为有效控制湖北省宜昌市华重楼[Paris polyphylla Smith var. chinensis(Franch.)Hara]茎腐病的发生,对该病害的病原菌进行了分离鉴定。采用常规组织分离法,获得1株导致华重楼茎部腐烂的白色丝状真菌菌株,并将其命名为CLY-2。通过显微...为有效控制湖北省宜昌市华重楼[Paris polyphylla Smith var. chinensis(Franch.)Hara]茎腐病的发生,对该病害的病原菌进行了分离鉴定。采用常规组织分离法,获得1株导致华重楼茎部腐烂的白色丝状真菌菌株,并将其命名为CLY-2。通过显微形态观察,CLY-2的大型分生孢子呈柱状,具隔膜,大小为(22.0~33.0)μm×(3.1~4.4)μm;小型分生孢子肾形或卵形,单胞,单生或串生,大小为(2.5~8.2)μm×(1.2~3.5)μm。结合rDNA-ITS序列系统进化分析,最终将CLY-2确定为镰刀菌属真菌Fusarium foetens。展开更多
This study investigates the corrosion-assisted fatigue crack growth rate(FCGR)of 16 mm thick AA 7075-T651 friction stir welded(FSW)joints.Compact tension(CT)specimens were extracted from both the base material and FSW...This study investigates the corrosion-assisted fatigue crack growth rate(FCGR)of 16 mm thick AA 7075-T651 friction stir welded(FSW)joints.Compact tension(CT)specimens were extracted from both the base material and FSW joints to evaluate FCGR under varying corrosion exposure durations(0,7,30,60,and 90 days)at a constant stress ratio of 0.5.Microstructural analysis of the welds was conducted using optical and transmission electron microscopy(TEM).Results indicate that the critical stress intensity factor range(ΔK_(cr))of FSW joints is lower than that of the base material,primarily due to precipitate dissolution in the weld zone during the FSW process,as confirmed by TEM analysis.The fatigue life of FSW joints was significantly lower than that of the base material,but with prolonged exposure to seawater corrosion,the gap in fatigue life narrowed.Specimens exposed to seawater for more than 60days exhibited minimal differences in fatigue life between the base material and the FSW joints.This was attributed to the higher corrosion rate of the base material compared to the weld nugget,resulting in the formation of deeper pits that facilitated crack initiation and accelerated fatigue failure.The findings conclude that extended corrosion exposure leads to similar fatigue life and crack growth behaviour in both the base material and FSW joints.SEM and EDX analysis of AA7075-T651 revealed corrosion pits and rust products in initiation zones,ductile striations in growth regions,and secondary cracks with micro voids in fracture zones.FSW joints exhibited ultra-fine grains,smooth ductile fracture in initiation and growth regions,and brittle fracture in the fracture zones under both corroded and uncorroded conditions.展开更多
以华重楼[Paris polyphylla Smith var.chinensis(Franch.)Hara]植物多种器官为外植体,经不同消毒处理和培养基诱导培养后,观察其愈伤组织的诱导生长情况;并以TTC法检测诱导产生的愈伤组织中的薯蓣皂苷含量。结果表明,华重楼的隐芽、内...以华重楼[Paris polyphylla Smith var.chinensis(Franch.)Hara]植物多种器官为外植体,经不同消毒处理和培养基诱导培养后,观察其愈伤组织的诱导生长情况;并以TTC法检测诱导产生的愈伤组织中的薯蓣皂苷含量。结果表明,华重楼的隐芽、内层芽鞘、根茎、预处理后根茎和子房外植体经诱导培养后,均可不同程度地产生愈伤组织;其中以预处理后根茎外植体产生的愈伤组织生长速度最快,诱导率也最高,为33.5%。经检测结果显示,多次继代培养的华重楼愈伤组织中含有与华重楼对照药材和薯蓣皂苷对照品相同的薯蓣皂苷或其类似物。展开更多
文摘为有效控制湖北省宜昌市华重楼[Paris polyphylla Smith var. chinensis(Franch.)Hara]茎腐病的发生,对该病害的病原菌进行了分离鉴定。采用常规组织分离法,获得1株导致华重楼茎部腐烂的白色丝状真菌菌株,并将其命名为CLY-2。通过显微形态观察,CLY-2的大型分生孢子呈柱状,具隔膜,大小为(22.0~33.0)μm×(3.1~4.4)μm;小型分生孢子肾形或卵形,单胞,单生或串生,大小为(2.5~8.2)μm×(1.2~3.5)μm。结合rDNA-ITS序列系统进化分析,最终将CLY-2确定为镰刀菌属真菌Fusarium foetens。
文摘This study investigates the corrosion-assisted fatigue crack growth rate(FCGR)of 16 mm thick AA 7075-T651 friction stir welded(FSW)joints.Compact tension(CT)specimens were extracted from both the base material and FSW joints to evaluate FCGR under varying corrosion exposure durations(0,7,30,60,and 90 days)at a constant stress ratio of 0.5.Microstructural analysis of the welds was conducted using optical and transmission electron microscopy(TEM).Results indicate that the critical stress intensity factor range(ΔK_(cr))of FSW joints is lower than that of the base material,primarily due to precipitate dissolution in the weld zone during the FSW process,as confirmed by TEM analysis.The fatigue life of FSW joints was significantly lower than that of the base material,but with prolonged exposure to seawater corrosion,the gap in fatigue life narrowed.Specimens exposed to seawater for more than 60days exhibited minimal differences in fatigue life between the base material and the FSW joints.This was attributed to the higher corrosion rate of the base material compared to the weld nugget,resulting in the formation of deeper pits that facilitated crack initiation and accelerated fatigue failure.The findings conclude that extended corrosion exposure leads to similar fatigue life and crack growth behaviour in both the base material and FSW joints.SEM and EDX analysis of AA7075-T651 revealed corrosion pits and rust products in initiation zones,ductile striations in growth regions,and secondary cracks with micro voids in fracture zones.FSW joints exhibited ultra-fine grains,smooth ductile fracture in initiation and growth regions,and brittle fracture in the fracture zones under both corroded and uncorroded conditions.
文摘以华重楼[Paris polyphylla Smith var.chinensis(Franch.)Hara]植物多种器官为外植体,经不同消毒处理和培养基诱导培养后,观察其愈伤组织的诱导生长情况;并以TTC法检测诱导产生的愈伤组织中的薯蓣皂苷含量。结果表明,华重楼的隐芽、内层芽鞘、根茎、预处理后根茎和子房外植体经诱导培养后,均可不同程度地产生愈伤组织;其中以预处理后根茎外植体产生的愈伤组织生长速度最快,诱导率也最高,为33.5%。经检测结果显示,多次继代培养的华重楼愈伤组织中含有与华重楼对照药材和薯蓣皂苷对照品相同的薯蓣皂苷或其类似物。
