Single-cell Multi-core Tubular Green Algae Protoplasm Reunion And Developmental Research

The aggregation of the protoplasm of Bryopsis hypnoides, Codium fragile and Caulerpa serrulata, which were coenocytic Siphonales, formation and development of the newly formed protoplasts were studied in laboratory conditions. The results indicated that:The number of the protoplasts formed under Na+ concentration of 0.5 M was the most, for the Ca2+ was under 0.2 M. The nuclei of B. hypnoides were changed in appearance from spherical to triangle or long strands during protoplasm aggregation. The protoplasm without mature chloroplasts (PMC) of B. hypnoides aggregated together in artificial seawater and protoplasts without mature chloroplasts (PTCs) were formed. Cell membrane was regenerated from the PTCs, however, the cell wall was not regenerated and the PTCs died in 72 h. For the isolated chloroplasts, when they were transferred into seawater, there were only two or three chloroplasts aggregated together, which were very small. In comparison with the PMC and the chloroplasts, the isolated mitochondria and the mixed six layers cell organelles (separated by the PMC with sucrose density centrifugation) could not aggregate in the artificial seawater. An incompatibility barrier was present during protoplast formation in B. hypnoides to exclude foreign conchospores. Even when the conchospores were incorporated into protoplasts in some experimental condition, they were expelled from the protoplasts or the protoplasts were degenerated within several days. However, the regeneration polarity was changed from one direction to two or three directions when conchospores were added to the protoplasm. There were three generations regenerated from the protoplasts of B. hypnoides. The number, diameter and regeneration of the protoplasts trait were inherited stably for 3 generations in succession. The protoplasm of B. hypnoides could be aggregated and new protoplasts from June to December; however, the newly formed protoplasts were regenerated from August to December. The protoplasm of C. fragile could be aggregated in artificial seawater. The newly formed sub-protoplasts of C. fragile disintegrated in 72h. The enzyme and staining experiments showed that the long and gelatinous thread involved in the formation of the protoplasts was composed of protein and saccharide. The experiments indicated that C. fragile would be a suitable model alga for studying the formation of protoplasts. The propagation bud, swimming cell, filamentous thalli and utricle could be regenerated and developed to mature individuals which would be propagation methods in C. fragile life history. The optimum concentration of HCO3—C and NO3—N were 3mM and 70μM. No significant differences in growth of thalli were detected when the nitrate that was normally used in the culture medium was replaced by nitrite, ammonium or urea. The light saturation point of C. serrulata was 200μmol/(m2 s) and the optimum growth temperature was 25-30°C. The recruitment of the fragmented C. serrulata showed a negative correlation with the light intensity and it was only recruited at 20-35°C. The protoplasm of C. serrulata could be aggregated and new protoplasts could be formed in the artificial seawater. However, compared with the number of formed by B. hypnoides in the artificial seawater, it formed by C. serrulata was very little.