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1.
In late 2018, the fall armyworm(FAW) Spodoptera frugiperda Smith(Lepidoptera: Noctuidae) made its arrival in China and its populations have since proliferated across most of eastern Asia. While S. frugiperda exhibits a considerable dispersal capacity and engages in long-distance migration, there's only scant information on the species' flight capability. Here, we empirically assessed S. frugiperda flight activity under varying climatic conditions using a flight mill. More specifically, under laboratory conditions, FAW exhibited superior flight performance at 20–25°C and 60–90% relative humidity(RH). When quantifying flight performance over five consecutive nights(i.e., 10 h/night), all flight parameters initially increased and then gradually dropped and FAW adults attained a total flight distance, duration and velocity equal to 63.73 km(48.42–94.12 km)(median, quartile range), 24.12 h(20.87–27.73 h) and 2.73 km h~(–1)(2.13–3.33 km h~(–1)), respectively. Our work constitutes a first comprehensive assessment of S. frugiperda flight performance and provides baseline information for future efforts to forecast spatiotemporal changes in its geographical distribution, movement patterns and invasion trajectories. Such can ultimately permit a timely and targeted deployment of area-wide pest management measures against this newly-invasive pest in China and across eastern Asia. 相似文献
2.
Fall armyworm, Spodoptera frugiperda(J. E. Smith, 1797), a crop pest native to tropical and subtropical regions of America, has invaded and spread into most regions in China, posing a severe threat to China's agriculture. The cold hardiness directly determines its geographic distribution through adapting to winter temperatures of different regions. Here, we measured supercooling points and lethal time(LT) at low temperatures of S. frugiperda. The supercooling points for developmental stages in increasing order were: adults(–15.05°C)pupae(–13.25°C)prepupae(–10.50°C)larvae(–9.03°C). Among eggs and 1 st to 4 th instar larvae, the 99% lethal time(LT_(99)) was the highest for 4 th instar larvae, with 99% of larvae dying after 18.59 d at 2°C, 58.72 d at 7°C, and 66.28 d at 13°C. LT_(99) was the lowest for eggs with LT_(99) of 5.33 d at 2°C, 9.28 d at 7°C, and 12.97 d at 13°C. This study provides an understanding of overwintering regions of S. frugiperda in China, which will be helpful for population forecasting and management. 相似文献
3.
Expression profiles of Cry1Ab protein and its insecticidal efficacy against the invasive fall armyworm for Chinese domestic GM maize DBN9936 
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下载免费PDF全文 Jin-gang LIANG Dan-dan ZHANG Dong-yang LI Sheng-yuan ZHAO Chen-yao WANG Yu-tao XIAO Dong XU Yi-zhong YANG Guo-ping LI Li-li WANG Yu GAO Xue-qing YANG Hai-bin YUAN Jian LIU Xiu-jie ZHANG Kong-ming WU 《农业科学学报》2021,20(3):792-803
The fall armyworm(FAW) Spodoptera frugiperda, which originated in the Americas, is advancing across China and threatening the nation's maize crops. Currently, one widely used tool for its control is genetically modified(GM) Bacillus thuringiensis(Bt) maize. Sufficient content of Bt protein in appropriate plant parts is crucial for enhancing resistance against insect pests. In this study, we conducted a systematic investigation of Cry1 Ab levels in Chinese domestic GM maize DBN9936, which has recently obtained a biosafety certificate, and evaluated its efficacy against FAW. Quantification of expression levels of Cry1 Ab, via ELISA, indicated a spatio-temporal dynamic, with significant variation of mean Cry1 Ab, ranging from 0.76 to 8.48 μg g–1 FW with the Cry1 Ab protein level ranked as: V6–V8 leafR1 leafR4 leafR1 silkVT tasselR4 kernel. Among the nine locations, the Cry1 Ab levels in DBN9936 of the Xinxiang, Langfang, and Harbin fields were significantly lower than those from Wuhan and Shenyang, and were slightly, but not significantly lower than those from the other four fields. Furthermore, the artificial diet–Cry1 Ab mixture and plant tissue feeding bioassays revealed that DBN9936 has high efficacy against FAW. The insecticidal efficacy of different tissues against FAW larvae reached 34–100% with a descending order of lethality as follows: VT leafR4 leafR1 huskR1 silkVT tasselR4 kernel. Taken together, our results showed that Bt-Cry1 Ab maize DBN9936 has potential as a promising strategy to manage FAW. 相似文献
4.
