Reduced crown root number improves water acquisition under water deficit stress in maize (Zea mays L.).
Reduced crown root number improves water acquisition under water deficit stress in maize (Zea mays L.).
复制标题
减少冠根数量可改善玉米 (Zea mays L.) 在缺水胁迫下的水分获取
DOI：
10.1093/jxb/erw243
复制
发表时间：
2016-08
影响因子：
6.9
通讯作者：
Lynch JP
中科院分区：
文献类型：
--
作者：
Gao Y;Lynch JP
冠根数减少的玉米基因型在干旱条件下具有较好的水分捕获、生长和产量。在本研究中，我们验证了冠根数（CN）减少的玉米基因型具有更大的根深和更好的从干燥土壤中获取水分的假设。在温室中生态系统和大田雨棚条件下，对具有不同CN的玉米重组自交系进行了水分胁迫评价。基因型的CN在25 ~ 62之间变化。在水分胁迫下，种植后35 d，低CN基因型比高CN基因型的冠根减少31%，生根深度增加30%，气孔导度增加56%，叶片CO2同化增加45%，净冠层CO2同化增加61%，地上部生物量增加55%。在田间水分胁迫下，CN低的基因型比CN高的基因型冠根减少21%，根深41%，茎水氧同位素富集（δ18O）特征轻48%，表明水捕获更深，叶片相对含水量高13%，开花时茎部生物量高33%，产量高57%。这些结果支持了低CN通过增加根系深度和从底土获得水分来提高抗旱性的假设。
Maize genotypes with reduced crown root number have superior water capture, growth, and yield under drought. In this study we test the hypothesis that maize genotypes with reduced crown root number (CN) will have greater root depth and improved water acquisition from drying soil. Maize recombinant inbred lines with contrasting CN were evaluated under water stress in greenhouse mesocosms and field rainout shelters. CN varied from 25 to 62 among genotypes. Under water stress in the mesocosms, genotypes with low CN had 31% fewer crown roots, 30% deeper rooting, 56% greater stomatal conductance, 45% greater leaf CO2 assimilation, 61% net canopy CO2 assimilation, and 55% greater shoot biomass than genotypes with high CN at 35 days after planting. Under water stress in the field, genotypes with low CN had 21% fewer crown roots, 41% deeper rooting, 48% lighter stem water oxygen isotope enrichment (δ18O) signature signifying deeper water capture, 13% greater leaf relative water content, 33% greater shoot biomass at anthesis, and 57% greater yield than genotypes with high CN. These results support the hypothesis that low CN improves drought tolerance by increasing rooting depth and water acquisition from the subsoil.