秋水仙素浓度和处理时间对茉莉腋芽生长发育的影响

为了解秋水仙素处理对茉莉﹝Jasminum sambac (Linn.) Aiton〕腋芽生长发育的影响，以长度为0(未萌发)、3~5和8~10 mm腋芽为实验材料，对500、1000和2000 mg·L-1秋水仙素溶液分别处理24和48 h后腋芽的生长状况以及萌发枝条和叶片的生长和发育状况进行分析，同时，对各处理组花粉母细胞的减数分裂行为进行观察；在此基础上，对秋水仙素处理后茉莉腋芽及萌发枝条的各生物学效应指标进行相关性分析。结果显示：经秋水仙素处理后，各处理组腋芽的生长率和处理指数，以及萌发枝条的长度、最大节间长、最大叶长、最大叶宽、现蕾数、现蕾率、最大蕾长、最大蕾宽和开花率总体上显著(P<0.05)低于对照组(用清水处理未萌发腋芽48 h)，而腋芽的抑制率和死亡率显著高于对照组。总体上看，随秋水仙素质量浓度提高，腋芽的生长率和处理指数降低，而抑制率和死亡率升高，萌发枝条的长度和最大节间长缩短，开花率升高，其他指标呈波动变化；随处理时间延长，腋芽的生长率、死亡率和处理指数降低，但抑制率升高，萌发枝条仅现蕾数和开花率降低，其他指标均逐渐提高；随腋芽长度增加，腋芽的抑制率和处理指数降低，但死亡率升高，萌发枝条的现蕾率、现蕾数、最大蕾长和开花率均呈波动变化，其他指标均降低。经秋水仙素处理后，茉莉花粉母细胞在减数分裂过程中存在落后染色体、染色体桥和微核等异常现象，且随秋水仙素质量浓度和腋芽长度增加及处理时间延长，减数分裂后期的细胞异常率逐渐升高。相关性分析结果显示：细胞异常率与腋芽生长率呈显著负相关，与腋芽死亡率呈极显著正相关；腋芽生长率与腋芽抑制率和开花率分别呈显著和极显著(P<0.01)负相关；腋芽抑制率与现蕾率呈显著正相关；处理指数与细胞异常率呈极显著负相关。研究结果表明：秋水仙素浓度和处理时间对茉莉腋芽的生长发育有一定影响；综合考虑各生物学效应指标，茉莉腋芽适宜的诱导条件为用500 mg·L-1秋水仙素溶液处理3~5 mm腋芽24 h。此外，建议将处理指数作为秋水仙素对茉莉腋芽细胞减数分裂影响效应的评价指标之一。

Effects of concentration and treatment time of colchicine on growth and development of axillary buds of Jasminum sambac

In order to understand the effect of colchicine treatment on growth and development of axillary buds of Jasminum sambac (Linn.) Aiton, taking axillary buds with length of 0 (un-germinated), 3-5 and 8-10 mm as experimental materials, growth status of axillary buds and growth and development status of sprouting branches and leaves were analyzed after treated by 500 , 1 000 , and 2 000 mg · L-1 colchicine solution for 24 and 48 h, respectively. Meanwhile, meiotic behavior of pollen mother cells of different treatment groups was observed. On this basis, analysis on correlation among different biological effect indexes of axillary buds and sprouting branches of J. sambac after treated by colchicine was carried out. The results show that after treated by colchicine, growth rate and treatment index of axillary buds,length of sprouting branches, length of the longest internode, length of the largest leaf, width of the largest leaf, floral bud number, floral budding rate, length of the largest floral bud, width of the largest floral bud and flowering rate of different treatment groups are generally significantly ( P<0 . 05 ) lower than those of the control group ( un-germinated axillary buds treated by water for 48 h) , while inhibition rate and mortality of axillary buds are significantly higher than those of the control group. Overall, with increasing of mass concentration of colchicine, growth rate and treatment index of axillary buds decrease, while inhibition rate and mortality increase, lengths of sprouting branches and the longest internode shorten, flowering rate increases, other indexes appear fluctuant change. With prolonging of treatment time, growth rate, mortality and treatment index of axillary buds decrease, but inhibition rate increases, and in sprouting branches, only floral bud number and flowering rate decrease, other indexes all increase gradually. With increasing of length of axillary buds, inhibition rate and treatment index of axillary buds decrease, but mortality increases, floral budding rate, floral bud number, length of the largest floral bud and flowering rate of sprouting branches all appear fluctuant change, while other indexes all decrease. After treated by colchicine, there are abnormal phenomena including lagging chromosome, chromosomal bridge, micronucleus and so on, during meiotic process of pollen mother cells of J. sambac, and with increasing of mass concentration of colchicine and length of axillary buds and prolonging of treatment time, abnormal cell rate at meiotic anaphase increases gradually. The result of correlation analysis shows that abnormal cell rate has a significantly negative correlation with growth rate of axillary buds, and has an extremely significantly positive correlation with mortality of axillary buds; there is a significantly and extremely significantly ( P<0 . 01 ) negative correlation of growth rate of axillary buds with inhibition rate of axillary buds and flowering rate, respectively; there is a significantly positive correlation of inhibition rate of axillary buds with floral budding rate; there is an extremely significantly negative correlation of treatment index with abnormal cell rate. It is suggested that concentration and treatment time of colchicine have a certain effect on growth and development of axillary buds of J. sambac. Comprehensively considering on different biological effect indexes, the appropriate induction conditions of axillary buds of J. sambac is treating 3-5 mm axillary buds for 24 h by 500 mg·L-1 colchicine. In addiition, treatment index is proposed to be one of evaluation index of influential effect of colchicine on cell meiosis of axillary buds of J. sambac.