Maize with fewer nodal roots allocates mass to more lateral and deep roots that improve nitrogen uptake and shoot growth
Maize with fewer nodal roots allocates mass to more lateral and deep roots that improve nitrogen uptake and shoot growth
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DOI：
10.1093/jxb/erz258
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发表时间：
2019-10-01
影响因子：
6.9
通讯作者：
York, Larry M.
中科院分区：
文献类型：
--
作者：
Guo, Haichao;York, Larry M.
模拟结果表明，减少节根（NR）数（NRN）是有希望的玉米育种，并部分证实了依赖于自交系之间的NRN的变化。使用玉米自交系B73，在含有固体培养基的水培和高大中围生态系统中进行实验，其中处理涉及不切除NR（0%NRE）或在高或低水平氮（N）下出现时切除33%或67%的NR。假设减少NRN，以增加所有剩余的根类的伸长，低N下的N获取，和拍摄质量。植物与67%NRE有12%和19%的根质量分数，61%和91%更大的侧根与轴向根的长度比，无论N水平，和61%和182%的生物量高胚根低N下，与0%NRE的水培和围隔研究，分别。在低氮条件下，67%NRE的植株地上部生物量比0%NRE的植株高52%，深层根长比0%NRE的植株高450%，地上部深层注射的N-15含量比0%NRE的植株高232%。这些结果揭示了机制，即植物与较少的NR增加N捕获和拍摄质量的生物量的重新分配侧根，胚根，和第一轮NR，提高固体介质中的觅食效率。
Simulations indicated that reduced nodal root (NR) number (NRN) was promising for maize breeding, and were partially confirmed by relying on variation in NRN among inbreds. Using maize inbred line B73, experiments were conducted in hydroponics and tall mesocosms containing solid media with treatments involving no NR excision (0% NRE) or excising either 33% or 67% of the NRs as they emerged under high or low levels of nitrogen (N). Reduced NRN was hypothesized to increase elongation of all remaining root classes, N acquisition under low N, and shoot mass. Plants with 67% NRE had 12% and 19% less root mass fraction, 61% and 91% greater lateral to axial root length ratio regardless of N levels, and 61% and 182% greater biomass of embryonic roots under low N, compared with 0% NRE for hydroponics and mesocosms studies, respectively. Under low N in mesocosms, plants with 67% NRE had 52% greater shoot biomass, 450% greater root length at depth, and 232% greater deep-injected N-15 content in the shoot relative to 0% NRE. These results reveal the mechanism by which plants with fewer NRs increase N capture and shoot mass by reallocation of biomass to lateral roots, embryonic roots, and first whorl NRs that increases foraging efficiency in solid media.