黄瓜抗感材料接种尖孢镰孢菌后根系游离氨基酸的差异分析

为阐明尖孢镰孢菌侵染黄瓜抗感材料后根系游离氨基酸的差异，对黄瓜抗感材料进行接种，以接种灭菌水为对照，分析接种后8、12、16、20 d 根系游离氨基酸的动态变化。结果表明：接种病原菌后，抗病材料游离氨基酸总量呈下降趋势，感病材料游离氨基酸总量呈上升趋势。抗感材料接种病原菌处理的游离氨基酸总量均较对照增加，接种后8、12、16、20 d，抗病材料分别较对照增加9.37%、38.81%、33.09%、25.72%，感病材料分别较对照增加19.89%、49.49%、101.11%、208.96%，游离氨基酸总量受病原菌的影响表现为感病材料大于抗病材料。接种病原菌后，β- 丙氨酸、鸟氨酸、亮氨酸、天冬氨酸、苯丙氨酸、赖氨酸、尿素、精氨酸和γ- 氨基丁酸在抗感材料中的变化规律明显不同。     

Evaluation of Heat Tolerance in Wheat Germplasm Resources

【Objective】 High-throughput evaluation of winter and spring wheat accessions for heat tolerance via heat susceptibility index (HSI) could provide the potentially superior accessions for heat-tolerant breeding programs. 【Method】 In order to expose plants to high temperatures during grain filling period, winter wheat accessions were sown in normal and late seasons, and spring wheat accessions were sown in different geographical environments with contrasting temperatures. The thousand grain weight (TGW) of winter and spring wheat accessions were measured under normal and heat stress environments, respectively. HSI was calculated from the TGW data of two different conditions. Using heat susceptibility index, 1 325 wheat germplasms from different wheat ecological zones of China, and international areas and organizations, including 688 winter wheat accessions and 637 spring wheat accessions, were evaluated for heat tolerance. Genotypes were classified into four tolerant grades, i.e. highly heat-tolerant (HSI<0.50), medium heat-tolerant (0.5≤HSI<1), medium heat-susceptible (1≤HSI<1.5) and highly heat-susceptible (HSI>1.5). 【Result】 The average maximum temperature at grain filling stage under heat stress condition was higher than that of the controls by 1.91℃ for winter wheat and 7.09℃ for spring wheat, respectively. TGW under heat stress condition was significantly lower than that of the corresponding control. According to the grading evaluation results of HSI, thirty-one and 48 highly heat-tolerant winter and spring wheat accessions accounted for 4.51% and 7.54% of the test materials, 19 and 58 highly heat-susceptible winter and spring wheat accessions accounted for 2.76% and 9.11% of the tested materials, and the rest were medium germplasms (medium heat-tolerant and medium heat-susceptible). According to the geographical distribution of wheat ecological regions, winter wheat from the southern wheat region (Southwestern Winter Wheat Zone, Qinghai Tibetan Plateau Spring and Winter Wheat Zone, and Middle and Lower Yangtze Valley Winter Wheat Zone) were more tolerant than that from northern wheat region (Northern Winter Wheat Zone, and Yellow and Huai River Winter Wheat Zone). For spring wheat, the average HSI of accessions from Xinjiang Spring and Winter Wheat Zone was 0.70, which was the most heat-tolerant, and 88.00% of the accessions belong to heat-tolerant (highly heat-tolerant or medium heat-tolerant) germplasms. In addition, the average HSI of spring wheat from the International Center for Agricultural Research in the Dry Areas (ICARDA) with 0.88 showed heat-tolerant. The synthetic hexaploid wheats from CIMMYT had the weakest heat tolerance, with an average HSI of 1.18, of which 69.58% were heat-susceptible germplasms (medium heat-susceptible and highly heat-susceptible). 【Conclusion】 Delayed sowing or planting in environment with high temperatures can make wheat encounter high temperature stress at grain filling stage. High-throughput method based on the HSI of TGW was performed to evaluate heat tolerance of 1 325 winter and spring wheat germplasms. Overall, one hundred and three heat-tolerant germplasms with high yield potential were identified, which could be used as parents developing heat-tolerant wheat varieties.     

