| Protoplasts of Bryopsis hypnoides were regenerated into individuals under laboratory conditions. The regeneration process, including the form of aggregations, cell membranes and cell walls, the changes of chloroplasts and nucleoli, as well as the changes of photosynthetical properties were all recorded; physiological and biochemical indexes were detected to determine the changes brought by the regeneration; phototropism and negative phototropism of thalli and rihzoid developed from the thalli of B. hypnoides were also studied; before the aggregation of protoplasts, foreign DNA were added into the protoplast to see if there was feasibility of integrating and expressing the foreign DNA by the regenerated individuals. And the results are shown as follows:1. Protoplasts of Bryopsis hypnoides could regenerate into new individuals in seawater. In 3 minutes protoplasts aggregated into aggregations and formed pre-membrane in 20 minutes. After 6 hours and 12 hours onset of the culuture cell membrane and cell wall formed separately. Only some of the sub-protoplasts regenerated into new lives and the survival rate of sub-protoplasts was about 15% with the material and culture medium well sterilized, while the survival rate is much lower if the material and culture medium is not sterilized.2. During the regeneration period, peaks originated from photosystem II (PS II) and photosystem I (PS I) in the excitation spectra shifted to lower wavelength apparently. The peak from PS I presented first in the spectrum of 12th hours excited by wavelength of 436 nm, while a weak peak of PS I appeared originally in the spectrum of protoplast (0) excited by wavelength of 660 nm, which turned stronger with the regeneration process. The results suggested that the regeneration of protoplasts from B. hypnoides comprised a recombination or renaissance procedure of the organelles, including some important systems or elements, such as PS II.3. There was a transfiguration in the chloroplast before the aggregation, which turned into sphericity from the shape of ellipse under normal conditions as soon as seawater was added. Usually, several nucleoli enwrapped in one sub-protoplast, whicheventually found their positions in certain granularity to each other from unordered state at the beginning.4. Obvious discrepancies in both the total soluble proteins and the ratio of chlorophyll a to chlorophyll b between the regenerated B. hypnoides and the wild type were found, which may be related to the exchange of genetic material during aggregation of the organelles; As under laboratory conditions, individual regenerated from thalli and protoplasts in the field were also found, so the two propagation styles were both list into the life history of Bryopsis hypnoides.5. Being regeneration parts of a segment of a cell, thalli and rhizoid exhibited ' phototropism and negative phototropism separately. The action spectrum had a large range, from ultraviolet radiation to green light. Based on the bending curvatures, the blue light had the highest efficiency, while the effect of longer wavelengths significantly declined. External added Ca2+ had no effect on the bending curvature of thalli and rihzoid. Blue light induced thallus branching from rhizoid, while red line had no such function. Fast occurring chloroplast accumulation in the outermost cytoplasmic layer of the blue light irradiated region in the rhizoid was observed, from which protrusions (thalli) aroused after 4 h of the onset of illumination, and this action was supposed to be driven by the dynamics of actin microfilaments.6. Foreign DNA (GFP) was added into the protoplasts before aggregation to see if the foreign DNA could be integrated and expressed in the regenerated individuals. The results showed that foreign DNA expressed in both the aggregations and developed individuals of protoplasts, suggesting that the aggregation of protoplasts can act as a receptor and a vector of foreign DNA.
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