中国沿海甲藻两个新记录属——艉杆藻属和易碎藻属

The first record of Ensiculifera Balech and Fragilidium Balech (Dinophyceae) from Chinese coast

艉杆藻属Ensiculifera Balech和易碎藻属Fragilidium Balech的营养细胞和孢囊在中国沿海还未被记录过,作者在中国东海发现了它们的孢囊并通过萌发建立了株系,在光镜和电镜下研究了其细胞形态。一种艉杆藻的孢囊为圆形,直径22μm,双层壁,孢囊体内充满淡绿色的颗粒,有一个鲜艳的红色体,孢囊外壁覆盖着2μm长的有机质短刺;营养细胞上壳圆锥形,下壳圆形,细胞平均长17.7μm,宽12.5μm,甲板方程式为po,x,4′,3a,7″,5c,4s,5′′′,2′′′′。墨西哥易碎藻Fragilidium mexicanum Balech的孢囊为圆形,直径54–60μm,孢囊内充满淡白色的颗粒物以及淡褐色的原生质体,有一个鲜艳的黄色体,萌发孔圆形,偏在孢囊的一侧;营养细胞平均长45.3μm,宽42.8μm,甲板方程式po,5′,7″,10c,7s,7″′,2″″,1P。一种易碎藻的孢囊为圆形,直径45μm,孢囊内充满淡白色的颗粒物以及淡褐色的原生质体,黄色体不明显,细胞壁较厚,2–3μm,无色,萌发孔圆形,偏在孢囊的一侧。细胞平均长41.6μm,宽35.3μm,甲板方程式po,5′,7″,7″′,2″″,1P。对该种艉杆藻的转录间隔区(ITS)、2种易碎藻的小亚基(18S)序列进行了测定并建立了系统发育树,它们的系统发育位置和形态学分类相吻合。

Resting cysts and vegetative cells of Ensiculifera Balech and Fragilidium Balech have never been reported in China Sea. Such kinds of cysts were collected in the East China Sea and were allowed to germinate. The cyst of Ensiculifera sp. is spherical with a diameter of 22 μm. The cyst consists of two layers and is full of greenish granules, with a bright red body inside. The cyst wall is covered with short organic spines （2 μm long）. The cell of Ensiculifera sp. comprises a conical epitheca and a rounded hypotheca, with the dimension of 17.7 μm long and 12.5 μm wide on the average. The plate pattern is po, x, 4＇, 3a, 7＂, 5c, 4s, 5＇＂, 2＇＂＇. The cysts of Fragilidium mexicanum Balech are spherical with the diameter ranging from 54-60 μm. They are full of pale white granules and brown protoplasm, with a bright yellow body present. The archeopyle is spherical. The cells ofF. mexicanum are 45.3 μm long and 42.8 μm wide, with the plate formula of po, 5＇, 7＂, 10c, 7s, 7＂＇, 2＇＂＇, IP. The cyst of Fragilidium sp. is also spherical with a diameter of 45 μm, which is similar to that of F. mexicanum except that the yellow body is not present. The cells of Fragilidium sp. are 41.6 μm long and 35.3 μm wide with the plate formula of po, 5＇, 7＂, 7＂＇, 2＂＂, IP. The Internal Transcribed Spacers （ITS） of Ensiculifera sp. and the small subunit （18S） rDNA of Fragilidium spp. were amplified and sequenced. Their phylogenetic positions agree with the morphological taxonomy.