杉木小孢子发生与雄球花发育相关性研究

Correlations between microsporogenesis and male cone development ofCunninghamia lanceolata

【目的】探究杉木小孢子母细胞减数分裂过程与雄球花外部形态变化的关系,为进一步开展杉木生殖生物学研究提供参考。【方法】以杉木雄球花为材料,采用数码相机实地拍照、体视镜以及醋酸洋红染色压片法研究杉木小孢子母细胞减数分裂和雄球花生长发育的过程。【结果】杉木雄球花着生于新枝顶端,外部有芽鳞包裹。随着小孢子母细胞减数分裂进行,雄球花的芽鳞逐渐打开,小孢子叶的体积增大,逐渐伸长到芽鳞之外,最终将雄球花的芽鳞挤压脱落;而小孢子叶颜色和大小也有着明显的变化,颜色经过翠绿色、黄绿相间、黄褐色、并最终变成红褐色,其长度变化范围为3.278~5.229 mm,直径变化范围为2.626~3.868 mm。观察杉木减数分裂过程发现:小孢子母细胞染色体行为存在异常,如减数分裂中期Ⅰ的落后染色体,后期Ⅰ和后期Ⅱ染色体分裂不同步,以及在四分体时期观察到不均等分裂,如二分体、三分体。不同着生位置的雄球花发育具有不同步性;同一个雄球花的不同小孢子叶以及相同小孢子叶的小孢子母细胞减数分裂进程也不相同,整个减数分裂过程大约持续3 d。【结论】杉木小孢子母细胞减数分裂进程与雄球花外部形态及小孢子叶颜色和大小的变化密切相关,其减数分裂过程中存在染色体异常现象。

[Objective]This paper aims to explore the relationship between the meiosis process of Cunninghamia lanceolata microspore mother cell and the external morphological change of male cone,so as to provide references for further research on reproductive biology of C.lanceolata.[Method]We selected the male cones of C.lanceolata as the material,and studied the process of meiosis of C.lanceolata microspore mother cell and development of male cones using the digital camera,stereoscope and the acetate magenta staining method.[Result]The male cone of C.lanceolata was born on the top of new branch and was covered by bud scales.With the meiosis process of C.lanceolata microspore mother cells to carry out,the bud scales of male cone gradually open,the volume of the microsporophyll increased and gradually elongated beyond the bud scales eventually squeezing the bud scales of male cone to falling off.In addition,the color and size of the microsporophyll also varied markedly:the color changed from emerald green,yellow green,yellow brown,and finally to reddish brown;its length ranged from 3.278 to 5.229 mm,and diameter ranged from 2.626 to 3.868 mm.The observation of meiosis process of Chinese fir showed that the chromosome behavior of microspore mother cells was abnormal,such as the lagging chromosomes in the metaphase I of meiosis,the non-synchronous division of the late I and late II chromosomes,and the unequal division was observed in the tetrad stage,such as the diploid and the triad.The development of male cones in different positions was not synchronous;the meiosis process of different microspore leaves of the same male cone and the microspore mother cells of the same microspore leaf were also different,and the whole meiosis process lasted about 3 d.[Conclusion]The meiosis process of C.lanceolata microspore mother cell is closely related to the change in external morphology and the microsporophyll color and size of male cone,and there are chromosomal abnormalities in its process of meiosis.