紫菜共附生真菌次生代谢产物对坛紫菜生长的影响

采用室内培养法,分别测定了坛紫菜叶状体和丝状体的日生长速率和光合色素质量分数,研究了紫菜共附生真菌--枝孢霉Cladosporium sp.次生代谢产物的粗提物N5及纯化物DLF3、DLF4对坛紫菜Porphyra haitanensis生长的影响.结果表明:(1)粗提物N5在较低质量浓度时,对坛紫菜丝状体和叶状体的生...

Effect of the secondary metabolites of a fungus strain isolated from Porphyra on the growth of Porphyra haitanensis

A mixture of secondary metabolites,N5,was extracted from Cladosporium sp.which was isolated from Porphyra-epiphytic fungi.Two pure compounds of DLF3 and DLF4 were purified from N5,and their chemical construction was analyzed,which shows that both are cyclopeptides.Then effects of the three compounds on the growth of P.haitanensis thallus and conchocelis were studied by single factor-controlled trials.In the experiments,the working solution of each compound had three different mass concentrations of 1.0×10-8,1.0×10-6 and 1.0×10-4 mg/mL,since we found in our preliminary experiments that the mixture N5 played a role as plant growth hormone when its mass concentration changed from 1.0×10-8 mg/mL to 1.0×10-4 mg/mL.The working solution was prepared by dissolving the compounds separately into seawater which was filtered through cotton and gauze by about 0.5 mL/s and boiled,and inorganic nutrient salt stock-solution was added by 2∶1 000 to make the final culture solution for conchocelis and III stock-solution was added by 1∶1 000 for thallus.Specimen,P.haitanensis thallus and conchocelis,were both cultured under asepsis condition first.Then the experiment proceeded under conditions of 18 ℃,L∶D=12∶12,3 000 to 4 000 lx,10 days for thallus and 15 days for conchoceils.At the end of experimental cycle,the day growth rate of P.haitanensis thallus and conchocelis were calculated by the ratio of the biomass difference between the test group and control group to days.And the changes of phycobiliprotein,total amount of soluble protein and chlorophyll a were also analyzed.The results shows that N5 has a function as plant growth regulators on both P.haitanensis thallus and conchocelis.When the mass concentration of N5 ranged from 1.0×10-8 mg/mL to 1.0×10-6 mg/mL,it could stimulate the day growth rates and biosynthesis of phycobiliprotein(phycoerythrin,phycocyanin,and allphycocyanin) of P.haitanensis.The day growth rate of mass conchocelis rose by nearly 18.8% compared to the control group and the biosynthesis of phycobiliprotein rose by nearly 7.32×10-3 when the mass concentration of N5 was 1.0×10-6 mg/mL,while that of thallus by nearly 2.76% and 14.16×10-3 when the mass concentration of N5 was 1.0×10-8 mg/mL.With rising of the mass concentration,the stimulating function of N5 became weaker,and even turned to playing a role as a growth inhibitor when the mass concentration was up to 1.0×10-4 mg/mL.The day growth rate of conchocelis decreased by nearly 38.1% and the biosynthesis of phycobiliprotein by nearly 4.87×10-3 at the mass concentration.N5 inhibited the phycobiliprotein biosynthesis of thallus when its mass concentration was just 1.0×10-6 mg/mL.At the same time,the study demonstrates that the stimulus intensities of N5 on thallus and conchocelis were different.N5 had marked effects on the growth of P.haitanensis thallus(p<0.05),and extremely marked effects on the growth of P.haitanensis conchocelis(p<0.01).In addition,the effects of N5 on the synthesis of soluble protein of P.haitanensis thallus were studied.The results indicate that N5 had an extremely marked effect on it.The total soluble protein content of thallus compared to the control group markedly increased by 63.00×10-3 when N5 was at the lowest mass concentration,1.0×10-8 mg/mL,but decreased when it ranged from 1.0×10-6 mg/mL to 1.0×10-4 mg/mL.When it was at 1.0×10-4 mg/mL,the total soluble protein content of thallus compared to the control group decreased by 22.00×10-3.On the other hand,both DLF3 and DLF4 could completely inhibit the growth of P.haitanensis conchocelis,and the higher mass concentration the stronger inhibition.When the mass concentration of DLF4 was 1.0×10-8 mg/mL,the day growth rate of conchocelis decreased by 12.8% compared to the control group.And the inhibitory effect of DLF3 was weaker than DLF4.At the mass concentration of 1.0×10-8 mg/ml,the day growth rate of conchocelis compared to the control group decreased only by 4.5%.When it came to the effects on P.haitanensis thallus,these two pure compounds both stimulate its growth at lower mass concentration range but inhibit its growth at higher concentration range,just as the natural auxins do.They have different optimum mass concentration range.And both have extremely marked effects on the growth of conchocelis(p<0.01).At the end of the test cycle,the morphological changes of P.haitanensis cell were found under microscope.When the mass concentration of DLF4 and N5 were 1.0×10-6 mg/mL,the diameter of conchocelis thickened and its branches increased.But when their mass concentration was 1.0×10-4 mg/mL,the growth of conchocelis degenerated,its diameter thinned and many branches of conchocelis lost pigments.When the mass concentration was 1.0×10-6 mg/mL,N5 improved the development of thallus and at the edge of thallus,there were some cells like carpospores appeared.But when the mass concentration was 1.0×10-4 mg/mL,many thallus cells lost their pigments and degenerated.These results present synchronism with the results of day growth rate and phycobiliprotein biosynthesis.