• ISSN 1008-505X
  • CN 11-3996/S
任云, 刘静, 李哲馨, 李会合, 李强. 不同铁效率玉米品种苗期适应低铁胁迫的根系特征与铁积累差异[J]. 植物营养与肥料学报, 2021, 27(3): 500-510. DOI: 10.11674/zwyf.20396
引用本文: 任云, 刘静, 李哲馨, 李会合, 李强. 不同铁效率玉米品种苗期适应低铁胁迫的根系特征与铁积累差异[J]. 植物营养与肥料学报, 2021, 27(3): 500-510. DOI: 10.11674/zwyf.20396
REN Yun, LIU Jing, LI Zhe-xin, LI Hui-he, LI Qiang. Root morphology and partitioning of Fe accumulation in maize cultivars under low iron stress condition at seedling stage[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(3): 500-510. DOI: 10.11674/zwyf.20396
Citation: REN Yun, LIU Jing, LI Zhe-xin, LI Hui-he, LI Qiang. Root morphology and partitioning of Fe accumulation in maize cultivars under low iron stress condition at seedling stage[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(3): 500-510. DOI: 10.11674/zwyf.20396

不同铁效率玉米品种苗期适应低铁胁迫的根系特征与铁积累差异

Root morphology and partitioning of Fe accumulation in maize cultivars under low iron stress condition at seedling stage

  • 摘要:
    目的 石灰性土壤高pH和高重碳酸盐含量严重影响土壤中有效铁含量,导致作物缺铁黄化、减产,铁高效玉米品种的推广应用是实现石灰性土壤玉米高产稳产的重要途径。 本研究探讨不同铁效率玉米品种适应低铁胁迫的根系特征与铁积累差异,旨在为铁高效玉米品种的推广应用提供科学依据。
    方法 试验以铁高效玉米品种正红2号 (ZH2)、正大619 (ZD619) 和铁低效玉米品种川单418 (CD418)、先玉508 (XY508) 为材料,设置极低铁处理 (Fe0,Fe浓度为0 μmol/L)、低铁处理 (Fe10,Fe浓度为10 μmol/L) 和正常供铁 (Fe100,Fe浓度为100 μmol/L) 3个处理,通过砂培试验,研究不同铁效率玉米品种适应低铁胁迫的根系形态特征、干物质重、铁积累及铁吸收利用差异。
    结果 低铁胁迫下,玉米幼苗的根干重、单株干重、铁积累量、根系相对铁吸收效率均显著降低,而根冠比与铁素生理效率均显著升高,且随胁迫程度的增加变幅加大;总根长、根表面积、根体积和根直径则表现出明显的品种差异,与正常铁处理 (Fe100)相比,低铁处理下铁低效品种的总根长、根表面积和根体积显著降低,根直径显著增加,而铁高效品种的总根长和根表面积差异不显著,根体积显著增加,根直径在极低铁处理(Fe0)下显著降低,低铁处理 (Fe10)下差异不显著;铁高效品种总根长、根表面积、根体积、根干重、单株干物重、铁积累量和根系铁吸收效率的降幅及根冠比的增幅均明显低于铁低效品种,而铁生理效率的增幅高于铁低效品种。相关性分析结果表明,玉米幼苗铁积累量与总根长、根表面积、根体积和根干重均呈显著正相关,而与根冠比呈负相关,其中与总根长 (R2 = 0.8546) 和根表面积 (R2 = 0.8983) 相关性最强。
    结论 与铁低效玉米品种相比,铁高效玉米品种低铁胁迫下具有较优的总根长、根表面积及较高的根系铁吸收效率与铁生理效率,促进了其对铁的高效吸收与利用,提高了其对低铁环境的适应能力。

     

    Abstract:
    Objectives The high pH and bicarbonate content in calcareous soil seriously affect the availability of Fe to crops, resulting in Fe deficiency, chlorosis, and reduction of yield. Fe-efficient maize cultivars are thus used as an effective way against Fe deficiency in calcareous soil. The root morphology of different Fe-efficient maize cultivars to adapt to low Fe stress were assessed in this study.
    Methods A hydroponic experiment was carried out using four maize cultivars, two Fe-efficient cultivars (ZH2 and ZD619) and two Fe-inefficient cultivars (XY508 and CD418). Fe levels of very low (No Fe added, Fe0), low (Fe 10 μmol/L, Fe10, ) and normal (Fe 100 μmol/L, Fe100) were setup in nutrient solution. Root morphological characteristics, dry matter accumulation and Fe absorption and utilization by maize were measured at seedling stage.
    Results Under low-Fe stress, the dry weight of root and plant, the Fe accumulation and relative absorption efficiency of maize seedlings were drastically reduced, while the root to shoot ratio and the Fe physiological efficiency increased significantly. The total root length, root surface area and root volume of Fe-inefficient cultivars were reduced whereas the root diameter was significantly increased under low Fe stress. Even though, the total root length and surface area of the Fe-efficient cultivars were comparable, the root volume increased significantly but the root diameter decreased significantly under the extremely low iron (Fe0) treatment as it was under the low (Fe10) treatment. The reduction in total root length, root surface area, root volume, root dry weight, dry matter per plant, iron accumulation, and Fe absorption efficiency of roots and the increase in root to shoot ratio of Fe-efficient cultivars were notably lower than those of Fe-inefficient cultivars. Correlation analysis results revealed that the Fe accumulation of maize seedlings was positively and significantly correlated with total root length, root surface area, root volume and root dry weight, but negatively correlated with root-shoot ratio. Among them, the correlation with total root length (R2 = 0.8546) and root surface area (R2 = 0.8983) was the strongest.
    Conclusions Compared to the Fe-inefficient cultivars, Fe-efficient maize cultivars have larger total root length and root surface area at seedling stage, and higher root Fe absorption efficiency and physiological efficiency to adapt to low Fe stress, which could enhance absorption and utilization of Fe, thereby improve the adaptability to low-Fe environment.

     

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