Abstract: 【Objective】The objective of this study is to investigate the effect of Sophora alopecuroides alkaloids on tomato growth and development for evaluating its biological function and providing a basis for its application.【Method】 Avermectins was chosen as the contrast agent. Tomato plants were sprayed with different concentrations (333.0, 166.5 and 111.0 mg?L^-1) of S. alopecuroides alkaloids and the changes of morphology, fruit quality and yield were measured. Tomato plant height, stem diameter, the number of leaves, the length-width rate of the maximal leaves and the chlorophyll content were measured in a pot experiment. The effect of S. alopecuroides alkaloids on tomato yield, soluble sugar content, titratable acid content, vitamin C content and nitrate content were investigated in a field plot experiment.【Result】S. alopecuroides alkaloids could regulate the plant growth and fruit quality. The pot experiment showed that the effect on stimulating growth of tomato seedlings was most obviously at concentration of 166.5 mg?L^-1. Compared with the blank control (water treatment), 7th day after each spray, the relative growth rate of tomato plant height increased by 55.07%, 103.03% and 60.60%, respectively, net increase of stem diameter of tomato plant increased by 31.54%, 225.80% and 185.45%, respectively, but the alkaloids did not significantly influence leaf morphological factors. At concentration of 333.0 and 166.5 mg?L^-1, after spraying S. alopecuroides alkaloids, the chlorophyll content in treated leaves increased by 6.16%-13.79% and 6.89%-17.12%, respectively, but in 111.0 mg?L^-1 treatment the chlorophyll content decreased by 0.60%-9.40% compared with blank control. Field plot experiment showed that tomatoes treated by 333.0, 166.5 and 111.0 mg?L^-1 of S. alopecuroides alkaloids, the single fruit weight increased by 13.07%, 20.92% and 9.15%, respectively, on the first cluster compared with the blank control, did not have a significant difference on the second cluster, and increased by 12.23%, 20.86% and 17.27%, respectively, on the third cluster. At concentration of 166.5 mg?L^-1, the tomato yield was 16.48% more than blank control, and there was no significant increase in other treatments. Fruit quality results showed that at concentrations of 333.0 and 111.0 mg?L^-1, the soluble sugar content declined obviously compared with the blank control, but it did not have a significant difference in tomatoes treated by 111.0 mg?L^-1 of alkaloids. At concentrations of 333.0, 165.6 and 111.0 mg?L^-1, the mean of titratable acid content in tomatoes increased by 37.01%, 23.88% and 27.16%, respectively, compared with the blank control. At concentrations of 333.0 and 166.5 mg?L^-1, the vitamin C content decreased by 28.06% and 21.91%, respectively, on the first cluster, decreased by 27.37% and 26.34%, respectively, on the second cluster, but increased by 7.28% and 7.69%, respectively, on the third cluster, and showed a trend of increase at first and then decrease. At concentration of 111.0 mg?L^-1, the vitamin C content declined on both the first and second clusters, but did not have a difference on the third cluster compared with the blank control. The nitrate content all increased compared with the blank control, and the nitrate content accumulated more as the concentration increased, but it was still far below the tomato nitrate allowance in China. 【Conclusion】At the field commonly used concentration (166.5 mg?L^-1), S. alopecuroides alkaloids could stimulate seedling growth and increase the yield of tomato remarkably, and it had no adverse influence on fruit quality.

Key words: Sophora alopecuroides alkaloids, tomato, fruit quality, crop yield, botanical pesticide