Guan J-Z, Wang J-J, Cheng Z-H, Liu Y, Li Z-Y
Institute of Medicinal Plants, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, PR China.
Genet Mol Res. 2012 Jan 17;11(1):121-30. doi: 10.4238/2012.January.17.2.
Houttuynia cordata (Saururaceae) is a leaf vegetable and a medicinal herb througout much of Asia. Cytomixis and meiotic abnormalities during microsporogenesis were found in two populations of H. cordata with different ploidy levels (2n = 38, 96). Cytomixis occurred in pollen mother cells during meiosis at high frequencies and with variable degrees of chromatin/chromosome transfer. Meiotic abnormalities, such as chromosome laggards, asymmetric segregation and polyads, also prevailed in pollen mother cells at metaphase of the first division and later stages. They were caused by cytomixis and resulted in very low pollen viability and male sterility. Pollen mother cells from the population with 2n = 38 showed only simultaneous cytokinesis, but most pollen mother cells from the population with 2n = 96 showed successive cytokinesis; a minority underwent simultaneous cytokinesis. Cytomixis and irregular meiotic divisions appear to be the origin of the intraspecific polyploidy in this species, which has large variations in chromosome numbers.
蕺菜（三白草科）在亚洲大部分地区是一种叶菜类蔬菜和药用草本植物。在两个不同倍性水平（2n = 38、96）的蕺菜种群中发现了小孢子发生过程中的细胞融合和减数分裂异常。细胞融合在减数分裂期间的花粉母细胞中高频发生，且染色质/染色体转移程度不同。减数分裂异常，如染色体落后、不对称分离和多联体，在第一次分裂中期及后期的花粉母细胞中也很普遍。它们是由细胞融合引起的，导致花粉活力极低和雄性不育。2n = 38种群的花粉母细胞仅表现出同时型胞质分裂，但2n = 96种群的大多数花粉母细胞表现出连续型胞质分裂；少数进行同时型胞质分裂。细胞融合和不规则减数分裂似乎是该物种种内多倍体的起源，其染色体数目存在很大差异。
