水科学中应用数理统计方法应注意

对回归方程误差的影响因素进行了分析，导出了回归方程的均方误差与其影响因素之间的关系式。分析表明，复相关系数(或相关系数)一定时，倚变量的变差系数越大，回归方程的均方误差就越大；回归分析时，应对回归方程的误差进行分析。对于样本均值估计总体均值，给出了基于误差限制的样本容量的计算式。研究表明，应考虑样本变差系数对估计精度的影响。     

保种群体遗传结构变化的模拟研究

本文运用电子计算机模拟的方法,分析了影响畜禽保种的主要因素,并通过不同参数组合(包括起始基因频率、群体有效含量和世代数等)的模拟试验得出三个主要结论: 1 在有性繁殖的有限群体中,原封不动地保存群体基因库中的每个基因(包括频率很低的基因)是根本不可能的。 2 在完全实行随机交配的情况下,长期保存频率较高的基因也需要相当大的群体才有可能。 3 频率较高基因的保存也不能单纯依靠群体大小,还需借助于选择。只有这样才能在小群体内长期保存频率较高的基因。     

毒死蜱对桔小实蝇体内代谢酶的影响

为了解毒死蜱对桔小实蝇体内代谢酶的影响,采用不同浓度的毒死蜱对桔小实蝇敏感种群进行连续处理,测定其体内的羧酸酯酶（CarE）、谷胱甘肽S-转移酶（GSTs）、过氧化氢酶（CAT）、过氧化物酶（POD）的活性。结果表明：随着毒死蜱浓度的增加,桔小实蝇的敏感性出现逐渐下降的趋势,体内的CarE活性得到显著提升（F=43.21,p=0.024）,抗性倍数为1.74,GSTs活性也显著上升（F=47.73,p=0.018）,抗性倍数为1.98,但对CAT、POD的提升作用较小,表明毒死蜱对桔小实蝇体内的CarE、GSTs活力具有一定的诱导作用。     

控制小菜蛾的赤眼蜂田间种群保护与增殖研究

通过建立十字花科蔬菜间作甜玉米、黑光灯诱虫育蜂笼这2种田间保护增殖措施,探讨了玉米螟赤眼蜂Trichogramma ostriniae、拟澳洲赤眼蜂T.confusum以及卷蛾分索赤眼蜂Trichogranunatoidea baarae对小菜蛾Plutella xylonella种群数量控制的作用．结果表明：十字花科蔬菜地间作甜玉米使得玉米螟赤眼蜂对小菜蛾卵寄生率有明显的提高,为4．62％～11．47％;黑光灯诱虫育蜂笼的设立对田间小菜蛾卵寄生蜂的种群数量起到了良好的增殖作用,自2002年4月初到6月底,诱集小菜蛾产卵127300粒,培育卷蛾分索赤眼蜂10万多头．在育蜂笼设立初期,笼内小菜蛾卵的寄生率为87．34％,距笼5m之外其寄生率急剧下降,其有效扩散范围不超过20m．2个月后的调查表明,赤眼蜂可逐步扩散到离育蜂笼30m处,各调查点之间寄生率的差距逐渐缩小,在距笼25m范围内,小菜蛾卵的寄生率维持在50％以上,有效地抑制了小菜蛾种群数量的增长．     

农村女性人口素质与未来人口素质的关系

妇女是人口再生产的主要承担者,当前我国城乡妇女生育状况表明,农村母亲对人口再生产的作用明显增强,城市母亲对人口再生产作用下降,而农村女性人口的素质状况堪忧.农村女性人口素质不仅关系到农村未来人口素质,而且关系到整个国家未来人口素质,提高农村女性人口素质十分迫切.提出目前提高农村女性人口素质的重点是:提高农村女性人口的文化水平,提高农村妇女家庭教育能力,引导农村妇女学习市场经济知识,确立与时代发展相适应的思想观念,提高农业科技水平.提高农村女性人口素质的途径是:政府、群团组织、事业单位各自发挥应有的作用;充分发挥各种媒体的作用,特别是发挥电视、网络、图书和报刊的作用.     

Effect of transferring lignocellulose-degrading bacteria from termite to rumen fluid of sheep on in vitro gas production,fermentation parameters,microbial populations and enzyme activity

The digestive tract of termite(Microcerotermes diversus) contains a variety of lignocellulose-degrading bacteria with exocellulases enzyme activity, not found in the rumen, which could potentially improve fiber degradation in the rumen. The objectives of the current study were to determine the effect of inoculation of rumen fluid(RF) with three species of bacteria isolated from termite digestive tract, Bacillus licheniformis, Ochrobactrum intermedium, and Microbacterium paludicola, on in vitro gas production(IVGP), fermentation parameters, nutrient disappearance, microbial populations, and hydrolytic enzyme activities with fibrous wheat straw(WS) and date leaf(DL) as incubation substrate. Inoculation of RF with either of three termite bacteria increased(P0.05) ammonia-N concentration compared with the control group(free of termite gut bacteria). Termite bacteria inoculation had no effect(P0.05) on gas production characteristics, dry matter, organic matter and neutral detergent fiber disappearance, pH, and concentration and composition of volatile fatty acids. Population of proteolytic bacteria and protozoa, but not cellulolytic bacteria, were increased(P0.05) when RF was inoculated with termite bacteria with both WS and DL substrates. Inoculation of RF with termite bacteria increased protease activity, while activities of carboxymethyl-cellulase, microcrystalline-cellulase, α-amylase and filter paper degrading activity remained unchanged(P0.05). Overall, the results of this study indicated that transferring lignocellulose-degrading bacteria, isolated from digestive tract of termite, to rumen liquid increased protozoa and proteolytic bacteria population and consequently increased protease activity and ammonia-N concentration in vitro, however, no effect on fermentation and fiber degradation parameters were detected. These results suggest that the termite bacteria might be rapidly lysed by the rumen microbes before beneficial effects on the rumen fermentation process could occur.     

