植物根际促生菌Pseudomonas putida UW4对菊花扦插苗生长及生理特性的影响

Effects of plant growth promoting rhizobacteria Pseudomonas putida UW4 on the growth and physiological characteristics of chrysanthemum cuttings

为探讨植物促生菌恶臭假单胞菌(Pseudomonas putida) UW4对菊花扦插苗根系生长及插穗生理特性的影响,以‘金陵赤心’、‘金陵红荷’和‘金陵玫瑰金’ 3个菊花的扦插苗为研究对象,浇施促生菌为处理,测定了根系生长指标、叶绿素含量及抗氧化酶活性等生理指标。结果表明,施加促生菌后,菊花扦插苗的根系形态生长指标均显著提高,与对照相比,促生菌处理下‘金陵赤心’的根体积显著增加了193%,‘金陵红荷’和‘金陵玫瑰金’的根系表面积分别显著增大了38%和30%,‘金陵玫瑰金’的根系活力显著提高了50%。促生菌能够促进菊花插穗的光合作用及生长代谢,扦插苗叶片的总叶绿素、可溶性蛋白以及游离氨基酸的含量较对照显著提高了11%~157%。促生菌通过降低插穗的过氧化物质含量,提高抗氧化酶活性缓解扦插过程中的机械损伤,其作用在不同品种间差异显著,其中促生菌处理的‘金陵玫瑰金’中MDA和H2O2含量分别显著降低了17%和24%,各抗氧化酶活性均提高了50%以上。对不同处理的19个测定指标进行主成分分析,提取了2个主成分,发现载荷较高的因素依次为主成分1的根系生长因子以及主成分2的抗氧化因子、光合色素因子和生长代谢因子。结合聚类热图,发现促生菌对菊花不同品种的促生效果差异显著,施加促生菌后各品种的生根能力及生理水平依次为‘金陵玫瑰金’>‘金陵红荷’>‘金陵赤心’。综合促生菌对菊花扦插苗各指标的影响,发现对‘金陵玫瑰金’插穗生长的促进作用最佳,并且对各品种根系生长(总根长、根系表面积、根体积、根尖数、分支数)和抗氧化能力(SOD、POD、APX和GR)的提高尤为显著,这为菊花繁殖提供了理论基础。

In order to investigate the effect of plant growth promoting bacterium Pseudomonas putida UW4 on the root growth and physiological characteristics of chrysanthemum cuttings, the cuttings seedlings of ‘Jinling Chixing’, ‘Jinling Honghe’ and ‘Jinling Meiguijing’ were irradiated by P. putida UW4. And the root growth index, chlorophyll content, antioxidant enzyme activities and other physiological indexes were investigated. The results showed that, the root morphology and growth indexes of different chrysanthemum were significantly improved after treating the growth-promoting bacteria. Compared with the control(CK),the growth-promoting bacteria significantly improved the root volume of ‘Jinling Chixing’ by 193%, and significantly improved the root surface of ‘Jinling Honghe’ and ‘Jinling Meiguijing’ by 38% and 30% respectively, the root activity of ‘Jinling Meiguijing’ increased by 50% significantly. Growth-promoting bacteria could promote photosynthesis and growth metabolism of different chrysanthemum cuttings, the content of total chlorophyll, soluble protein and free amino acid in cuttings leaves were significantly improved by 11%–157% compared with the control. Growth-promoting bacteria reduce the content of peroxides in cuttings and increase the activities of antioxidant enzymes to alleviate mechanical damage during cutting. The mitigation effects of growth-promoting bacteria were significantly different among different varieties, the growth-promoting bacteria significantly reduced the contents of MDA and H2O2 by 17% and 24% respectively, and increased the activities of antioxidant enzymes by more than 50%. By principal component analysis, 2 principal components were extracted in 19 indexes. It was indicated that the factors with higher loading were root growth factor of principal component 1, and antioxidant factor photosynthetic pigment factor and growth metabolism factor of principal component 2. Combined with the clustering heatmap,the rooting ability and physiological level of different chrysanthemum after treating growth-promoting bacteria were ‘Jinling Meiguijing’ > ‘Jinling Honghe’ > ‘Jinling Chixing’, and the growth-promoting effects of growth-promoting bacteria on different chrysanthemum were significantly different. According to the effects of growth-promoting bacteria on various indexes of chrysanthemum cuttings, it was found that the growth promoting effect on ‘Jinling Meiguijin’ cuttings was the best, and the root growth(total root length,root surface area, root volume, root tip number, branch number) and antioxidant capacity(SOD, POD, APX and GR) of all varieties were significantly improved, which provided a theoretical basis for chrysanthemum reproduction.