红辣椒“花皮”致病菌对果实细胞结构的影响

 分析能引起红辣椒变色斑块的细菌和真菌侵染后果肉组织中丙二醛含量、细胞膜相对透性及细胞微观结构的变化，结果显示，“花皮”致病菌侵染后，果肉组织丙二醛含量、细胞膜相对透性较对照明显增加（P < 0.05），导致细胞结构、细胞内有色体结构破坏，色素组分分解，其中致病细菌主要是对果肉组织的外层与内层细胞同时破坏，而致病真菌主要从果实内层向外层破坏细胞结构，且对细胞壁破坏作用较细菌强，更容易破坏有色体结构。不同致病菌对辣椒组织破坏能力存在差异，枯草芽孢杆菌（Bacillus subtilis）、白腐菌（Phanerochaete sordida）和白囊耙齿菌（Irpex lacteus）对细胞壁、细胞膜及有色体结构破坏较球形赖氨酸芽孢杆菌（Lysinibacillus sphaericus ）、枝状枝孢菌（Cladosporiumcladosporioides）严重，使大部分内含物及类胡萝卜素分解，剩下少许脂滴。试验结果表明，“花皮”致病菌侵染辣椒严重破坏其组织细胞结构并导致细胞有色体破坏，色素分解，从而引起外观色泽褪变。

Effects of Pathogens Causing Discoloration on the Microcosmic Structure of Red Pepper Cells

By analyzing the changes of malondialdehyde（MDA）concentration，relative permeabilityof cells and microstructure of red pepper tissues，the results indicated that the pulp tissues infected bypathogens causing discoloration had significantly increased in MDA concentration，relative permeabilitycompared with control group（P < 0.05），as well as they destroyed cell membrane，tissue cells andchromoplast structure，increased cell permeability，and decomposed pigment component. The bacteriadamaged the external and internal cell tissues，while the fungus damaged from the internal to externaltissues. The fungus had stronger damage to cell wall than bacteria，and were prone to destroy chromoplaststructure. Meanwhile，various pathogens damaged pepper tissues differently. Compared with Lysinibacillussphaericus and Cladosporium cladosporioides，the Bacillus subtilis，Phanerochaete sordida and Irpexlacteus had more serious damage to cell wall，membrane and chromoplast structure，which decomposedmost inclusion and carotenoids，leaving a little lipid droplet. The experiment showed that the pathogens causing discoloration damaged red pepper cell microstructure，resulted in the damage of chromoplast，decomposed pigment and consequently depigment.