Abstract: 【Objective】 At present, facility cultivation has become the main cultivation method of jujube, facility cultivation is a kind artificially created form of cultivation, through the construction of greenhouses, greenhouses and other protective measures, to provide favorable environmental conditions for the growth and development of Dongzao jujube, to reduce the impact of the natural environment on the growth of the plant to increase the production of Dongzao jujube, and at the same time, facility cultivation can also be adjusted to the photosynthesis of the jujube. Although facility cultivation has great advantages, in the actual application, jujube farmers to control the internal technology of the facility is still not comprehensive enough, the growth characteristics of Dongzao jujube and other related understanding are insufficient, resulting in the current facility cultivation being prone to improper regulation phenomenon, which will directly affect the development and yield. However, the optimal photosynthetic model of jujube and the dynamic change law of different climatic periods under different facility cultivation modes are still unclear. This research carried out model fitting and light response curve determination for Dongzao jujube in different periods under three facility cultivation modes. 【Methods】 The photosynthesisof Dongzao jujube was quantitatively assessed through a randomized sampling of plants grown in the greenhouse, rain shelter, and open field. During the various growth stages of Dongzao jujube, including the bud stage, full flowering stage, young fruit stage, expanding stage, brittle ripening stage, and post-harvest stage, measurements were conducted on more than three sunny days for plants exhibiting consistent growth patterns in each cultivation mode. For accurate data collection, plants with identical growth states and branch lengths were selected, and measurements were taken by suspending 3-6 leaves from four different directions of the tree. The pertinent photoresponse parameters were determined, encompassing net photosynthetic rate, intercellular carbon dioxide concentration, stomatal conductance transpiration rate, and water use efficiency. Subsequently, the average values of these parameters were computed for a comprehensive analysis. The measurement time was from 9 a.m. to 11 a.m. Each time, the leaves were photoinduced for 20 minutes with 2200μmol m-2 s-1 light intensity. When measuring, wipe the dust on swipe the dust on the surface of the leaf with a paper towel; The exponential model, non-rectangular hyperbola model, rectangular hyperbola model, and its modified form were all applied to fitting, with the certainty coefficient, mean square error, and mean absolute error serving as criteria for evaluating the accuracy of the fittings. Finally, the photosynthetic physiological characteristics of Dongzao jujube under different phenological periods were compared. Simultaneously, during the peak flowering season (mid-July), the photosynthetic properties of Dongzao jujube were assayed on a sunny day, encompassing both their diurnal variation in photosynthesis and their light response curve. The correlation indexes of photosynthesis between ringed and non-girdling were compared to analyze the effect of ringed on the photosynthetic efficiency of Dongzao jujube. 【Result】 The results showed that: by comparing and analyzing the fitting effects of four models, namely the right-angled hyperbola modified model, right-angled hyperbola model, non-right-angled hyperbola model, and exponential model, R2, MSE, and MAE were introduced to analyze the fitting accuracy of the fitting results. The research analysis showed that, from the fitting results, there is a certain deviation between the fitting points of the four models and the measured values, and the fitting results of the four models are as follows: non-rectangular hyperbola model ＞ rectangular hyperbola model ≈ measured value ≈ rectangular hyperbola modified model ＞ exponential model. By combining the results of R2, , LSP and LCP, as well as MSE and MAE. The light response curve of Dongzao jujube was best fitted by the right-angle hyperbolic modified model, which was closest to the measured value and could fit the light response curve of Dongzao jujube under different cultivation modes. The LCP, LSP, AQY, and of Dongzao jujube at different phenological stages were the lowest at the full flowering stage (after stripping), and then gradually recovered to the highest at the brittle maturity stage. In addition, the , LSP, LCP, and AQY values of the annulled plants were lower than those of the non-girdling plants at the full flowering stage, and the average daily net photosynthetic rate of the non-girdling plants was significantly higher than that of the non-girdling plants. Under high light-intensity conditions, the photoinhibition of the annulled plants was more obvious. Girding can not only change the growth potential of Dongzao jujube but also inhibit the photosynthetic efficiency of Dongzao jujube leaves. This effect is not restored until the brittle ripening stage. 【Conclusion】 This study fitted the optimal light response model of Dongzao jujube, through which the photosynthetic physiological characteristics of Dongzao jujube could be accurately evaluated, the influence of different facility cultivation models on the photosynthesis of Dongzao jujube was clarified, and the law of light demand in the whole growth process of Dongzao jujube was revealed, which provided theoretical guidance for the reasonable regulation of photosynthetic environment in facility cultivation and the promotion of growth and fruit setting of jujube trees.
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