Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India..
Sci Total Environ. 2020 Apr 20;714:136837. doi: 10.1016/j.scitotenv.2020.136837. Epub 2020 Jan 21.
The response of a wheat cultivar (HD 2967) under the combination of elevated ozone (O) and water deficit stress (WS) was evaluated in terms of morphological, physiological and yield parameters along with nutrient uptake and their redistribution to different plant parts. An open-top chamber experiment has been conducted under O exposures (ambient (A) and ambient +20 ppb O (E)) along with two different water regimes (well-watered; WW and water deficit with 50% of soil capacity; WS). Most of the growth parameters showed significant reductions due to elevated O under both WW and WS conditions. Stomatal conductance and assimilation rate reduced significantly under the combined stress as compared to their controls (AWW). The maximum decrease in grain yield was observed under the additive effect of both the stresses of water deficit and elevated O (-43.6%), followed by water deficit stress (-19.8%) and elevated O (-17.9%) as compared to the control (AWW). Furthermore, the study displayed that reduced water availability has checked the uptake of nutrients in the roots, shoot and leaves, while, a higher carbon accumulation has been observed with subsequent increases in C: N and C: K ratios in the leaves. Such limitation of nutrients uptake and photosynthates availability weakened the antioxidative defense system of the test cultivar, making it more sensitive against combined stresses. Besides, the study displayed that the defense system has been remarkably suppressed under the presence of interactive stress factors, which allowed us to predict that the distribution of limited carbon pool has inverse relationship between the plant's defense system and growth.
在水分亏缺胁迫（WS）与臭氧（O）浓度升高的复合胁迫下，对小麦品种（HD 2967）的形态、生理和产量参数以及养分吸收和向不同植物部位的再分配进行了评估。在开顶式气室实验中，在 O 暴露（环境（A）和环境+20 ppb O（E））以及两种不同水分条件（充分供水；WW 和土壤容量的 50%供水不足；WS）下进行了研究。在 WW 和 WS 条件下，由于 O 浓度升高，大多数生长参数均显著降低。与对照（AWW）相比，在复合胁迫下，气孔导度和同化率显著降低。与对照（AWW）相比，在水分亏缺和 O 浓度升高这两种胁迫的累加效应下，籽粒产量最大降幅为-43.6%，其次是水分亏缺胁迫（-19.8%）和 O 浓度升高（-17.9%）。此外，研究表明，减少水分供应会抑制根系、地上部和叶片对养分的吸收，而在叶片中观察到更高的碳积累，同时 C:N 和 C:K 比增加。养分吸收和光合产物供应的这种限制削弱了试验品种的抗氧化防御系统，使其对复合胁迫更加敏感。此外，研究表明，在互作胁迫因素存在下，防御系统受到明显抑制，这使我们能够预测，有限的碳库分配与植物防御系统和生长之间呈负相关关系。
