鼠尾藻群体资源调查及人工繁育的研究

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	鼠尾藻群体资源调查及人工繁育的研究
其他题名	Surveys of natural populations and artificial breeding of Sargassum thunbergii
	刘玮1
学位类型	博士
导师	段德麟
	2015-05-23
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	海洋生物学
关键词	鼠尾藻生态学调查人工繁育遗传多样性
摘要	通过对荣成俚岛湾鼠尾藻种群的全年生态学调查，发现该地区鼠尾藻群体成熟期为6月至8月中旬，海水温度在14.4～25.1℃。温度升高和日照时间延长可促进鼠尾藻的成熟。鼠尾藻群体成熟时，其藻体平均长度、干重处于全年最高水平，成熟藻体长度主要在20～39.9 cm。随后，藻体逐渐衰退，从固着器上脱落，平均长度和干重在11月时达到最低。潮间带不同位置对鼠尾藻长度和生物量有明显影响，低潮带实验组的藻体长度和生物量明显高于中潮带和高潮带实验组。鼠尾藻群体长度分布频度和生物量在长度梯度组中的分布在鼠尾藻成熟期前后具有明显变化。在鼠尾藻人工繁育过程中，为了提高鼠尾藻受精卵的利用率、降低人工幼苗的损失，对受精卵放散、假根发育、幼苗附着和冲刷影响等因素进行了研究。结果表明，受精卵放散率在开始的60h内随时间延长而增加。随着幼苗假根出现及假根丝的延长，幼苗附着力明显增强。幼苗的脱苗率随首次冲刷时间的延后和冲刷流速的降低而降低。但是在幼苗附着后的20天内，实验中采用的三种冲刷流速都造成附着幼苗的大量脱落。在鼠尾藻海上暂养过程中，对苗帘上幼苗的叶片长度、宽度、数量、密度进行了连续观察统计，结果表明较浅的水层（水下0～10 cm）相比于其它深度的水层（水下40～50 cm、80～90 cm）更利于鼠尾藻幼苗的生长。在幼苗下海培育初期，不同养殖水层均有脱苗现象，水层深度对脱苗率没有显著影响。采用RAPD分子标记方法对我国沿海大连、威海、青岛、温州、福州地区的鼠尾藻群体进行了遗传多样性研究。从60条随机引物中筛选出21条引物，对150份5个鼠尾藻群体DNA样本进行了扩增，共检测到207个有效位点，多态位点达89.5%，Nei基因多样性指数（H）为0.2966，Shannon信息指数（I）为0.4508；群体间的分化系数Gst为0.6131，基因流Nm为0.3155。分子方差分析表明Fst值为0.6185。研究结果表明鼠尾藻群体遗传多样性水平相对偏低，群体间存在相对较高水平的遗传分化。
其他摘要	An annual ecological investigation was conducted related to the seasonal pattern of Sargassum thunbergii, a dominant species distributed along the coast of Lidao Bay, Rongcheng, China. The local S. thunbergii population entered the maturation period from early June to mid-August, when seawater temperature was 14.4 - 25.1℃. Both the accumulation of temperature and the increase of photoperiod promoted reproduction of the S. thunbergii population. Primary branches reach the maximal length and biomass during the maturation stage and the mature thalli in 20- 39.9 cm had a relatively high frequency. Subsequently, branches reduce drastically due to senescence and shedding, with minimal branch length and biomass in November. The tidal position had significantly affected on the thallus length and biomass that the thalli from the low tidal position were obviously superior to that from the middle tidal position and the high tidal position both in length and biomass. The frequency and biomass in length hierarchies varied greatly around the maturity. In order to conduct artificial seedling production of S. thunbergii, we observed the zygotes release, the rhizoids development and the attachment of germlings, and conducted jet washing influence on the juvenile seedling. It showed that the percent of zygotes released was increased with time in the first 60 hrs. The capacity of germlings attached to the substratum was significantly increased, especially coincident with the time of the new rhizoids emerged and elongated. The detachment rate of germlings significantly decreased with the delay of starting time of jet washing or the reduction of jet washing velocity. However, the jet washing at any level applied in the experiment could cause considerable loss of germlings within the 20 days after the attachment.We investigated the variations about leaf length of germlings, leaf width of germlings, leaf number of germlings, and germling density on collector during the early culture at sea. Results showed that the germlings cultured at the lower depth (0-10 cm depth) were significantly better than that at other depth (40-50 cm, 80-90 cm). The germling detachment was all found at different depth groups and germling detachment rate was not significantly influenced by depth. Five populations of S. thunbergii which were respectively collected from Dalian, Weihai, Qingdao, Wenzhou, and Fuzhou were analyzed for a better understanding about the genetic diversity of the species along Chinese coast. Random amplified polymorphism of DNA (RAPD) analysis was conducted in these populations. Twenty one out of 60 polymorphic 10-base random primers were selected, by which 207 useful loci were detected. The polymorphic loci, Nei’s gene diversity and Shannon diversity index were: 89.5%, 0.2966, 0.4508, respectively. The coefficient of genetic differentiation was 0.6131 and the gene flow (Nm) was 0.3155. The results of AMOVA showed significantly genetic differentiation among populations. High level of genetic differentiation among different populations and low level of genetic diversity of S. thunbergii were revealed.
学科领域	海洋生物学
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/23249
专题	实验海洋生物学重点实验室
作者单位	1.中国科学院海洋研究所 2.中国科学院大学 3.山东省海洋生物研究院
第一作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	刘玮. 鼠尾藻群体资源调查及人工繁育的研究[D]. 北京. 中国科学院大学,2015.

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