Effects Of Genetic And External Factors On Sex Development Of Gametophytes In Porphyra Katadai Var. Hemiphylla

The conchosporelings derived from different genetically original conchocelis of Porphyra katadai Miura var. hemiphylla Tseng et T.J.Chang are mainly investigated for its pigmentation differentiation in young stage and sex differentiation in maturation. Sex differentiation of monosporelings are also studied. The five conchocelis named PKWC, PKTF, PKTM, PKSTF and PKSTM of P. katadai var.hemiphylla are cultured respectively into conchosporangia, and then conchospores release from mature conchosporangia at lower temperature. Conchospores are cultured at temperatures 9℃,13℃,17℃in order to got conchosporelings. Percentages of pigmentation differentiation of young conchosporelings at different temperatures are counted and those of sex differentiation are followed when conchosporelings get mature. Monosporelings are also formed at all experimental temperatures and those sex differentiation are observed too.Main results are as followed:1. Conchosporelings from 5 conchocelis can differentiate into young germlings with pigmentation differentiation. The potentiality is different with the sequence from high to low: PKWC>PKTF>PKSTF≈PKSTM>PKTM. 9~17℃, Capability of pigmentaion differentiation in PKTF gets higher with temperature increasing; those in PKWC, PKSTF and PKSTM get lower with temperature increasing.2. Conchosporelings from 5 conchocelis produce pigmentation differentiation with half deep and half ligh on thalli at all temperatures. But other sex arrangement patterns occur when conchosporelings become mature at all temperatures, i.e. sex change has occurred.3. Capability of 5 original conchosporelings producing diversal sex arrangement patterns is different with the sequence from higher to lower: PKWC>PKSTF>PKTF>PKTM≈PKSTM. Sex arrangement pattern in mature conchosporelings has 3 types: (1)monoecious with female and male mixed; (2) monoecious with demarcation between female and male;(3)female. At experimental temperatures, the most diversal sex arrangement patterns occur at 9℃which is the optimal temperature for conchosporeling growth. In general, monecious thalli with mixing reproductive structures become more with temperature increasing, which means this sex arrangment pattern prefers higher temperature.4. Monosporelings can form at temperatures 9～20℃. Both conchosporelings with pigmentation differentiation and without pigmentation differentiation can produce monosporelings. Sex arrangement pattern in mature monosporelings is monoecious with mixing female and structures.Conclusions can be drawed out from above results:1. Diversal sex developmental patterns and sex change exist in P. katadai var. hemiphylla conchosporelings; the sex arrangement patterns are influenced genetically and environmentally, especially temperature.2. Potentiality of different original conchospores in sex diversity is different with sequence from high to low: PKWC>PKSTF>PKTF>PKTM≈PKSTM.3. Sex developmental mechanism in P. katadai var. hemiphylla is not sex determination.