| Ziziphus jujuba Mill.cv.Lingwu changzao is a local fresh-eating fruit cultivar of Ningxia, with rich fruit nutrition, sweet and sour taste and strong adaptability. In order to further improve the economic benefit, the local government takes great efforts to develop the protected cultivation of jujube trees and early market entrance in recent years. In protected cultivation condition, if the chilling requirement of fruit trees is not satisfied, the germination and growth will be affected. Zizyphus jujuba Mill. cv. Lingwuchangzao and Zizyphus jujuba Mill. cv. Dongzao, which are the main varieties of protected cultivation in Ningxia, were selected as experiment materials in this research. The aim of this research was to characterize the phenological behavior of two jujube cultivars and to quantify their chilling and heat requirements by evaluating and comparing the branch soaking sprouting and air temperature recorder based on three different chilling requirement models based on three different chilling requirement models(≤7.2℃model,0-7.2℃ model and Utah model)and two heat requirement models (growing degree hour model and effctive temperature model).Some other phenological indices of jujube twigs during their dormancy period and the temperature management research of facilities were also taken into consideration for the purpose of providing reference for cultivation production.Main results are follows1、A significant difference occurs in chilling requirement and heat requirement of the same variety under different estimation models however, the difference of chilling requirement of the same variety between ≤7.2℃ model and 0-7.2℃ model is very slight.Taking 0-7.2℃ model for estimation, the chilling requirement of Zizyphus jujuba Mill. cv. Lingwu Changzao in open field culture was 442h-443h, in protected cultivation it was 410h-421h, and that for Zizyphus jujuba Mill. cv. Dongzao was 413h-424h. Regarding to≤7.2℃ model the chilling requirement of Zizyphus jujuba Mill. cv. Lingwu Changzao in open field culture was 454h-478h, in protected cultivation it was 429h-446h and 449h-470h for Zizyphus jujuba Mill. cv. Lingwuchangzao and Zizyphus jujuba Mill. cv. Dongzao respectively. According to Utah model the chilling requirement were 355CU-454CU,288CU-297CU, and 305CU-326CU.2、In terms of growing degree hour model and effective temperature model, the heat requirement of Zizyphus jujuba Mill. cv. Lingwu Changzao in protected cultivation were 8827 GDH℃-8857GDH℃, 216 D℃-227D℃, and 9593 GDH℃-10373 GDH℃,236 D℃-400 D℃ for Zizyphus jujuba Mill. cv. Dongzao. In open field cultivation the heat requirements of Zizyphus jujuba Mill. cv. Lingwu Changzao were 9534 GDH℃-16661 GDH℃,420 D’C-449 D℃.3、Suitable bud sprouting germination temperature distribution of Zizyphus jujuba Mill. cv. Lingwuchangzao and Zizyphus jujuba Mill. cv. Dongzao ranges from 20 ℃ to 25 ℃. During the late period of dormancy to germination, the content of starch and protein in the twigs increased, yet that of soluble sugar decreased. At dormancy stage the content of endogenous hormones GA rose, while ABA declined. At post-dormancy stage GA slowly went up, and ABA went down. Along with the reduction of outside air temperature, electrical conductivities of experiment twigs of the two cultivars in dormancy show ascending trends.4、The protected cultivation period of Zizyphus jujuba Mill. cv. Lingwuchangzao in Ningxia region is from early October to mid-October, the heat preservation quilt covering the greenhouse is taken to lower the temperature when the outside temperature drops to 5-10℃,35 days later, from mid-to-end of November to early December the curtain is lifted for warming up. Take precool management according to the outside air temperature, lift the curtain during the day and drop it in the night to cover the greenhouse. |
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