Somatic embryogenesis in Triticum aestivum L. Morphological observations on germination

Somatic embryos were induced from scutellar callus of immature zygotic embryos of T aestivum cv. Chinese Spring. Observations on precociously germinating somatic embryos revealed that: (i) In the initial stages the coleoptile is split, exposes the shoot apex and forms a green trichomatous leafy structure. In the germinating zygotic embryo, the coleoptile is tubular, (ii) Unlike what has been inferred earlier the leafy structure is the coleoptile and not the scutellum, (iii) Bipolarity of the embryoid is established later when root develops at the basal end.

Development of Cell Culture Systems from Selected Species of Fish and Prawns

The present work deals with the development of primary cell culture and diploid cell lines from two fishes, such as Poecilia reticulata and Clarias gariepinus. The greatest difficulty experienced was the avoidance of bacterial and fungi contamination. Three types of cell cultures are commonly developed, primary cell culture, diploid cell lines and heteroploid cell lines. Primary cell culture obtained from the animal tissues that have been cultivated in vitro for the first time. They are characterized by the same chromosome number as parent tissue, cultivated in vitro for the first time, have wide range of virus susceptibility, usually not malignant, six chromatin retarded and do not grow as suspension cultures. Diploid cell lines arise from a primary cell culture at the time of subculturing. Diploid cell lines commercially used in virology are W1-38 (human embryonic lung), W1-26 (human embryonic lung) and HEX (Human embryonic kidney). Heteroploid cell lines have been subcultivated with less than 75% of the cells in the population having a diploid chromosome constitution. Tissue cultures have been extensively used in biomedical research. The main applications are in three areas, Karyological studies, Identification and study of hereditary metabolic disorders and Somatic cell genetics. Other applications are in virology and host-parasite relationships. In this study an attempt was made to preserve the ovarian tissue at low temperature in the presence of cryoprotectants so that the tissue can be retrieved at any time and a cell culture could be developed.

Studies on the systematics, biology and fishery of rainbow sardines, dussumieria spp., from Indian waters

Rainbow sardines of the genus belonging to the family Dueenaieriidae. are small pelagic fishes forming a fairly good, though not abundant. seasonal fishery all along the coasts of India inhabiting the coastal waters. There have been some earlier reports on such individual aspects as their systematic, distribution, abundance. Ostecology and a few biological factors but no attempt has been made towards a comprehensive study on this group. Two species of rainbow sardines are known to occur in the Indian seas and while a knowledge about their biology would be useful from the fishery point of view. it was also thought a study of their systematic position, especially regarding the identity or the two species which had raised doubts among earlier workers would lead to a better understanding or the group as a whole. This thesis is mainly based on studies during the period from April 1969 to march 1971 with a continued investigation of fishhery aspects till December 1975. from the Gulf of manar: and the Palk Bay around mandapam area. on the south-east coast of India. Thus the work deals with the systemtics, biology and fishery of rainbow sardines of Indian seas.

Energetics 0f A Few Marine Crustaceans

Success achieved in seed production and culture of prawns induced researchers to explore the feasibiltiy of culture of other important crustaceans like lobsters and crabs. The CMFRI initiated a project to study the prospects of spiny lobster’ culture and I was associated with this project from the beginning. Compared to shrimp farming, culture of spiny lobsters is an entirely different proposition due to inherent problems in producing their seeds. The emphasis on .obster culture, therefore, shifted to rearing of juvenile lobsters, which form a major portion in commercial lobster landings in India. Commendable success was achieved in enhancing growth rate of four important speices of spiny lobsters by bilateral eyestalk ablation. But due to strong reservations expressed against the "blinding" of lobsters by people from all walks of life, this technique could not be tested commercially for its economic viability. As in prawns, energetics of reproduction and egg development have not yet been documented in spiny lobsters and so these aspects were included in this study. Though some limited informations on food conversion efficiency are availble in spiny lobster, a detailed study on the effect of size and sexual maturity on food conversion was wanting and this also was included in this investigation. The most dominant spiny lobster in south east and south west coast of India, Panulirus homarus (Linnaeus) was selected for this study. Uptake, accumulation and utilization of minerals and trace elements are important events during embryogenesis of aquatic invertebrates. The scope of this study was widened to include these aspects also in order to understand how specific requirements of minerals and trace elements are met in the developing eggs of these two species of crustaceans.

The Major Digestive Enzymes in Etroplus suratensis and Oreochromis mossambicus: Distribution and Characteristics

The major digestive enzyme activities and digestive indices were compared between Etroplus suratensis and Oreochromis mossambicus. Pepsin - like acid proteases that acts on low pH has been identified all along the digestive tract of both the fishes. Comparatively low alpha amylase activity is shown by the E. suratensis and the enzyme is distributed almost equally throughout the intestinal segments in both the species. Very low alkaline protease activity is found in the stomach of both the fishes and in O. mossambicus, the enzyme activity diminishes extensively towards the posterior portion of the intestine whereas in E. suratensis the activity increases towards the posterior part. The present study showed that lipase is one of the prominent digestive enzymes in O. mossambicus with a remarkable specific activity throughout the digestive tract than that of E. suratensis .It has been noted that O. mossambicus has a higher values for digestive somatic index, hepato somatic index, intestinal coefficient and gut Vs standard length ratio than that of E. suratensis indicating its higher digestive and metabolic capabilities. The early maturity and fast growth of O. mossambicus can be explained by their enhanced digestive indices. The compa ratively low activities of acid protease, amylase, lipase and total alkaline protease of E. suratensis revealed poor digestive capacity than that of O. mossambicus