木醋液对桃蚜生长繁殖的急慢性效应

为了明确木醋液对桃蚜短、长期影响,以桃蚜为试虫,用100倍稀释木醋液处理小白菜饲养蚜虫,测得桃蚜繁殖发育数据。结果显示,木醋液处理显著缩短桃蚜繁殖期,而F₁代繁殖期比F₀代繁殖期延长37%;F₀代和F₁代产蚜总量与对照组相比分别降低62%和66%;处理组F₁代和F₂代的存活率比对照组降低23%和24%,但F₁代和F₂代之间差异不显著;F₁代寿命缩短25%,F₂代差异不显著。本研究证明木醋液能够缩短桃蚜的繁殖期,延长其若蚜历期,整体缩短桃蚜寿命,降低子代存活率。总之,木醋液对桃蚜的生长发育和繁殖具有一定的抑制作用,但是这种抑制作用会随着施用频次增加而逐渐减弱,即木醋液的短期效应和长期效应存在差异,所以木醋液具有开发为生物农药的价值。     

稻虱缨小蜂耐热品系的生物和生态学特征

稻虱缨小蜂Anagrus nilaparvatae Pang et Wang是控制稻飞虱种群暴发的主要寄生性天敌之一，高温是制约其种群动态的重要因子。为了解35℃高温驯化获得的稻虱缨小蜂耐热品系（NR品系）的生防潜力，对不同温度下该品系的发育历期、有效积温、寄主卵选择、产卵量以及极端高温胁迫参数进行了测定。结果发现，与未经高温驯化的稻虱缨小蜂品系（HZ品系）相比，20℃时，NR品系雄蜂的发育速率显著高于HZ品系，这一差异主要表现在卵-幼虫中期和蛹期的发育时间明显缩短。NR品系在高温下能维持正常的产卵能力，35℃下NR品系产卵量仍能达到18.80粒/雌。NR品系有更强的耐极端温度的能力，50℃下NR品系雄蜂的热击倒时间为15.19 min，比HZ品系雄蜂长3.03 min。补充不同营养对NR品系的产卵量存在影响，35℃条件下补充10%蔗糖既能延长其寿命，也能提高产卵量。以上研究结果表明高温驯化得到的稻虱缨小蜂品系在35℃高温环境中能维持正常的生长发育和寄生能力，具备适应稻田夏季高温环境的潜力。     

Screening and identification of soybean varieties with high phosphorus efficiency at seedling stage

In order to simplify the workload and find a reliable method for screening soybeans with different phosphorus(P)efficiencies,47 soybean varieties were screened from 90 varieties according to yield under normal phosphorus,and 10 indicators including root phenotype,phosphorus utilization efficiency at the seedling stage and yield were measured.Through single-index cluster analysis,the performance value and relative value of the abovementioned indexes under low-phosphorus conditions were analyzed,and then,the combined indexes were analyzed by principal components method.The membership function method and the cluster analysis method was used to calculate and analyze the comprehensive score value.Three indexes of root P utilization efficiency(X₁),relative value of root P utilization efficiency(X₂),and root volume(X₃)under low P at the seedling stage were selected as the most consistent with the yield screening results under low P condition,and the mathematical model of the comprehensive score value was obtained:D=1.218X₁t 0.320X₂t 0.007X₃-0.664(P=0.000,R²=1.000).The comprehensive score can screen and identify the P efficiency of soybeans with fewer indexes in the early growth stages,which provides a more rapid and reliable mathematical model for screening and identifying a larger number of germplasm resources for P efficiency.     

Dynamics of Cotton Rhizosphere Bacterial Community Structure in Cotton Continuous Cropping Field Soil

[Objective] The aim of this study is to understand the dynamics of cotton rhizosphere bacterial community structure in cotton continuous cropping field soil. [Method] 16S rDNA genes were sequenced by high-throughput sequencing technology to determine the community structure of cotton rhizosphere bacteria in different developmental stages using an upland cotton cultivar (Gossypium hirsutum cv. TM-1). [Result] Four dominant phyla were found in the cotton rhizosphere bacterial community including Proteobacteria, Acidobacteria, Planctomycetes, and Bacteroidetes. The four dominant phyla and Firmicutes were largely influenced by cotton root. The relative abundances of Acidobacteria, Planctomycetes, Bacteroidetes were promoted, and Proteobacteria and Firmicutes were inhibited, by cotton root. There were significant differences in community structure, but not species richness or α-diversity among different developmental stages of the cotton rhizosphere bacterial community; the differences between the flowering stage and the budding stage were greater than the differences between the budding stage and the seedling stage. The diversity of the rhizosphere bacterial community in cotton continuous cropping field soil was significantly higher than that of the bulk soil; the β-diversity values of both the rhizosphere and bulk soil bacterial communities were highest in the flowering stage. [Conclusion] The structure and dynamics of the cotton rhizosphere bacterial community in cotton continuous cropping field soil was defined by high-throughput sequencing. The effect of cotton on the rhizosphere bacterial community structure was most significant in the flowering stage.     

