Abstract Arbuscular mycorrhizal fungi (AMF) improves phosphorus (P) uptake in plants and regulates growth under environmental stresses. Present trials were undertaken to study the effect of phosphorus (P, 40 mg kg−1 soil) supplementation and AMF (Glomus versiforme) inoculation on the growth performance of tobacco (Nicotiana tabacum L. variety Yunyan 87) under drought stress. Supplementation of P and inoculation of AMF significantly enhanced growth, biomass accumulation and root activity of tobacco plants under normal conditions and mitigated the drought induced decline. Chlorophyll and carotenoid contents, photosynthesis and PSII efficiency increased due to AMF and P treatment attaining maximal values due to their combined treatment. Drought resulted in generation of reactive oxygen species (ROS) like superoxide (O2−) and hydrogen peroxide (H2O2) resulting in increased lipid peroxidation hence reducing membrane stability. Plants inoculated with AMF and/or supplemented with P exhibited reduced accumulation of ROS and lipid peroxidation. Content of osmolytes including proline, sugars and free amino acids were enhanced due to P and AMF treatment under normal as well as drought conditions that influenced the leaf relative water content. Reduction in oxidative damage in AMF and P treated plants was apparently linked with the stimulation of antioxidant system in them. Activities of SOD, CAT, APX, POD and GR, and the content of AsA and GSH improved significantly due to P and AMF treatment both under normal and drought conditions thereby ameliorating the oxidative effects. Further, accumulation of phenols increased more obviously due to P and/or AMF inoculation than in drought. Increased osmolyte and phenol content due to P and/or AMF helped tobacco plants to counteract the drought mediated damage by strengthening the non-enzymatic antioxidant system. P and/or AMF ameliorated the decline in contents of nitrogen, potassium and phosphorous, and activity of nitrate reductase more due to their combined treatments. Drought induced decline in nicotine content was mitigated because of P and/or AMF treatment. Additionally, mycorrhizal inoculation along with P supplementation increased indole-3-acetic acid (IAA) and abscisic acid (ABA) concentrations both in roots and leaves under drought stress. Hence P supplementation along with AMF inoculation mitigates the photosynthetic alteration and growth in tobacco plants by up-regulating antioxidant system and osmolyte accumulation.

中文翻译：

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AMF接种和磷补充通过上调抗氧化代谢和渗透物积累减轻干旱诱导的烟草生长和光合下降

摘要 丛枝菌根真菌 (AMF) 可提高植物对磷 (P) 的吸收并在环境胁迫下调节生长。目前的试验是为了研究磷（P，40 mg kg-1 土壤）补充和 AMF（Glomus versiforme）接种对干旱胁迫下烟草（烟草品种云烟 87）生长性能的影响。在正常条件下，补充磷和接种 AMF 显着增强了烟草植物的生长、生物量积累和根系活动，并减轻了干旱引起的衰退。叶绿素和类胡萝卜素含量、光合作用和 PSII 效率由于 AMF 和 P 处理而增加，由于它们的组合处理而达到最大值。干旱导致产生活性氧 (ROS)，如超氧化物 (O2-) 和过氧化氢 (H2O2)，导致脂质过氧化增加，从而降低膜稳定性。接种 AMF 和/或补充 P 的植物表现出减少的 ROS 积累和脂质过氧化。由于在正常和干旱条件下影响叶片相对含水量的 P 和 AMF 处理，包括脯氨酸、糖和游离氨基酸在内的渗透物的含量增加。AMF 和 P 处理的植物中氧化损伤的减少显然与它们中抗氧化系统的刺激有关。在正常和干旱条件下，由于P和AMF处理，SOD、CAT、APX、POD和GR的活性以及AsA和GSH的含量显着提高，从而改善了氧化作用。更多，由于P和/或AMF接种，酚类的积累增加比干旱更明显。由 P 和/或 AMF 引起的渗透物和苯酚含量增加有助于烟草植物通过加强非酶促抗氧化系统来抵消干旱介导的损害。P和/或AMF联合处理更能改善氮、钾、磷含量的下降，以及硝酸还原酶活性的下降。由于 P 和/或 AMF 处理，干旱引起的尼古丁含量下降得到缓解。此外，在干旱胁迫下，菌根接种和 P 补充增加了根和叶中的吲哚-3-乙酸 (IAA) 和脱落酸 (ABA) 浓度。