【摘要】 采用室外盆栽实验的方法,初步探究了Bacilus firmus 3A,Thalassospirasp.4G,Bacillus hemicentroti S3-2Y和Bacillus jeotgali S3-4R4种固氮菌单株及其组合（按照1∶1∶1∶1比例混合,简写为Mix）共5个接菌处理组对鳗草植株的存活、生长、生理及根际土壤酶活性的影响。研究显示:5个接菌处理组鳗草植株的存活、生长、生理及根际土壤酶活力等指标均有不同程度的提高或改善,其中菌株4G（Thalassospirasp.）对鳗草生长指标的影响最显著,植株存活率、单株新叶面积和新茎节长比对照组分别提高了57.50%、66.56%和66.95%;菌株3A（B.firmus）处理组鳗草叶片中总叶绿素、类胡萝卜和可溶性糖含量最高,分别为67.94μg·cm^-2、9.90μg·cm^-2和103.72μg·g^-1,分别是对照组的1.58、1.85和1.92倍;各处理组根际土壤中脱氢酶和脲酶含量均有显著提高（P<0.05）,但碱性磷酸酶对固氮微生物的响应不显著。总体促生效果表现为4G>3A>Mix>S3-2Y>S3-4R,其中菌株3A、4G在海草床生态系统恢复中具有较高的应用价值,具备进一步研制固氮微生物肥料的潜力。研究结果为深入探究高效固氮菌株功能与代谢调控及其在鳗草植株人工促繁中的作用奠定了基础。更多还原

【Abstract】 Eelgrass(Zostera marina L.)beds,as one of the most important coastal ecosystems,are highly valuable ecologically and economically.However,eelgrass beds have been reduced worldwide because of natural and anthropogenic causes and their restoration has become increasingly important in the past decades.To restore the degraded eelgrass beds,lots of studies have been performed and various techniques have been developed.Among them,eelgrass transplantation is the most widely used and intensively studied technology.Eelgrass transplantation is labor-intensive and time-consuming,thus transplant survival is critical to the transplantation success.The development of growth-promoting substances is necessary for the success of eelgrass transplantation.Lots of studies among terrestrial plants have shown that nitrogen-fixing microorganisms provide nitrogen for the growth of plants,their metabolites play significant roles in promoting plant growth and controlling diseases.These understandings have been widely applied in major economic and ecological species.Until now,the techniques which may be used for growth-promoting of transplanted eelgrass are still absent.Therefore,investigating nitrogen-fixing bacteria in the eelgrass rhizosphere is necessary.In this study,apot test was conducted to investigate the effect of four nitrogen-fixing bacterial strains on eelgrass growth,in which Bacilus firmus3 A,Thalassospirasp.4 G,B.hemicentroti S3-2 Y,B.jeotgali S3-4 Rwere inoculated either separately or as a mixture(1∶1∶1∶1).The results showed the survival rate,growth,physiological status and enzyme activity of rhizosphere soil of the five inoculation treatments were,to some extent,all increased.Compared with the control,Thalassospirasp.4 Gshowed the best promoting effect.After inoculation with this strain,the survival rate,the new leaf area,and the new internode length of eelgrass shoots increased by 57.50%,66.56%and 66.95%,respectively.The highest contents of total chlorophyll,carotenoid and soluble sugar were found in treatment 3 A,which were 67.94μg·cm-2,9.90μg·cm-2 and 103.72μg·g-1,respectively,1.58,1.85 and 1.92 fold higher than those of the control,respectively.All of the five inoculations resulted in significant increases in soil dehydrogenase activity and soil urease activity(P<0.05).However,no significant difference was observed in the soil alkaline phosphatase activity between inoculations and the control.These results indicated that the overall growth effects of these inoculations present as 4 G>3 A>Mix>S3-2 Y>S3-4 R,and among these inoculants Bacilus firmus 3 Aand Thalassospira sp.4 Gshowed the highest efficiency.This research preliminarily explored the effects of four nitrogen-fixing bacterial strains and their mixture on eelgrass growth,which have laid a foundation for further research on the function and metabolic regulation of highly effective nitrogen-fixing bacteria,and should facilitate the recovery of Z.marina beds in future.更多还原