香蕉根系活力及物理结构与枯萎病抗性的关系

Relationship between root activity, root physical structure of banana and resistances to fusarium wilt

  • 摘要: 【目的】探讨不同品种香蕉根系活力和根系微观结构差异与抗枯萎病水平间的相互关系,为香蕉枯萎病的抗性评估提供理论依据。【方法】以12份香蕉品种(系)组培杯苗为试验材料,采用伤根浸菌接种法分析香蕉被枯萎病菌4号生理小种(Fusarium oxysporum f.sp.cubense race 4,Foc4)侵染后的发病情况,评价不同香蕉品种(系)对Foc4的抗性水平;通过显微观察和理化分析比较不同品种(系)香蕉根系组织结构及接种Foc4后根系活力指标的差异变化;运用单因素方差分析及Duncan氏显著性分析研究根系活力和解剖结构性状与病害发生程度间的相关性。【结果】供试香蕉品种(系)中,6个品种(宝岛蕉、175b、ZR1、23b、MJ9和43b)为中抗、4个品种(79b、169b、265b和264b)为感病、2个品种(173b和桂蕉6号)为高感。接菌40 d,各香蕉品种(系)根系活力均升高,其中宝岛蕉上升幅度为701.00%,抗病品种(系)根系活力显著高于感病品种(系)(P<0.05,下同),宝岛蕉与桂蕉6号相比显著增加674.24%;抗病品种(系)比感病品种(系)导管数目多,导管直径小,薄壁细胞数目多,导管细胞壁厚度厚,宝岛蕉相比桂蕉6号分别显著多106.98%、小50.20%、多65.07%和厚63.51%;根系活力、导管数目、薄壁细胞数目和导管细胞壁厚度与病害严重度呈显著或极显著(P<0.01,下同)负相关,导管直径与病害严重度呈显著或极显著正相关。【结论】根系活力、根系木质部导管数目、导管直径、薄壁细胞数目和导管细胞壁厚度与香蕉品种(系)的抗病性有较强的相关性,根系活力和根系解剖结构性状可作为香蕉苗期筛选抗枯萎病品种的参考指标。

     

    Abstract: 【Objective】This paper explored the differences of root activity and root microstructure among different banana varieties and their relationship with the resistance to fusarium wilt,so as to provide theoretical basis for the evaluation of banana resistance to fusarium wilt.【Method】The tissue culture cup seedlings of 12 banana varieties(strains)were used as experimental materials. Through the inoculation treatment on wound root,the situations of bananas after inoculation of Fusarium oxysporum f. sp. cubense race 4 (Foc4)were analyzed, and the resistance levels of different banana varieties(strains)to physiological race 4 of fusarium wilt were evaluated. The difference of root tissue structure of different banana varieties and root activity indexes under the conditions of Foc4 inoculation were compared and analyzed by microscopic observation and physical and chemical analysis. Correlation between root activity as well as anatomical structure and disease occurrence was studied by single factor variance analysis and Duncan significance analysis.【Result】Among the banana varieties(strains)tested,6 banana varieties(Baodao banana, 175b, ZR1, 23b, MJ9, 43b)were medium resistant, 4 banana varieties (79b, 169b, 265b, 264b)were susceptible, and 2 banana varieties (173b, Guijiao No.6)were highly susceptible. On day 40 after inoculation,the root activity of all banana varieties increased. The increase range of Baodao banana was 701.00%. The root activity of resistant varieties (strains)was significantly higher than that of susceptible varieties(strains) (P<0.05,the same below). Compared with Guijiao No.6,Baodao banana significantly increased 674.24%. Compared with susceptible varieties (strains), resistant varieties (strains)had more vessel number, smaller vessel diameter, more parenchyma cells,and thicker vessel cell wall. Compared with Guijiao No.6,vessel number,vessel diameter, parenchyma cell number and vessel cell wall thickness of Baodao banana significantly increased by 106.98%,decreased by 50.20%,increased by 65.07%,and increased by 63.51% respectively. Root activity,vessel number,parenchyma cell number and vessel cell wall thickness were significantly or extremely significantly negatively correlated with disease severity (P<0.01,the same below),while vessel diameter was significantly or extremely significantly positively correlated with disease severity.【Conclusion】Root activity,vessel number in root xylem,vessel diameter,parenchyma cell number and vessel cell wall thickness are strongly related to the disease resistance of banana varieties(strains). Root activity and anatomical structure can serve as indicators to screen resistant varieties of fusarium wilt at the seedling stage of banana.

     

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