黄色伪角毛虫和扇形游仆虫对盐度的适应性

Salinity Adaptability of Ciliates Pseudokeronopsis flava and Euplotes vannus

为了阐明原生动物纤毛虫对盐度变化的适应性,在(25±1)℃下,将生活在盐度30下的黄色伪角毛虫(Pseudokeronopsis flava)和扇形游仆虫(Euplotes vannus)分别接种于容积3 mL海水的六孔培养板中,虫体密度为10 ind.·mL-1,由高温灭菌的蒸馏水与海水晶配成盐度为10、15、20、25、30、35、40、45、50、55、60、65,及70的海水。每组3个平行,每24 h对两种纤毛虫进行计数并测量其体长和体宽,观察其种群密度变化和生态学变化。7 d的实验发现,两种纤毛虫在盐度10~70中均可存活,40盐度组生长率最高,随着盐度升高,黄色伪角毛虫的停滞期延长,而扇形游仆虫的停滞期下降;盐度高于55时,两种纤毛虫的细胞均皱缩,黄色伪角毛虫的长轴、短轴分别下降68.17%和69.26%,虫体变为圆形、梭形或其他不规则形状;盐度由55升至60时,扇形游仆虫的长轴下降了69.88%,短轴下降了72.01%;盐度升高至65后,虫游动减慢甚至停止,食物泡逐渐扩大直至充满整个虫体,体色改变;盐度70时,虫体变为圆型。两种纤毛虫的最适生长盐度为40。本研究结果可为水生生物适应海洋盐度变化的研究提供数据支持。

In order to understand the effects of salinity changes on marine ciliates,Pseudokeronopsis flava and Euplotes vannus,the two species of ciliates living at salinity of 30 were inoculated in six-well culture plates containing 3 mL of seawater with a salinity of 10,15,20,25,30,35,40,45,50,55,60,65 or 70 prepared by high-temperature sterilized distilled water and sea crystals at a density of 10 ind.mL-1 at water temperature of(25±1)℃for 7 d with triplication for each group,via counting and measuring the body length and body width of the two ciliates every 24 h to observe density and morphological changes of the two ciliates.The results showed that P.flava and E.vannus were survival in salinities ranging from 10 to 70,with a wide adaptability to salinity.The maximal growth rate was observed in the two ciliates exposed to the salinity of 40,and the lag phases(λ)lengthened in P.flava,and was shortened in E.vannus with the increase in salinity.The cells of the two ciliates were shown to be wrinkled,being shortened by 68.17%in long axis,by 69.26%in short axis in P.flava,with round,fusiform or other irregular shape at salinity of over 55.When the salinity was changed from 55 to 60,the long axis of E.vannus was decreased by 69.88%and the short axis decreased by 72.01%.The ciliates exposed to the salinity of 65 swam slowly down or even stopped,had gradually expanded food bubble until filled the entire worm body,and changed in the body color.At a salinity of 70,the body of the worm turned into round in shape.It was found that 40 was of the optimal growth salinity for the two ciliates.The findings provide data support for the research on the adaptation of aquatic organisms to the variation in marine salinity.