Susceptibility breakpoint for cefquinome against Escherichia coli and Staphylococcus aureus from pigs 下载免费PDF全文
下载免费PDF全文 Cefquinome is the only fourth-generation cephalosporin used solely for veterinary applications.In this study,we established the wild-type cut-off (CO_(WT)) and pharmacokinetic/pharmacodynamic cut-off (CO_(PD)) of cefquinome against Escherichia coli and Staphylococcus aureus.A total of 210 E.coli and 160 S.aureus isolates were collected from pigs in Guangdong Province between 2014 and 2018.The minimum inhibitory concentrations (MICs) were determined using a microdilution broth method.MIC_(50) and MIC_(90) were 0.06 and 0.25μg m L~(–1) for E.coli and 0.5 and 1μg m L~(–1) for S.aureus,respectively.Statistical analysis and the ECOFFinder Program showed that the CO_(WT )for cefquinome against E.coli and S.aureus were0.125 and 2μg m L~(–1),respectively.The resistance rates were 11.9%for E.coli and 6.25%for S.aureus.Based on a5 000-subject Monte Carlo simulation,the CO_(PD) value for cefquinome against E.coil and S.aureus was 0.25μg m L~(–1) under the recommended dose (2 mg kg~(–1),twice a day for 3 days),confirming that infections caused by strains with MIC≤0.25μg m L~(–1) could be effectively treated.Following adjustment of the dosing regimen to 4.5 mg kg~(–1),effective treatment (90)was achieved for S.aureus infections with MIC_(90) 1μg m L~(–1).This susceptibility breakpoint determination is significant for resistant surveillance and cefquinome dosage guidance against E.coli and S.aureus in pigs. 相似文献
5.
二十六种杀虫剂对不同龄期草地贪夜蛾幼虫的室内毒力 总被引：3，自引：0，他引：3
2019年初,草地贪夜蛾(Spodoptera frugiperda)入侵中国云南地区并迅速扩散。为筛选杀虫效果较好的药剂,室内测定了26种商品药剂对草地贪夜蛾初孵、3龄和5龄幼虫的毒力。结果表明,除6%鱼藤酮微乳剂、0.5%藜芦碱乳油外,其他药剂对初孵幼虫72 h后的校正死亡率均在70%以上。与初孵幼虫相比,大部分药剂对3龄幼虫的毒力有所下降,包括4.5%高效氯氟氰菊酯乳油、1.8%阿维菌素微乳剂、20%氯虫苯甲酰胺悬浮剂、0.5%苦参碱水剂等在内的11种药剂对3龄幼虫72 h后的校正死亡率均在70%以下。选取18种对3龄幼虫效果相对较好的药剂测定其对5龄幼虫的毒力,结果显示,除30%噻嗪·毒死蜱乳油、1.8%阿维菌素微乳剂、3.2%高氯·甲维盐微乳剂、56%阿维·炔螨特微乳剂、20%氯虫苯甲酰胺悬浮剂和10%氟苯虫酰胺悬浮剂外,其他12种药剂对5龄幼虫的校正死亡率均高于70%,包括6%甲维·虫螨腈乳油、44%氯氰·丙溴磷乳油、25%丙溴·灭多威乳油、15%茚虫威悬浮剂、30亿PIB·mL-1甘蓝夜蛾核型多角体病毒悬浮剂、25%甲维·灭幼脲悬浮剂、2%甲氨基阿维菌素苯甲酸盐微乳剂、45%毒死蜱乳油、34%乙基·甲氧虫悬浮剂、5%虱螨脲乳油、40%氟虫·乙多素水分散粒剂、1%苦皮藤素乳油。 相似文献
6.
