刈割次数对紫花苜蓿根系中保护酶活性的影响

在哈尔滨地区对当年种植的紫花苜蓿进行不同刈割次数处理,越冬期间取样测定其根系中过氧化物酶(POD)和超氧化物岐化酶(SOD)活性.结果表明:不同刈割次数对越冬期间紫花苜蓿的POD和SOD活性具有显著的影响,超过1次的刈割会显著降低紫花苜蓿的POD和SOD活性及抗寒能力,并且随着刈割次数的增加紫花苜蓿的POD和SOD活性及抗寒能力随之下降.     

四个紫花苜蓿品种对秋冬低温条件的生理适应性

通过测定4个紫花苜蓿品种根部游离脯氨酸、可溶性糖、可溶性蛋白质、过氧化物酶(POD)的含量,研究了不同紫花苜蓿品种对低温的生理适应能力.结果表明:在不同时期,阿尔冈金苜蓿的可溶性糖、游离脯氨酸、可溶性蛋白质、过氧化物酶(POD)活性都明显高于其它品种,抗寒能力较高;品种牧歌401和驯鹿居中,三得利根部中的积累比其它品种低,三得利抗寒能力较弱.     

钾肥对紫花苜蓿根颈丙二醛、可溶性蛋白含量与抗氧化系统的影响

为探究钾肥种类及用量对苜蓿(Medicago sativa)抗寒性的影响,本研究以‘北极熊’为供试紫花苜蓿品种,采用二因素随机区组试验设计,研究了秋季施用不同钾肥(硫酸钾和氯化钾)及不同施用量(0,50,100,150,200 kg·hm^-2 K₂O)对越冬期苜蓿根颈在不同温度(4℃,—20℃)处理下抗氧化酶[过氧化物酶(peroxidase,POD),超氧化物歧化酶(superoxide disimutase,SOD),过氧化氢酶(catalase,CAT)]活性和可溶性蛋白(soluble protein,SP)、丙二醛(malondialdehyde,MDA)含量变化的影响。结果表明:在4℃温度处理下,不同钾肥种类和施肥量处理中,苜蓿越冬根颈中MDA和SP含量及POD,SOD,CAT活性均无显著差异;但经—20℃低温冷冻后,不同钾肥种类和施肥量处理下,苜蓿越冬根颈中MDA含量下降,SP含量增加,POD,SOD,CAT活性增强,适应低温环境能力变强,且硫酸钾效果强于氯化钾;两种钾肥均在150 kg·hm^-2(K₂O)钾肥处理下,MDA含量最低,POD,SOD,CAT活性最强,SP含量最高,表明苜蓿受伤程度最小,抗寒保护能力最强。因此,在科尔沁沙地秋季施用300 kg·hm^-2K₂SO₄有利于苜蓿安全越冬。     

播期、品种对沙地紫花苜蓿抗氧化特性与越冬率的影响

为探讨不同播种时期紫花苜蓿（Medicago saliva L.）根颈抗氧化特性变化规律及其与越冬的关系,本试验选择3个紫花苜蓿品种（骑士T、公农1号、擎天柱）,于2017年7月1日开始,每5天播种一期,播种至8月15日。2017年10月11日（土壤冻融交替期）、11月11日（土壤封冻期）取样测定紫花苜蓿根颈中超氧化物歧化酶（Superoxide dismutase,SOD）、过氧化物酶（Peroxidase,POD）、过氧化氢酶（Catalase,CAT）活性和丙二醛（Malondialdehyde,MDA）含量,翌年春季调查越冬率。结果表明：随着播种时期的推迟,3个紫花苜蓿品种的越冬率均明显下降,紫花苜蓿根颈中CAT,POD,SOD酶活均呈下降趋势;越冬率与10月11日紫花苜蓿根颈的SOD酶活性及11月11日根颈的POD酶活性呈显著正相关关系,与10月11日和11月11日根颈的MDA含量呈负相关关系。研究认为,紫花苜蓿根颈中SOD,POD,CAT 3种抗氧化酶是其适应低温的关键酶,在阿鲁科尔沁地区,7月21日之前播种可有效提高紫花苜蓿越冬率。     

覆雪对不同秋眠型紫花苜蓿生理特性及抗寒基因表达的影响

为明确田间覆雪对不同秋眠型紫花苜蓿生理特性及抗寒基因表达的影响,选择秋眠型紫花苜蓿肇东(1级)、半秋眠型紫花苜蓿Archer(5级)及非秋眠型紫花苜蓿WL903(9级),测定越冬期间苜蓿的越冬率、根部渗透调节物质(可溶性糖、脯氨酸)含量、抗氧化物酶(超氧化物歧化酶、过氧化物酶)活性以及抗寒相关基因(CAS15A、DRE...     

