<Emphasis Type="Italic">Grateloupia ramosa</Emphasis> Wang &amp; Luan sp. nov. (Halymeniaceae,Rhodophyta), a new species from China based on morphological evidence and comparative <Emphasis Type="Italic">rbc</Emphasis>L sequences

Grateloupia ramosa Wang & Luan sp. nov. (Halymeniaceae, Rhodophyta) is newly described from Hainan Province, southern China. The organism has the following morphological features: (1) purplish red, cartilaginous and lubricous thalli 5–10 cm in height; (2) compressed percurrent axes bearing abundant branches with opposite arrangement; (3) claw-like apices on top, constricted to 2–4 cm at the base; (4) cortex consisting of 3–6 layers of elliptical or anomalous cells and a medulla covered by compact medullary filaments; (5) reproductive structures distributed throughout the thallus, especially centralized at the bottom of the end portion of the branches; and (6) 4-celled Carpogonial branches and 3-celled auxiliary-cell branches, both of the Grateloupia-type. The morphological diff erences were supported by molecular phylogenetics based on ribulose-1, 5-bisphosphate carboxylase/oxygenase (rbcL) gene sequence analysis. There was only a 1 bp divergence between specimens collected from Wenchang and Lingshui of Hainan province. The new species was embedded in the large Grateloupia clade of the Halymeniaceae. The pairwise distances between G. ramosa and other species within Grateloupia ranged from 26 to 105 bp, within pairwise distances of 13–111 bp between species of the large genus Grateloupia in Halymeniaceae. Thus, we propose this new species as G. ramosa Wang & Luan sp. nov.     

主要环境因子对细弱蜈蚣藻(Grateloupia tenuis)孢子发育的影响及生活史的研究

在实验室条件下,以细弱蜈蚣藻(Grateloupia tenuis Wang et Luan)为材料,进行了不同温度和光照强度等主要环境因子对其发育影响的研究,同时对其生活史进行了详细观察。结果表明:(1)在4—30°C范围内,盘状体形成与直立枝生长的最适温度为24°C;(2)在光照强度10—200μmol范围内,盘状体形成和直立枝生长的最适光照强度为120μmol/(m2s);(3)孢子(果孢子和四分孢子)发育类型为间接盘状体类型;(4)生活史由单倍体的雌、雄配子体,双倍体的果孢子体(囊果)及四分孢子体构成,四分孢子体和配子体在形态上完全相同,属于典型的同型世代交替;与属模蜈蚣藻(G.filicina)一致。