印度产紫菜Pyropia chauhanii的细胞学观察

Cytological studies on Pyropia chauhanii from Indian

本研究对印度产紫菜Pyropia chauhanii不同生活史阶段的染色体进行了系统的细胞学观察。分别对室内培养的P.chauhanii各生活史阶段的活体组织进行固定和用醋酸铁苏木精染色后进行观察,结果表明:叶状体阶段的营养细胞、精子囊内未成熟精子和果胞均为单倍核型(n=3);而丝状体阶段的果孢子、丝状体的营养细胞和膨大细胞均为双倍核型(2n=6);由丝状体产生的壳孢子在萌发初期发生减数分裂后,由双倍核型(2n=6)变成了单倍核型(n=3)。当叶状体进行单性生殖产生丝状体时,游离出来的类果孢子发生了染色体自然加倍,其萌发体和随后形成的丝状体的营养细胞和膨大细胞均为双倍核型(2n=6)。当叶状体放散单孢子进行无性繁殖时,单孢子和其萌发体的细胞均为单倍核型(n=3)。

In this paper,a chromosomal observation on different growth phases of Pyropia chauhanii from India was conducted. The living materials of different life phases in P. chauhanii were fixed in Carnnoy ＇s fixative fluid,and stored at the light conditions to leach phycobilin pigments. The samples were then stained with Wittmann ＇s aceto- iron haematoxylin chloral hydrate and examined under a photomicroscope.Chromosome counts indicated that vegetative cells of gametophytic blade,spermatia and carpogonium are haploid（ n = 3）; whereas carpospores,vegetative and conchosporangial cells of conchocelis are diploid（ 2n = 6）. The meiosis happened during the first division of the germinating conchospores,and after that,the chromosome changed from diploid to haploid. The spontaneous chromosome doubling occurred in the carpospore- like cells during the parthenogenesis of the gametophytic blades,and chromosome counts indicated that the germinating carpospore- like cells,their germ- tube cells,the vegetative cells and conchosporangial branch cells of parthenogenetic conchocelis are diploid（ 2n = 6）. Monospores and the cells of their germlings are haploid（ n = 3）. The above results showed that the haploid and diploid phases of P.chauhanii have 3 and 6 chromosomes,respectively.