水稻早衰产生原因及防治技术

根据多年从事基层水稻生产指导工作实践,分析水稻早衰产生的主要原因,并总结其防治技术措施.     

接触二甲苯实验人员淋巴细胞染色体畸变分析

目的:研究二甲苯对实验人员外周血淋巴细胞染色体畸变的影响.方法:外周血培养制备染色体标本,分析外周血淋巴细胞染色体畸变.结果:二甲苯接触组的染色体数目畸变细胞率(11.3%)高于对照组(6.8%)(P＜0.05);结构畸变细胞率(包括裂隙)(3.57%)高于对照组(2.6%)(P＜0.05)并且呈剂量效应关系;接触组的未成熟着丝粒分离细胞率(1.85%)与对照组(1.34%)相比无显著差异(P＞0.05).结论:二甲苯接触导致外周血淋巴细胞染色体畸变增加;二甲苯接触是否诱导未成熟着丝粒分离有待进一步深入研究.     

打顶后棉花倒四叶内源激素的变化及与早衰的关系

测定新疆石河子垦区棉花打顶后倒四叶内源激素含量的变化,分析激素在不同时间段的变化。结果表明:(1)打顶能改变倒四叶中IAA(生长素)、CTK(细胞分裂素)和ABA(脱落酸)含量的变化趋势,并在72 h内和对照有显著差异。(2)打顶后涂抹NAA(萘乙酸)不能完全取代IAA的作用,但能明显改变IAA、CTK和GA3(赤霉素)含量的变化规律,保持ABA含量的稳定。(3)棉花倒四叶中各激素的比值在含量上存在相互制约的动态平衡关系;外用生长素能降低衰老激素和生长激素中的比值;打顶打破了这种平衡关系,大幅度增加了ABA/IAA和ABA/CTK的比值,这可能是打顶能促进棉花早衰的生理原因。     

沥青混凝土桥面铺装早期病害原因的分析

对混凝土桥梁沥青砼桥面铺装的早期病害及其原因进行了分析与研究，在总结当前国内桥面铺装结构主要方法的基础上，通过理论分析，提出了用有限元进行结构受力分析以及需要重点研究分析的几个方面的问题。     

粒子群算法及其应用研究

粒子群优化算法（PSO）源于对鸟群捕食系统的模拟,是近年来被广为关注和研究的一种智能优化算法。PSO算法属于进化算法的一种,比遗传算法（GA）更简单易实现,且没有交叉和变异操作,需要设定的参数也不多,收敛速度快。目前已广泛应用于函数优化、神经网络训练、模糊系统控制以及其他遗传算法等领域。目前PSO的研究主要集中在算法本身和算法的应用研究两个方面。     

Genotype by environment interactions of heat stress disorder resistance in crisphead lettuce

Lettuce is a cool season crop susceptible to physiological disorders when exposed to supra optimal temperatures. Genotype (G) by environment (E) interaction (GE) of rib discolouration, tipburn, premature bolting and ribbiness in crisphead lettuce was characterized under high temperature and long day growing conditions. Replicated data of 10 crisphead lettuce varieties from two plantings in each of four growing seasons at two locations in Quebec were analysed using the GGE biplot method. Head-weight-over-stem-length ratio, ribbiness, rib discolouration incidence and tipburn incidence were affected (P = 0.00001) by E, G and GE. E explained more variation in head-weight-over-stem-length ratio (77.1%) and rib discolouration incidence (77.3%) than G and GE, whereas GE explained more variation (72.4%) in tipburn incidence and G explained more variation (38%) in ribbiness. Strong crossover GE was detected with rib discolouration and tipburn incidence, but not with head-weight-over-stem-length ratio and ribbiness. Under heat stress, varieties of the Vanguard group had lower ribbiness than those of the Great Lakes group. Cultivar 'Estival' showed consistent resistance to bolting, ribbiness, tipburn and rib discolouration across all E.     

Characterization of semen collected by pharmacologically induced ejaculation from a stallion with seminal vesiculitis

The present study compared the quality of sperm collected by artificial vagina or pharmacologically induced ejaculation from a 10-year-old thoroughbred stallion with seminal vesiculitis. The pharmacological protocol involved intravenous administration of detomidine (0.01 mg/kg) and oxytocin (20 IU) and successfully induced ejaculation in all attempts of semen collection. Sperm motility, plasma membrane and acrosome integrity (PMAI), reactive oxygen species (ROS) levels, polymorphonuclear neutrophil (PMN) percentage, and bacterial profiles of fresh and cooled semen (5°C for 24 hr) were evaluated. Semen obtained by the pharmacological method presented reduced seminal volume, decreased PMN percentage and superior sperm motility in cooled samples. Moreover, higher PMAI and lower ROS levels were observed in semen collected by the pharmacological method. Therefore, pharmacologically induced ejaculation is an alternative to obtain semen with minimal contamination and with sperm of superior quality and longevity from stallions with seminal vesiculitis.     

抗早花烤烟新品系的生育特征及其品质研究

华烟06是从K326田间变异株系中选育出来的抗早花烤烟新品系。2008年在梅州烟区试种该品系,并对该品系的生育期、植物学性状、化学成分、抗病性以及经济性状进行观测分析。结果表明,华烟06的有效叶数为21.64片,产量为2 465.28 kg/hm2,明显优于云烟87,化学成分与云烟87差异不显著。华烟06具有优质高产,适应性广,抗早花能力强等优点,但上部叶糖含量、下部叶烟碱含量以及上等烟比例稍低,易感黄瓜花叶病,还需进一步改良。     

百脉根早熟品系农艺性状初报

对里奥、迈瑞伯和百脉根早熟品系(源于迈瑞伯)在甘肃景泰的生长状况进行了观察,并对3个品种的物候期、产草量、越冬率等进行了比较.结果表明:早熟品系较其他2个品种物候期明显提前,生育天数明显缩短.早熟品系年均鲜、干草产量分别达42.593、10.553 t/hm2,迈瑞伯分别为29.490、7.562 t/hm2,早熟品系干、鲜草产量极显著高于迈瑞伯;里奥的干草产量为9.604 t/hm2,极显著低于早熟品系.试验结果还表明,早熟品系的生长速度及越冬率均优于迈瑞伯,其在景泰地区的生长表现良好.     

一种用于防止早熟收敛的改进遗传算法

针对遗传算法中的早熟收敛现象,提出了一种改进的遗传算法.该算法利用种群多样性算子产生较好的初始种群分布,并以该算子作为判断种群是否早熟收敛的依据.一旦出现早熟收敛或早熟收敛的趋势,则进行灾变,以恢复算法的进化能力.同时结合种群的最优个体和引入的随机种群,设计了一种包含选择、交叉算子的一般性算子,使算法能有效维持种群的多样性,快速找到全局最优解.