Study On The Meiosis And Apomixis Of Porphyra

Porphyra is the highest-economic-value seaweed in the world at present. Recently, there has been a great loss in Porphyra farming due to the degeneration of cultivar quality and the increasing diseases, which shows the weak basis study on Porphyra. Meiosis is the important theoretical basis of genetic and breeding in Porphyra. Meiosis keeps germ plasm or chromosome numbers stable. Crossing over in homologous chromosomes and random combination in nonhomologous chromosomes take place during meiosis, which increases the variability of germ plasm and adaptability to the environment. It has been more than eighty years from 1920s about the study on the meiosis of Porphyra. The position and timing of meiosis has been a problem for the algologists.An improved staining method of modified carbol fuchsin was successfully introduced to the karyotype analyses of marine algae, including Porphyra at different stages and the gametophytes of Undaria pinnatifida and Laminaria japonica. Haploid numbers of chromosomes were observed clearly in the vegetative cells, spermatangial cells and most conchosporangial cells with five chromosomes of P. haitanensis and three chromosomes of P. yezoensis. Diploid numbers of chromosomes were observed in some conchosporangial cells with ten chromosomes of P. haitanensis and six chromosomes of P. yezoensis. Pit-connections of red algae and chromosomes at the prophase in conchocelis cells were found markedly stained with modified carbol fuchsin. One molar per liter hydrochloric hydrolysis is necessary for the staining of chromosomes in conchosporangial branches of Porphyra at 60℃for 7-8min to get a very transparent cytoplasm. Compared with iron alum acetocarmine and aceto-iron- haematoxylin-chloral hydrate, modified carbol fuchsin gives the better results with simple, rapid, deep staining and good contrast between nucleus and cytoplasm. It provides a new staining method for the...