文章摘要
张源,严兴洪.自然条件下的坛紫菜(Pyropia haitanensis)四分体发育与性别表型观察[J].水产学报,2013,37(6):871~883
自然条件下的坛紫菜(Pyropia haitanensis)四分体发育与性别表型观察
Observation on tetrad development and formation of sex phenotype of Pyropia haitanensis blades in natural conditions
投稿时间:2013-04-15  修订日期:2013-05-22
DOI:10.3724/SP.J.1231.2013.38670
中文关键词: 坛紫菜,四分子体,叶状体,雌雄同体,性别表型
英文关键词: Pyropia haitanensis, tetrad, blade, monoecious, sex phenotype
基金项目:国家“八六三”高技术研究发展计划(2012AA10A411);国家自然科学基金项目(31072208);公益性行业(农业)专项(200903030);国家农业科技成果转化资金项目(2011GB2C000005);上海市科委重点科技攻关项目(10391901100);国家海洋公益性行业科研专项(201105008,201105023)
作者单位E-mail
张源 上海海洋大学 zy7704@foxmail.com 
严兴洪 上海海洋大学 xhyan@shou.edu.cn 
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中文摘要:
      为揭示野生坛紫菜的性别真相以及野外的性别观察与室内遗传杂交实验所得性别结果相反的原因,对可能影响天然坛紫菜性别的几个关键问题进行了研究,结果如下:5.8S rDNA保守区域的序列分析结果证实,野生坛紫菜群体中的雌雄同体与雌雄异体个体均属同一物种。坛紫菜颜色突变体与野生型间的杂交品系在天然条件下栽培所产生的F1叶状体出现了亲本色的分离与重组,95.6%的小叶状体(约5 mm)为由2-4色块构成的颜色嵌合体,它们长大后的每个色块只出现一种性别,颜色嵌合体也是性别嵌合体,该结果与室内杂交实验一致,这表明在自然条件下,坛紫菜的减数分裂位置与性别分离模式均未改变。但在随后的发育过程中,近基部的1–2个色块严重滞育,仅形成肉眼较难发现的小藻块,构成假根和基部,它们基本不成熟,造成嵌合体的绝大部分藻体由梢部的1-2个色块发育而来,嵌合体比例降至42.1%。但即使是雌雄嵌合的个体,由于梢部色块面积通常较大且成熟远早于中、基部色块,在成熟期的初、中期, 成熟个体几乎均为梢部色块成熟,表现为单性,在成熟期的晚期,中部色块开始成熟,雌雄同体比例大幅度上升。本研究表明,在天然条件下生长的坛紫菜仍以雌雄同体为主,但减数分裂产物的四分体不均衡发育以及藻体的梢、中、基部的不同步成熟均极大地降低了叶状体真实性别被观察到的概率,单凭肉眼一次性抽检,其性别往往以雌雄异体为主,少数为雌雄同体。
英文摘要:
      The cross between a red-mutant (R, ♀) and a wild type (W, ♂) of Pyropia haitanensis in laboratory demonstrated that its gametophytic blades were mainly monoecious. However, sexual observations showed a contrary result in the wild populations of this species. In order to clarify the real sex of the wild blades, some of the key issues related to this discrepancy were studied in this paper. Sequencing analysis of 5.8S rDNA region demonstrated that the monoecious and dioecious blades in wild populations of P. haitanensis were the same species. In nature, the heterozygous conchocelis produced in the cross between a red mutant and the wild type was cultivated, and the conchospores released from mature conchocelis were cultivated into F1 blades. Microscopic observation showed that two parental color sectors (W sector and R sector) and two recombinant color sectors (R′ sector and W′ sector) appeared in F1 blades, and 95.6% of the young blades (about 5 mm in length) were linearly sectored with 2-4 color-sectors. Besides, when those young blades grow up, each mature color-sector in the sectored blade was unisexual (either male or female). Therefore, the color-sectored blades were also the sex-sectored blades. Those findings tallylied with those obtained in laboratory, indicating that neither the position of meiosis nor segregation mode of the parental sex was change in natural conditions. However, during subsequent development of the young blades, one or two basal color-sector(s) was arrested severely. As a result, they formed very small areas on the blade which were hardly discerned by naked eyes. The area composed the rhizoid or basal part of the adult blade which could hardly maturate. Nearly entire blade was derived from one or two top color-sector(s), therefore color-sectored blades dropped to 42.1%. However, the uppermost sector took very large area of the blade and its maturity was much earlier than the middle and basal part. As a result, in the beginning and middle stages of the maturity, almost all the mature parts of the blades were in the upmost sector, and their phenotype showed unisexual even though they were monoecious actually. At the end of maturity of the blades, the middle sectors started to maturate, so the percentage of monoecious blades increased significantly. The results above showed that the wild blades of P. haitanensis in nature were also mainly monoecious. However, the probability for observation of its real sex was greatly reduced because of the uneven development of the tetrad and the asynchronous maturity of the top, middle and base of the blades. Due to these factors, one-time sampled by naked eyes often revealed that the wild blades were dioecious phenotype, with a few exceptions of monoecious phenotype.
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