Variation for N Uptake System in Maize: Genotypic Response to N Supply.
Variation for N Uptake System in Maize: Genotypic Response to N Supply.
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DOI：
10.3389/fpls.2015.00936
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发表时间：
2015
影响因子：
5.6
通讯作者：
Kaiser BN
中科院分区：
文献类型：
--
作者：
Garnett T;Plett D;Conn V;Conn S;Rabie H;Rafalski JA;Dhugga K;Tester MA;Kaiser BN
了解植物氮素吸收系统对氮素供应减少的适应性对提高作物氮素吸收效率（NUpE）具有重要意义。27个不同基因型的玉米（Zea mays，L.）在有限或足够的N供应下在水培中生长3周。根据生物量特征和硝酸盐和铵高亲和性运输系统的活性，评估了对氮的基因型反应。基因型在维持生物量和减少氮的能力方面差异很大。虽然，N响应在底层的生物量和N运输相关的特征是小于生物量，有明确的关系，最重要的是，线，保持生物量减少N保持净N吸收没有变化的根相对于地上部的大小。根系对氮素的吸收能力随施氮量的减少而增加.转录水平的推定和转运基因在根组织的一个子集的基因型显示，占主导地位的ZmNRT2转录水平响应N处理。ZmNRT 2.2的转录本的比例之间的两个N水平和基因型的能力，以保持生物量与减少N之间的相关性表明这些转运蛋白在增强NUPE的作用。所观察到的在低N下捕获N的能力的变化为改善玉米的NUPE以及更好地理解谷物中的N吸收系统提供了范围。
An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate () and ammonium () high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both and increased with reduced N. Transcript levels of putative and transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype's ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals.