Effects of drought stress on agronomic traits and bulb quality of in Lilium davidii var. unicolor

In order to study the effects of drought stress on the agronomic traits of plants and the quality of the bulb, this paper takes the Lilium davidii var. unicolor as the research object and compares and analyses the growth status of Lilium davidii var.unicolor under different drought stress conditions, including no stress group, mild stress group, moderate stress group and severe stress group, the relative soil moisture content of each group was 70.00% to 75.00%, 50.00% to 55.00%, 40.00% to 45.00% and 30.00% to 35.00%, respectively, and the agronomic traits and active substance contents of Lilium davidii var. unicolor were measured at 10, 20 and 30 d of stress and at the harvesting stage. The effects of drought stress on the agronomic traits and bulb quality of Lilium davidii var. unicolor were investigated. The results showed that compared with the no stress group, the height, stem thickness and number of leaves of Lilium davidii var. unicolor decreased by 19.93%, 14.17% and 9.38% (t=-6.77, -1.01 and -15.00, P < 0.05) at flowering stage in the severe stress group, while the number of basal roots and stem roots of Lilium davidii var.unicolor increased by 15.34% and 15.52% (t=1.46 and 6.00, P < 0.05) at flowering stage in the mederate stress group. The chlorophyll content of Lilium davidii var. unicolor at the seedling stage, bud stage and flower stage decreased by 29.87%, 7.36% and 9.36%(t=-7.37, -2.00 and -2.66, P < 0.05) in the severe stress group. The total flavonoids, saponins, soluble sugars and soluble proteins in the bulb of Lilium davidii var. unicolor at flowering stage increased by 22.22%, 26.43%, 16.96% and 13.43%, respectively (t=0.09, 51.39, 0.01 and 0.21, P < 0.05) and the polysaccharide content in the bulbs of Lilium davidii var.unicolor at harvesting stage at bud stage increased by 10.12% in the mild stress group (t=60.68, P < 0.05). Therefore, mild-drought stress during flowering is most beneficial to the growth and development of Lilium davidii var. unicolor and enhances the quality of Lilium davidii var. unicolor.