SULFUR DEPRIVATION AND NITROGEN-METABOLISM IN MAIZE SEEDLINGS
SULFUR DEPRIVATION AND NITROGEN-METABOLISM IN MAIZE SEEDLINGS
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DOI：
10.1104/pp.61.6.900
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发表时间：
1978-01-01
期刊：
影响因子：
7.4
通讯作者：
SCHRADER, LE
中科院分区：
文献类型：
--
作者：
FRIEDRICH, JW;SCHRADER, LE
研究了氮营养对氮代谢的影响。玉米（Zea mays L.）幼苗在萌发后12天出现缺硫症状。在出现这些症状之前，与正常幼苗相比，缺硫幼苗的叶片硝酸盐还原酶（NR, EC 1.6.6.1）活性下降。出苗后12 d，体外NR活性较正常苗降低50%。第12天，谷氨酰胺合成酶（EC 6.3.1.2）和nadl -谷氨酸脱氢酶（EC 1.4.1.2）活性受影响较小（分别为19%和13%）。S剥夺对叶片鲜重和nadp -谷氨酸脱氢酶（EC 1.4.1.4）活性无显著影响。第12天，叶片中可溶性蛋白和叶绿素（a和b）浓度分别降低了18%和25%。缺硫植株叶片和茎（茎、叶鞘和展开叶）部分NO3——N浓度显著高于缺硫植株（分别为46%和31%）。与测定的其他参数相比，添加SO42-可以很容易地将缺硫幼苗的NR活性恢复到正常水平。S剥夺对NR活性的明显优先效应可能与NO3—N和可溶性蛋白浓度的变化有因果关系。
The manner in which N metabolism is influenced by S nutrition was studied. Maize (Zea mays L.) seedlings supplied with Hoagland solution minus SO42- exhibited S deficiency symptoms 12 days after emergence. Prior to development of these symptoms, a decline in leaf blade nitrate reductase (NR, EC 1.6.6.1) activity was observed in S-deprived seedlings compared to normal seedlings. Twelve days after emergence, in vitro NR activity was diminished 50% compared to normal seedlings. Glutamine synthetase (EC 6.3.1.2) and NAD-glutamate dehydrogenase (EC 1.4.1.2) activities were less severely affected (19 and 13%, respectively, at day 12). NADP-glutamate dehydrogenase (EC 1.4.1.4) activity and leaf blade fresh weight were not altered by S deprivation. Concentrations of soluble protein and chlorophyll (a and b) in leaf blades were reduced 18 and 25%, respectively, at day 12. A significantly higher concentration of NO3--N was observed for leaf blade and stem (culms, leaf sheaths and unfurled leaves) fractions (46 and 31%, respectively) in S-deprived plants. In contrast to the other parameters measured, NR activity in S-deprived seedlings could be readily restored to the normal level by addition of SO42-. The apparent preferential effect of S deprivation on NR activity could be causally related to the observed changes in NO3--N and soluble protein concentration.