采果期甜椒氮素营养特性及分配规律

利用^15N示踪技术研究了水培甜椒果实收获期间吸收的氮素在体内的动态分配规律。结果表明：甜椒果实收获期间营养器官与生殖器官干物质积累动态呈一平行的线性增长趋势，果实干物质积累量于始采期以后开始超过叶片，而果实氮素积累到盛采期才超过叶片，果实含氮量在整个采果期间保持稳定，随生长发育，叶片含氮迅速下降，盛采期时与果实和根相近，且均高于茎和侧枝，始采期通过根吸收的标记态氮主要贮存在叶片与果实中，叶片、果实是甜椒始采用氮素分配的最主要器官。此后，叶片和根成为主要的氮素输出器官，而果实则成为主要的输入器官。研究发现，甜椒体内的氮即使一度成为结合态，能能够被再度输出，但是，氮素在植株体内滞留的时间越长，越难以再度向外输出，并且不同器官输出的难易程度也是不相同的，比较而言，叶片和根中一度成为结合态的氮素容易被再交输出，甜椒果实是氮的强力库，氮素竞争力最强。

CHARACTERISTICS AND DISTRIBUTION DYNAMICS OF NITROGEN ABSORBED FROM SWEET PEPPER (CAPSICUM ANNUUM L. )DURING FRUIT HARVEST

Sweet pepper ( Capsicum annuum L.) growing under water culture was used to study the characteristics and distribution dynamics of nitrogen absorbed from root during fruit harvest by using 15 N tracer technique. The results indicated that: the accumulation dynamics of dry matter of vegetable and reproductive organs displayed parallel linear increase, dry matter accumulation from fruit was greater than that from leaves after the early picking. The nitrogen concentration in fruit was kept steady during fruit harvest, while that in the leaves it decreased rapidly as the plant grew, and the nitrogen concentration was not much different from that in root and fruit at peak fruiting stage but higher than that in stem and branch. Labeled N absorbed from roots at early fruiting stage remained mainly in leaves and fruits, which became the most important organs for nitrogen distribution. After forward the leaves and root became the important output organs for nitrogen and fruit the input organs. It was found in this experiment that even if the nitrogen in the plant of sweet pepper became the combined nitrogen for a time it could be exported once again. But the longer the 15 N stayed in the organs of plant, the more difficult for the 15 N was exported again to the other new organs. There were differences for different organs in the nitrogen export. Compared with the other vegetable organs, the nitrogen once combined in the leaves and root, it was easy to be exported to fruit. Fig 6, Tab 2, Ref 17