不同棉花品种抗黄萎病性与其组织结构的关系

Relationship between Tissue Structure and Resistance to Verticillium wilt in Different Cotton Varieties

【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] This project aims to provide theoretical basis for optimizing resistance identifica- tion system on tissue structure in cotton by analyzing the relationship between the tissue structure and the re- sistance to Verticillium wilt in different cotton varieties. [ Method] Five different cotton varieties were used as experimental materials, before and after inoculation with cotton Verticillium wilt fungus V76, roots, stems and leafs, and made paraffin sections on those tissues were collected, and the differences in tissues transverse structure among cotton varieties with different resistance were observed. [ Result] 1. With increase of relative disease index of cotton before inoculation, average cell area of root epidermal and root vessel cell increased, and cell density decreased ; with increase of relative disease index of cotton after inoculation, averaze cell areaof root cortex parenchyma cell increased, and the cell density decreased. 2. With increase of relative disease index of cotton before inoculation, average cell area of stem epidermal cell increased, and the cell density de- creased, and average cell area of xylem cell decreased, cell density increased; with increase of relative dis- ease index of cotton after inoculation, average cell area of stem cortex parenehyma cell and xylem cell in- creased, and the cell density decreased. 3. With increase of relative disease index of cotton before inocula- tion, average cell area of leaf upper epidermis cell increased, and the cell density decreased; with increase of relative disease index of cotton after inoculation, average cell area of mesophyll cell increased, and the cell density decreased. I Conclusion ] Toot epidermal ceils and root vessel cells of susceptible variety of per unit ar- ea were loosely arranged before inoculation, and the root cortex parenchyma cell number of its per unit area was less than that of the resistant variety. After inoculation, hyphae could grow rapidly because of the widened intercellular space ; stem epidermal cell number of susceptible variety of per unit area was less than that of the resistant variety, and the stem xylem cells were more than thoset of the resistant variety before inoculation; due to the average cell area of stem epidermal cell of susceptible variety after inoculation, it was significant less than that of the resistant variety, which would lead to slowly growth of the hyphae in them or prevent rapid growth and it was advantageous to the normal growth and development of cotton; leaf upper epidermis cell number of susceptible variety of per unit area was less than that of the resistant variety before inoculation, and its mesophyil cell number of per unit area was less than that of the resistant variety after inoculation.