小麦与叶锈菌互作过程中细胞程序性死亡的细胞学观察

HISTOLOGICAL OBSERVATION ON PROGRAMMED CELL DEATH IN WHEAT-LEAF RUST FUNGUS INTREACTIOIN

小麦(Triticum aesetivum)品种洛夫林10和叶锈菌(Puccinia recondita f.sp tritici)小种162、165分别组成不亲和组合与亲和组合。透射电镜观察表明,在小麦与叶锈菌的不亲和组合中,接种后12h,侵染点周围叶肉细胞核变形;接种后24h,核内染色质开始凝聚,并趋于细胞核边缘,同时叶绿体膨胀;接种后48h,核内染色质凝聚加剧,叶绿体开始解体;最终在接种后72h,细胞核、叶绿体完全解体,线粒体开始退化。此外,内质网和液泡共同行使溶酶体功能,吞噬各种细胞器残体及原生质降解组分。以上结果表明:在小麦与叶锈菌不亲和组合的互作过程中,寄主细胞呈现细胞程序性死亡的典型特征。而在亲和组合中,叶肉细胞间隙中可见有大量菌丝蔓延,菌丝与寄主细胞壁接触后分化产生吸器母细胞。菌丝的存在对寄主细胞的超微结构产生一定影响。从接种后24h开始,与菌接触的细胞出现质膜下陷,叶绿体稍显膨胀;在接种后48h、72h,大部分叶绿体膨胀,而其它细胞器无明显变化。

The ultrastructural features of mesophyll cell surrounding the fungus in different interaction between wheat and Puccinia recondita f. sp tritici were observed with transmission electron microscopy. In incompatible combination(cv. lorvin10×race 162) , the nuclei gradually became irregular with highly condensed chromatin towards the nuclear envelope, while the chloroplast became swelling since 12h to 24h after inoculation(a. i. ). At 48h a. i. , the condensation of the chromatin became more prominent and the chloroplast began to disintegrate. Finally, when some mitochondria started to degrade at 72h a. i. , the nuclei and the chloroplast became disruption completely. During the process, endoplasmic reticulum and vesicles did play a vital role in the further degeneration of other organelles and protoplasmic components just similar to the lysosome acting in the animal cells. These results suggest that the ultrastructural feature of cell death is a form of programmed cell death (PCD). In compatible combination (cv. lorvin10×race 165), ultrastructural of mesophyll cell exhibited different features from incompatible combination. At 24h a. i. , the plasmic membrane showed sunken and the chloroplast slightly exhibited swelling. Since 48h to 72h a. i. , most of the swelling chloroplasts were observed while the other organelles still remained unaltered. At the same time, the hypha and haustorium mother cell in the intracellular space also could be observed.