温度和营养条件对管侧沟茧蜂成虫寿命的影响 总被引：2，自引：0，他引：2
在室内控温条件下,研究了不同温度和营养条件对管侧沟茧蜂成虫寿命的影响。结果表明：成虫寿命随温度的升高而缩短,不同温度条件下成虫寿命存在显著差异;补充水分对管侧沟茧蜂成虫寿命没有明显影响,补充蜂蜜水能明显延长成虫寿命。在18℃饲喂20%蜂蜜水条件下,成虫寿命最长（雌虫为24.6±3.0d,雄虫为13.8±2.5d）,且相同条件下雌成虫寿命长于雄成虫;在30℃不饲喂条件下,成虫寿命最短（雌成虫为1.4±0.1 d,雄成虫为1.2±0.1 d）。 相似文献
7.
测定和分析了4种鱚属(Sillago)鱼类:斑鱚(Sillago aeolus)、亚洲鱚(S. asiatica)、多鳞鱚(S. sihama)和少鳞鱚(S. japonica)线粒体细胞色素b基因序列片段,比较了不同鱚属鱼类种间的序列差异,探讨了彼此间系统发育关系和分类地位。结果显示,4种鱼类平均核苷酸组成为T 29.9%、C 29.2%、A 21.5%、G 19.3%,种间平均净遗传距离在0.157到0.280之间。最大似然法构建的系统树显示,少鳞鱚和亚洲鱚首先聚类、再与多鳞鱚和斑鱚相聚,斑鱚是最晚分化出的鱼类。基于Cyt b基因序列核苷酸分歧速率计算得出4种鱼类发生遗传分化时间在距今785—1400年前的第三纪中新世(Miocene)。 相似文献
8.
Larval diet affects development and reproduction of East Asian strain of the fall armyworm,Spodoptera frugiperda 下载免费PDF全文
下载免费PDF全文 Li-mei HE Teng-li WANG Yu-chao CHEN Shi-shuai GE Kris A.G. WYCKHUYS Kong-ming WU 《农业科学学报》2021,20(3):736-744
In December 11, 2018, the fall armyworm(FAW), Spodoptera frugiperda invaded China and has since impacted local maize, sorghum and other crops. Here, we draw on laboratory experiments to show how different host crops(i.e., maize, sorghum, wheat and rice) and artificial diet affect larval growth and adult reproduction of one local FAW strain. Larval diet affected development duration, pupation rate, survival and emergence rate of pupae, and S. frugiperda adult fecundity. FAW attained the slowest larval development(19.4 days) on sorghum and the fastest(14.1 days) on artificial diet, with larvae attaining 99.6% survival on the latter food item. On rice, FAW larvae attained survival rate of 0.4% and were unable to pupate successfully. Pupation rate and pupal survival varied substantially between artificial diet and live plantlets at different phenological stages. Pupal weight was the highest(0.26 g) on artificial diet and the lowest(0.14 g) on sorghum, while FAW females reached the highest fecundity(699.7 eggs/female) on 2-leaf stage maize. Egg hatching rate equaled 93.6% on 4-or 5-leaf stage maize and 36.6% on artificial diet. FAW intrinsic rate of natural increase and the finite rate of increase varied between larval diets, reflecting how young maize leaves are the most suitable diet. Our findings can help to refine laboratory rearing protocols, devise population forecasting models or guide the deployment of ‘area-wide' integrated pest management(IPM) modules in FAW-invaded areas of China and other Asian countries. 相似文献
9.
Flight activity promotes reproductive processes in the fall armyworm,Spodoptera frugiperda 下载免费PDF全文
下载免费PDF全文 The fall armyworm(FAW), Spodoptera frugiperda(Lepidoptera: Noctuidae), has invaded many countries in Africa and Asia since 2016, posing a major threat to world food security. Long-distance migration and strong reproductive ability form the biological basis of its rapid population expansion, but the relationship between the flight and reproduction of FAW has not been studied in depth. Here, an empirical assessment of this relationship in an invasive FAW population in China found that 1–3-day-old adults which had undergone 10-h tethered flights had a significantly shorter pre-oviposition period and greater oviposition synchronization, but did not show any differences in fecundity, oviposition period, mating percentage or other reproductive variables. Further studies on moths after 1.25–15-h tethered flights indicated that the reproductive process of adults could be fully triggered by flight activity longer than 2.5 h. Dissection of the reproductive organs also showed that tethered flight promoted ovarian and testicular development of FAW. These results show that appropriate moth flight activity significantly speeds up the reproductive process of FAW, which increases our knowledge on its migratory biology in relation to regional outbreaks. 相似文献
10.
