Abstract:In order to explore the effects on physiological characteristics and growth of loquat under drought stress, we conducted a pot experiment of 4 treatments which were CK, light stress (LS), moderate stress (MS) and severe stress (SS) by using 3yearold ‘Dawuxing loquat. The results showed that: (1) Plant height, stem leaf biomass and root biomass were inhibited under drought stress. (2) The chlorophyll contents increased under light and moderate drought stress, the leaf relative water content (LRWC) and chlorophyll contents decreased significantly following the lack of the relative water content of soil. (3) Net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) showed decreasing trends significantly and Gs was the most sensitive one to drought stress. However, intercellular CO2 concentration (Ci) increased and then declined with increasing drought stress. Water use efficiency (WUE) got the minimum under severe stress. (4) With water stress intensifying, superoxide dismutase (SOD) activity and peroxidase (POD) activity decreased after an initial increase. Catalase (CAT) played a pivotal role at light stress, while reduced at severe stress. Malondialdehyde (MDA) content enhanced significantly under moderate stress for 10 days. (5) Free proline (Pro) content increased when drought stress was fortified and was the highest after severe stress for 10 days. However, soluble protein (SP) content had no significant difference under the late of drought stress. The soluble sugar content peaked in the later of severe stress and had significant difference with the contrast. The results proved that loquat leaves enhanced their tolerance and adaptability by controlling the activities of antioxidant enzymes and osmotic adjustment and protective enzyme system under light or moderate stress, though the water deficit restrained its photosynthesis. The membrane system and photosynthetic system of loquat were damaged and enzyme activities affected so that the growth of loquat were badly inhibited with the increase of drought stress.