Nitrate Reductase Activities in Rice Genotypes in Irrigated Lowlands
Nitrate Reductase Activities in Rice Genotypes in Irrigated Lowlands
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灌溉低地水稻基因型中的硝酸还原酶活性
DOI：
10.2135/cropsci1998.0011183x003800030019x
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发表时间：
1998
期刊：
影响因子：
2.3
通讯作者：
M. Ichii
中科院分区：
文献类型：
--
作者：
E. Barlaan;H. Sato;M. Ichii
硝酸盐还原酶（NR）是参与作物硝酸盐同化的关键酶。在灌溉低地，水稻 (Oryza sativa L.) 中 NADH- 和 NADPH-NR 的比活性尚未得到研究。本研究的目的是评估低地灌溉条件下不同 NRA 水平的水稻基因型的硝酸还原酶活性 (NRA) 模式，并确定 NR 缺乏对硝酸盐利用、谷物产量、生物量和其他农艺特性的影响。七个品种和七个 NR 突变体在灌溉低地条件下生长；不同生长阶段的 NRA 体外生物测定；并评估谷物产量、生物量和其他农艺特性。移植前所有品种中 NADH-NRA 的含量都极低。移栽后15 d（DAT），各品种NADH-NRA均达到最佳水平，并逐渐下降直至成熟。在大多数 NR 突变体中观察到类似的模式，但活性水平较低。品种和突变体中的 NADPH-NRA 从 15 DAT 逐渐增加至 45 DAT，然后在 5 至 10 nmol NO -∼2 min -1 g - 1 鲜重之间波动，直至成熟。土壤中的硝酸盐有效性可能会显着影响灌溉低地水稻的 NRA 和硝酸盐积累。 NR 水平低或不足对突变体评估性状的影响各不相同。相对于原始品种，突变体的籽粒产量下降了 27% 至 73%。这项研究表明，水稻在厌氧和淹水条件下吸收硝酸盐，这可能对水稻的遗传改良和硝酸盐或氮管理策略产生影响。
Nitrate reductase (NR) is a key enzyme involved in nitrate assimilation in crops. In irrigated lowlands, specific activities of NADH- and NADPH-NR in rice (Oryza sativa L.) have not been investigated. The objectives of this study were to evaluate the nitrate reductase activity (NRA) patterns of rice genotypes with different NRA levels under irrigated lowland conditions, and to determine the effects of NR deficiency on nitrate use, grain yield, biomass, and other agronomic characteristics. Seven cultivars and seven NR mutants were grown under irrigated lowland conditions; bioassayed in vitro for NRA at different growth stages; and evaluated for grain yield, biomass, and other agronomic characters. NADH-NRA was present at minimal levels in all cultivars before transplanting. At 15 d after transplanting (DAT), NADH-NRA in all cultivars reached optimum levels and gradually declined until maturity. A similar pattern was observed in most of the NR mutants but with lower levels of activity. NADPH-NRA in cultivars and mutants gradually increased from 15 to 45 DAT and then fluctuated between 5 to 10 nmol NO -∼2 min -1 g - 1 fresh weight until maturity. Nitrate availability in the soil may significantly influence NRA and nitrate accumulation in rice in irrigated lowlands. Effects of low or deficient levels of NR on traits evaluated varied among mutants. A decrease of 27 to 73% in grain yield was observed in mutants relative to original cultivars. This study demonstrates that rice assimilates nitrate in anaerobic and flooded conditions, which may have implications for genetic improvement and nitrate or nitrogen management strategies in rice.