Artificial Diet Influences Population Growth of the Root Maggot Bradysia impatiens (Diptera: Sciaridae)

In order to investigate the effects of artificial diets on the population growth of root maggot Bradysia impatiens, its population growth parameters were assayed on eight artificial diets (Diet 1, D2, D3, D4, D5, D6, D7, and D8). Results showed that developmental duration from egg to pupa was successfully completed on all eight artificial diets. However, the egg to pupal duration was shortest, while the survival rate of four insect stages was lowest when B. impatiens was reared on D1. When B. impatiens was reared on D7 and D8, the survival rate, female longevity, and female oviposition were higher than those reared on other diets. When B. impatiens was reared on D7, the intrinsic rate of increase (r_m = 0.19/d), net reproductive rate (R₀ = 39.88 offspring per individual), and finite rate of increase (λ = 1.21/d) were higher for its population growth with shorter generation time (T = 19.49 d) and doubling time (Dt = 3.67 d). The findings indicate that the D7 artificial diet is more appropriate for the biological parameters of B. impatiens and can be used an indoor breeding food for population expansion as well as further research. We propose that vitamin C supplement added to the D7 is critical for the improvement of the B. impatiens growth.     

间作番茄对甘蓝生长及其主要害虫种群数量的影响

研究了甘蓝、番茄不同间作比例对甘蓝生长及主要害虫种群数量的影响,以期找到适宜的间作比例,为生产实践中进一步推广应用提供理论依据。试验结果表明,甘蓝与番茄间作模式,对甘蓝主要害虫菜青虫、小菜蛾、菜蚜等有一定的趋避效果,但6∶1的间作处理效果较差,4∶1、2∶1的间作处理效果良好,且差异不明显;2∶1的间作处理由于间作密度小,甘蓝受番茄生长的影响大,植株生长不良,6∶1的间作处理由于间作密度较大,甘蓝受虫害影响大,叶球虫孔数多,商品性差,4∶1的间作处理,植株生长良好,叶球饱满、质量大、商品性好。综合各项数据分析,4∶1的间作比例更合适。     

入侵害虫红棕象甲转移为害本土棕榈树的风险评估

为评估入侵害虫红棕象甲Rhynchophorus ferrugineus对本土农林生态系统的风险,于2016—2019年采用受害植株调查和成虫诱捕的方法跟踪监测该虫在加拿利海枣Phoenix canariensis引种点及周边1 600 m半径范围内本土棕榈Trachycarpus fortune上的发生情况,并对来自野外加拿利海枣与棕榈上的成虫形态及繁殖力进行比较。结果显示,红棕象甲可随加拿利海枣引种定植而入侵当地生态系统,当其在加拿利海枣上暴发成灾后,还能转移到周边棕榈上继续为害,红棕象甲为害致死的棕榈植株数随着引种植物死亡数的增加而增加。野外加拿利海枣与棕榈上红棕象甲成虫的体重、体长以及按雌雄1∶1配对交配后的产卵量、孵化率相当,但棕榈种群雌虫的翅展较加拿利海枣种群明显变短,表明红棕象甲转移取食本土棕榈后可成功定殖、建立种群,且适合度并未降低。雌虫翅展变短可能与该入侵种表型可塑性有关,反映出其对棕榈的快速适应与进化,表现为"前适应"策略。考虑红棕象甲成虫飞行能力强,建议调高棕榈分布省份该虫的风险预警等级、调整防控策略,开展跟踪监测以了解入侵地实情。     

Evaluation on the fitness and population projection of Nilaparvata lugens in response to elevated CO2 using two-sex life table

Abstract

The life history and fitness of Nilaparvata lugens being reared under ambient level (current CO₂ concentration), medially elevated (550?µL/L) and highly elevated (750?µL/L) CO₂ concentration for long-term generation were compared using two-sex life table instead of traditional age-specific life table. The results showed that significantly longer larval duration and lower fecundity of N. lugens were observed in 750?µL/L relative to 550?µL/L treatment (P?<?0.05). Accordingly, 550?µL/L CO₂ significantly enhanced population parameters of N. lugens, including significantly higher intrinsic rate of increase (r), finite rate (λ) and net reproductive rate (R_O), but not for 750?µL/L CO₂. Taken together, N. lugens performs enhanced development rate, fecundity and survival in individual life history and higher potential in population multiplication under 550?µL/L CO₂ level, while only indicates the less enhanced development rate and survival without significant increased capacity of population expansion under 750?µL/L CO₂ level. These results should facilitate predicting the fitness and potential population damage of N. lugens, which is valuable for the integrated control of N. lugens in the future increasing CO₂ concentration.