苹果树形改造对树冠结构和冠层光合能力的影响

Influences of Tree Form Reconstruction on Canopy Structure and Photosynthesis of Apple

为解决乔化密植苹果园树冠郁闭、光照差、产量低、品质差的问题,于2001～2004年在北京昌平区十三陵农场(东经116°13′,北纬40°13′,海拔79m)对1986年定植的富士苹果(Malusdomestica Borkh.‘Fuji’)进行树形改造试验,将三主枝疏散分层形逐步改造为高干开心形。经过3年的改造,主干高度从0·29m提高到1·37m,主枝数从15·8个减少到4·58个,冬剪后枝数从2119·73×103·hm-2减少到814·07×103·hm-2,叶面积指数从3·98减少到2·31。改造后树冠的叶片和光照分布更加均匀,低于30%的无效光区从43%减少到24%。通过对冠层光合作用的数值模拟发现,改造树冠层的光合作用比未改树略有降低,在整个生长季(5～9月)改造树的冠层光合能力比未改造树小14·6%,但平均单叶光合速率却增加40·4%。改造后苹果产量从27·3t·hm-2增加到54·5t·hm-2,可溶性固形物从12·83%增加到15·55%。

Tree form reconstruction of ＇Fuji＇ apple （Malus domestica Borkh. ‘Fuji’ ） was carried out from 2001 to 2004 in the Ming Tombs Farm （longitude 116°13′ east, latitude 40°13′ north, altitude of 79 m） in Changping of Beijing. The three branch form was reconstructed into open-center system to resolve the problem of badly light distribution, yield and quality. By three years of experiment the height of trunk was advanced from 0. 29 m to 1.37 m. The number of bough was reduced from 15.58 to 4. 58. The number of spurs was reduced from 2 119.710^3·hm^-2 to 814. 110^3·hm^-2 and leaf area index was reduced from 3.98 to 2.31. The distribution of leaves and relative light intensity in canopy were uniform in open-center system. The useless light space was reduced from 43% to 24%. The simulation showed that photosynthesis rate of canopy in open-center system was reduced by 14. 6% compared with control in growth period, but the mean photosynthetic rate was 40. 4% higher than control. And the output was increased from 27.3 t·hm^-2 to 54. 5 t ·hm^-2 and the soluble sugar of fruit was increased from 12. 83% to 15.55%.