Characteristics of absorption, distribution and utilization of ‘zaodaguo’ sweet- cherry to . 5n in different fertilizer application stages | “早大果”甜樱桃对不同时期施. 5N-尿素的吸收、分配与利用特性研究

Chinese. 大田条件下利用. 5N-示踪技术，研究‘早大果’甜樱桃对不同时期施. 5N-尿素的吸收、分配及利用特性。结果表明：果实采收期测定，秋季和萌芽前施肥处理细根的Ndff％较高，分别为4．86％和2．37％；盛花期施肥处理果实的Nd缸％最高，为1．18％；各时期中果实和新梢及叶片中Ndff％均较高。细根的Ndff％随施肥时期的推迟而显著减少。营养器官中. 5N-分配率以萌芽前施肥最高，其次是秋季施肥，而盛花期施肥最低；贮藏器官中. 5N-分配率以盛花期施肥最高，其次是秋季施肥，萌芽前施肥最低；果实中以萌芽前和盛花期施肥较高，而秋季施肥较低。果实采收期测定，秋季施肥、萌芽前施肥和盛花期施肥处理的. 5N-利用率分别为24．61％、14．74％和9．24％。因此，秋季施肥有利于缓和器官间营养竞争矛盾；萌芽前和盛花期施肥有利于果实发育，考虑到果实品质，此期施肥要慎重。

English. The technique of isotope . 5N -urea is used to study the characteristics of . 5N absorption, allocation and utilization of Zaodaguo’ sweet - cherry in different fertilizer application stages under the field condition. At fruit harvest stage, Ndff% in fine roots were the highest when fertilized in autumn and before sprout, reaching to 4.86% and 2.37% respectively. While it was the highest in fruit when fertilized at full -blooming stage （1. 18% ）. Ndff% of fruit and leaves was higher at the three fertilizer application stages. With the fertilization time delayed, Ndff% in fine roots decreased significantly. Allocation rate of 15N in nutritional organs was the highest when fertilized before sprout, followed by autumn and the lowest at full - blooming stage ; But in storage organs, it was the highest when fertilized at full -blooming stage, followed by fertilized in autumn,lowest before sprout; The allocation rate of fruit was higher when fertilized before sprout and at full - blooming stage, while it was lower when fertilized in autumn. At fruit harvest stage, the utilization rate of 15N was 24.61%, 14.74% and 9. 24% when fertilized in autumn, before sprout and at full -blooming stage respectively. Fertilized in autumn can help to ease the nutrient competition between organs; fertilized before sprout and at full - blooming stage were benefit for fruit growth, but it should be discretion when fruit quality was taking into account.