Effects Of Plant Hormones On The Physiological And Biochemical Characteristics Of Economic Microalgae

Plant hormones are a class of small molecule compounds that play an important role in plant signaling and stress responses.In this paper,the effects of salicylic acid(SA),abscisic acid(ABA)and jasmonic acid(JA)at different concentrations on the growth,photochemical activity and lipid accumulation of Nannochloropsis maritime and Phaeodactylum tricornutum were studied.The results showed that below 4 ?g/mL of SA promoted the growth of Nannochloropsis maritime,whereas above 12 ?g/mL of SA inhibited its growth.Treatment with ABA below 5 ?g/mL promotes the growth of Nannochloropsis maritime,whereas above 10 ?g/mL inhibits its growth.Treatment with JA below 2.5 ?g/mL promoted the growth of Nannochloropsis maritime,whereas above 5 ?g/mL inhibited its growth.The treatment of three plant hormones had inhibitory effects on the growth of Phaeodactylum tricornutum.A certain concentration of SA promoted the actual photosynthetic efficiency of Nannochloropsis maritime,and ABA and JA promoted the actual photosynthetic efficiency of Phaeodactylum tricornutum.The three plant hormones have a certain role in promoting the accumulation of lipids in Nannochloropsis maritime and Phaeodactylum tricornutum.At the same time,the effects of three plant hormones on the growth,photochemical activity and astaxanthin accumulation of Haematococcus pluvialis were studied.The results show:Three kinds of phytohormones promoted the biomass and dry weight of Haematococcus pluvialis.In terms of photosynthetic efficiency,SA and JA significantly reduced its actual photosynthetic efficiency,while 5 ?g/mL of ABA promoted its actual photosynthetic efficiency.Both 20 ?g/mL SA and 10 ?g/mL JA promoted accumulation of astaxanthin in Haematococcus pluvialis,while abscisic acid had no effect.