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通过对成龄苹果密植园和间伐园树冠不同层次和部位叶片光合潜力及辐射通量密度、叶片N含量和比叶重等指标的比较分析,研究了苹果园改造前后辐射能和氮素利用效率差异及其与产量品质的关系.结果表明:间伐显著改善了冠层内的辐射环境,间伐园冠层内的辐射分布明显比密植园均匀,相对辐射通量密度小于30%的无效光区接近0,而密植园冠层内的最低相对辐射通量密度为17%,在相对高度0.3以下均为无效光区;间伐园内冠层叶片的光合效率显著提高,间伐园树冠中、下部叶片的光合速率比密植园分别提高了7.8%和10.2%;叶片的最大羧化速率和最大电子传递速率也有较大幅度的提升.苹果园冠层叶片的光合效率与叶片N含量存在显著的相关关系,而叶片N含量又与辐射通量密度存在显著的相关关系,因此,可根据冠层叶片相对N含量的垂直分布间接和定量地判断叶片的光合效率或相对辐射通量密度的空间分布.
Through comparative analysis of photosynthetic potential and radiant flux density, leaf N content and specific leaf weight at different levels and positions of canopy in mature apple orchards and intercropping canopies, the effects of radiant energy and nitrogen use efficiency The results showed that the thinning significantly improved the radiation environment in the canopy and the radiation distribution in the thinning canopy was significantly higher than that in the close planting plantation and the relative light flux density was less than 30% 0, while the lowest relative radiation flux density in the canopy canopy was 17%, and the relative lightness was below 0.3 in the canopy. The photosynthetic efficiency of the canopy leaf was significantly increased in the canted field, Photosynthetic rate increased by 7.8% and 10.2% respectively compared with that in the dense plantations.The maximum carboxylation rate and maximum electron transfer rate of the leaves also increased significantly.Photosynthetic efficiency of apple orchard canopy leaves had a significant correlation with leaf N content, However, the leaf N content has a significant correlation with the radiant flux density. Therefore, the photosynthesis of the leaves can be indirectly and quantitatively determined according to the vertical distribution of the relative N content of the canopy leaf Spatial distribution of efficiency or relative radiant flux density.