Objectives of our research were to investigate the improvement of triploid bermudagrass(Cynodon dactylon×C.transvaalensiscv.TifEagle) for stress tolerance by biotechnological methods.The results were summarizedin...Objectives of our research were to investigate the improvement of triploid bermudagrass(Cynodon dactylon×C.transvaalensiscv.TifEagle) for stress tolerance by biotechnological methods.The results were summarizedin the following:1.Drought tolerance and its chemical control in turfgrass speciesThe drought tolerance in 3 turfgrass species were comparatively studied by measuring relative watercontent(RWC),ion leakage,antioxidants enzyme activity during withholding irrigation.The results indicatedtriploid bermudagrass cultivar,Tifdwarf,had highest drought tolerance,followed by manilagrass andcarpetgrass.ABA and S3307treatments increased the drought tolerance of turfgrasses,which were associatedwith their induced antioxidants enzyme activity.2.Establishment of tissue culture and regeneration in triploid bermudagrassSterilized node segments with 5 mm were used as explants and callus induction,suspension subculture,and regeneration were studied.Basal medium composition,proline,phytohormones were compared in thecallus induction,suspension culture and regeneration.High effective tissue culture system was established intriploid bermudagrass.Somatic embryogenesis during regeneration in triploid bermudagrass was demonstratedby using scanning electron microscope and light microscope observations.3.Somaclonal variations and selections for cold resistance in triploid bermudagrassMorphological variations in leaf color,leaf length and width,stolons internodes length were observedamong the regenerated plants from the initial 138 embryogenic calluses,which had been continuouslysubcultured for over 18 months by suspension culture.Several lines grew fast in the field during spring andsummer.Partial lines maintained green color and continuous growth in the winter.The results indicated thatsomaclonal variations were induced during the long-term subculture of callus and among them useful variantscould be selected.It is suggested that somaclonal variation may be used for triploid bermudagrass breeding.4.A dwarf somaclonal variant in triploid bermudagrassA dwarf somaclonal variant,TV4,and its parent TifEagle were comparatively studies in morphologicalcharacters and response to chilling stress.In comparison to TifEagle,TV4 showed significant morphologicalvariation with decrease in stolons internodes length and leaf length,increase in leaf width.TV4 had extensiveroot system which would allow it higher drought tolerance,showed higher chilling resistance than TifEagle.5.Selection of salt-tolerant lines in triploid bermudagrass and their physiological analysisThe salt-tolerant callus lines selected on the medium contained 0.3 mol/L NaCl were regenerated on themedium contained 0.1 mol/L NaCl.Half of the regenerated plants lines showed tolerance to 0.25 mol/L NaClstress,compared to its parent Tifeagle.Na+,K+,Na+/K+,proline,soluble sugars and antioxidant enzymeactivity were measured after the plants were subjected to salt stress.The results showed that the tolerant linesshowed diversity in physiological index in response to salt stress.All the tolerant lines had much higher prolinecontent and lower Na+/K+ratio under non-stress condition.6.Transgenic plants production,molecular analysis and their stress tolerance in triploid bermudagrassTransgenic plants for betaine aldehyde dehydrogenase gene(BADH) under the control by Ubi promoterwere produced by particle bombardment.PCR amplification and PCR-Southern blot analysis showed partialregenerated plants positive.Southern blot of genomic DNA filter demonstrated that BADHwas integrated intothe genomics in transgenic plants in a manner of multiple copies.Three transgenic lines showed greatlyincreased tolerance to salt and drought stress.展开更多
文摘Objectives of our research were to investigate the improvement of triploid bermudagrass(Cynodon dactylon×C.transvaalensiscv.TifEagle) for stress tolerance by biotechnological methods.The results were summarizedin the following:1.Drought tolerance and its chemical control in turfgrass speciesThe drought tolerance in 3 turfgrass species were comparatively studied by measuring relative watercontent(RWC),ion leakage,antioxidants enzyme activity during withholding irrigation.The results indicatedtriploid bermudagrass cultivar,Tifdwarf,had highest drought tolerance,followed by manilagrass andcarpetgrass.ABA and S3307treatments increased the drought tolerance of turfgrasses,which were associatedwith their induced antioxidants enzyme activity.2.Establishment of tissue culture and regeneration in triploid bermudagrassSterilized node segments with 5 mm were used as explants and callus induction,suspension subculture,and regeneration were studied.Basal medium composition,proline,phytohormones were compared in thecallus induction,suspension culture and regeneration.High effective tissue culture system was established intriploid bermudagrass.Somatic embryogenesis during regeneration in triploid bermudagrass was demonstratedby using scanning electron microscope and light microscope observations.3.Somaclonal variations and selections for cold resistance in triploid bermudagrassMorphological variations in leaf color,leaf length and width,stolons internodes length were observedamong the regenerated plants from the initial 138 embryogenic calluses,which had been continuouslysubcultured for over 18 months by suspension culture.Several lines grew fast in the field during spring andsummer.Partial lines maintained green color and continuous growth in the winter.The results indicated thatsomaclonal variations were induced during the long-term subculture of callus and among them useful variantscould be selected.It is suggested that somaclonal variation may be used for triploid bermudagrass breeding.4.A dwarf somaclonal variant in triploid bermudagrassA dwarf somaclonal variant,TV4,and its parent TifEagle were comparatively studies in morphologicalcharacters and response to chilling stress.In comparison to TifEagle,TV4 showed significant morphologicalvariation with decrease in stolons internodes length and leaf length,increase in leaf width.TV4 had extensiveroot system which would allow it higher drought tolerance,showed higher chilling resistance than TifEagle.5.Selection of salt-tolerant lines in triploid bermudagrass and their physiological analysisThe salt-tolerant callus lines selected on the medium contained 0.3 mol/L NaCl were regenerated on themedium contained 0.1 mol/L NaCl.Half of the regenerated plants lines showed tolerance to 0.25 mol/L NaClstress,compared to its parent Tifeagle.Na+,K+,Na+/K+,proline,soluble sugars and antioxidant enzymeactivity were measured after the plants were subjected to salt stress.The results showed that the tolerant linesshowed diversity in physiological index in response to salt stress.All the tolerant lines had much higher prolinecontent and lower Na+/K+ratio under non-stress condition.6.Transgenic plants production,molecular analysis and their stress tolerance in triploid bermudagrassTransgenic plants for betaine aldehyde dehydrogenase gene(BADH) under the control by Ubi promoterwere produced by particle bombardment.PCR amplification and PCR-Southern blot analysis showed partialregenerated plants positive.Southern blot of genomic DNA filter demonstrated that BADHwas integrated intothe genomics in transgenic plants in a manner of multiple copies.Three transgenic lines showed greatlyincreased tolerance to salt and drought stress.
