三倍体丹参杂交种的花粉形态研究

Pollen morphology of triploid Salvia miltiorrhiza hybrid

关键词:  丹参, 白花丹参(变型), 二倍体, 三倍体, 花粉形态

Key words:  Salvia miltiorrhiza, S. miltiorrhiza f. alba, diploid, triploid, pollen morphology

摘要:

三倍体丹参是以二倍体丹参为父本、人工染色体加倍的四倍体白花丹参为母本杂交选育的杂交种。为深入了解三倍体丹参花粉的特性,以及为三倍体种质利用提供孢粉学依据,该文以二倍体丹参为对照,研究了三倍体丹参杂交种花粉的形态变异规律。利用光学显微镜和扫描电镜对二倍体和三倍体丹参的花粉萌发沟、外壁纹饰、花粉粒形状等特征进行了显微和超微形态观察,综合进行了花粉形态差异比较,并对花粉大小和形状数据进行了差异显著性分析和正态检验。结果表明:(1)二倍体丹参为6沟花粉,三倍体花粉萌发沟有6沟和8沟两种类型,沟内疣状颗粒分布不匀,出现畸形萌发沟。(2)二倍体和三倍体花粉外壁均为网状雕纹。二倍体花粉网眼内具多个多边形穿孔,穿孔大; 6沟和8沟两种类型的三倍体花粉网眼无穿孔或仅有几个小穿孔,6沟和8沟花粉的外壁雕纹相同。(3)三倍体花粉的极轴长(P)和赤道宽(E)均值显著小于二倍体花粉,花粉大小呈偏正态分布,P*E的差异系数大于二倍体花粉,且有极值存在。三倍体和二倍体丹参的萌发沟和雕纹存在差异,而花粉形状差异不显著。综上结果表明三倍体丹参花粉在倍性效应和杂合性的双重影响下发生了形态变异,且有多种形态变化。

Abstract:

To study pollen characteristics of triploid Salvia miltiorrhiza(tetraploid S. miltiorrhiza f. alba × diploid S. miltiorrhiza)hybrid, morphological variation of triploid pollen during the triploid process was examined. Triploid and diploid pollen were observed at microscopic and ultra-microscopic level using light and scanning electron microscopes. Pollen size and shape data were analyzed to determine statistical significance. The results were as follows:(1)Compared to typical 6-colpate diploid pollen grains, triploid S. miltiorrhiza are 6- or 8-colpate, with increased number of colpi and heterogenous granules on colpus membranes, and abnormal colpate.(2)Exine sculpturing of triploid pollen was reticulate like the diploid. Both 6- and 8-colpate triploid pollen had no perforation or a few small perforations, whereas diploid pollen had many large polygonal perforations in each lumen.(3)In terms of size, mean of the polar axis(P)and equatorial axis(E)in triploid pollen were significantly smaller than that of diploid pollen. The pollen size of triploid hybrid followed a skewed normal distribution, and the coefficient of variation(CV)in P*E value of triploid was greater than that of diploid and existed extreme values. Comparison data revealed variance in colpi and sculpture between triploid and diploid, however no significant differences in pollen shape is found. Overall, the triploid S. miltiorrhiza pollen has more morphological variations due to genetic effect of both ploidy level and heterozygosity.