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【目的】分析不同棉花品种黄萎病抗性与其生理结构之间的关系,为优化棉花组织结构抗性鉴定体系提供理论依据。【方法】以5个不同棉花品种为材料,采集接种棉花黄萎病菌V76前后的棉花根、茎、叶部组织,对其横切面做连续石蜡切片,观察不同抗性品种之间的组织结构差异。【结果】(1)接菌前随棉花相对病情指数的增高,根表皮与导管细胞的平均细胞面积增大,细胞密度降低;接菌后随棉花相对病情指数的增高,根皮层薄壁细胞的平均细胞面积增大,细胞密度降低。(2)接菌前随棉花相对病情指数的增高,茎表皮细胞的平均细胞面积增大,细胞密度降低,而木质部细胞的平均细胞面积减小,细胞密度增高;接菌后随棉花相对病情指数的增高,茎皮层薄壁细胞与木质部细胞的平均细胞面积增大,细胞密度降低。(3)接菌前随着相对病情指数的增高,叶上表皮细胞的平均细胞面积增大,细胞的密度降低;接菌后随着相对病情指数的增高,叶肉细胞的平均细胞面积增大,细胞密度减小。【结论】接菌前感病品种单位面积的根表皮细胞与根导管细胞排列疏松;接菌后感病品种单位面积的根皮层薄壁细胞数目少于抗病品种,因而细胞间隙扩大,导致菌丝在其内快速生长;接菌前感病品种单位面积的茎表皮细胞数目少于抗病品种,而茎木质部细胞多于抗病品种,接菌后发生了明显的变化,即感病品种单位面积的茎木质部细胞数目少于抗病品种,导致菌丝在其内生长缓慢或者阻止迅速生长,有利于棉株的正常生长发育;接菌前感病品种单位面积的叶上表皮细胞数目少于抗病品种,而接菌后感病品种单位面积的叶肉细胞数目少于抗病品种。
【Objective】 The objective of this study is to analyze the relationship between the resistance of different cotton varieties to their physiological structure and to provide a theoretical basis for optimizing the identification system of cotton structural resistance. 【Method】 Five different cotton cultivars were used as material to collect cotton root, stem and leaf tissue before and after inoculation with Verticillium dahliae V76, and the paraffin sections were made on the transverse section of the cotton. The differences of tissue structure among different resistant varieties were observed . 【Result】 (1) Before the inoculation with cotton, the relative disease index increased, the average cell area of root epidermis and ductal cells increased, and the cell density decreased. With the increase of relative disease index of cotton, The average cell area increased, cell density decreased. (2) Before inoculation with cotton, the relative disease index increased, the average cell area of stem epidermal cells increased, the cell density decreased, and the average cell area of xylem cells decreased, the cell density increased; Increased, the average cell area of stem cell parenchyma cells and xylem cells increased, cell density decreased. (3) With the increase of relative disease index before inoculation, the average cell area of the epidermal cells on the leaf increased and the density of the cells decreased. With the increase of the relative disease index, the average cell area of the mesophyll increased, Decreased cell density. 【Conclusion】 The number of root epidermal cells and root duct cells per unit area of pre-inoculated susceptible varieties was loosely arranged. The number of parenchyma cells per unit area of susceptible cultivars was less than that of disease-resistant cultivars, and the intercellular space was enlarged, The number of stem epidermal cells per unit area of susceptible cultivars was less than that of disease-resistant cultivars, while that of stem xylem cells was more than that of resistant cultivars. Significant changes occurred after inoculation, that is, susceptible cultivars The number of xylem cells in the area was less than that in the disease-resistant varieties, which led to the slow or slow growth of the mycelium in it, which was beneficial to the normal growth and development of cotton plants. The number of leaf epidermal cells per unit area of the susceptible varieties before inoculation was less than Resistant varieties, whereas the number of mesophyll cells per unit area of susceptible varieties after inoculation was less than that of resistant varieties.