Abstract: Studying the relationship among ambient temperature, photosynthetically active radiation and physiological characteristics, nutritional quality of Chinese cabbage in greenhouse can provide reference for growth management and environmental optimization of facility cultivating Chinese cabbage. From June to September 2020, the ＂New Zaoshu No.5＂ Chinese cabbage was used as the test material for carrying out 3 experiments. Ambient temperature and photosynthetically active radiation data in greenhouse were collected automatically by automatic acquisition system, and physiological characteristics, nutritional quality of Chinese cabbage were measured once every 3 days. Light and temperature function, thermal effectiveness and photosynthetically active radiation, growing degree days of experiment days were calculated. One period experiment data was used to establish dynamic simulation models of physiological characteristics and nutritional quality. The prediction effect of the dynamic simulation models was verified and compared with the data of another 2 period experiments. The results showed that the average daily ambient temperature during the experiments was 33.06−38.31℃, and the daily photosynthetically active radiation was 3.84−19.37mol·m−2·d−1. The simulation effect of LTF models on physiological characteristics and nutritional quality of Chinese cabbage was good, which R2 was > 0.956, RMSE was < 46.752 and RE was < 11.99%. The degree of fit and simulation accuracy of LTF models were better than that of GDD and TEP models. Among them, soluble sugar, soluble protein and vitamin C showed the change of single peak curve, which LTF model could be expressed as extreme function. Nitrate showed the change of N-shaped curve, which LTF model could be expressed as Poly5 function. Cellulose, root activity, chlorophyll (a, b, a+b) and carotenoids showed the change of S-type curve, among them, Cellulose LTF model could be expressed as Gompertz function, and the other indexes LTF model could be expressed as Logistic function. LTF method can accurately predict physiological characteristics and nutritional quality of Chinese cabbage in greenhouse based on ambient temperature and photosynthetically active radiation. LTF method can provide a reference for the establishment of a more general growth model of Chinese cabbage in greenhouse.

Key words: Greenhouse, Chinese cabbage, Physiological characteristics, Nutritional quality, Light and temperature function