湿度对褐背小萤叶甲生长发育的影响 总被引：6，自引：1，他引：6
研究了相对湿度(RH)对褐背小萤叶甲生长发育的影响,结果表明,在不同RH下,褐背小萤叶甲各虫态的发育历期、存活率、成虫繁殖力和成虫寿命明显不同.卵期、幼虫期、蛹期、产卵前期、世代历期、孵化率、幼虫存活率、羽化率、成虫平均产卵量均与湿度呈抛物线模型关系.不同RH下的成虫产卵期存在显著性差异,在75%RH下最长,达到59.25d,在95%RH下最短,仅24.17d.不同RH下的雌、雄成虫的寿命也明显不同,均为75%下最长,雌成虫达到65.00d,雄成虫57.19d. 相似文献
11.
Li-hong WU Cao ZHOU Gui-yun LONG Xi-bin YANG Zhi-yan WEI Ying-jiang LIAO Hong YANG Chao-xing HU 《农业科学学报》2021,20(3):755-763
The fall armyworm(FAW), Spodoptera frugiperda Smith(Lepidoptera: Noctuidae) is an important agricultural pest that invaded China in the middle of December 2018. As a polyphagous pest, FAW is identified as a serious threat to agricultural production and food security in China. Pepper(Capsicum annuum L.), tomato(Solanum lycopersicum Mill.) and eggplant(Solanum melongena L.) are three of dominant solanaceous vegetables of this country. To our knowledge, the effects of these plants on the performances of FAW have not been well studied. In this study we assessed the fitness of this pest to these three plants. Results showed that FAW can complete its life cycle when fed with tomato and pepper, but not on eggplant. The population parameters of FAW fed with maize(Zea mays L.) and the three solanaceous vegetables were compared using the age-stage, two-sex life table method. Developmental duration was significantly different in the larval stage, but not in the pupae stage. FAW fed with pepper had the longest pre-adult period(41.73 d) and the lightest pupal weight(0.1134 g); the survival rate was lower than FAW fed with tomato. Significant differences were observed in the mean fecundity of female, with the highest(943.95 eggs) laid by FAW fed with tomato. FAW had the shortest mean generation time(T), the highest intrinsic rate of increase(r) and finite rate of increase(λ) on maize, and the highest net reproductive rate(R_0) on tomato. Overall, FAW fitness on the three solanaceous vegetables was: tomatopeppereggplant. This study provides the foundation for further assessment of FAW risk to solanaceous vegetables and for establishing corresponding control strategies in China. 相似文献
12.
胡瓜钝绥螨以苹果与石松混合花粉为食料,研究对其生长发育、存活和繁殖的影响.在取食花粉时,胡瓜钝绥螨前若螨期的存活时间明显长于对照,而且可以明显延长成螨的寿命,但雄成螨寿命与对照没有明显区别;只供给水时,胡瓜钝绥螨雌成螨不产卵,但取食混合花粉时胡瓜钝绥螨产卵量也很低. 相似文献
13.
