树冠覆膜对沙糖橘光合作用及果实品质的影响

为探讨树冠覆膜对沙糖橘树冠环境、光合作用和果实品质的影响,以沙糖橘为试验材料,树冠覆膜为处理、不覆膜为对照,分别记录树冠的温度、湿度和光照强度等环境因子指标,测定叶片的净光合速率、气孔导度、蒸腾速率和胞间二氧化碳浓度等光合作用指标,分析果实的可溶性固形物、总糖、可滴定酸及维生素C等品质指标。与对照相比,树冠覆膜后,总体上沙糖橘树冠白天的光照强度和湿度降低,降幅分别为36.36%~63.64%和5.25%~7.56%,月均温度和月均昼夜温差增加,最大分别增加1.21℃和3.88℃,净光合速率下降,最大降幅45.95%;果实的可溶性固形物、总糖及糖酸比等果实品质指标显著提高,分别增加7.81%、23.46%和4.87%。树冠覆膜在延长沙糖橘采收期的同时,总体上保持了较好的果实品质。

Influence of Canopy Film-covering on Photosynthesis and Fruit Quality of Citrus reticulata ‘Shiyueju’

To study the influence of the canopy film-covering on canopy environment, photosynthesis and fruit quality in Citrus reticulata ‘Shiyueju’, the temperature, humidity, and light intensity in the canopy of both the trees with (treatment) or without (control) canopy film-covering were measured, as well as the leaf photosynthetic parameters including net photosynthetic rate, stomatal conductance, transpiration rate, intercellular carbon dioxide and etc., likewise, the contents of total soluble solids(TSS), total sugar (TS), titratable acid (TA) and vitamin C (Vc) in fruits were also measured. Compared with the control, the light intensity and humidity was generally decreased in daytime under canopy film-covering and the decrease was from 36.36% to 63.64% and 5.25% to 7.56%, respectively; the monthly average temperature and diurnal temperature variation of the canopy film-covering trees were increased and the maximum increase was 1.21℃ and 3.88℃, respectively; the net photosynthetic rate of the trees with canopy film-covering was decreased and the maximum decrease was 45.95%; the canopy film-covering trees had a significant higher total soluble solids(TSS), total sugar (TS) and TS/TA and the increase was 7.81%, 23.46% and 4.87%, respectively. Canopy film-covering could maintain better fruit quality and prolong the harvest time of C. reticulata ‘Shiyueju’.