GENOTYPIC VARIATION AND ALTERNATING DNA LEVELS AT CONSTANT CHROMOSOME NUMBERS IN THE LIFE HISTORY OF THE BROWN ALGA HAPLOSPORA GLOBOSA (TILOPTERIDALES)1

Despite the large amount of work which has already been devoted to the study of the Coccidia and Gregarines, very little indeed is known definitely about the behaviour of the chromosomes in these Protozoa. Not only has the chromosome cycle been left uninvestigated and undescribed in the majority of these organisms which have hitherto been studied, but the very existence of chromosomes in the nuclear divisions at many stages in the life-history of certain forms has even been denied; and the most contradictory and unsatisfactory accounts have been given of that most important phase in the life-cycle of the chromosomes—the phase of meiosis, or reduction. In order to fill up this gap in our knowledge of the Sporozoa, we have made —during the last few years—a very detailed study of the chromosomes of a coccidian and a gregarine. One of us (C. D.) has investigated the coccidian Aggregate eberthi Labbé, whilst the other (A. P. J.) has studied the gregarine Diplocystis schneideri Kunstler. Careful investigation of these two organisms has shown that the nuclear divisions at all stages in the life-histories are mitotic, and that the chromosome numbers are remarkably constant.

Download Full-text

Life history and iodine nutrition of the marine brown alga, Petalonia fascia (O. F. Müll.) Kuntze

Canadian Journal of Botany ◽

10.1139/b69-231 ◽

1969 ◽

Vol 47 (10) ◽

pp. 1611-1616 ◽

Cited By ~ 19

Author(s):

Stephen I. C. Hsiao

Keyword(s):

Life History ◽

Brown Alga ◽

Culture Media ◽

Essential Element ◽

Iodine Nutrition ◽

History Of ◽

Defined Culture ◽

Free Media ◽

Marine Brown Alga ◽

Petalonia Fascia

The morphological life history of the marine brown alga, Petalonia fascia (O. F. Müll.) Kuntze, has been investigated in unialgal culture, using defined culture media with different iodide concentrations. The zoospores produced from the plurilocular sporangia of P. fascia blades developed directly into protonemata, plethysmothalli, or Ralfsia-like thalli, depending upon the iodide concentration. Protonemata and plethysmothalli survived in iodide-free media. For development of Ralfsia-like thalli and blades the minimal iodide concentrations required were 50.76 × 102 μg/1 and 50.76 × 101 μg/1, respectively. Iodine appears to be an essential element for growth, morphogenesis, and reproduction of P. fascia.

Download Full-text

Breeding in the Economically Important Brown Alga Undaria pinnatifida: A Concise Review and Future Prospects

Frontiers in Genetics ◽

10.3389/fgene.2021.801937 ◽

2021 ◽

Vol 12 ◽

Author(s):

Tifeng Shan ◽

Shaojun Pang

Keyword(s):

Life History ◽

Brown Alga ◽

Undaria Pinnatifida ◽

Raw Materials ◽

Saccharina Japonica ◽

History Plays ◽

Seaweed Farming ◽

History Of ◽

Genomics Tools ◽

Farming Industry

Undaria pinnatifida is the commercially second most important brown alga in the world. Its global annual yield has been more than two million tonnes since 2012. It is extensively cultivated in East Asia, mainly consumed as food but also used as feed for aquacultural animals and raw materials for extraction of chemicals applicable in pharmaceutics and cosmetics. Cultivar breeding, which is conducted on the basis of characteristics of the life history, plays a pivotal role in seaweed farming industry. The common basic life history shared by kelps determines that their cultivar breeding strategies are similar. Cultivar breeding and cultivation methods of U. pinnatifida have usually been learned or directly transferred from those of Saccharina japonica. However, recent studies have revealed certain peculiarity in the life history of U. pinnatifida. In this article, we review the studies relevant to cultivar breeding in this alga, including the peculiar component of the life history, and the genetics, transcriptomics and genomics tools available, as well as the main cultivar breeding methods. Then we discuss the prospects of cultivar breeding based on our understanding of this kelp and what we can learn from the model brown alga and land crops.

Download Full-text