为探究具有较高观赏价值的鼠尾草属植物的耐湿热性，以马德雷鼠尾草、腺毛鼠尾草、紫红鼠尾草、总苞鼠尾草、‘山顶公园’药用鼠尾草为试验材料，分析5种鼠尾草在40 ℃/35 ℃（昼/夜）、空气湿度90%~95%、土壤湿度95%~100%模拟环境下的形态变化，以及叶绿素相对含量（SPAD）、细胞质膜透性、超氧化物歧化酶（SOD）活性、可溶性蛋白含量、丙二醛（MDA）含量、游离脯氨酸(Pro)含量的变化。结果表明，在高温高湿胁迫下，5种鼠尾草均受到不同程度的伤害；SPAD随着胁迫时间的延长而下降，相对电导率变化趋势则相反；SOD活性、MDA含量呈现先上升再下降的变化趋势，两者之间存在一定关联；可溶性蛋白和脯氨酸含量总体呈上升趋势，说明5种鼠尾草在湿热胁迫下产生了一定的适应性，但不同鼠尾草的调节机制侧重不同，其中马德雷鼠尾草、腺毛鼠尾草和‘山顶公园’药用鼠尾草以增加脯氨酸含量为主，而总苞鼠尾草以增加可溶性蛋白为主，紫红鼠尾草两者均不突出。使用隶属函数法对5种鼠尾草进行耐湿热性综合评定，结果为:‘山顶公园’药用鼠尾草>腺毛鼠尾草>紫红鼠尾草>马德雷鼠尾草>总苞鼠尾草。 相似文献
14.
为研究滇南中蜂的周年状况及气候的相关性,探明各压力因素间与蜜蜂群势的联系,为滇南中蜂保种提供依据,于2018年1—12月每隔15 d用测子框测定90群蜜蜂群势,并以气候仪观察气象变化,分析蜜蜂的幼虫数、蛹数、工蜂量与蜜粉存储量的相关性,并探讨危及蜜蜂健康的各类潜在因素。结果表明:蜂群在冬、春季增殖激烈,全年中群势呈波澜起伏状;全年气候表现为冬春季降雨量少,温度波动较大,夏秋季节炎热湿润;主成分分析表明,温度是构成蜂群变化的最主要的成分(a=0.977);蜂群内部蜜粉存储量与工蜂量(r=0.580)及卵/幼虫量(r=0.386)呈显著的正相关性,与温度(r=-0.248)呈显著的负相关。在周年变化中,滇南中蜂群势受蜂群外部因素和蜂群内部因素影响,外部因素具有季节性,内部因素由蜂群管理方式决定。 相似文献
15.
对2016年7—10月采集自浙江和上海部分地区肉鸡屠宰端、零售端鸡肉样品及屠宰场环境样品中的沙门氏菌进行分离,研究102株分离株的血清型及其对常用抗生素的药敏性。使用世界卫生组织(world health organization,WHO)指定的泰国S&A公司沙门氏菌诊断血清,采用玻片凝集法确定沙门氏菌的血清型。使用临床实验室标准化委员会(clinical laboratory standard institute,CLSI)推荐的纸片扩散法测定沙门氏菌的药敏性。研究发现,204份样品中,85份检出沙门氏菌,阳性样品平均检出率为41.67%。脱羽、净膛、清洗、包装、整鸡和预冷检出率依次降低,而冷藏检出率回升到70.00%。102株沙门氏菌共涵盖15个血清型,以德尔卑沙门氏菌(Salmonella Derby,23.53%)、阿贡纳沙门氏菌(Salmonella Agona,17.65%)、印第安纳沙门氏菌(Salmonella Indiana,12.75%)、鼠伤寒沙门氏菌(Salmonella Typhimurium,11.76%)和达布沙门氏菌(Salmonella Dabou,7.84%)较为常见。屠宰端德尔卑沙门氏菌最为流行,零售端则主要为阿贡纳沙门氏菌。所有菌株对阿莫西林/克拉维酸和头孢西丁敏感,75株(73.53%)菌对四环素产生抗性;对氯霉素、氨苄西林、萘啶酮酸、甲氧苄啶/磺胺甲噁唑、链霉素、环丙沙星、头孢曲松、头孢哌酮、卡那霉素、庆大霉素和阿米卡星耐药的菌株比例分别为49.02%、41.18%、38.24%、37.25%、28.43%、23.53%、22.55%、22.55%、20.59%、19.61%和17.65%。零售端样品源沙门氏菌对大部分供试抗生素的抗性显著低于屠宰端和环境样品源沙门氏菌。102株菌中,97株(95.10%)可抗至少1种抗生素,17株(16.67%)可抗10种或10种以上的抗生素。不同地区采集的样品中,源于绍兴的样品沙门氏菌检出率最高(78.95%),且极显著高于湖州及上海地区的阳性样品检出率(P<0.01)。沙门氏菌阳性样品在不同月份的检出率存在极显著差异,9月份检出率最高(80.00%)。研究结果表明,在整个肉鸡生产消费链条中,沙门氏菌检出率、血清型和耐药率、耐药谱呈现明显的变化,即沙门氏菌不是单纯来源于该批次肉鸡携带菌,各环节固有存在和人员携带的菌株也加入了其中,造成终端产品的现状。本研究揭示了沙门氏菌在鸡肉产品中分布的状况和来源,为采取合理的干预措施,预防该省肉鸡生产全产业链中沙门氏菌的污染及耐药菌的出现、确保食品安全提供了相应的数据和理论支持。 相似文献
16.
