高盒形藻的有性生殖发生

Morphology and Morphogenesis in Amphisiella sp. (Ciliophora, Hypotrichida)

从厦门沿岸分离高盒形藻，培养观察其有性生殖发生．该藻在光诱导下每天发生一次性分化，每次持续４ｈ．从海区采样观察和实验室培养，性分化在６２μｍ以下宽度的细胞中发生．每个精原孢囊产生１２８个单鞭毛精子，精子生活１９ｈ之后存活率大大下降，每个卵囊形成成对的卵子，精子和卵子几乎同步发生．结果表明，该藻可能存在小型和中型细胞分段发生性化和两次细胞复大现象．生殖中呈现的相似和相异特征，显示种间的亲缘关系．

The morphology and morphogenesis were studied during asexual reprodution of Amphisiella sp..Oral primordium appeared between median ventral cirral row and left marginal cirral row. Six kineties for proter originated from right anterior end of oral primordium, then another six kineties for opisthe originated from the middle of median ventral cirral row.The anterior two cirri of median cirral row (ACR) were formed by anteriorly migrated cirri of the rightmost anlange; the middle three cirri of ACR by anterior cirri of fourth anlage from left; the posterior segment of ACR by cirri of fifth anlage from left. the formation of ACR of Amphisiella sp. was the same as that of Gastrostyla , and diffenent from that of A.mariom and A.australis .transverse cirri were formed by the most posterior cirri of second, third, fourth anlage from left, and two most posterior cirri of the rightmost anlage. the pattern forming transverse cirri was similar to that of A.australis and Gastrostyla steinii . The 'posterior right cirrus' which located at the anterior of the righimost transverse cirrus was fromed by third cirrus of the rightmost anlage. It was homologous to a single cirrus right of ACR in Amphisiellides illuvislis, and two cirri anterior of rightmost transverse cirrus in G. steinii . It was considered that Amphisiella sp. should be closer to Gastrostyla in phylogeny. The suggestion that Amphisiella would be transfered from Urostylidae to Oxytrichida was supported by the similar morphogenesis of oral primordium and dorsal bristle between A . sp. and Oxytricha agilis .