朝鲜黄杨种源试验苗期效果初报

利用引进的锦州、沈阳、大连、鞍山4个产地朝鲜黄杨(Buxus microphylla var.koreana)种源进行播种试验,对幼苗出苗率、保存率、苗高、地径、分枝数、冠幅调查测量。结果表明:4个种源的出苗率、当年苗高、分枝数、冠幅均存在显著差异,地径差异不显著。沈阳种源播种出苗率最高,为75.48%;沈阳、大连种源当年苗高14.53 cm、14.08 cm,分枝数9.43条、9.21条,冠幅12.02 cm、10.00 cm,显著高于鞍山、锦州种源;苗木越冬保存率均在90%以上。沈阳种源表现最好。鞍山和锦州种源表现较差。     

优质水稻新品种芽期耐冷性鉴定

对来自不同地区的多个水稻品种进行芽期耐冷性试验,结果表明:15份优质水稻品种发芽期14℃、7 d处理,耐冷性均表现为极弱;14℃、14 d处理,龙稻18、通禾66耐冷性表现为极强,九稻68、吉粳511耐冷性表现为强。在芽期试验中,所有品种芽期耐冷性为强。     

灌水对强筋小麦籽粒产量及营养品质的影响

为明确水地强筋冬小麦高产、优质、高效的灌溉技术，试验设3个灌水时期8个灌溉处理［越冬期灌1水（W₁），拔节期灌1水（W₂），孕穗期灌1水（W₃），越冬期和拔节期灌2水（W₁₂），越冬期和孕穗期灌2水（W₁₃），拔节期和孕穗期灌2水（W₂₃），越冬期、拔节期和孕穗期灌3水（W₁₂3），全生育期不灌水处理（CK）］,于小麦成熟期测定籽粒产量、总蛋白及其组分含量和淀粉含量。结果表明，与不灌水的CK比较，所有灌水处理的籽粒产量、有效穗数、穗粒数、千粒重、蛋白质产量以及籽粒淀粉含量均显著增加，但籽粒的总蛋白及其组分含量均呈不同程度降低（W₁处理除外）。越冬期灌水对有效穗数、籽粒产量、总蛋白及其组分含量、淀粉含量的提升作用较大；拔节期灌水对穗粒数的提升作用较大，但对淀粉含量的提升作用较小，对总蛋白及其组分含量的降低作用较大；孕穗期灌水对千粒重的提升作用较大，对蛋白质产量的提升作用较小。随着灌水次数增加，小麦籽粒产量显著提高，淀粉含量先显著提高后基本不变，而籽粒总蛋白及其组分含量降低。W₁₂3处理籽粒产量最高，其次是W₁₃处理；W₁处理籽粒蛋白质及其组分含量最高，其次是W₁₂及W₁₃处理；W₂₃处理淀粉含量最高，其次是W₁₂或W₁₃处理。综合各项指标，最好的灌水组合是越冬期和孕穗期灌2水（W₁₃）。     

温度对草地贪夜蛾生长发育及繁殖的影响

草地贪夜蛾是新近入侵我国的重大农业害虫,为了弄清其入侵生物学特性,为草地贪夜蛾的监测预警及综合治理提供理论依据,本研究在光照培养箱内设置6个温度(17、22、27、32、37、42℃)饲养草地贪夜蛾,测定其不同阶段的存活率、发育历期、体重及繁殖力等,探究温度对草地贪夜蛾生长发育及繁殖的影响。结果表明,草地贪夜蛾在42℃条件下仅能短暂存活,在17～32℃范围内可正常生长发育,其幼虫期、蛹期及世代历期均随着温度的升高而缩短,17℃条件下世代历期和幼虫期分别为(58.73±1.46)d和(21.79±1.03)d,37℃条件下则分别仅为(22.57±0.84)d和(11.12±0.31)d。成虫寿命在17～27℃范围内差异不大,之后随温度升高而缩短,37℃下成虫寿命仅为27℃下的1/4左右,且在该温度下成虫无法正常羽化,雌成虫不产卵。17～32℃下雌成虫产卵前期随温度的升高而缩短,产卵期则随温度升高而有所延长,平均单雌产卵量在27℃下最高,为(565.50±143.40)粒。说明温度升高会导致草地贪夜蛾发育历期缩短,年发生世代数增加,幼虫取食量增大,对作物的为害加重。     

烘烤凋萎期失水速度对烟叶质量的影响

凋萎期失水速度在烟叶质量的形成过程中具有重要作用,是影响烟叶质量的关键指标。为了优化烘烤工艺,寻找最佳的凋萎期失水速度,以秦烟96为试验材料,2014~2015年在甘肃陇南地区应用变频技术通过风量调节研究了烘烤凋萎期7组失水速度对烟叶质量的影响。试验结果表明,凋萎期失水速度控制在5~7 g∕(kg·h)之间,不但可以让未变黄的烟叶继续变黄,消除青烟,让已变黄的烟叶适度失水,同时降低了变黄后烟叶的水分含量,为烟叶定色创造了条件,有利于防止棕色化反应的发生。