叶幕微域环境对无患子果实产量和品质的影响

Effects of canopy micro-environment on fruit yield and quality characteristics of Sapindus mukorossi

【目的】在叶幕尺度上,通过分析微域环境和果实产量、品质的关系来揭示叶幕微域环境对无患子果实的影响,并为后续无患子叶幕结构优化和营造适宜微环境提供理论依据和技术支持。【方法】以福建建宁地区进入稳定结实期的10年生自然圆头形无患子为研究对象,采用小格子法将整个叶幕分成144个小区,在整个生长期内逐月测定小区的微域环境因子,并在采收期测定各小区果实产量指标,以此来绘制整个生长期微域环境因子和产量的叶幕空间分布三维图;根据距离树干位置远近和自然分层现象将144个小区归并到9个不同的叶幕大区域中,对大区域的微域环境因子和果实产量、品质进行差异显著性分析;分层探讨微域环境因子和果实特征的相关性,并依此构建果实产量、品质与叶幕微域环境因子的回归预测模型,最终得到无患子果实优质丰产的微域环境条件。【结果】①随着叶幕区域由内膛到外围、由下层到上层,整个生长季的平均温度分别增加了0.3和1.5℃、平均光合有效辐射分别增加了330.76和463.53μmol/(m2·s)、平均相对湿度分别下降了1.1%和3.0%,果实产量显著增加,下、中和上层果实产量比例为8∶17∶75,内、中和外围果实产量比例为24∶32∶44。水平方向上微域环境和果实产量的差异明显小于垂直方向的差异,结实部位主要集中在叶幕外围和上层;②叶幕9个大区域的果实数量、鲜果产量、干果产量、果实含水率、单果干质量和油产量均存在显著性差异,但假果皮占果质量比、出籽率、种子出仁率和种仁含油率的差异均不显著;③果实产量、种子出仁率、油产量与温度、光合有效辐射均呈显著正相关而与相对湿度呈显著负相关。光合有效辐射对果实产量、品质的影响最大,与果实产量的相关系数高达0.8,温度对果实特征的影响仅次于光合有效辐射,而相对湿度对果实特征的影响相对较小;④通过构建叶幕微域环境因子和果实特征的单因素二次回归模型可以得到无患子果实优质丰产的微域环境条件为:温度28~30℃,相对湿度小于74%,光合有效辐射830~1 203μmol/(m^2·s);⑤构建的多元回归模型拟合度更高,对果实和油产量的估算更准确,可用于自然圆头形无患子果实和油产量的初步预测。【结论】叶幕微域环境因子影响果实特征的形成,其协同效应对无患子果实产量、品质的影响更大;叶幕中、下层果实产量、品质更强烈地受到微域环境的影响,通过基于叶幕结构和结实特性的园艺措施改善中、下层叶幕微域环境有利于无患子果实产量、品质的整体提高。

【Objective】Fruit yield and quality characteristics are closely related to the canopy micro-environment, but the specific relationships have been unclear.Analyzing the relationship between micro-environmental factors and fruit characteristics can reveal the effect of the canopy micro-environmental factors onSapindus mukorossifruit characteristics,and provide a theoretical basis and technical information for optimization of canopy structure and the construction of favorable micro-environments. 【Method】In this study, in Jianning County of Fujian Province, 10-year-oldS.mukorossi trees with a stable fruiting stage were chosen as test samples.The whole of the natural round-head canopy was divided into 144 small measuring areas.During the whole growing period from May to October in 2017, the canopy micro-environmental factors were measured monthly in these areas.The fruit yield and quality characteristics were determined immediately after harvest.Based on the measured values of micro-environmental factors and fruit yield in different parts of the canopy, 3 D distribution maps were drawn.According to the distance from the trunk and the vertical stratification of the canopy, the small measuring areas were grouped into nine different canopy areas, and the significant differences in micro-environmental factors and fruit characteristics were analyzed.The correlations between micro-environmental factors and fruit characteristics in different vertical layers were also analyzed, and the regression models of fruit characteristics were established.Finally, the micro-environmental conditions for the high fruit yield and quality were assessed. 【Result】① Within the canopy from inside to outside and from bottom to top, the average temperature in the growing season increased by 0.3 and 1.5 ℃, respectively;the average photosynthetically active radiation of the growing season increased/(m^2·s), respectively;the average relative humidity of growing season decreased by 1.1% and 3.0%, respectively.The ratio of fruit yield of the lower, middle and upper layers was 8 ∶17 ∶75, and that of the inner, middle and peripheral layers was 24∶32∶44.The differences in the micro-environment and fruit yield in the horizontal direction were obviously smaller than that in the vertical direction.Fruits were mainly distributed in the periphery and upper layer. ② There were significant differences in the fruit number, fresh fruit yield, dry fruit yield, the water content of the fruit, single dried fruit weight and oil yield in nine canopy areas, but there were no significant differences in the dried aril content ratio, the dried seed content ratio, the kernel content of the dried seed, and the oil content of the kernel. ③ Fruit yields, the kernel content of the dried seed, and the oil yield all had significant positive correlations with temperature and photosynthetically active radiation, but a significant negative correlation with relative humidity.Photosynthetically active radiation had the greatest impact on fruit yield and quality, followed by temperature and relative humidity. ④ From the single factor regression models, it was deduced that suitable micro-environmental conditions for high fruit yield and quality are: temperature between 28-30 ℃, relative humidity no more than 74%, and photosyntheti-/(m^2·s). ⑤Multivariate regression models were suitable for theS.mukorossifruit and oil yield prediction with a natural round-head canopy. 【Conclusion】The synergistic effect of microenvironmental factors greatly influences fruit yield and quality characteristics ofS.mukorossi.The fruit characteristics in the central and lower layers are strongly affected by the micro-environment, so the improvement of the micro-environment of the middle and lower layers through horticultural measures based on the canopy structures and fruit-bearing habits can improve fruit characteristics.