翟晓芳,周君玺,孙浩然,唐靓,沈玉芳.局部高浓度硝酸盐供应对玉米根系形态及氮累积的影响[J].干旱地区农业研究,2019,37(4):91~99
局部高浓度硝酸盐供应对玉米根系形态及氮累积的影响
Effects of localized high nitrate supply on maize roots morphology and N accumulation
  
DOI:10.7606/j.issn.1000-7601.2019.04.12
中文关键词:  玉米  主根  种子根  硝酸盐供应  水分胁迫
英文关键词:maize  primary root  seminal root  nitrate supply  water stress
基金项目:国家自然科学基金(41671307,41401343);国家重点研发计划(2017YFD0201807);陕西省自然科学基础科学研究计划(2017JM3011)
作者单位
翟晓芳 西北农林科技大学资源环境学院陕西 杨凌 712100西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室陕西 杨凌 712100 
周君玺 西北农林科技大学资源环境学院陕西 杨凌 712100西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室陕西 杨凌 712100 
孙浩然 西北农林科技大学资源环境学院陕西 杨凌 712100 
唐靓 西北农林科技大学资源环境学院陕西 杨凌 712100西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室陕西 杨凌 712100 
沈玉芳 西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室陕西 杨凌 712100 
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中文摘要:
      以郑单958和鲁单981为研究对象,进行水培分根试验,在正常供水和水分胁迫条件下,分别以均匀低浓度硝酸盐处理主根和种子根(LPR-LSR)、局部高浓度硝酸盐处理主根(HPR-LSR)和局部高浓度硝酸盐处理种子根(LPR-HSR),测定分析根系形态、生物量以及氮含量。结果表明:与氮低效鲁单981相比,氮高效郑单958具有较高的主根根长、根表面积、根系生物量、地上部生物量和氮累积量。水分胁迫条件下,郑单958和鲁单981的主根的根长、根表面积、根体积、地上部生物量和氮累积量总体上均低于正常水分条件。玉米主根和种子根对局部高浓度硝酸盐的反应存在差异。与均匀低浓度硝酸盐处理相比,局部高浓度硝酸盐处理促进正常水分条件下主根和种子根根系的生长,尤其是根长和根系表面积;在正常水分条件下,主根根长和根系表面积增加幅度范围为6.8%~27.3%和1.9%~21.9%,除HPR-LSR处理条件下的郑单958外,种子根根长和根系表面积增加幅度范围为30.4%~92.7%和10.5%~135.1%;在水分胁迫条件下,主根根长和表面积增加幅度范围为24.6%~152.9%和62.1%~229.9%,然而种子根根长降低了10.0%~29.9%,表明水分胁迫会影响种子根对高浓度硝酸盐的响应。除水分胁迫条件下LPR-HSR处理外,局部高浓度处理可同时增加两侧根系的生物量和氮累积量。无论是正常供水还是水分胁迫,与LPR-LSR处理相比,局部高浓度硝酸盐供应均能够增加地上部生物量以及氮累积量,在LPR-HSR处理条件下,增加幅度范围分别在35.0% ~107.9%和162.9%~291.1%,在HPR-LSR处理条件下分别为56.7%~109.4%和204.1%~377.0%,HPR-LSR处理条件下增加幅度较大,表明在氮素非均匀分布环境中,当主根处于高浓度硝酸盐区域时将会更显著促进生物量的增加和氮累积。
英文摘要:
      The root system development displays a high plasticity to heterogeneous distribution of N in soil. Nitrate is the most common N source used by higher plants in arid environment. How maize roots coordinate the growth of primary roots (PR) and seminal roots (SR) in response to heterogeneous localized high nitrate supply remains unclear. Maize seedlings, Zhengdan 958 and Ludan 981, were grown in split-root systems for three weeks by hydroponic culture. The roots received a uniform low nitrate supply of 0.5 mM nitrate (LPR-LSR), or a high nitrate supply of 5 mM nitrate for primary roots and low for seminal roots (HPR-LSR), or low nitrate supply for primary roots and high for seminal roots (LPR-HSR) under the normal water supply and water stress environment. Morphology, biomass, and N accumulation in roots were measured. The results showed that Zhengdan 958 had greater root length and surface area of primary roots, root biomass, shoot biomass, and N accumulation than Ludan 981. The length, surface area, volume of primary roots, shoot biomass and N accumulation were lower under water stress treatment than that of normal water treatment. Maize primary roots and seminal roots responded differently to local high nitrate supply. Localized high nitrate treatments could promote the growth of primary and seminal roots, especially root length and surface area, under the normal water supply. Under the normal water condition, the increment of root length and surface area of primary roots ranged from 6.8% to 27.3% and 1.9% to 21.9%, respectively; except the Zhengdan 958 under the HPR-LSR treatment, the increment of root length and surface area of seminal roots ranged from 30.4% to 92.7% and 10.5% to 135.1%, respectively. However, under the water stress condition, the increment of root length and surface area of primary roots ranged from 24.6% to 152.9% and 62.1% to 229.9%, respectively, but the reduction of length of seminal roots randge from 10.0% to 29.9%, suggesting that water stress could affect the response of seminal roots to localized high nitrate supply. Localized high nitrate treatments increased the biomass and N accumulation of roots in both sides at the same time except for the LPR-HSR treatment under the water stress condition. Localized high nitrate could enhance the biomass and N accumulation of shoot both under the normal water supply and water stress environment compared with LPR-LSR treatment, under the LPR-HSR treatment, the increment ranged from 35.0% to 107.9% and 162.9% to 291.1% respectively, under the HPR-LSR treatment, the increment ranged from 56.7% to 109.4% and 204.1% to 377.0%, respectively. And the increment of HPR-LSR treatment was higher than LPR-HSR treatment. It indicated that the enhancement effects were more significant when the primary root was in the localized high nitrate supply.
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