低温驯化及封冻后不同抗寒性小麦品种细胞超微结构的比较

为分析不同抗寒性小麦品种在低温胁迫下细胞超微结构的差异，以抗寒品种东农冬麦1号和对照济麦22为材料，分别在低温驯化期和封冻期用透射电镜观察两个品种分蘖节和叶片的细胞超微结构。结果表明，低温驯化期（11月2日）两个品种分蘖节的细胞超微结构均没有受损。抗寒品种东农冬麦1号分蘖节细胞内有少量质体，且分蘖节的液泡占整个细胞的比例较济麦22小；封冻后10 d，济麦22分蘖节发生严重的质壁分离，线粒体外膜不再清晰，而东农冬麦1号分蘖节内除有的线粒体内外脊不再清晰外，其他细胞器官没有明显变化。封冻后30 d东农冬麦1号发生轻微的质壁分离，细胞核完整，线粒体膜不清晰；济麦22分蘖节细胞内含物基本没有，细胞空泡化。调查期内，济麦22叶片的叶绿体紧贴细胞壁排列，细胞内有较大的中央大液泡，11月2日叶绿体内出现拟脂颗粒，封冻后30 d叶片细胞基本空泡化；东农冬麦1号有一部分叶片细胞的叶绿体在细胞中部聚集，调查期内未见叶绿体内出现拟脂颗粒，封冻后30 d线粒体出现破损，叶绿体排列不再规则，但细胞核仍然清晰。

Comparison of Cell Ultrastructure between Winter Wheat Cultivars during Cold Acclimation and Freezing Period

The cell ultrastructure in the tiller nods and leaves of 2 winter wheat cultivars of Dongnong dongmai 1(winter hardy cultivar) and Jimai 22 (CK, nonhardy cultivar) planted in the pots under the cold acclimation and frozen period was observed with transmission electron microspcope to investigate the differences of winter wheat cultivars in the cellullar ultrastructure upon cold stress. The results showed that on Nov. 2 (cold acclimation period), the cells of the tiller nods of 2 cultivars were not injured, but a little of plastids in the part of Dongnong dongmai 1 were found and the proportion of vecuole in tiller nod cell volum of Dongnong dongmai 1 was less than that of Jimai 22. At the 10th day after frozen date, the severe plasmolysis and no more clear image of mitochondia outer membrane was observed in the tiller nod of Jimai 22, but no change of cell organs was observed in the tiller nod cell of Dongnong dongmai 1 except no more sharp image of crista in mitodnondra. At the 30th day after frozen date, a slight plasmolysis occurred but the caryon was complete and the image of membrane not clear in the tiller nod cell of Dongnong dongmai 1; and in the same part of Jimai 22 nothing was observed in cell. The chloroplasts were arranged near wall and larger vacuoles were found in cell of leaf in Jimai 22 at investigation period and on Nov. 2 lipoid granules appeared in chloroplast and nothing was in the cell at the 30th day after frozen date. The chloroplasts were gethered in the center of some leaf cells and no lipiod granules appeared in the chloroplasts in the survey days and at the 30th day after frozen date the disruption was observed in mitochondria and chloroplasts and were not arranged in order, but the image of karyon was still clear.