采煤塌陷裂缝对降雨后坡面土壤水分的影响

为探究采煤塌陷裂缝对坡面储蓄降水的影响,本文对降雨后不同坡向上裂缝两侧的不同土层水分动态变化特征进行了研究。结果表明:降雨主要补充坡面地表0~20 cm土层土壤水分,且在雨后0~20 cm土层土壤水分散失也较为严重;雨后阴坡土壤含水率最高,0~10cm、10~20cm和20~40 cm土层土壤水分差异显著(p0.05)。降雨结束8 d后,裂缝附近的土壤水分变化幅度较大,尤以坡面裂缝上部边缘处最为明显,裂缝处与远离裂缝的土壤水分之间差异显著(p0.05);阳坡土壤水分损失最高,阳坡裂缝周边土壤水分平均损失量高达3.31%。可见,裂缝的出现会在一定程度上打破坡面储蓄降水的格局,加剧坡面局部土壤水分散失,这一点在植被恢复与建设过程中不容忽视。     

Availability of polycyclic aromatic hydrocarbons in aging soils

Purpose  

The soil contamination by hydrophobic organic contaminants (HOCs), such as polycyclic aromatic hydrocarbons (PAHs), poses great threats to human health and ecological security and attracts worldwide concerns. The total HOC concentrations overestimate its available fraction to the soil biota. Increased understanding of the availabilities of PAHs in soil environment will have considerable benefits for their risk assessment and be very instructive to food safety and remediation strategies in contaminated sites. However, the availability of PAHs in aging soils and particularly the correlations of the availabilities with their forms in soils have yet to be elucidated. In this work, the availabilities of PAHs in aging soils were evaluated using a sequential mild extraction technique.     

洛川苹果虫害的动态监测

为了研究洛川苹果虫害的发生规律及其动态监测,以对渭北黄土高原果园有害生物生态调控具有实践指导意义。2001-2010年在洛川苹果园,通过田间试验与室内实验相结合的方法,对苹果虫害进行了动态监测。结果表明：该地区果园虫害不同年度的发生规律和危害评价有不同程度的差异。因此,每年和常年动态监测可为苹果虫害的生态调控提供更准确的信息。     

The Bankruptcy System and the Auction Model of Management Buyout

This paper studied how the auction processis influenced by bankruptcy probability, bankruptcy cost, and the corporatetax rate. The study found thatthe bidding price of the management is negatively associated with bankruptcy cost and probability, and positivelyassociated with the corporate tax. However, the expected profit of the outside investor is positivelyassociated with bankruptcy cost and probability, and negatively associated with the corporate tax. When the bankruptcy cost and probabilityis high enough, the acquisition market would be totally inefficient.     

宁夏灌区春小麦高产磷肥施用增产效果研究

宁夏灌区土壤多为灌淤土和淡灰钙土,磷肥施用受Ca、Mg离子的束缚,易被固定成难溶性磷酸盐,从而影响到作物产量及磷肥当年利用效率。本文在高磷（速效P 42.8mg/kg）和低磷（速效P 6.55mg/kg）的不同土壤上,分别进行了春小麦磷肥（P2O5）施量0–330kg/hm2的回归试验。其结果得出：在低磷土壤上,磷肥（P2O5）施量（x,kg/hm2）与春小麦产量(Y, kg/hm2)的回归方程为：Y=4072.1+5.014x+0.1296x2-0.0003133x3,增产效果极显著;而在高磷土壤上磷肥增产效果不显著。磷肥施量在0-240 kg/hm2的施用范围内,低磷土壤有显著的投入产出效益,试验投入产出效益为10-24元/元（小麦价格2.1元/kg,磷肥P2O5价格8.61元/kg）,最高投入产出效益对应的磷肥施量为135 kg/hm2。因此针对宁夏灌区土壤肥力,提出了中低产田春小麦高产的推荐施磷方案以及高肥力土壤条件下小麦磷肥的施肥建议,可结合耕翻深施磷肥或磷肥、有机肥混合施,改善土壤PH值及微生物活性,提高磷肥肥效。     

中国休闲农业的现状与趋势

中国休闲农业发展迅速。目前,全国休闲农业特色农户（农家乐）已发展至150多万家,具有一定规模的休闲农业园区发展至12000多家,直接从业人员近300万人,年接待游客7亿人次,年经营收入达900亿元左右。已成为农业和农村经济发展的亮点之一,彰显出广阔的发展前景,必将成为中国特色农业现代化建设和农民增收的重要举措。当前应着力解决好基础设施条件差,人才队伍短缺,规划滞后,特色不突出,管理不规范,服务水平不高等问题。     

Mining of favorable marker alleles for flag leaf inclination in some rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) accessions by association mapping

Flag leaf angle (FLA) in rice (Oryza sativa L.) is one of the important traits affecting F₁ seed production by mechanization. To elucidate the genetic mechanism of FLA and mine favorable marker alleles for F₁ seed production in rice, we performed a genome-wide association study using phenotypic data over 2 years and genotypic data of 262 pairs of simple sequence repeat (SSR) markers collected from 441 rice accessions. We detected seven SSR marker loci associated with FLA and four loci were novel. The four newly found loci were RM6266 on chromosome 3, RM348 on chromosome 4, RM258 on chromosome 10 and RM7303 on chromosome 11. We found a total of 27 favorable alleles, of which four, i.e., RM348-130 bp, RM7303-90 bp, RM258-180 bp, and RM4835-230 bp, had phenotypic effects larger than 10°. Nine combinations, which increased FLA by 45.7°–94.7° through pyramiding the favorable alleles contained in seven typical accessions, were predicted.     

RNA干扰对烟草NtPPO8基因沉默的效应分析

多酚氧化酶（PPO）是发生酶促褐变的关键酶,PPO活性过高会使烟叶变褐。为明确烟草NtPPO8基因对PPO活性的影响,建立降低NtPPO8基因表达量的病毒诱导的基因沉默（virus induced gene silencing,VIGS）体系,探究使用RNA干扰技术对烟叶NtPPO8基因表达量及PPO活性的影响。以中烟100和K326为材料,分析在移栽后50d进行VIGS载体侵染的植株,并在侵染后10、20、30、40d分别测定NtPPO8基因表达量及PPO活性。结果表明,接种VIGS载体的转化植株,其中在侵染后20d时NtPPO8基因的沉默效率最高,为78.46%;随着侵染时间推移,NtPPO8基因的沉默效率逐渐降低,在接种后40d内有效表达;且转化植株中的病毒载体会随着植株的生长而向上传导,随着接种部位的上移,沉默效率逐渐降低。因此,研究建立VIGS体系能够有效沉默NtPPO8基因的表达,并且有效降低PPO活性,为提高烟叶耐烤性及降低烟叶褐变比例提供了新的思路和方法。     

桑籽皮多酚的提取工艺研究

通过单因素试验,分析了不同浸提剂、浸提剂浓度、料液比、浸提时间、浸提温度5个因素对桑籽皮多酚提取量的影响,通过正交试验,确定了桑籽皮多酚的最佳提取条件为:浸提剂(丙酮)体积分数为70%,料液比1∶35,回流温度45℃,回流时间1.5h。在此提取条件下,提取量达到1.332mg/g干籽皮,为桑籽皮多酚的工业化提取提供科学依据。     

太白山兰科植物资源及其保护利用

2005年4月-2006年7月,对太白山兰科植物种类及分布进行了全面调查,根据野外调查和文献考证,太白山共有兰科植物25属35种,均属本地区珍稀濒危植物。分析了太白山兰科植物资源现状,提出了今后保护管理的具体意见。