遮荫对燕红桃光合作用及果实品质的影响

Effects of Shading on Photosynthesis and Fruit Quality of Peach

以桃品种燕红为材料,研究了不同遮荫强度(遮荫20%、40%、60%、80%及全光照)对桃叶片光合作用及果实品质的影响。结果表明:遮荫消除了燕红桃夏季全光照下的光合"午休"现象,净光合速率日变化由双峰型变为单峰型。但是,随着遮荫程度的增加,全天的净光合速率逐渐降低。与全光照相比,遮荫20%处理对果实品质未造成影响;遮荫40%、60%、80%处理则不同程度影响了果实品质,主要表现为:果实外观品质指标如单果质量、纵横径和着色度降低,内在品质指标如硬度、可溶性固形物、可溶性糖、维生素C和花青苷含量明显减少,而可滴定酸和可溶性淀粉的含量增加。20%的轻度遮荫既不影响果实品质,又保证了桃树夏季午间光合作用的正常进行;而60%及以上的重度遮荫则造成光合能力显著下降,从而严重影响了果实品质。

Yanhong （Prunus persica cv.Yanhong ） was used to study the effects of different shading levels（20%,40%,60%,80%and full sunlight as control）on photosynthesis and fruit quality.The results showed that the diurnal variation of net photosynthetic rate appeared to be a single peak curve in Yanhong peach under shading in summer,which suggested that photosynthetic‘noon break’phenomenon vanished.With the increase of shading level,the net photosynthetic rate gradually decreased.In terms of the fruit quality,there was no difference between the full sunlight and the 20% shading treatment.However,40%,60%,80% shading treatments had a negative impact on fruit quality.For example,the exterior quality such as fruit mass,the vertical and transverse diameter and color significantly decreased.Meanwhile,firmness, the contents of soluble solid,soluble sugar,ascorbic acid,and anthocyanin significantly reduced, but the contents of titratable acid and soluble starch significantly increased.The 20% shading treatment did not affect fruit quality,and had a normal net photosynthesis rate in the summer noon.The photosynthetic capability of 60% and 80% shading treatments declined significantly, which had a negative impact on fruit quality.