以飞播马尾松林为研究对象,按其树种组成分为10马(10马尾松,类型Ⅰ)、8马2木(8马尾松-2木荷,类型Ⅱ)、7马3木(类型Ⅲ)、6马4木(类型Ⅳ)4种类型设置典型样地,分析比较其林下植被物种组成及多样性。结果表明:1)从类型Ⅰ至类型Ⅳ林下植被的物种数增加,类型Ⅰ为11种,类型Ⅳ为28种;随着木荷比例的增加,林下植被阳生植物的优势地位表现为先增强再逐渐减弱或消失,而喜湿植物的地位逐步提升甚至成为优势种。2)林下灌木及草本Shannon-Wiener多样性指数、Patrick丰富度指数、Pielou均匀度指数均在类型Ⅳ时达到最大,表现为类型Ⅳ>类型Ⅲ>类型Ⅱ>类型Ⅰ。3)木荷比例与林下灌木及草本Shannon-Wiener多样性指数和Patrick丰富度指数呈显著(P<0.05)或极显著正相关(P<0.01),与Pielou均匀度指数相关不显著(P>0.05);拟合得出林下灌木及草本Shannon-Wiener多样性指数和Patrick丰富度指数达峰值的木荷比例分别为0.43、0.54、0.57、0.50,对拟合曲线分析表明飞播马尾松林补植木荷比例在43%~57%之间其林下植被多样性达到最大值。 相似文献
17.
大型海藻养殖是一种低成本、高效、环保的水体富营养化生物修复方法,而水流则是影响大型海藻生长的一个重要因素。研究结果表明,水流交换率为200 vol·d-1时,羊栖菜(Sargassum fusiforme)比生长率最高达(4.34±0.11) %·d-1,而水流交换率为100 vol·d-1、中高浓度营养盐条件下石莼(Ulva pertusa)比生长率最大值分别可达(6.31±1.42) %·d-1、(8.00±0.79) %·d-1,营养盐浓度决定了两种大型海藻的生长率,石莼更适宜在高营养盐环境中生长。石莼体内叶绿素a、可溶性蛋白和可溶性碳水化合物在不同应用情境间均存在明显差异,而羊栖菜体内仅可溶性蛋白表现出明显变化。水流交换的增强明显改变了石莼的生长和羊栖菜可溶性碳水化合物含量。陆基中试实验表明,与低水流速度相比,中、高流速条件下羊栖菜的比生长率分别增加80%、14%,石莼则分别增加41.3%、33.3%。 相似文献
18.
采用酵母菌单菌和酵母菌、乳酸菌混菌对玉米、豆粕和麸皮组成的饲料进行好氧固态发酵,探索其对饲料营养成分和体外功能活性的影响。结果表明,发酵后,粗蛋白、总磷和低分子量肽含量显著(P<0.05)提高,而粗脂肪含量显著(P<0.05)降低。氨基酸方面,酵母单菌和混菌发酵后,天冬氨酸、丝氨酸、酪氨酸、苯丙氨酸和精氨酸的含量显著(P<0.05)提高。与发酵前相比,酵母单菌发酵还显著(P<0.05)提高了总氨基酸含量。饲料经过单菌和混菌发酵后,总酚含量、维生素B2、B6以及咖啡酸、没食子酸的含量亦显著(P<0.05)提高。体外功能评价试验表明,发酵饲料提取液对大肠埃希菌、金黄色葡萄球菌、藤黄微球菌和沙门氏菌等4种指示菌均有抑制效果,并对酵母菌和乳酸菌有促生长作用。由此可知,在本试验条件下,酵母单菌发酵和酵母、乳酸菌混菌发酵处理可有效提高饲料的营养品质。 相似文献
19.
