Abstract: High temperature during tuber formation is an important factor affecting the yield and quality of potatoes in mountainous areas of southern Ningxia. A 2year field experiment was conducted to investigate the effects of normal temperature (CK), low temperature and high temperature on the photosynthesis and antioxidant enzyme activities of potato cultivar ‘Qingshu 9’ during the initial, middle, and late stages of tuber formation, stage of tuber expansion, and main stage of starch accumulation. The results showed that net photosynthetic rate (P_n), fluorescent composite index (P_I), maximal efficiency of light energy conversion (F_v/F_m), and potential photochemical activity (F_v/F_o) in potato decreased significantly under high temperature compared with normal temperature and low temperature. In the late stage of tuber formation, P_n at high temperature decreased by 34.55% and 53.15% compared to normal and low temperature respectively, while P_I at high temperature decreased by 42.22% compared to low temperature. At high temperature, root activity, and the activities of protective enzymes such as superoxide dismutase SOD and POD significantly decreased, whereas malondialdehyde (MDA), proline (Pro) and catalase (CAT) increased in varying degrees. The yield of potato was negatively correlated with CAT activity, MDA and Pro concentrations in the antioxidant system, while it was positively correlated with other measured variables, especially the root activity. High temperature in the middle stage of tuber formation was not conducive to the photosynthesis in functional leaves of potatoes, which reduced P_n,P_I and other photosynthetic indices. Meanwhile, the antioxidant system of functional leaves was damaged in a certain extent, resulting in a yield decline.

Key words: shrimp aquaculture, intestinal microbes, disease prevention, indicator species, Illumina sequencing.