Gribble Kristin E, Anderson Donald M, Coats D Wayne
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA.
J Eukaryot Microbiol. 2009 Jan-Feb;56(1):88-103. doi: 10.1111/j.1550-7408.2008.00378.x.
A suite of morphological, histological, and molecular techniques was used to reveal for the first time division, sexuality, mandatory dormancy period of hypnozygotes, and identity of life-history stages of any Protoperidinium spp. In both Protoperidinium steidingerae and Protoperidinium depressum, asexual division occurred by eleutheroschisis within a temporary cyst, yielding two daughter cells. Daughter cells were initially round and one-half to two-thirds the size of parent cells then rapidly increased in size, forming horns before separating. Gamete production and fusion was constitutive in clonal and non-clonal cultures, indicating that both species may be homothallic. Gametes were isogamous, approximately half the size and lacking the pink pigmentation of the vegetative cells, and were never observed to feed. Gamete fusion resulted in a planozygote with two longitudinal flagella. Planozygotes of P. steidingerae formed hypnozygotes. The fate of planozygotes of P. depressum is unknown. Hypnozygotes of P. steidingerae had a mandatory dormancy period of ca. 70 days. Germination resulted in planomeiocytes with two longitudinal flagella. Nuclear cyclosis occurred in the planozygotes of P. depressum, but in the planomeiocytes of P. steidingerae. The plate tabulation and gross morphology of gametes of P. steidingerae and P. depressum differed markedly from those of vegetative cells. Thus, misidentification of morphologically distinct life-history stages and incomplete examination of thecal plate morphology in field specimens has likely led to taxonomic confusion of Protoperidinium spp. in previous studies.
一套形态学、组织学和分子技术首次被用于揭示原多甲藻属（Protoperidinium spp.）任何物种的裂殖、有性生殖、休眠合子的强制休眠期以及生活史阶段的特征。在施氏原多甲藻（Protoperidinium steidingerae）和凹陷原多甲藻（Protoperidinium depressum）中，无性分裂通过在临时孢囊中进行的自由破裂发生，产生两个子细胞。子细胞最初呈圆形，大小为母细胞的二分之一到三分之二，然后迅速增大，在分离前形成角状突起。配子的产生和融合在克隆培养和非克隆培养中都是组成性的，这表明这两个物种可能都是同宗配合的。配子是同形配子，大小约为营养细胞的一半，且缺乏营养细胞的粉红色色素沉着，从未观察到它们摄食。配子融合产生具有两条纵向鞭毛的游动合子。施氏原多甲藻的游动合子形成休眠合子。凹陷原多甲藻游动合子的命运未知。施氏原多甲藻的休眠合子有大约70天的强制休眠期。萌发产生具有两条纵向鞭毛的游动减数分裂细胞。核环流发生在凹陷原多甲藻的游动合子中，但发生在施氏原多甲藻的游动减数分裂细胞中。施氏原多甲藻和凹陷原多甲藻配子的板片排列和总体形态与营养细胞明显不同。因此，在以前的研究中，对形态上不同的生活史阶段的错误鉴定以及对野外标本中壳板形态的不完整检查可能导致了原多甲藻属物种的分类混乱。
