Sun Wen Tai, Niu Jun Qiang, Dong Tie, Liu Xing Lu, Yin Xiao Ning, Ma Ming
Institute of Forestry, Fruits and Floriculture, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China.
Ying Yong Sheng Tai Xue Bao. 2018 Sep;29(9):3008-3016. doi: 10.13287/j.1001-9332.201809.026.
In order to examine the effects of thinning and reshaping on canopy structure, leaf physio-logical property at late growth stage, characteristic of nutrient accumulation and distribution in leaf, and the spatial and temporal distribution of soil moisture, 18 year-old 'Fuji' apple trees in dense apple orchards were used to measure the canopy size, types and numbers of branches, leaf area index before and after the thinning and reshaping practices. The results showed that before pruning, the photosynthesis was limited by non-stomatal factors, with a reduction in F/F, F/F PIabs by 1.2%, 11.5%, 13.9%, respectively. However, the thinning and reshaping practices reduced leaf area index and canopy coverage, increased light interception up to 79% and improved tree construction. The total number of shoots decreased to 1100400 per hectare, while the individual shoot numbers were increased by 5.0% and the ratio of spur increased up to 73%. Due to the improvement of canopy lighting distribution, the average leaf area, specific leaf quality, hundred leaf mass and chlorophyll content were increased. With the increases of photosynthesis, the accumulation of photosynthate such as starch was increased by 143.5%. There was a close correlation between leaf development and light interception. Our results indicated that tree structure and canopy light interception could be improved by thinning and reshaping the dense trees, which resulted in higher leaf growth, development and photosynthetic capability but less water loss. Thinning and reshaping should be recommended to the renewal of the dense apple orchards in Loess Plateau of eastern Gansu.
为了研究疏枝整形对树冠结构、生长后期叶片生理特性、叶片养分积累与分配特征以及土壤水分时空分布的影响，以18年生密植苹果园‘富士’苹果树为试材，测定疏枝整形前后树冠大小、枝类及枝量、叶面积指数等指标。结果表明，修剪前光合作用受非气孔因素限制，F/F、F/F PIabs分别降低了1.2%、11.5%、13.9%。而疏枝整形处理降低了叶面积指数和树冠覆盖率，提高了光能截获率达79%，改善了树体结构。每公顷新梢总数降至1100400条，单枝数量增加了5.0%，短枝比例提高到73%。由于树冠光照分布的改善，叶片平均面积、比叶质量、百叶质量和叶绿素含量均有所增加。随着光合作用增强，淀粉等光合产物积累量增加了143.5%。叶片发育与光能截获密切相关。结果表明，对密植树进行疏枝整形可改善树体结构和树冠光照截获，使叶片生长、发育和光合能力增强，水分消耗减少。建议在陇东黄土高原密植苹果园更新中采用疏枝整形技术。
