Rahimzadeh Saeedeh, Pirzad Alireza
Department of Agronomy, Faculty of Agriculture, Urmia University, Urmia, Iran.
Mycorrhiza. 2017 Aug;27(6):537-552. doi: 10.1007/s00572-017-0775-y. Epub 2017 May 10.
Drought stress, which is one of the most serious world environmental threats to crop production, might be compensated by some free living and symbiotic soil microorganisms. The physiological response of flax plants to inoculation with two species of arbuscular mycorrhizal (AM) fungi (Funneliformis mosseae or Rhizophagus intraradices) and a phosphate solubilizing bacterium (Pseudomonas putida P13; PSB) was evaluated under different irrigation regimes (irrigation after 60, 120, and 180 mm of evaporation from Class A pan as well-watered, mild, and severe stress, respectively). A factorial (three factors) experiment was conducted for 2 years (2014-2015) based on a randomized complete block design with three replications at Urmia University, Urmia, located at North-West of Iran (37° 39' 24.82″ N44° 58' 12.42″ E). Water deficit decreased biomass, showing that flax was sensitive to drought, and AM root colonization improved the performance of the plant within irrigation levels. In all inoculated and non-inoculated control plants, leaf chlorophyll decreased with increasing irrigation intervals. Water deficit-induced oxidative damage (hydrogen peroxide, malondialdehyde, and electrolyte leakage) were significantly reduced in dual colonized plants. All enzymatic (catalase, superoxide dismutase, glutathione reductase, and ascorbate peroxidase) and non-enzymatic (glutathione, ascorbic acid, total carotenoids) antioxidants were reduced by water-limiting irrigation. Dual inoculated plants with AM plus Pseudomonas accumulated more enzymatic and non-enzymatic antioxidants than plants with bacterial or fungal inoculation singly. Dual colonized plants significantly decreased the water deficit-induced glycine betaine and proline in flax leaves. These bacterial-fungal interactions in enzymatic and non-enzymatic defense of flax plants demonstrated equal synergism with both AM fungi species. In conclusion, increased activity of enzymatic antioxidants and higher production of non-enzymatic antioxidant compounds in symbiotic association with bacteria and mycorrhiza can alleviate reactive oxygen species damage resulting in improve water stress tolerance.
干旱胁迫是全球对作物生产最严重的环境威胁之一，一些自由生活和共生的土壤微生物可能会对其起到补偿作用。在不同灌溉制度下（分别以A类蒸发皿蒸发60、120和180毫米后进行灌溉，即充分灌溉、轻度胁迫和重度胁迫），评估了亚麻植株接种两种丛枝菌根（AM）真菌（摩西斗管囊霉或根内根孢囊霉）和一种解磷细菌（恶臭假单胞菌P13；PSB）后的生理反应。基于随机完全区组设计，在伊朗西北部乌尔米亚大学（北纬37°39′24.82″，东经44°58′12.42″）进行了为期两年（2014 - 2015年）的析因（三因素）实验，设置三个重复。水分亏缺降低了生物量，表明亚麻对干旱敏感，且在灌溉水平范围内，AM根定殖改善了植株的表现。在所有接种和未接种的对照植株中，随着灌溉间隔时间延长，叶片叶绿素含量下降。在双重定殖的植株中，水分亏缺诱导的氧化损伤（过氧化氢、丙二醛和电解质渗漏）显著降低。水分限制灌溉降低了所有酶促（过氧化氢酶、超氧化物歧化酶、谷胱甘肽还原酶和抗坏血酸过氧化物酶）和非酶促（谷胱甘肽、抗坏血酸、总类胡萝卜素）抗氧化剂的含量。与单独接种细菌或真菌的植株相比，AM与假单胞菌双重接种的植株积累了更多的酶促和非酶促抗氧化剂。双重定殖的植株显著降低了水分亏缺诱导的亚麻叶片中甘氨酸甜菜碱和脯氨酸的含量。亚麻植株在酶促和非酶促防御中的这些细菌 - 真菌相互作用表明，与两种AM真菌均具有同等的协同作用。总之，与细菌和菌根共生时，酶促抗氧化剂活性增加以及非酶促抗氧化化合物产量提高，可以减轻活性氧损伤，从而提高水分胁迫耐受性。
