树冠覆膜对金柑光合作用及果实品质的影响

树冠覆膜技术已在金柑生产中得到广泛应用。该研究以阳朔金柑为材料,树冠覆膜作为处理,不覆膜作为对照,分别测定处理和对照的树冠的温度、湿度和光照强度等环境因子的变化,观测处理和对照的叶面积、叶长、叶宽及叶绿素含量,测定处理和对照的净光合速率、气孔导度、蒸腾速率和胞间二氧化碳浓度等光合作用指标,并分析处理和对照的果实硬度、可溶性固形物、总糖、可滴定酸及维生素C含量等果实品质指标。结果表明:与对照相比,金柑树冠覆膜处理后,树冠的光照强度降低、温度上升、湿度下降、叶面积增大、叶绿素含量提高,净光合速率下降且最大降幅是对照的21.39%,果实的可滴定酸降低,但硬度、可溶性固形物、总糖、固酸比及糖酸比等果实品质指标提高。金柑树冠覆膜处理减少了树冠的光照,降低了净光合速率,但增加了叶面积和叶绿素含量,从而保障了光合同化物的累积,提高了果实的可溶性固形物和总糖。同时,树冠覆膜处理还提高了树冠白天的气温,降低了可滴定酸,增大了固酸比和糖酸比,因此从总体上提高了果实品质。

Influences of canopy film-covering on photosynthesis and fruits qualities in kumquat

The canopy film-covering technology had been widely used in kumquat cultivation management, in this experiment, taking Yangshuo kumquat as experimental materials, the temperature, humidity, and light intensity of the canopy and the leaf areas, leaf length, leaf width, the chlorophyll contents in leaf of both the trees with(treatment)or without(control)canopy film-covering were measured, and the measured parameters also contained the photosynthetic parameters including net photosynthetic rate, stomatal conductance, transpiration rate, and intercellular carbon dioxide, likewise, the fruits firmness, the contents of total soluble solids(TSS), total sugar(TS), titratable acid(TA)and vitamin C(Vc)in fruits were also measured. The results showed that, compared with the control trees, the temperature was increased, the light intensity and humidity was decreased of the canopy film-covering trees; the leaf areas and chlorophyll contents in the leaf of the canopy film-covering trees were higher compared with the control trees; the net photosynthetic rate of the trees with canopy film-covering was smaller than that in the control trees and the maximum drop up to 21.39% compared to the control; the canopy film-covering trees had a lower TA, higher fruits firmness, TSS, TS, TSS/TA and TS/TA than that in the fruits of the control trees. Although having a lower light intensity and net photosynthetic rate, the canopy film-covering trees had a greater leaf areas and chlorophyll contents in the leaf so as to satisfying the accumulation of products of photosynthesis, as a result, the TSS, TS in the fruits of canopy film-covering trees was higher than that in the control trees; result from a higher day temperature in the canopy, the fruits TA of the canopy film-covering trees was smaller than that of the control trees and lead to a higher TSS/TA and TS/TA. Generally speaking, canopy film-covering had improved the fruits qualities of kumquat