套袋苹果黑点病的发病诱因、机制与条件

 “套袋苹果斑点病”是套袋果实的重要病害,每年导致3%~10%损失,而“套袋苹果黑点病”是套袋苹果斑点病的一种类型。本研究采用病原菌分离、接种、诱导发病等方法,揭示了黑点病发病的诱因、机制与条件,可为病害的防治提供科学依据。结果表明,诱发套袋苹果黑点病的病原菌是粉红单端孢(Trichothecium roseum);苹果谢花30 d后,幼果上就潜带有大量病原菌;自未喷施过杀菌剂的果园内摘取苹果幼果,在20℃~30℃、100%的相对湿度条件下保湿培养3 d可以诱发黑点病斑;在2周时间内,保湿培养的时间越长,诱发的黑点病斑数量越多;黑点病菌侵入果肉组织后能诱发寄主细胞木栓化,木栓化细胞进一步阻止了病菌的生长与扩展;5月下旬(谢花后30 d)采摘的幼果可诱发产生黑点病斑,但病斑较小;7月上旬(谢花后60 d)苹果果实对黑点病菌最敏感,保湿后诱发的病斑数量最多,形成的病斑大;进入8月份,果实的抗病性明显增强;所测试的9种杀菌剂都能有效抑制黑点病斑的形成,降低果实发病率,但不能完全阻止黑点病斑的形成。苹果果实套袋前,喷施杀菌剂降低果实的带菌量是防治黑点病的重要技术措施。     

Resistance in the highly DDT-resistant 91-R strain of Drosophila melanogaster involves decreased penetration,increased metabolism,and direct excretion

Resistance to 4,4′-dichlorodiphenyltrichloroethane (DDT) in the 91-R strain of Drosophila melanogaster is extremely high compared to the susceptible Canton-S strain (>1500 times). In addition to enhanced oxidative detoxification, the 91-R strain also has a reduced rate of DDT penetration, increased levels of reductive and conjugative metabolism, and substantially more excretion than the Canton-S strain. Contact penetration of DDT was ∼30% less with 91-R flies, which also had significantly more cuticular hydrocarbons and a thicker, more laminated cuticle compared to Canton-S flies, possibly resulting in penetration differences. DDT was metabolized ∼1.6-fold more extensively by 91-R than Canton-S flies, resulting in dichlorodiphenyldichloroethane (DDD), two unidentified metabolites and polar conjugates being formed in significantly greater amounts. 91-R flies also excreted ∼4-fold more DDT and metabolites than Canton-S flies. Verapamil pretreatment reduced the LD₅₀ value for 91-R flies topically dosed with DDT by a factor of 10-fold, indicating that the increased excretion may involve, in part, ATP-binding cassette (ABC) transporters. In summary, DDT resistance in 91-R is polyfactorial and includes reduced penetration, increased detoxification and direct excretion.     

不同抗性小麦品种对药剂防治赤霉病效果的影响

探究了同一药剂对赤霉病不同抗性小麦品种防治效果的影响。结果表明,在同一药剂处理下,中抗品种赤霉病的防治效果最好,中感品种次之,高感品种防治效果最差;在赤霉病大面积流行期间,对于高感品种采取药剂防治的效果并不理想。     

褐飞虱共生菌抗感吡虫啉菌株体内抗氧化酶活性的比较

在含不同浓度吡虫啉的综合马铃薯葡萄糖琼脂液体培养基中接种抗感吡虫啉褐飞虱共生菌菌株且培养2～6天后,通过测定抗吡虫啉菌株和敏感菌株的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)等活性,阐明抗感菌株在吡虫啉胁迫下体内抗氧化酶活性的变化.结果显示,抗吡虫啉菌株和敏感菌株三种抗氧化酶活性差异明显不同,抗性菌株的SOD、POD活性(极)显著高于敏感菌株,其中抗性菌株SOD活性比敏感菌株提高了45.89％～222.53％;抗性菌株的CAT活性与敏感菌株差异无明显规律性.说明褐飞虱共生菌对吡虫啉的抗药性与其体内SOD和POD的活性增强有关.     

香蕉炭疽病菌和黑星病菌对丙环唑的敏感性基线

用生长速率法测定了杀菌剂丙环唑对香蕉炭疽病菌和香蕉黑星病菌的毒力,测定结果表明,丙环唑对2种病原真菌的有效中浓度EC50分别为(0 1976±0 0148)μg/mL和(0 0092±0 0006)μg/mL.     

