中越水稻迁飞性害虫稻飞虱、稻纵卷叶螟发生关系分析

中越两国同属东亚季风区,水稻病虫害在发生危害上为一个整体。每年水稻稻飞虱、稻纵卷叶螟(以下简称"两迁"害虫)随着季节和气温变化,在两国间往返迁飞,发生为害,相互影响。研究两国水稻迁飞性害虫发生的关系和影响规律,对于提高监测预警的早期预见性和防控工作的主动性,有效控制其危害具有重要意义。2010年以来,中越两国实施了中越水稻迁飞性害虫监测与防治合作项目,通过连续多年开展交流合作,初步明确了越南"两迁"害虫发生规律。本文简要分析了影响越南"两迁"害虫发生的主要因素,探讨了中越两国水稻"两迁"害虫发生规律的相关性,对提高中国"两迁"害虫中、长期预报能力和综合治理水平发挥了积极作用。     

In vitro and in silico studies of salicylic acid on systemic induced resistance against bacterial leaf blight disease and enhancement of crop yield

Salicylic acid (SA) is an effective elicitor to promote plant defenses and growth.  This study aimed to investigate rice (Oryza sativa L.) cv. Khao Dawk Mali 105 treated with salicylic acid (SA)-Ricemate as an enhanced plant protection mechanism against bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo).  Results indicated that the use of SA-Ricemate as a foliar spray at concentrations of more than 100 mg L^–1 can reduce the severity of BLB  by 71%.  SA-Ricemate treatment also increased the hydrogen peroxide (H₂O₂) content of rice leaf tissues over untreated samples by 39–61%.  Malondialdehyde (MDA) in rice leaves treated with SA-Ricemate also showed an increase of 50–65% when comparing to non-treated samples.  The differential development of these defense compounds was faster and distinct when the SA-Ricemate-treated rice was infected with Xoo, indicating plant-induced resistance.  Besides, SA-Ricemate elicitor at a concentration of 50–250 mg L^–1 was correlated with a substantial increase in the accumulation of total chlorophyll content at 2.53–2.73 mg g^–1 of fresh weight which suggests that plant growth is activated by SA-Ricemate.  The catalase- and aldehyde dehydrogenase-binding sites were searched for using the CASTp server, and the findings were compared to the template.  Chemsketch was used to design and optimize SA, which was then docked to the catalase and aldehyde dehydrogenase-binding domains of the enzymes using the GOLD 3.0.1 Software.  SA is shown in several docked conformations with the enzymes catalase and aldehyde dehydrogenase.  All three catalase amino acids (GLN7, VAL27, and GLU38) were discovered to be involved in the creation of a strong hydrogen bond with SA when SA was present.  In this mechanism, the aldehyde dehydrogenase amino acids LYS5, HIS6, and ASP2 were all implicated, and these amino acids created strong hydrogen bonds with SA.  In field conditions, SA-Ricemate significantly reduced disease severity by 78% and the total grain yield was significantly increased which was an increase of plant height, tiller per hill, and panicle in three field trials during Aug–Nov 2017 and 2018.  Therefore, SA-Ricemate can be used as an alternative elicitor on replacing harmful pesticides to control BLB disease with a high potential of increasing rice defenses, growth, and yield components.     

棉铃虫作供试虫的苏云金杆菌制剂毒力生物测定的研究

本研究采用棉铃虫初孵幼虫为试虫,结果表明:初孵幼虫个体间差异小,测定结果准确性高;36℃下培养48小时,其药剂浓度与供试虫死亡相关系数皆在0.9以上。测定周期仅需2天;供试虫数40头以上,结果重复性好;利用本测定技术,检测100多批试验样品和产品,结果准确可靠,变异系数在20％以下。     

苏云金杆菌血清H_(3a3b)标准品CS_(3ab—1986)的性状考核及其毒力效价测定

考核了湖北农科院微生物实验工厂制备的苏云金杆菌血清H_(3a3)b型参考标准品CS3ab-1986的性状,表明含活芽孢数为180×10_s/g,含水量3.7％,悬浮率64％.采用棉铃虫初孵幼虫为供试虫,美国标准品HD-1-S-1080为标准,进行了24次毒力生物浏定.确定CS_(aab)-1986毒力效价为7400IU/mg。     

Scale and scope economies in small household rice farming in Vietnam

The Vietnamese agricultural sector has experienced a dramatic structural change based on increased specialization in rice cultivation. However, small-scale rice-farmers have continued to grow multiple crops, especially in less developed provinces. While the literature advocates crop diversification for reasons of both economic and ecological sustainability, there lacks empirical evidence as to whether crop diversification brings efficiency and productivity gains to small farms. The present study is the first applications of the input-oriented stochastic distance function approach in estimating scale and scope economies using data of multi-crop farming households in Vietnam. We find strong evidence of product-specific economies of scale. Scope economies are also present for rice, vegetable, and other annual crop production. This suggests that crop diversification enhances efficiency and productivity. However, there still exists significant technical inefficiency in crop production, indicating opportunities to expand farm output at the existing level of inputs and technologies. More specifically, our empirical results indicate that it is desirable to expand vegetable and other annual crop production in mountainous areas while rice cultivation can be further expanded in delta and coastal regions.     

棉铃虫作供试虫的Bt毒力生物测定感染饲料的研究

研究表明,酵母粉、黄豆粉和维生素C是棉铃虫生长发育的必需成分;仅用醋酸即可达到防腐的目的。本研究确定生物测定感染饲料配方为:黄豆粉7g、酵母粉4g、维生素CO.5g、36％醋酸1.25ml、琼脂1.5g,水100ml.醋酸用量占饲料重量的1～1.5％为宜。     

SOLUTIONTO IMPROVE THE VIETNAMESE PERSONAL INCOME TAX SYSTEM IN THE CONTEXT OF INTERNATIONAL ECONOMIC INTEGRATION

Laws on Personal Income Tax in Vietnam officially effected and implemented in social,economic life on 01/01/2009.However,management of personal income tax is posing big challenges on managers.First of all,the law includes some new points as compared to Ordinance of Personal Income tax on high income earners,especially the regulation related to family situation to calculate taxable income.The implementation started in context of economic recession,stagnation in investments,increasing in unemployment and reduction in citizens income.Besides there are problems related to bilateral and multilateral commitments among countries about range for levying personal income tax.Due to those reasons,the author chose topic "Solution to improve the Vietnamese Personal Income Tax system in the context of international economic integration".     

北京市汉石桥湿地浮游植物调查与水质评价

2007年对北京汉石桥湿地水系进行浮游植物和水质理化指标的评价调查。浮游植物群落由蓝藻、绿藻、硅藻、隐藻、裸藻和甲藻构成,平均密度为2.4×10^8个/L,其中绿藻占55.7%。湿地水体4项指标透明度、全氮、全磷、化学需氧量的卡尔森营养指数分别为87.80、88.70、98.15和98.69,水质明显富营养化,夏秋季水面有微囊藻藻胞层（微囊藻藻水华）。V形水道水域夏秋季水面也出现裸藻水华。