomass accumulation. Nitrogen confirmed its positive role by ameliorating the detrimental effects of salt stress on significant levels when supplied at 2.5 mmol·L⁻¹ as compared to 5 mmol·L⁻¹. Nitrogen application at 5 mmol·L⁻¹ concentration suggestively increased all the morphological and physiological traits under the non-saline environment. Nitrogen at 2.5 mmol·L⁻¹ progressively improved the root morphology of both tolerant and sensitive genotypes and ensured better nitrogen uptake under saline conditions. Besides, nitrogen supplementation at 2.5 mmol·L⁻¹ proved beneficial in positively enhancing the photosynthetic pigment biosynthesis (3.05- and 4.14-fold for TChl, 1.72- and 2.06-fold for Car, and 2.84- and 2.96-fold for An for ST and SS), nitrogen content (9.26- and 11.19- fold for ST and SS), and the seed cotton yield (7.20 times in ST and 7.25 times in SS) of cotton genotypes as compared to the salinity treatment alone. Conclusively, the study results evidenced that nitrogen at moderate concentration can be advantageous in preventing NaCl induced damage.

摘要

补充矿物质营养是消除氯化钠引起的盐分胁迫致死效应的重要策略。为探索矿质营养（氮）的作用，对整个生长季进行了水培试验，以了解不同水平的氮（0.25、2.5和5 mmol·L ^-1 N）对生长和生长的影响。暴露于盐胁迫（200 mmol·L ^-1 NaCl）的陆地棉基因型（耐盐，ST，Z9807和盐敏感，SS，Z0102）的产量。盐胁迫的棉花基因型表现出生长性状和干生物量积累的显着减少。与 5 mmol·L 相比，当以 2.5 mmol·L ^-1供应时，通过显着改善盐胁迫的不利影响，证实了其积极作用^-1。^{5 mmol·L -1}浓度的施氮显着增加了非盐环境下的所有形态和生理特征。2.5 mmol·L ^-1的氮逐渐改善了耐受和敏感基因型的根系形态，并确保了在盐碱条件下更好的氮吸收。此外，2.5 mmol·L ^{-1的氮补充}证明有利于积极增强光合色素生物合成（TChl 为 3.05 和 4.14 倍，Car 为 1.72 和 2.06 倍，ST 和 SS 为 An 为 2.84 和 2.96 倍），氮含量（9.26 和 11.19 - ST 和 SS 的倍数）以及与单独盐度处理相比的棉花基因型的籽棉产量（ST 的 7.20 倍和 SS 的 7.25 倍）。总之，研究结果表明，中等浓度的氮可以有利于防止 NaCl 引起的损害。