A study on seeding improvement of Porphyra dentata (bangiales, rhodophyta)

To improve the seeding rate of Porphyra dentata, experiments on promotion of conchosporangia-maturation and seeding of conchospores were performed in laboratories. Ultraviolet ray irradiation-seawater hastened the conchosporangia-maturation. Water exchange at five-days intervals and short-day (8L:16D) treatment produced a good effect on conchosporangia-maturation : with treatments of vitamin mixtures and KH₂PO₄, it was of little effect. The degree of conchosporangia-maturation by depths of conchocelises infiltrating into shells was the highest in the most deep inhabiters. The irradiation of 650 ㎚ wavelength, irradiation of ultraviolet ray to seawater and water exchange at five-days intervals after seven and ten days’ dark treatment to pounded shell-inhabiting conchocelis generally led to release of great amounts of conchospores. As two to five times’ seeding brought about an increase in the ratio of attachment of conchospores to net twines, mass seeding of P. dentata was strongly possible.