Liu Cai-Juan, Lyu Chun-Yu, Ai Xi-Zhen, Bi Huan-Gai
College of Horticulture Science and Engineering, Shandong Agricultural University/State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation in Huang Huai Region of Ministry of Agriculture/Collaborative Innovation Center of Shandong Province with High Quality and Efficient Production of Fruit and Vegetable, Tai'an 271018, Shandong, China.
Ying Yong Sheng Tai Xue Bao. 2022 May;33(5):1300-1310. doi: 10.13287/j.1001-9332.202205.014.
Fulvic acid (FA) participates in the regulation of drought stress tolerance in plants, but the underlying mechanisms remain unclear. We carried out an experiment with cucumber cultivar 'Jinyou 35' as the test material and the polyethylene glycol (PEG-6000) being used to simulate drought stress. The concentration effect of FA on drought alleviation of cucumber as well as the effect of FA on photosynthetic enzymes activities, chloroplast ultrastructure, fluorescence parameters, water use efficiency, yield and quality of cucumber plants were studied through spraying FA with different concentrations (0, 100, 300, 500, 700 and 900 mg·L). The results showed that FA with different concentrations significantly promoted the relative water content and leaf area and decreased drought injure index as well as the electrolyte leakage and malondialdehyde (MDA) content, compared with the control (0 mg·L) under drought stress. The mitigative effect of FA increased first and then decreased with the increases of FA concentration, with 700 mg·L FA showing the best effect. FA significantly enhanced the chlorophyll content, Rubiasco and Rubisco activase (RCA) activities and gene expression, net photosynthesis (), maximal photochemical efficiency of PSⅡin darkness, actual photochemical efficiency, absorbed light energy per unit area, captured light energy per unit area, quantum yield of electron transport and PSⅠ activity, decreased the increase of K point and maintained chloroplast ultrastructure. The experiment in solar-greenhouse showed that FA obviously increased water use efficiency, promoted dry matter accumulation as well as the contents of Vc, soluble sugar, soluble protein and free amino acid, and decreased tannin content. Our results suggested that FA could improve the yield and quality of cucumber in solar greenhouse under drought stress.
黄腐酸（FA）参与植物干旱胁迫耐受性的调控，但其潜在机制尚不清楚。我们以黄瓜品种‘津优35’为试验材料，用聚乙二醇（PEG - 6000）模拟干旱胁迫进行了一项实验。通过喷施不同浓度（0、100、300、500、700和900 mg·L）的FA，研究了FA对黄瓜干旱缓解的浓度效应以及FA对黄瓜光合酶活性、叶绿体超微结构、荧光参数、水分利用效率、产量和品质的影响。结果表明，与干旱胁迫下的对照（0 mg·L）相比，不同浓度的FA显著提高了相对含水量和叶面积，降低了干旱伤害指数、电解质渗漏率和丙二醛（MDA）含量。FA的缓解效应随着FA浓度的增加先升高后降低，700 mg·L的FA效果最佳。FA显著提高了叶绿素含量、核酮糖-1,5-二磷酸羧化酶（Rubisco）和Rubisco活化酶（RCA）活性及基因表达、净光合速率（ ）、PSⅡ在黑暗中的最大光化学效率、实际光化学效率、单位面积吸收光能、单位面积捕获光能、电子传递量子产率和PSⅠ活性，降低了K点的升高幅度并维持了叶绿体超微结构。日光温室试验表明，FA明显提高了水分利用效率，促进了干物质积累以及Vc、可溶性糖、可溶性蛋白和游离氨基酸含量的增加，并降低了单宁含量。我们的结果表明，FA可以提高干旱胁迫下日光温室黄瓜的产量和品质。