套袋苹果黑点病的发病诱因、机制与条件

 “套袋苹果斑点病”是套袋果实的重要病害,每年导致3%~10%损失,而“套袋苹果黑点病”是套袋苹果斑点病的一种类型。本研究采用病原菌分离、接种、诱导发病等方法,揭示了黑点病发病的诱因、机制与条件,可为病害的防治提供科学依据。结果表明,诱发套袋苹果黑点病的病原菌是粉红单端孢(Trichothecium roseum);苹果谢花30 d后,幼果上就潜带有大量病原菌;自未喷施过杀菌剂的果园内摘取苹果幼果,在20℃~30℃、100%的相对湿度条件下保湿培养3 d可以诱发黑点病斑;在2周时间内,保湿培养的时间越长,诱发的黑点病斑数量越多;黑点病菌侵入果肉组织后能诱发寄主细胞木栓化,木栓化细胞进一步阻止了病菌的生长与扩展;5月下旬(谢花后30 d)采摘的幼果可诱发产生黑点病斑,但病斑较小;7月上旬(谢花后60 d)苹果果实对黑点病菌最敏感,保湿后诱发的病斑数量最多,形成的病斑大;进入8月份,果实的抗病性明显增强;所测试的9种杀菌剂都能有效抑制黑点病斑的形成,降低果实发病率,但不能完全阻止黑点病斑的形成。苹果果实套袋前,喷施杀菌剂降低果实的带菌量是防治黑点病的重要技术措施。     

小麦种质资源耐热性评价

【目的】利用热感指数作为耐热性鉴定指标,分别对冬、春小麦种质资源进行高通量耐热性鉴定,筛选耐热种质资源,为小麦耐热性育种提供材料基础。【方法】冬小麦材料采用延期播种、春小麦材料种植在温度有显著差异的地理环境下,人为致使小麦灌浆期遭遇高温胁迫。根据不同环境处理的千粒重值计算冬、春小麦各个材料的热感指数。依据热感指数,对来自中国不同小麦生态区和国外不同地区和组织的1 325份小麦种质资源,包括688份冬小麦和637份春小麦,分别进行耐热性评价。热感指数小于0.5为极耐热材料、大于等于0.5小于1为中等耐热材料、大于等于1小于1.5为中等热敏感材料、大于等于1.5为极敏感材料。【结果】冬小麦和春小麦热胁迫处理组灌浆期平均最高温度分别高于对照组1.91℃和7.09℃,且热胁迫处理组千粒重与对照组相比均有显著降低。根据热感指数分级评价结果,极耐热冬、春小麦材料31和48份,占供试材料的4.51%和7.54%;极敏感冬、春小麦材料19和58份,占供试材料的2.76%和9.11%;其余大多数材料为中间类型（中等耐热材料和中等热敏感材料）。从中国小麦生态区域的地理分布来看,来自南部麦区（西南冬麦区、青藏春冬麦区、长江中下游冬麦区）的冬小麦材料耐热性整体高于来自北部麦区（北部冬麦区、黄淮冬麦区）的冬小麦材料。对于春小麦,来自新疆春冬麦区的材料耐热性最强,平均热感指数为0.70,且其中88.00%的材料属于耐热材料（极耐热材料或中等耐热材料）;此外,来自国际干旱地区农业研究中心的春小麦平均热感指数为0.88,也表现出较强的耐热性。来自CIMMYT的人工合成六倍体材料耐热性最弱,平均HSI为1.18,其中69.58%的材料为热敏感材料（中等热敏感材料和极敏感材料）。【结论】采用延期播种或在高温的地理环境下种植能使小麦在灌浆期遭遇高温胁迫。以千粒重热感指数作为评价指标,对1 325份小麦种质资源进行高通量耐热性鉴定,综合考虑正常条件下的产量潜力和高温条件下的耐热性,筛选出优异耐热资源103份,可用于相应生态区小麦的耐热性遗传改良。     

胡瓜钝绥螨抗阿维菌素品系的筛选及抗性稳定性分析

为了使“以螨治螨”生防技术与病虫害综合治理中的其他防治方法合理结合,通过用玻片浸渍法对不同阿维菌素产品进行了毒力测定,确定了阿维菌素类农药对胡瓜钝绥螨具有中等毒性后,用在室内繁殖的多年未接触过任何农药的胡瓜钝绥螨敏感品系为材料,在实验室内用阿维菌素原粉进行胡瓜钝绥螨抗阿维菌素品系的汰选,并对筛选出的抗性品系进行抗性衰退...