| A study is planned to optimize the isolution and purification conditions on auxin indole-3-acetic acid(IAA)and abscisic acid(ABA),to establish their identification and quantification of tAA and ABA in the kelp(Laminariajaponica Aresch.)extracts,on the base of that,to investigate their distribution in the different parts of the mature kelp and the changes of their content in the kelp with different growth,and to research on their bioactivities on the marine microalgae.Conditions on isolation and purification of auxin IAA in the kelp extracts were optimized and the optimal process was established including cell burst by ultrasonic, extraction with 90%methanol and ether,decoloration with silica gel,and purification by Sephadex LH 20 and Reverse-phase high performance liquid chromatography(RP-HPLC). The optimized conditions on isolation and purification of ABA in the kelp extracts were investigated and the optimal process was also established including cell burst by ultrasonic, extraction with 80%methanol and ethyl acetate,decoloration with silica gel,and purification by Sephadex LH 20 and RP-HPLC.The identification of IAA and ABA was based on co-chromatography and comparative chromatography with the standard,analysis of UV spectra,and atmospheric pressure electrospray mass spectrometry(APESI-MS).Evidence is provided for IAA of 65～95/μg/Kg·fresh weight and ABA of 65～70μg/Kg·fresh weight in the extracted samples by the method of RP-HPLC.IAA and ABA are isolated by silica gel, Sephadex LH 20 and HPLC.The processes lay the foundation for further study on their bioactivities with convenience,quickness,accurateness and better fidelity.The results show that the distribution of auxin IAA is not equal in the different parts of the mature kelp and the effect of the different parts in the mature kelp on the content of auxin IAA is statistically marked(0.01＜p＜0.05).The content of auxin IAA in the bottom of the mature kelp is highest,secondly in the middle and fewest in the top.However,the distribution of ABA is basically equal in the different parts of the mature kelp.And the effect of the mature kelp with different parts on the content of ABA is not marked(p＞0.05).The results show that the effect of the kelp with different growth on the content of auxin IAA andABA is statistically marked(p＜0.01).The content of auxin IAA is highest in the childish kelp with the initial stage when clamped in rafts,and along with growing up,the content of auxin IAA gradually decreases.But the content of ABA gradually increases in the kelp along with growing up,and the content of ABA is highest in the mature kelp.The research shows that exogenously added IAA in the kelp enhanced the growth of Chlorella sp.,Dunaliella salina and Porphyridium Cruentum except Chaetoceros muelleri.. IAA in the kelp significantly inhibited the accumulation of cellular dissolvable proteins in Chlorella sp.(0.01＜p＜0.05)and Porphyridium Cruentum(0.01＜p＜0.05).And it had a very significant effect on the chlorophyll biosynthesis of Chlorella sp.(0.0001＜p＜0.0005).But it was not obvious to regulate biosynthesis of cellular polysaccharide in the four marine microalgae(p＞0.05).The research shows that the growth of Chlorella sp.,Dunaliella salina,Isochrysis galbana and Porphyridium Cruentum is all inhibited in the treatments with ABA in the extracted samples.And the results are significantly different that the effects of ABA in the extracted samples with different concentrations on their growth(0.01＜p＜0.05)and the inhibition becomes distincter and distincter in the treatments with the increasement of ABA in the extracted samples.In the four marine,microalgae,Isochrysis galbana is best impressible for ABA in the extracted samples,and secondly Porphyridium Cruentum,Chlorella sp.and Dunaliella salina.The result shows that,for Porphyridium Cruentum,it is significantly different that the effects of ABA in the extracted samples with different concentrations on the content of cellular solvable proteins and Cellular dissolvable saccharide(0.001＜p＜0.005), however,there is not significantly different that the effects of ABA in the extracted samples with different concentrations on the content of chlorophyll(p＞0.05);for Chlorella sp.,there is significantly different that the effects of ABA in the extracted samples with different concentrations on cellular solvable proteins(0.01＜p＜0.05),but it is not significantly different that the effects of ABA in the extracted samples with different concentrations on the content of cellular dissolvable saccharide and chlorophyll(p＞0.05);for both Dunaliella salina and lsochrysis galbana,there is not significantly different that the effects of ABA in the extracted samples with different concentrations on cellular solvable proteins and cellular dissolvable saccharide(p＞0.05),but it is chlorophyll that the effects of ABA in the extracted samples with different concentrations on the content in both the two algae are significantly different, respectively Dunaliella salina(0.0001＜p＜0.0005)and Isochrysis galbana(0.001＜p＜0.005). In addition,ABA in the extracted samples can protect the four marine microalgae cells from oxidantion stress by the paraquat.And the protection of ABA in the extracted samples is most marked for Dunalieila salina in the four marine algae.
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