Characterisation of magnesium nutrition and interaction of magnesium and potassium in rice
Characterisation of magnesium nutrition and interaction of magnesium and potassium in rice
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DOI：
10.1111/j.1744-7348.2006.00080.x
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发表时间：
2006-01-01
影响因子：
2.6
通讯作者：
Xu, G.
中科院分区：
文献类型：
--
作者：
Ding, Y.;Luo, W.;Xu, G.
镁（Mg）是高等植物必需的营养元素之一，然而，大田作物对Mg缺乏或过量的初步生理反应，特别是Mg与钾（K）的相互作用，在很大程度上仍不清楚。在这项研究中，我们观察到水稻（Oryza sativa）缺镁[地上部低于1.1 mg g（-1）干重（DW）]导致地上部生物量显著减少，总叶绿素浓度和净光合速率降低，叶片中硝酸还原酶[NR;酶分类（EC）1.6.6.1]和谷氨酰胺合成酶（EC 6.3.1.2）活性降低。然而，镁缺乏植物含有较高的淀粉在叶片中，并分配到根的生物量较大。过量的Mg（地上部超过3.0 mg g（-1）DW）和低的K供应抑制了NR活性，降低了叶片中可溶性糖的浓度。K、Mg之间存在强烈的拮抗和中度的协同效应，但K对K、Mg的吸收、转运、NR活性和净光合速率的影响远大于Mg。分蘖期叶片中钾镁的最佳配比为22 ~ 25。镁缺乏没有补偿适度供应钾，但加剧了过量供应钾，镁在水稻干物质生产和碳同化物分配的具体作用。
Magnesium (Mg) is known as one of the essential nutrients for higher plants; yet, the preliminary physiological responses of field crops to its deficiency or excess, particularly to its interaction with potassium (K), remain largely unknown. In this study, we observed that Mg deficiency in rice (Oryza sativa) [less than 1.1 mg g(-1) dry weight (DW) in the shoot] resulted in significant reduction in shoot biomass, decrease in total chlorophyll concentration and net photosynthetic rate and reduction in activities of both nitrate reductase [NR; enzyme classification (EC) 1.6.6.1] and glutamine synthetase (EC 6.3.1.2) in the leaves. However, the Mg-deficient plant contained higher starch in the leaves, and partitioned larger biomass into roots. Excess of Mg (more than 3.0 mg g(-1) DW in the shoot), together with low K supply, suppressed NR activity and decreased concentration of soluble sugar in the leaves. There were great antagonistic and moderately synergistic effects between K and Mg, but the effects of K were much more significant than those of Mg on their uptake and translocation, NR activity and net photosynthetic rate in the leaves. The optimum weight ratio of K to Mg ranged between 22 and 25 in the leaves at tillering stage. Mg deficiency was not compensated for by moderate supply of K but was aggravated by excess supply of K, suggesting specific roles of Mg in both dry matter production and partition of carbon assimilates in rice.