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作 者 ：李悦, 师尚礼^*

期 刊 ：草业学报 2016年 25卷 2期 页码：141-149

关键词：清水苜蓿；秋水仙素；染色体；叶片下表皮细胞；

Keywords:Medicago sativa cv. Qingshui, colchicine, chromosome, lower epidermis cell of leafs,

摘 要 ：利用不同浓度的秋水仙素(0.05%、0.10%、0.20%)按处理时间(4,8和12 h)对清水紫花苜蓿萌动种子胚根进行诱变,通过观察清水苜蓿根尖细胞染色体数的变化确定出诱变清水苜蓿多倍体的秋水仙素适宜剂量,并观察叶片下表皮细胞内含物的变化。结果表明:秋水仙素的诱变可使苜蓿根尖细胞染色体数发生变异,产生出多种变异类型(4x<2n<8x、2n=8x、2n>8x的类型)。能够诱变出较高频率八倍体细胞(2n=8x)的秋水仙素剂量为0.1%+8h,诱变率为13.33%。随秋水仙素处理剂量的增加,叶片下表皮细胞内保卫细胞尺寸(长、宽、长/宽)、内部叶绿体数目均发生不同程度的增加,气孔密度则出现不同程度的减少。秋水仙素不同处理剂量下保卫细胞长度、宽度、长/宽、叶绿体数目均在0.1%+8h、0.1%+12h及0.2%+4h剂量较其他处理剂量增大,而气孔密度则在这3个处理剂量下相对较小,尤其是在0.1%+8h处理剂量变化程度最大。

Abstract:The objective of this experiment was to determine the appropriate colchicine dose levels to produce polyploids of Medicago sativa cv. Qingshui. Three different colchicine concentrations (0.05%, 0.10%, 0.20%) and three treatment durations (4 h, 8 h, 12 h) were used to induce the radicle of gemmiferous seeds and changes were observed in the root tip cell chromosome number and in inclusions in the lower epidermis of leaves. The results showed that colchicine can change chromosomes in the root tip cells of alfalfa seedlings, producing a variety of different mutant types (4x<2n<8x, 2n=8x and 2n>8x). The appropriate dose and treatment period of colchicine to induce a higher proportion of octaploid cells (2n=8x) is 0.1%+8h, with a mutation rate of 13.3%. Increasing levels of colchicine were associated with increases in the size (length, width, length/width) of guard cells and in the number of chloroplasts in the leaves’ lower epidermis, while the density of stomata decreased. The size of guard cells and number of chloroplasts were largest in the 0.1%+8h, 0.1+12h and 0.2%+4h treatments, where stomatal densities were also relatively the smallest. The largest mutagenic effects were observed under the 0.1%+8h treatment.

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