Study on the dynamics of kiwifruit tree biomass and calcium accumulation in the growth cycle | 猕猴桃树体年生长周期内生物量及不同器官钙累积动态研究

Chinese. 研究猕猴桃树对钙素的吸收及分配规律，为猕猴桃的合理适时施肥提供参考依据。以10年生“秦美”猕猴桃树为试材，采用彻底刨根、分解取样的方法，研究了年生长周期内猕猴桃树各器官的生物量、钙含量和钙累积量的变化动态。在猕猴桃树的年生长周期内，根、茎、叶、果实的生物量（干质量）分别增加了2.21，7.06，2.73和8.21 t/hm2，共计为20.21 t/hm2。猕猴桃整株生物量在生育前期的3月底到5月中旬增加较慢，5月中旬以后生物量快速增加，9月上旬以后由于果实的收获和落叶使整株生物量大幅下降。各器官钙含量水平表现为叶＞根＞茎＞果实。果实钙含量在生育前期较高，随生长发育逐渐降低。木质部钙含量全年没有明显变化，而皮层钙含量波动较大。茎皮层的钙含量为13.21～27.54 g/kg，木质部为1.12～2.14 g/kg；根皮层的钙含量为19.03～25.00 g/kg，根木质部的钙含量大于茎木质部，为6.35～7.55 g/kg。每生产50 kg果实，根、茎、叶、果实当年钙吸收量分别为68.04，116.36，154.19和40.26 kg/hm2，共计达378.85 kg/hm2；整株钙累积量表现为3月底到11月上旬直线增加，从3月底的106.97 kg/hm2增加到最高值255.21 kg/hm2，到休眠期降低到195.89 kg/hm2。猕猴桃树各器官钙含量水平以叶最高，果实最低，叶中的钙素难以运输到果实；由于果实钙含量随生长发育而降低，因此要提高猕猴桃果实的钙含量，应在生长后期对果实直接施钙。

English. The research is to study the dynamics of calcium nutrient in kiwifruit tree, in order to provide a theoretical foundation for high quality kiwifruit tree and timely and proper fertilization of kiwifruit. A field experiment was carried out on 10-year-old Actinidia deliciosa, Qinmei kiwifruit trees in growing seasons in Shaanxi Province, China. Biomass, calcium content and accumulation in different organs were studied in this paper. The results showed that biomass increment of roots, stems, leaves and fruits was 2.21, 7.06, 2.73 and 8.21 t/hm2, total plant increased 20.21 t/hm2 in one year. Biomass of plant vegetated slowly from March 28 to May 18, and developed more quickly from May 18 to September 8, and dropped rapidly after fruit harvest and defoliation. Calcium content order in organs was leavesrootsstemsfruits. Calcium content of fruit was high in spring and dropped slowly after July. Calcium content in xylem changed less, but fluctuated in cortex. Calcium content in cortex of stems was 13.21-27.54 g/kg, in xylem of stems 1.12-2.14 g/kg, in cortex of roots between 19.03 g/kg and 25.00 g/kg, and in xylem of roots 6.35-7.55 g/kg. The study showed that trees could produce 50 kg fruits by absorbing calcium 378.85 kg/hm2. The calcium accumulation rose perpendicularly from March 28 to November 6, from 106.97 kg/hm2 to 255.21 kg/hm2, then dropped to 195.89 kg/hm2 in January 11 (tree dormancy). Calcium content in leaves is the highest and in fruits the lowest, as calcium is difficult to transport from leaves to fruits. Fruits calcium content is higher in the earlier stage of growth and declines in the later stage of growth, so to increase the calcium content of ripe fruit, calcium should be fertilized directly on fruits in the later growth stage.