以羊栖菜(Sargassum fusiforme)幼体为实验材料,设置不同海水盐度(15‰、20‰、29‰、45‰),对羊栖菜幼体进行梯度胁迫处理,探讨不同盐度胁迫对羊栖菜幼体光合作用的影响。结果表明,在盐胁迫条件下,羊栖菜的光合作用会受到明显影响。在盐度20‰条件下,羊栖菜幼体光合作用受到的抑制作用较弱,羊栖菜幼体对低盐度海水有一定的耐受性。海水盐度过低(15‰)时,羊栖菜光合作用受到明显抑制。高盐(45‰)条件下,羊栖菜幼体受到损伤,羊栖菜幼体光合作用和无机碳利用受到显著抑制。短时间(1~12 h)处理,羊栖菜光合作用受到的影响较小,各盐度处理的羊栖菜幼体色素含量、最大相对电子传递速率(rETRmax)、最大光化学量子产量(Fv/Fm)出现先降低后升高的趋势。长时间(240 h)处理,盐度过低(15‰)或过高(45‰)均会抑制羊栖菜幼体的光合作用,其rETRmax、光能利用效率(α)、最大净光合作用速率(Pnmax)、最大光合固碳速率(vmax)均显著降低,而且过高盐度通过阻碍羊栖菜幼体光合色素合成影响其光合作用过程。实际生产中,当产生过高或过低盐度变化时,应当及时做好羊栖菜的防低盐或高盐胁迫处理,防止长时间的盐度变化影响羊栖菜特别是其幼体的生长。 相似文献
20.
【背景】草地贪夜蛾（Spodoptera frugiperda）是联合国粮食及农业组织（FAO）全球预警的重大迁飞性农业害虫,2018年底入侵中国后对玉米等农作物生产构成了严重威胁。远距离迁飞习性是草地贪夜蛾区域性转移危害的生物学基础,其在东亚季风和印度季风流行的气候环境下,可形成纵贯中国东部地区和西部地区的迁飞路线。据连续两年全国普查,草地贪夜蛾沿西线迁飞路线逐代北侵的终点位于我国西北地区的宁夏全境和内蒙古阿拉善左旗。但目前,入侵中国西北地区的草地贪夜蛾的虫源地尚未明确,该害虫在整个中国西部地区的迁飞路径研究也鲜有报道。【目的】阐释驱动草地贪夜蛾迁入中国西北地区的关键气象动力因子,明确该地区首次入侵种群的虫源地所在,精准解析亚洲季风气候背景下草地贪夜蛾的迁飞路径,为建设监测预警体系和指导区域性治理提供依据。【方法】利用2019—2020年草地贪夜蛾在西北地区宁夏的成虫种群动态监测数据和气象资料,采用中尺度气象数值模拟、昆虫迁飞轨迹模型、地理信息系统等技术手段,分析草地贪夜蛾远距离迁飞的大气动力背景场,模拟计算草地贪夜蛾在中国西北地区连续1—3个夜晚的迁飞路径和回推轨迹落点。【结果】7—9月份出现的偏南夏季风是影响宁夏等西北地区草地贪夜蛾不断迁入的关键气象因子,其虫源主要来自于甘肃东南部、四川东部,其次为陕西西部,此外,重庆西南部、云南东北部和山西西部局部也可为西北地区提供一定的虫源。【结论】在偏南夏季风的主导作用下,草地贪夜蛾经由多个夜晚的连续迁飞可构成其在中国西部地区的主要迁飞路径。该路径源自缅甸,自南向北依次经由中国“云南-四川和重庆-陕西和甘肃-宁夏”,最北可达内蒙古。在7—9月份偏南风盛行期提前和风速偏强的气候条件下要加强西北部玉米种植区草地贪夜蛾的监测预警与防治工作。 相似文献