A New Formation Based On Morphology, Life History And Rbcl Gene Sequence Analysis Of Phycodrys Radicosa F. Pacificua (Phycodrys, Delesseriaceae) From China

Base on morphology, life history and rbcL sequence analysis, identified a formationspecies P. radicosa Kützzing f. pacificua Wang et Guan, the variant is significantly differentfrom P. radicosa in morphological characteristics are thallus higher than P. radicosa, high is5~7cm, width branches5-10mm. rbcL sequences of the two species samples are consensus.InMP and ML tree, the divergence between P. radicosa f. pacificua and P. radicosa is7bp, theyform a small branch and embedded in the large clade of Delesserioideae.Exploring different temperature, light intensity and salinity conditions to impact theattachment and release of tetraspores and carpospores of P. radicosa, found the attachment andrelease of tetraspores and carpospores optimal temperature, light and salinity were25℃,120μmol·m-2·s-1and high salinity (24to40). The optimum temperature, light and salinity oftetraspores and carpospores attachment,were25℃,60μmol·m-2·s-1and in high salinity(24,32,40).Observing the stages of the development of tetraspores and carpospores, namely: Thegermination of carpospores, the progress of the growth of discoid and straight dimensional,the form of tetrasporophyte, the germination of tetraspores and gametophyte formation,carpogonium after fertilization developmental carposporophyte(cystocarp), and defined the lifehistory characteristics of P. radicosa. But also to grasp the effects of different growth factorson the various stages of the life history under laboratory culture conditions. The study providesan important theoretical basis to the germplasm preservation and artificial breeding of P.radicosa.Through setting different conditions of light and temperature to impact the earlydevelopment of tetraspores and carpospores of P. radicosa was noticeable, the results showedthat:(1) under the appropriate light intensity,20℃is the most appropriate temperature tothe discoid and orthostatic (tetraspore developing), and the optimum temperature to seedlinggrowth is25℃;25℃is the most appropriate temperature to the discoid, orthostatic andseedlings;(2) the temperature at10-20℃, low light intensity (200μmol·m-2·s-1) is moresuitable for the growth and development of the discoid, orthostatic and seedlings, while high light intensity (120μmol·m-2·s-1) will destroy the mechanism of the formation of algae andnormal pigmentation and inhibit the growth of thallus.