Effects Of Abscisic Acid And Gibberellin On Growth Of Porphyridiu Sp.

Porphyridium sp.which belongs to Rhodophyta,Bangiophyceae,Porphtridiales, Porphyridiaceae,is a unicellar red alga rich in valuable bioactive outcome such as phycobiliprotein,PUFA,exopolysaccharide,etc.Therefore,it has a broad application in the pharmaceutical,cosmetics,fine chemicals and other high value-added industries fields.This study was aimed to investigate the effects of ABA and GA on the growth of Porphyridium sp., dealed with three levels of nitrogen nutrition and seven concentrations of two phytohormones, by observing chlorophyll-a,extracellular polysaccharide,phycoerythrin and other indexes.The result were listed as follows:(1)For ABA and GA,the growth of Porphyridium sp.could be promoted growth by low concentration and inhibited by high concentration,when the concentration of ABA was 0.01～1.0 mg·L^-1,ABA played promoting effect on it with gradually increasing trend,ABA of 1.0 mg·L^-1 under the medium level of nitrogen nutrition Were the optimum conditions of its growth and metabolite accumulation;when the concentration was higher than 1.0 mg·L^-1,its growth was inhibited.ABA of 0.5 mg·L^-1 had the best effect on its growth density,but the exopolysaccharides was lower than 1.0 mg·L^-1 treatment;when the concentration of GA was 0.01～1.5 mg·L^-1,its growth increased following the increasing of GA concentration;when the concentration of GA was above 1.5 mg·L^-1,GA inhibited its growth.(2)The levels of nitrogen nutrition had impact on the affection of ABA and GA.High nitrogen treatment promoted the accumulation of total soluble protein,but inhibited the growth of Porphyridium sp.and its other metabolite accumulation;medium nitrogen increased its chlorophyll-a,biomass,extracellular polysaccharide and phycoerythrin contents significantly. Under low nitrogen nutrition level,the result of effect about ABA and GA was not remarkable.(3)Exogenous ABA could increase SOD,CAT and other antioxidant enzyme activity of Porphyridium sp.,and was concentration-dependent obviously;the exogenous GA to SOD and CAT had the accordance effect with ABA.The results had a certain reference value to how to use phytohormone to increase the output of Porphyridium sp.productivity effectively.