青海草地早熟禾耐寒性研究

青海草地早熟禾(Poa pratensis L.)可通过一系列生理反应提高越冬时的抗寒能力,如以较高的束缚水含量、较低的电解质外渗率和丙二醛(MDA)含量、增加脯氨酸和可溶性糖积累量等抵御严寒。(1)青海草地早熟禾的束缚水含量达到18.9%,显著高于引进品种,表明其通过提高束缚水含量避免细胞内外结冰来抵御寒冷。(2)青海草地早熟禾的电解质外渗率和丙二醛(MDA)含量显著低于引进品种,表明对低温导致的伤害具有较大抗御性。(3)秋末气温下降过程中,草地早熟禾叶片、根、分蘖节中的脯氨酸、可溶性糖积累显著。整体上,青海草地早熟禾脯氨酸和可溶性糖含量均高于引进的纳苏品种,但可溶性蛋白含量与引进纳苏品种无显著差异。     

锰渣-土壤混合基质上黑麦草和紫花苜蓿生长状况及其对锰的累积特征

以紫花苜蓿(Medicago sativa)和黑麦草(Lolium perenne)为材料,在盆栽条件下探讨紫花苜蓿和黑麦草在电解锰渣-土壤混合基质中的生长状况及其对锰(Mn)的吸收特点.结果表明:土壤添加7％、14％、21％、28％、35％的电解锰渣后,紫花苜蓿、黑麦草的发芽率明显下降,而总生物量随着电解锰渣添加量的增加先增加后降低;但两种植物的株高均出现不同程度的增加,特别是黑麦草.随着电解锰渣添加量的增加,黑麦草中光合色素含量增加,在锰渣添加为14％时叶绿素含量最大,显著高出无锰渣对照34.7％(P<0.05);紫花苜蓿中叶绿素和类胡萝卜素含量随着锰渣添加先增加后下降,在锰渣添加量为14％时达到最大,分别高出对照59.7％、28.0％.在土壤中添加锰渣后,紫花苜蓿中丙二醛(MDA)含量、抗氧化酶包括超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性明显提高,而黑麦草中MDA含量、SOD、CAT和POD活性没有明显变化,说明黑麦草的耐受性大于紫花苜蓿.同时,在锰渣-土壤混合基质上紫花苜蓿、黑麦草的地上部分和根系中的锰含量均随着电解锰渣的添加量增加而提高,总体上黑麦草的富集系数大于紫花苜蓿,而对Mn的转移能力是紫花苜蓿大于黑麦草.研究结果显示,两种植物都可作为锰渣堆场生态修复的备选植物,但锰渣对紫花苜蓿的抑制作用大于黑麦草,因此,黑麦草更适合作为锰渣堆场生态修复的先锋植物.     

锰渣-土壤混合基质上黑麦草和紫花苜蓿生长状况及其对锰的累积特征

以紫花苜蓿(Medicago sativa)和黑麦草(Lolium perenne)为材料,在盆栽条件下探讨紫花苜蓿和黑麦草在电解锰渣–土壤混合基质中的生长状况及其对锰(Mn)的吸收特点。结果表明:土壤添加7%、14%、21%、28%、35%的电解锰渣后,紫花苜蓿、黑麦草的发芽率明显下降,而总生物量随着电解锰渣添加量的增加先增加后降低;但两种植物的株高均出现不同程度的增加,特别是黑麦草。随着电解锰渣添加量的增加,黑麦草中光合色素含量增加,在锰渣添加为14%时叶绿素含量最大,显著高出无锰渣对照34.7%(P 0.05);紫花苜蓿中叶绿素和类胡萝卜素含量随着锰渣添加先增加后下降,在锰渣添加量为14%时达到最大,分别高出对照59.7%、28.0%。在土壤中添加锰渣后,紫花苜蓿中丙二醛(MDA)含量、抗氧化酶包括超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性明显提高,而黑麦草中MDA含量、SOD、CAT和POD活性没有明显变化,说明黑麦草的耐受性大于紫花苜蓿。同时,在锰渣–土壤混合基质上紫花苜蓿、黑麦草的地上部分和根系中的锰含量均随着电解锰渣的添加量增加而提高,总体上黑麦草的富集系数大于紫花苜蓿,而对Mn的转移能力是紫花苜蓿大于黑麦草。研究结果显示,两种植物都可作为锰渣堆场生态修复的备选植物,但锰渣对紫花苜蓿的抑制作用大于黑麦草,因此,黑麦草更适合作为锰渣堆场生态修复的先锋植物。     

根瘤菌共生对低温胁迫下紫花苜蓿抗寒生理变化的影响

为研究根瘤菌共生对紫花苜蓿(Medicago sativa)在低温胁迫下抗寒生理指标变化的影响,对低温胁迫下接种和不接种根瘤菌的紫花苜蓿的地上部分及地下部分的相对电导率、丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、脯氨酸、可溶性蛋白、可溶性糖等指标进行测定。结果显示:低温胁迫下,根瘤菌共生紫花苜蓿的相对电导率(-6℃,4~6 h)显著低于不接种紫花苜蓿(P < 0.05),且其MDA含量低于不接种紫花苜蓿;根瘤菌共生紫花苜蓿的SOD比活力、CAT活性、POD活性以及脯氨酸、可溶性蛋白、可溶性糖含量均高于不接种根瘤菌紫花苜蓿。根瘤菌共生紫花苜蓿在低温胁迫下具有更强的膜稳定性、活性氧防御以及渗透调节能力,具有更强的抗寒能力。     

温度胁迫对草地早熟禾苗期生理生化特性的影响

对草地早熟禾2个品种生长在4种不同温度下苗期的根、茎、叶中可溶性糖、脯氨酸、可溶性蛋白质含量及硝酸还原酶(NR)、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性的变化进行研究.结果表明,与适温25℃相比,草地早熟禾各组织中可溶性糖和脯氨酸含量均增加,而可溶性蛋白质含量在叶片中则随温度的降低而升高,在根和茎中则具有波动性;同时发现2个品种对温度胁迫的反应存在差异,且品种间各器官中酶活性的变化不同,说明2个品种间和同一品种的不同器官间的抗寒、耐热能力不同,但在-7℃和40℃时3种酶的活性均较高.     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.