Molecular Markers And Photosynthetic Charateristics Of Several Porphyra Cultivars

Porphyra is one of most important economic seaweed. Porphyra yezoensis is the main cultivar in the northern of our country while Porphyra haitanensis is the main cultivar in southern. Along with the development of the Porphyra industry the modern Porphyra industry has to enhance the research on molecular biology related to genetic breeding and phyotosynthetic physiological characteristics, then provide new references for Porphyra character evaluation.In this research, Simple Sequence Repeat (SSR) was used to analyze8porphyra samples.10pairs of SSR primers were screen out from73pairs of primers, a total of110loci were amplified of which23were polymorphism.2-4polymorphism were amplified for each primer with an average of1.508. The PIC valued for each locus were0.110-0.443with an average of0.254.8porphyra samples owned1.508effective alleles and0.323expected heterozygosity on average, and the Shannon index is0.496. The genetic similarity ranged from0.552to1.000with an average of0.771, and the genetic distance ranged from0.000-0.595with an average of0.272, the cluster result showed that the cultivars and wild types were divided into two clades. It indicated that there were genetic difference between cultivars and wild types, while higher similarity between cultivars.Using Sequence Related Amplified Polymorphism (SRAP) to analyze the genetic diversity of10porphyra samples,12out of25SRAP primer combinations were selected in the experiment, a total of401loci were obtained, among which353were polymorphic, with an average of33loci and an average of29polymorphic loci per primer combinations, the percentage of polymorphic loci were88%on average. The genetic distance ranged from0.210-0.628with an average of0.4673, the number of allele (Na) was1.985, effective number of allele (Ne) was1.538, Nei’s genetic diversity (H) was0.328, Shannon index (I) was0.499, The cluster result showed that P. yezoensis and P. haitanensis were obviously divided into two clades, then the cultivars and wild types of P. yezoensis were divided into two clades. It indicated that there was a distant genetic relationship between P. yezoensis and P. haitanensis, a high diversity between cultivars and wild types, while a close genetic relationship between cultivars. In this research, it screened out some specific bands for P. yezoensis identification.Using methods combined by pigment content and ratio, Net photosynthetic oxygen and chlorophyll fluorescence technology to analyze photosynthetic characters of porphyra cultivars. The results showed:during the whole growing period, the temperature of seawater decreased first and then increased, the content of chlorophyll (Chla) in march were obviously lower than January and february, while the content of phycobiliprotein (PE, PC, APC), PE/Chla, APC/Chla, actual light quantum efficiency (△F/Fm□), and The maximal relative electron transport rate (rETRmax) were obviously higher than January and february. The PE/PC, PE/APC, PE/APC, maxium quantum efficiency (Fv/Fm), Initial slope (a), semi-light saturation point (Ik), net photosynthetic oxygen had no obvious difference in january and february. The rapid light curve (RLC) showed that the relative electron transport rate (rETR) escalated with the light increasing and then reached a relatively stable stage. Each cultivar showed different character, Y-06D0had higher pigment content and ratio, Fv/Fm,△F/Fm□, net photosynthetic oxygen than the Fine varieties of major grain-producing areas Y-CK showing some superiorities, while Y-2011showed a higher capability of light using in low temperature of january and February. It indicated that the photosynthetic characters of P. yezoensis cultivars had closely relate to the growing period and temperature. Each cultivar showed different character in growing period.Using chlorophyll fluorescence technology to analyze vegetative and germ cells of P. haitanensis. It showed that there were no obvious difference between the vegetative cells and the female cells in△F/Fm’, rETR, non-photochemical quenching (NPQ). The vegetative cells and the female cells had obviously higher△F/Fm’, rETR and photochemical quenching (qP) than the male cells. It indicated that the vegetative cells and the female cells of P. haitanensis could use light efficiently and most of absorbed light energy was used for photosynthetic electron transport, but the male cells had low light energy use efficiency.