关键词: 外源激素, 外源激素

Abstract: In order to provide a scientific basis for promoting the advantages and avoiding disadvantages, ensuring the high and stable production of the winter wheat, the spatial distribution and the temporal variation of heat conditions and water conditions for different growth periods of the winter wheat were analyzed using the Mann-Kendall tendency verification method, the linear tendency method and the coefficient of variation method. This based on the daily meteorological data of 106 weather stations in the Huaihe basin during 1971 to 2010. Results showed that the mean air temperature and the cumulative temperature above 0℃ had obvious geographical characteristics and the heat conditions were higher in southwest, lower in east and north. The mean air temperature and the cumulative temperature above 0℃ both increased significantly during the 40 years in different growth periods, especially in the vegetative stage. The increasing heat conditions can shorten the growth periods, reduce the dry matter accumulation and affect the yield of the winter wheat. Besides, the increasing winter temperature is beneficial to the overwintering and propagation of pests, making diseases of the winter wheat worse. The precipitation of different growth stages decreased from south to north and the water demand showed less regional differences. Precipitation cannot meet the growth needs of the winter wheat in most regions of the study area except southwestern part along the Huaihe. The rainfall deficit of the northern part was greater than 200mm, and was biggest in vegetative and reproductive growth phase. The change trend of the precipitation during 40 years was not significant. The significant decreasing water demand in parts of the northern area can help alleviate the influence of lack of precipitation on the growth of the winter wheat. But the increasing water demand in most parts of area along the Huaihe and in parts of the mid-eastern area increased the risk of droughts. Meanwhile the greater inter-annual variation of precipitation increased the risk of droughts and floods, which took a part yield loss of winter wheat. To ensure the high and stable yield of the winter wheat, the agricultural department needs to nurture new varieties of high yield and strong resistance and increase investment in infrastructure construction to enhance the comprehensive capacity of agricultural disaster prevention and mitigation.