【目的】核桃(Juglans spp.)的冠层结构与核桃生长、产量和品质密不可分,研究不同树龄的核桃树冠层特性差异可为核桃树栽培管理及树体培养提供理论依据。【方法】采用数字植物冠层分析仪采集‘漾濞泡核桃’(J. sigillata cv. Yangpao)10、20、30、40 a树龄样树的冠层图像,使用冠层图像分析软件进行图片分析,得到不同树龄核桃树的总透光比、叶面积指数、冠层光立地系数和冠层截获的辐射能等相关参数,并对核桃树产量、质量和主要内含物进行测定,对冠层参数、产量和质量的相关数据进行比较和相关性分析。【结果】各树龄核桃树的叶面积指数变化趋势基本相同,冠层总透光比、光立地系数的变化与叶面积指数变化趋势相反;冠层截获的辐射能均呈先增加后减少的趋势。核桃树的单株产量随树龄增大而增加,核桃单株产量、青果质量和干果质量与叶面积指数、冠层截获的辐射能显著正相关。【结论】分析和了解核桃树冠层参数的动态变化规律,为核桃树整形修剪和树体培养提供参考。

【Objective】The canopy structure of walnuts (Juglans spp.) is closely related to their growth, yield and quality. By using a digital canopy analyzer to collect canopy parameters and investigate the differences in canopy characteristics among walnut trees of different ages and their correlations with yield and quality, this study aims to provide a theoretical basis for the cultivation management and tree training of walnut trees.【Method】Using a digital plant canopy analyzer (HemiView), canopy images of J. sigillata cv. Yangpao trees at 10, 20, 30 and 40 years of age were collected in the early morning when there was no direct sunlight. The canopy images were analyzed using canopy image analysis software to obtain parameters such as total light transmittance,leaf area index (LAI), canopy light site coefficient, and intercepted radiation by the canopy for trees of different ages. After fruit maturation, individual trees were harvested to measure the fresh fruit weight, dry fruit weight, and major internal components of the fruits. Correlation analysis was performed on the canopy parameters, yield, and quality data.【Result】The leaf area index (LAI) of walnut trees showed similar trends across different ages,with a slight increase from May to July, a slight decrease from July to August, and a rapid decrease from August to October. This result is consistent with the phenological patterns of walnuts in the region, where leaf expansion is mostly completed by May, with only a few new shoots still growing, and new shoot growth ceases in July. The total canopy light transmittance and light site coefficient exhibited opposite trends to the LAI. The intercepted radiation by the canopy increased initially and then decreased. The yield per walnut tree increased with age, with fresh fruit yields per tree at 10, 20, 30 and 40 years of age being 3.39, 10.34, 33.00 and 54.73 kg, respectively. The fresh fruit weight, dry fruit weight, and nut dimensions (longitudinal, transverse, and thickness diameters) increased with age, while the thickness of the fruit husk decreased with age. The moisture content of nuts was around 34% and the shell thickness was around 1 mm for all ages, with no significant differences. The kernel extraction rate increased with age, ranging from 48.59% to 51.61%. The oil content of nuts was around 64%, and the protein content increased with age, ranging from 15.14% to 17.13%. The yield per tree, fresh fruit weight, and dry fruit weight were significantly positively correlated with the LAI and intercepted radiation. The thickness of the fruit husk was significantly negatively correlated with the LAI. The thickness of the nut shell was significantly positively correlated with the intercepted diffuse radiation. The kernel extraction rate was significantly positively correlated with the total intercepted radiation and direct radiation. The protein content of nuts was significantly positively correlated with the LAI.【Conclusion】Analyzing and understanding the dynamic changes in canopy parameters of walnut trees can provide reference for specific guidance on different age groups of pruning and tree body cultivation.