简易压片法观察水稻有丝分裂和减数分裂行为

目的]建立一套简单易行的染色体压片技术，获得水稻染色体资料。方法]采用朱微的植物染色体及染色体技术中的压片法，并在此基础上作了进一步改进。细胞有丝分裂观察：①材料准备。种子浸泡24h后。置于培养皿中，于25℃暗培养箱中生根培养。②固定。当嫩根长至1～2cm时，于9：00～11：00用卡诺固定液（酒精：醋酸=3：1）固定2～24h。再用70％酒精清洗后置于70％酒精中保存备用。③解离。将固定好的材料取出放人解离液（无水乙醇：37％的浓盐酸=1：1）中室温下解离5～10min。解离时间根据温度的不同而不同，在试验中做好调整。④染色。彻底洗去解离液的根尖置于解剖镜下，找出分生区（一个解离良好的材料分生区在解剖镜下是不透明的，而成熟区和根冠部分则是透明的），用刀片将分生区切为2～3部分，使其细胞更易着色。然后在载玻片上滴卡宝品红染色液染色10rain。⑤压片。⑥镜检取像。细胞减数分裂观察：①取材。幼穗当剑叶的叶枕距为0左右时，处于减数分裂期。于8：00～11：00采集水稻幼穗，用卡诺氏固定液固定24h（置于4℃冰箱内），再用70％酒精清洗2—3次后，保存于70％酒精中备用。②制片。取1朵颖花的3～6枚花药置于洁净载玻片上，用刀片或解剖针将花药横向切断，用镊子挤压花药，使花粉母细胞从花药中逸出，再用镊子清除药壁等残渣。滴1滴卡宝品红染液于花药上，染色5min。之后压片。③观察取像。先在低倍镜下寻找具有分裂相的花粉母细胞，然后依次转换到高倍镜观察减数分裂各时期染色体的行为和形态特征。最后用油镜观察染色体分裂行为并取像。结果]水稻有丝分裂包括间期、前期、中期、后期、末期5个时期，中期的染色体缩至最短，是观察与研究染色体的好时期。水稻减数分裂包括减数分裂Ⅰ、减数分裂Ⅱ2个过程，其中在减数分裂Ⅰ过程中发生了染色体复制，减数分裂Ⅱ过程中仅发生了细胞分裂。结论]改进后的水稻染色体压片技术能够获得准确的染色体资料，可为育种和遗传操作提供依据。

Observation of Mitosis and Meiosis in Rice Cells by Simple Squash Method

Objective] The aim of this study was to establish a feasible squashing technique for chromosome and obtain data of rice chromosome. Method] With the materials of rice root tips and anther, the specimen was prepared by the modified squash method, and microscopic observation of mitosis and meiosis in rice cells was also carried out. Result] Mitosis in rice cells included interphase, prophase, metaphase, anaphase and telophase. Chromosome in metaphase shortened to the minmum, which was a good time for observing and investigating chromosome. However, meiosis in rice cells included meiosis Ⅰ and meiosis Ⅱ. Chromosome replication appeared in meiosis Ⅰ, while cell division only appeared in meiosis Ⅱ. Conclusion] The modified squashing technique for rice chromosome can obtain accurate data of rice chromosome, which provides evidence for genetic breeding.