土壤微生物膜对沙生植物幼苗光合和荧光特性的影响 postprint

Abstract: In order to reveal the effects of soil microbial film sand fixation on photosynthetic and fluorescence characteristics of psammophyte seedlings, Ammopiptanthus mongolicus and Astragalus laxmannii seedlings were selected. Pot experiment with different application methods (spray, mix) and application amount (0, 1, 3, 5, 7 and 10 g kg -1). The characteristics of plant gas exchange and chlorophyll fluorescence after soil microbial biofilm formation were analyzed. The results show that: (1) When the application amount of bacterial was greater than 3 g·kg-1, the hardness, thickness of the consolidated layer and soil urease and sucrase activities were significantly higher than those of the control group (P<0.05). (2) The net photosynthetic rate of Astragalus laxmannii in 3-7 g·kg-1 treatment was significantly higher than that of the control (P<0.05). And the transpiration rate, net photosynthetic rate and intercellular CO2 concentration were significantly higher than those of Ammopiptanthus mongolicus (P<0.05). (3) The Fv/Fm of Astragalus laxmannii treated with more than 5 g kg-1 was significantly higher than that of the control group (P < 0.05). Except for 3 g kg-1 treatment, the Fv/Fm and QP of Ammopiptanthus mongolicus were higher than those of Astragalus laxmannii. (4) Soil properties, photosynthetic gas exchange and chlorophyll fluorescence were partially mediated models. The change of soil characteristics can directly affect the chlorophyll fluorescence characteristics of Ammopiptanthus mongolicus and Astragalus laxmannii. The soil microbial film increased the hardness, thickness of the consolidated layer by 3.84% and 152.85% on average, and the activities of catalase, urease and sucrase were increased by 93.37%, 170.68% and 256.03% on average. By improving soil quality and stomatal conductance of leaves, the photosynthetic efficiency and capacity of the two plants were enhanced. The net photosynthetic rate and Fv/Fm were increased by 28.48% and 0.84% respectively.