Sahoo Ansuman, Madheshiya Parvati, Mishra Ashish Kumar, Tiwari Supriya
Laboratory of Ecotoxicology, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India.
Front Plant Sci. 2023 Feb 22;14:1125529. doi: 10.3389/fpls.2023.1125529. eCollection 2023.
The present study investigates the efficiency of nitrogen (N) amendments in the management of ozone (O) stress in two varieties (Kashi Sheetal and Kashi Harittima) of Indian bean ( L.). Two O concentrations, ambient (44.9 ppb) and elevated (74.64 ppb) were used, and each O concentration has 3 nitrogen (N) dose treatments viz recommended (N1), 1.5 times recommended (N2), 2 times recommended (N3) and no nitrogen, which served as control (C). The experiment concluded Kashi Sheetal as O tolerant, as compared to Kashi Harittima. N amendments were effective in the partial amelioration of O stress, with N2 being the most effective nitrogen dose, at both ambient and elevated O concentrations. Kashi Sheetal has been determined to be O tolerant due to greater endogenous levels of HO accumulation and enzymatic antioxidant contents with O exposure. The O-sensitive variety, Kashi Harittima, responded more positively to N treatments, at both O concentrations. The positive effect of N amendments is attributed to the stimulated antioxidative enzyme activity, rather than the biophysical processes like stomatal conductance. Strengthened defense upon N amendments was attributed to the enhanced activities of APX and GR in Kashi Sheetal, while in Kashi Harittima, the two enzymes (APX and GR) were coupled by SOD and CAT as well, during the reproductive phase. Yield (weight of seeds plant) increments upon N (N2) amendments were higher in Kashi Harittima (O sensitive), as compared to Kashi Sheetal (O tolerant) at both ambient and elevated O concentration, due to higher antioxidant enzymatic response and greater rate of photosynthesis in the former.
本研究调查了氮（N）添加对印度豆（L.）两个品种（喀什·希塔尔和喀什·哈里蒂马）臭氧（O）胁迫管理的效率。使用了两种臭氧浓度，即环境浓度（44.9 ppb）和升高浓度（74.64 ppb），每种臭氧浓度有3种氮（N）剂量处理，即推荐剂量（N1）、1.5倍推荐剂量（N2）、2倍推荐剂量（N3）以及不施氮作为对照（C）。实验得出，与喀什·哈里蒂马相比，喀什·希塔尔对臭氧具有耐受性。在环境和升高的臭氧浓度下，氮添加对部分缓解臭氧胁迫有效，其中N2是最有效的氮剂量。已确定喀什·希塔尔由于在臭氧暴露下具有更高的内源性过氧化氢积累水平和酶促抗氧化剂含量而对臭氧具有耐受性。对臭氧敏感的品种喀什·哈里蒂马在两种臭氧浓度下对氮处理的反应更为积极。氮添加的积极作用归因于抗氧化酶活性的刺激，而非气孔导度等生物物理过程。氮添加后防御能力增强归因于喀什·希塔尔中抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性的增强，而在喀什·哈里蒂马中，在生殖阶段这两种酶（APX和GR）还与超氧化物歧化酶（SOD）和过氧化氢酶（CAT）协同作用。在环境和升高的臭氧浓度下，由于前者具有更高的抗氧化酶反应和更高的光合速率，喀什·哈里蒂马（对臭氧敏感）在施氮（N2）后种子产量（单株种子重量）的增加高于喀什·希塔尔（对臭氧耐受）。
