低温胁迫下条斑紫菜的生长和光合生理生化响应OA北大核心CSTPCD

In order to explore the growth performance and photosynthetic physiological and biochemical responses of Neopyropia yezoensis to low temperature stress,we took the thallus of N.yezoensis as the studying material,and measured the relevant photosynthetic physiological indexes,photosynthetic pigment content and daily growth rate of N.yezoensis at 2℃.The results showed that the growth of N.yezoensis thallus slows down under low temperature stress,and the daily growth rate(DGR)of wild samples ranges from 1.59%·d-1 to 3.77%·d-1 in 4 days and from 2.19%·d-1 to 4.12%·d-1 in 20 days.At the seedling stage,the DGR was 3.75%·d-1 in 2 days ahead of stressing,8.79%·d-1 in 4 days after stressing,and 7.19%·d-1 in 6 days after stressing.Simultaneously,the photosynthetic capacity decreased,and Fv/Fm(maximum photochemical quantum yield of PSⅡ),ΦPSⅡ(actual photochemical quantum yield of PSⅡ)and qP(photochemical quenching coefficient)of wild samples decreased in 4 days under low temperature stress while NPQ(non-photochemical quenching coefficient)increased.After stressing for 20 days,Fv/Fm still decreased significantly and ΦPSⅡ and qP increased while NPQ decreased to the lowest.Fv/Fm,ΦPSⅡ,NPQ and qP decreased in the first 2 days under low temperature stress,and Fv/Fm,ΦPSⅡ,NPQ and qP increased in 4 days of stressing.There was no significant change in fluorescence parameters in 6 days of stressing in comparison with those in 4 days.After 6 days of low temperature stressing at the seedling stage,the content of chlorophyll a and phycocyanin significantly decreased(P＜0.05),the content of phycoerythrin significantly decreased(P＜0.01),and the content of allophycocyanin significantly increased(P＜0.01).The results showed that the photosynthetic physiology and biochemistry of N.yezoensis respond the low temperature stressing and eventually its growth rate is influenced,showing certain adaptability with the extension of low temperature stressing.Our findings provided a data reference for exploring the adaptation mechanism of N.yezoensis to low temperature stress and screening the low temperature resistant varieties.