Variations in the Natural Abundance of 15N in Nitrogenous Fractions of Komatsuna Plants Supplied with Nitrate |
| |
Authors: | Yoneyama Tadakatsu; Kaneko Akira |
| |
Institution: | Department of Soils and Fertilizers, National Agriculture Research Center Kannondai 3-1-1, Tsukuba, Ibaraki, 305 Japan |
| |
Abstract: | Komatsuna (Brassica campestris L. var. rapa) plants were grownhydroponically under various conditions with respect to thesupply of nitrate, and the variations in levels of natural 15Nabundance (15N) in nitrogenous fractions of leaf blades, petiolesplus midribs, and roots in these plants were analyzed. The fractionation of nitrogen isotopes during uptake of nitratewas null irrespective of the concentrations of nitrate in theculture medium. The roots had lower 15N values than that inthe nitrate applied to plants. The nitrate in the three tissuesexamined had higher 15N values than that in the nitrate applied:the values were highest in the leaf blades which were presumedto have highest activities in terms of reduction of nitrate.In contrast, the amino acids and residual fractions had lower15N values than those in the nitrate applied. These resultssuggest that reduction of nitrate is a critical step in thefractionation of nitrogen isotopes in plant tissues in vivo.
1Permanent address: Fukuoka Agricultural Experiment Station,Yoshiki 587, Chikushino, 818 Japan. (Received March 10, 1989; Accepted July 10, 1989) |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|