• ISSN 1008-505X
  • CN 11-3996/S
杜琪, 赵跃, 周东英, 王晓光, 蒋春姬, 王婧, 赵新华, 于海秋. 低钾胁迫下不同耐低钾玉米品种 (系) 开花后根系生长和结构的变化[J]. 植物营养与肥料学报, 2021, 27(2): 301-311. DOI: 10.11674/zwyf.20235
引用本文: 杜琪, 赵跃, 周东英, 王晓光, 蒋春姬, 王婧, 赵新华, 于海秋. 低钾胁迫下不同耐低钾玉米品种 (系) 开花后根系生长和结构的变化[J]. 植物营养与肥料学报, 2021, 27(2): 301-311. DOI: 10.11674/zwyf.20235
DU Qi, ZHAO Yue, ZHOU Dong-ying, WANG Xiao-guang, JIANG Chun-ji, WANG Jing, ZHAO Xin-hua, YU Hai-qiu. Response of root growth and structure of different potassium sensitive maize cultivars (lines) to low potassium stress after flowering stage[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(2): 301-311. DOI: 10.11674/zwyf.20235
Citation: DU Qi, ZHAO Yue, ZHOU Dong-ying, WANG Xiao-guang, JIANG Chun-ji, WANG Jing, ZHAO Xin-hua, YU Hai-qiu. Response of root growth and structure of different potassium sensitive maize cultivars (lines) to low potassium stress after flowering stage[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(2): 301-311. DOI: 10.11674/zwyf.20235

低钾胁迫下不同耐低钾玉米品种 (系) 开花后根系生长和结构的变化

Response of root growth and structure of different potassium sensitive maize cultivars (lines) to low potassium stress after flowering stage

  • 摘要:
    目的 土壤缺钾常引起植株早衰,严重影响玉米产量。从玉米开花后根系形态、结构和活性等参数的变化,研究低钾胁迫下玉米早衰的机理。
    方法 以耐低钾玉米自交系90-21-3和钾敏感玉米自交系D937为试材,进行池栽试验。设置天然低钾土壤 (低钾,–K) 和正常供钾 (CK,+K) 两个处理,分别于玉米开花后测定根系形态、结构和活性等参数。
    结果 与正常供钾处理相比,低钾处理降低了90-21-3和D937根系中钾素含量,抑制了根系的生长,破坏了根系结构,引起根系活力降低。低钾胁迫下,90-21-3的第一层节根数目和根系干重分别显著降低了20.37%和42.24%,D937分别显著降低了39.06%和59.64%;90-21-3的第二层节根数目和干重分别显著降低了23.40%和39.30%,D937分别显著降低了36.67%和59.86%。随着玉米的生长,低钾胁迫下90-21-3和D937的根系活力以及第一层和第二层根的长度、表面积、体积和侧根长度整体均呈现降低趋势,D937降低幅度大于90-21-3,根平均直径整体逐渐增加。低钾胁迫下90-21-3根系解剖结构完整,外皮层和内皮层完整,大、小导管形状规则,结构清晰可见;D937根系解剖结构受破坏严重,外皮层和内皮层结构被破坏,导管形状不规则,大、小导管结构模糊甚至消失。与正常供钾相比,低钾胁迫下90-21-3的大导管直径、小导管直径、大导管面积和小导管面积分别降低了11.15%、14.37%、21.07%和30.21%;D937分别显著降低了33.99%、22.86%、56.43%和40.55%。
    结论 低钾胁迫显著降低了玉米开花后根系的生长和结构的稳定性。与耐低钾玉米自交系 (90-21-3) 相比,钾敏感自交系 (D937) 在低钾胁迫下大面积皮层结构遭到严重破坏,内皮层结构不完整,导管形状不规则,大导管周围的小导管结构模糊,甚至消失,质膜透性高,影响养分和水分的吸收利用。而耐低钾玉米90-21-3在生育后期能够维持较大根系体积、根系活力以及输导组织,增强低钾胁迫下根系对外界钾素的吸收和运移能力,延缓根系衰老。

     

    Abstract:
    Objectives Premature senescence is often occurred in K-deficient soil, which seriously inhibites the yield of maize. In the study, the premature senescence of maize caused by K deficient stress was studied from root morphology, structure and activity after flowering stage.
    Methods Pool experiment was conducted using maize inbred line of K-tolerant 90-21-3 and K-sensitive D937 as tested materials. Both maize lines were grown in K-deficient soil without applying K (–K) and applying K (+K). The root morphology, microscopic structure and activity of maize were measured after flowering stage.
    Results Compared with +K controls, K contents in both maize lines were significantly decreased under –K stress; the crown number and weight of first layer root in line 90-21-3 were significantly decreased by 20.37% and 42.24%, and by 39.06% and 59.64% in line D937; the crown number and weight of second layer root in line 90-21-3 were significantly decreased by 23.40% and 39.30%, and by 36.67% and 59.86% in line D937. As maize grew, the root activity in line 90-21-3 and D937 were all decreased under-K stress, as well as the root length, surface area, volume and lateral length of first and second layer root, while root diameter was increased, more variation in D937 than in 90-21-3. Compared with controls, the anatomical structure of 90-21-3 root was intact and clearly visible, including complete cortex and endodermis, regular vessels. But the anatomical structure of D937 root was seriously damaged, including incomplete cortex and endodermis, irregular vessels. The diameter and area of large vessel in 90-21-3 root were decreased by 11.15% and 21.07%, and the diameter and area of small vessel were decreased by 14.37% and 30.21%. The diameter and area of large vessel in D937 root were significantly decreased by 33.99% and 56.43%, and the diameter and area of small vessel were significantly decreased by 22.86% and 40.55%.
    Conclusions The growth and structural stability of maize roots are significantly reduced under K-deficit stress. Compared with K-tolerant inbred lines (90-21-3), K-sensitive inbred lines (D937) suffers severe damage in cortex tissue and endodermis, irregular vessels and plasma membrane permeability, which decreases efficiency in absorption and utilization of nutrients and water. The root of K-deficit tolerant line 90-21-3 shows larger root volume, activity and conducting tissue, which could enhance the capability of absorption and transportation for nutrient, and delayed root premature under K deficiency stress.

     

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