关键词: 柑橘, 生育期, 高温热害, 空间分布, 时间变化

Abstract:

Daily meteorological data from 1981 to 2022 and citrus growth periods data were used in this paper. The daily mean temperature, daily maximum temperature and their duration were selected as indicators of heat stress in citrus to clarify the spatial distribution characteristic and temporal variation trend of heat stress during citrus growth periods. The spatial and temporal differences of heat stress in different growing periods of citrus were compared using a paired t-test. The results show that (1) the average frequency, times and intensity of heat stress during flowering-fruit expanding stage of citrus are 87.73%, 2.23times·y⁻¹ and 5.28d·times⁻¹, respectively. High-value areas are mainly concentrated in the southeast of Jiangxi province. The average frequency, times and intensity of heat stress during the fruit expanding-fruit coloring stage of citrus are 56.43%, 1.15times·y⁻¹ and 2.74d·times⁻¹, respectively. High-value areas are mainly in the northern and central parts of Jiangxi province. (2) The station ratios, times and intensity of heat stress during the flowering-fruit expanding stage of citrus show a decreasing trend, with an average decrease of 0.90 percent points, 0.02 times and 0.06 d·time⁻¹ every 10 years, respectively. The station ratios, times and intensity of heat stress during fruit expanding-fruit coloring stage of citrus show an increasing trend, with an average increase of 6.80 percent points, 0.26times and 0.50d·times⁻¹ every 10 years, respectively. (3) The paired t-test results show that, the frequency, times and intensity of heat stress during flowering-fruit expanding stage of citrus are significantly higher than that during fruit expanding-fruit coloring stage of citrus. However, the climate tendency of times and intensity of heat stress during flowering-fruit expanding stage of citrus are significantly lower than that during fruit expanding-fruit coloring stage of citrus. The flowering-fruit expanding stage of citrus in Jiangxi province is the most frequent period of heat stress. For now, it is necessary to strengthen citrus defenses against heat stress during the flowering-fruit expanding stage. In the future, we should improve the prevention of heat stress in citrus during the fruit expanding-fruit coloring stage.

Key words:

"> Citrus, Growth period, Heat stress, Spatial distribution, Time trend