Abstract:Pyropia suborbiculata has strong high-temperature resistance, but whether it is better than the Pyropia haitanensis remains unknown. In this study, the conchospore germlings and blades of the wild strain of P. suborbiculata (PS-WT) and the cultivated strain of P. haitanensis (PH-WT10) were cultured at 23 ℃ (normal temperature) and 30 ℃ (high temperature), respectively. The results showed that: after 14 days of culture at 23 ℃, the rates of survival and rhizoid germination of conchospore germlings in PS-WT and PH-WT10 were all over 99%, and there was no significant difference between them; At 30 ℃, the rates of survival and rhizoid germination of conchospore germlings were 32.9% and 99.3% in PS-WT, the rates of survival and rhizoid germination of conchospore germlings were only 16.8% and 49.3% in PH-WT10. In addition, the percentages of conchospore germlings with more than 9 cells of PS-WT and PH-WT10 were 86.1% and 1.0% at 30 ℃, respectively. When the blades were firstly cultured at 23 ℃ for 30 days, and then cultured at 30 ℃ for another 10 days, the blades of PS-WT showed no abnormalities except slower growth and cell color turning red, and no dead cells appeared, while the blades of PH-WT10 showed significantly slower growth, lighter cell color, the chromatophore changed from stellate to diffuse, and more dead cells appeared. In addition, compared with the initial value at the beginning of the experiment, the maximum photon yield (Fv/Fm) of the blades cultured at 30 ℃ for 10 days was increased by 1.8% in PS-WT, but decreased by 34.5% in PH-WT10. The above results preliminarily confirmed that the high-temperature resistance of the conchospore germlings and blades of the wild strain of P. suborbiculata (PS-WT) was significantly better than that of the cultivated strain of P. haitanensis (PH-WT10).