The Study Of Polyamines’ Regulatory Mechanism And Growth Of Skeletonema Costatum And Prorocentrum Donghaiense Under Salinity And Temperature Stress

This paper mainly studied the effects of different temperature and salinitylevels on the growth of Skeletonema costatum and Prorocentrum donghaiense,Activity of POD, DAO, PAO and content of MDA, Put, Spd, Spm extracted fromalgae cells was determined, final biomass and maximum growth rate of HABs algaewas obtained by logistic growth model. Based on these cultivation experiments, wediscussed variation characteristics and adjustment mechanism of polyamines in algaeunder temperature and salt stress. The results shows as follow.While under high or low salinity stress S. costatum can accumulate MDA whichindicates that active oxygen free radical damage enhanced and the growth wereinhibited. Under high salinity stress, S. costatum can enhance the activity of DAO andPAO, the polyamine especially the content of free polyamine. Raised PAs willimprove the tolerance of S. costatum in high salt environment by scavenging reactiveoxygen species, stability of membrane structure, regulation of osmotic pressure andother mechanisms. Under low salinity stress, S. costatum will enhance the freeputrescine to enhance peroxidase activity which deal with the accumulation of MDAand promote the growth of algae.Under high or low salinity stress P. donghaiense can also accumulate MDAwhich indicates that active oxygen free radical damage enhanced and the growth wereinhibited. Under high salinity stress, in algae three kinds of polyamines contentdeclined, while conjugated Spd and bound Spm raised, it also means that conversionhappened of Put and Spd to the bound form in algae, as well as the conversion of Spmfrom conjugated form to free form. The enhancement of conjugated Spd and free Spm may be the adjustment mechanism of P. donghaiense when response to high salt stress.Under low salt stress, in P. donghaiense various existing polyamine are showing arising trend, so three polyamines in vivo of P. donghaiense function together whensuffering to low salt stress.It does not show a strong variation of MDA content in vivo of S. costatum undertemperature stress, indicating that the difference between the membrane lipidperoxidation among the experimental groups is very little. S. costatum’s tolerance tolow temperature is better than to high temperature, they can grow well in lowtemperature environment. Under high temperature stress, S. costatum can significantlyenhance the activity of DAO and PAO, the total Spm content, as well as the content ofconjugated Spd, conjugated Spm, bound Spd and bound Spm. It is suggested thatconjugated Spd, conjugated Spm and bound Spd play the important role, and the mainmechanism is to stabilize the structure and function of nucleic acid and protein.While under high or low temperature stress P. donghaiense can accumulateMDA, which indicates that active oxygen free radical damage enhanced. Furthermore,DAO and PAO activity enhanced, free Put decreased, conjugated Spd, conjugatedSpm and bound PAs decreased, while conjugated Put content increased. At the sametime total Put, Spd, Spm were decreased, and the decline is similar, while Spm isalways the main components among these three kinds of polyamines. In addition tohigh temperature stress, free Spd and Spm content slightly increased, indicating DAO,PAO, free Spd and Spm plays an important role in high-temperature talerance.Meanwhile, under temperature and salinity stress the two algaes will enhance thepolyamine content to play the regulation role to relieve stress and promote growth.However, they are different in polyamine’s type and form.