Bast, Felix2019-04-292024-08-132019-04-292024-08-132011Bast, Felix (2011)Monostroma: the Jeweled Seaweed for Future Cultivation methods, Ecophysiology, Phylogeography and Molecular Systematics978-3-8473-2710-3https://kr.cup.edu.in/handle/32116/2313This thesis aims at providing a comprehensive picture of the reproductive physiology, growth, phylogeography, and phylogenetics of M. latissimum-nitidum complex in Southern Japan. A review on agronomy and utilization of seaweeds is provided as Chapter 2 to present a comprehensive overview of the seaweed biology and applications. Seasonality in the growth and occurrence of Monostroma sp. at three environmentally distinct habitats along Tosa Bay, Kochi Prefecture, Japan is explored and results of correlation analyses between environmental conditions and thallus size are presented in Chapter 3. Also investigated in the same chapter is the homology of nuclear encoded rDNA Internal Transcribed Spacer (ITS) sequences between naturally occurring and commercially cultivated populations. Findings of the culture studies sought to identify the species naturally occurring at the study sites are also summarized in Chapter 2. In the course of research, I observed that thalli of the naturally occurring populations of M. latissimum, changes its color during maturation, as reported elsewhere in the literature. Further to that observation, a thorough cytological investigation on the gametangial ontogeny of naturally occurring M. latissimum is presented in Chapter 4 and possible taxonomic implications of this finding are discussed. Once the thalli of M. latissimum release gametes, which mode of syngamy do they have? Is sex of the progenies environmentally determined? These are some of the questions being investigated in Chapter 5. Reported in the Chapter 6 is a serendipitous discovery of an asexually reproducing ecotype of M. latissimum in the marginal populations at low-saline habitat. Findings of the culture studies to complete its life cycle are presented. Molecular studies to investigate homogeneity of nrDNA ITS sequences between the two ecot ypes (i.e., sexual vs asexual) are also investigated in the same chapter. Results of phylogenetic analyses of the newly generated ITS sequence of M. latissimum with that of the related monostromatic green algal taxa retrieved from GenBank are also presented in Chapter 6 to understand relative taxonomical position of this species in the class Ulvophyceae. Chapter 7 is an investigation on the morphologic and genetic homogeneity of natural and cultivated populations of the two closely related species M. latissimum and M. nitidum along the Southern Japanese coast where the warm-water Kuroshio Current influences throughout the year. Combined phylogeographical analysis of nuclear encoded first internal transcribed spacer (ITS1) sequences and rDNA 18s gene are presented in addition to the comparison of morphological traits, to understand if they belong to the same taxa. In the final experimental chapter, Chapter 8, taxonomic hypothesis for Monostromataceae were tested and the systematic position of this family is explored using multi-local phylogeny. Relationships of this family with over 40 Ulvophycean genera were investigated and phylogeny reconstruction was conducted using five independent genetic markers; viz., nrDNA ITS1, nrDNA ITS2, nrDNA 5.8S, nrDNA 18S and cpDNA rbcL. Chapter 9 summarizes and discusses the results of this thesis, places them in a regional context and discusses avenues of future work.enBook