大型和小型萼花臂尾轮虫的遗传和生活史特征比较研究  

Comparison of the genetic and life history characteristics between large and small Brachionus calyciflorus morphs

作　　者：葛雅丽[1,3] 张峰 曹漫漫[1] 罗彤 席贻龙 GE Yali;ZHANG Feng;CAO Manman;LUO Tong;XI Yilong(College of Life Sciences,Anhui Normal University,Wuhu 241000,China;School of Ecology and Environmente,Anhui Normal University,Wuhu 241000,China;Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province,Wuhu 241000,China)

机构地区：[1]安徽师范大学生态与环境学院,芜湖241000 [2]安徽师范大学生命科学学院,芜湖241000 [3]安徽省高校“生物环境与生态安全”省级重点实验室,芜湖241000

出　　处：《生态学报》2023年第13期5491-5504,共14页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(32070463);安徽省高校生物环境与生态安全省级重点实验室、重要生物资源保护和利用研究安徽省重点实验室专项基金;安徽省高校协同创新项目(GXXT-2020-075)。

摘　　要：近年来,有关生物个体大小变异规律的研究已经成为生活史对策研究的重要内容之一。研究发现,大小相似的萼花臂尾轮虫(Brachionus Calyciflorus)母体所产休眠卵孵化出的不同克隆后代个体大小变化显著,其中,最大个体是最小个体体积的6.25倍。推测种群内产生不同大小的后代个体是轮虫应对环境变化的一种适应性进化策略,然而目前对上述不同大小轮虫克隆的遗传和生活史特征的研究尚未见报道。以mtDNA COI基因和rDNA ITS序列作为分子标记,比较了个体大小差异显著的不同克隆萼花臂尾轮虫的遗传分化程度和分类地位,并在不同温度(20℃、25℃、30℃)和不同斜生栅藻(Scenedesmus obliquus)食物密度(1.0×10^(6)、3.0×10^(6)、5.0×10^(6)个/mL)下比较了它们的生活史特征。结果表明,萼花臂尾轮虫种群内个体大小变异并非由于遗传特征的明显分化所导致,大型和小型个体轮虫克隆在两种分子标记上并不构成姐妹种,且两种形态型间还存在共享单倍型。温度、食物密度、轮虫形态型,以及温度和食物密度各自与轮虫形态型之间的交互作用,均显著影响轮虫的生活史特征。小型轮虫在1.0×10^(6)个细胞/mL食物密度下显著延长了胚胎和幼体的发育时间,缩短了生殖期历时;大型轮虫在1.0×10^(6)个细胞/mL和3.0×10^(6)个细胞/mL食物密度下显著延长了幼体的发育时间,但是其用于胚胎发育和生殖的时间却不随食物密度的变化而变化。各温度和食物密度条件下,大型轮虫的生殖期历时、平均寿命和世代时间均显著延长,或有延长趋势;而两者的种群增长能力之间的差异却因温度和食物密度的不同而异。20℃、25℃以及3.0×10^(6)个细胞/mL和5.0×10^(6)个细胞/mL食物密度下两种形态型轮虫的生殖能力相似;30℃条件下小型轮虫的生殖能力更强;1.0×10^(6)个细胞/mL食物密度下大型轮虫的生殖能力更强。小型轮In recent years,studies on the size variation of organism have become an important component of life history strategy research.In this study,the significant body size variations of different Brachionus calyciflorus clones hatched by resting eggs produced by different mothers with the same body size were found,and the largest body size was 6.25 times that of the smallest one.It is hypothesized that producing offspring with different body sizes in rotifer population is an adaptive evolutionary strategy to cope with environmental changes.However,few attempts have been made to investigate the genetic and life-history characteristics of those large and small rotifer clones.Hereby,in the present study,the genetic differentiation and classification status were compared between large and small B.calyciflorus clones by molecular markers of mtDNA COI genes and rDNA ITS sequences,and their life history characteristics were also examined at 20℃,25℃,30℃and 1.0×10^(6),3.0×10^(6),5.0×10^(6)cells/mL food densities of Scenedesmus obliquus.The results showed that body size variations in B.calyciflorus populationwere not attributed to a marked divergence of genetic traits.Large and small rotifer clones showed no differentiation of sibling species by the two molecular markers,and two morphs had the shared haplotypes.Temperature,food density,rotifer morphotype,and the interactions between temperature or food density and rotifer morphotype all significantly affected life history characteristics of B.calyciflorus.At the food density of 1.0×10^(6)cells/mL,small rotifers displayed longer embryo and juvenile periods and shorter reproduction period markedly.Large rotifers did not reveal significant changes of embryo and reproduction periods in response to food level variation,but showed longer juvenile period at 1.0×10^(6)and 3.0×10^(6)cells/mL food densities.Compared to small rotifers,the reproduction period,average lifespan and generation time of large rotifers became longer significantly,or tended to be longer significantly

关 键 词：萼花臂尾轮虫 个体体积 形态 遗传分化 生活史特征 

分 类 号：Q958.8[生物学—动物学]