Survivability of low pathogenic (H9N2) avian influenza virus in water in the presence of Atyopsis moluccensis (Bamboo shrimp)

Low pathogenic avian influenza virus (LPAIV) exhibits an ecological climax with the aquatic ecosystem. The most widely prevalent subtype of LPAIV is H9N2. Wild aquatic birds being the natural reservoirs and ducks, the “Trojan horses” for Avian Influenza Virus (AIV), can contaminate the natural water bodies inhabited by them. The virus can persist in the contaminated water from days to years depending upon the environmental conditions. Various aquatic species other than ducks can promote the persistence and transmission of AIV; however, studies on the role of aquatic fauna in persistence and transmission of avian influenza virus are scarce. This experiment was designed to evaluate the survivability of H9N2 LPAIV in water with and without Atyopsis moluccensis (bamboo shrimp) for a period of 12 days. The infectivity and amount of virus in water were calculated and were found to be significantly higher in water with A. moluccensis than in water without A. moluccensis. The study also showed that A. moluccensis can accumulate the virus mechanically which can infect chicken eggs up to 11 days. The virus transmission potential of A. moluccensis requires further studies.     

核桃新品种‘中核短枝’

 ‘中核短枝’核桃是1965 年从新疆引入的早实核桃中通过种子实生选种，经40 多年选育出 来的新品种。树势中庸，枝条节间短而粗；果实生育期125 d，果实近圆柱形，平均坚果质量15.1 g，壳 厚0.9 mm，核仁乳黄色，味香，出仁率65.8%；优质高产，适应性广，在抗黑斑病和冬季冻害方面具有 较强的抗逆性。     

An evaluation of gains in breeding for resistance to the cocoa swollen shoot virus disease in Ghana

The present study examines the gains in resistance to cocoa swollen shoot virus (CSSV) infection from investments in breeding over the past seven decades. The general susceptibility to CSSV infection of the West African Amelonado that dominated plantings prior to the start of formal research in 1938 necessitated the introduction of germplasm of Upper Amazon origin to better contain the disease spread. Included in this study are findings of two recent experiments. In the first, the genetic basis for resistance in the clone mvT85, developed from gamma radiation of clone T85/799 and putatively resistant to CSSV disease was investigated. In the second experiment, the comparative levels of resistance in sets of old, current and new cocoa varieties were tested following inoculations with the severe CSSV strain 1A. Absence of nucleotide differences at 29 single nucleotide polymorphism (SNP) loci between mvT85 and T85/799, and lack of segregation for resistance in the full-sib and backcross populations derived from mvT85 indicated that mvT85 did not carry novel genes for improving cocoa for CSSV disease resistance. Moreover, there were no differences in resistance to CSSV disease between mvT85 and T85/799. These observations conflict with the previous report that mvT85 is immune to CSSV disease, and distinct from T85/799. Between variety groups, disease severity scores based on three successive leaf flushes after inoculation were not effective in discriminating among them. Disease severity assessed eight months after inoculation was the most important criterion for separating varieties for resistance to CSSV disease. As expected, the older varieties were the most sensitive to infection. No differences were found between current varieties derived exclusively from Upper Amazon clones and new varieties. Contrary to the generally held opinion of a higher level of resistance in existing inter Upper Amazon cultivars, varieties derived from crosses using Catongo, RB 49 and C-SUL 7 (all of Lower Amazon origin) as males with specific Upper Amazon varieties were among the most resistant. A re-appraisal of variety recommendations for areas of mass infection and for less affected areas is advocated.     

Change of allometry between coarse root and shoot of Lodgepole pine (Pinus contorta DOUGL. ex. LOUD) along a stress gradient in the sub-boreal forest zone of British Columbia

Abstract

This transect study in 41–178 year-old stands of Lodgepole pine (Pinus contorta DOUGL. ex. LOUD.) in the southern boreal forest of British Columbia, Canada, analyses how site conditions modify the coarse root–shoot dynamics of trees. The allometric relationship between diameter growth of coarse roots and trunk is scrutinised for long-term site dependence, and short-term reactions to periodic climate conditions. Along a gradient from poor to rich sites, we analysed 54 trees. The sampling scheme provided two increment cores each from the three main roots and the shoot at breast height per tree. From the year-ring series, we calculated diameter time series for each shoot and each root. With these data, we show (1) that the trees’ coarse root diameter and shoot diameter are linearly related in a double-logarithmic coordinate system, thus representing constant allometry on the long run. Statistical analysis of these long-term trajectories reveals that (2) the relative allocation to coarse roots versus shoot is much higher on poor sites compared to rich sites. A closer look at the short-term reaction to stress events in the period from 1995 to 2000, where several dry years occurred, underpins that (3) a lack of water supply triggers biomass allocation in favour of coarse roots at the expense of shoot growth most pronouncedly on poor sites. Implications of this morphological plasticity for allometric theory, method development, tree and stand dynamics and carbon storage assessment are discussed.     

江西毛竹产业升级发展的思考——以江西省宜春市为例

宜春市位于江西西北部，毛竹资源丰富，是我国毛竹主产区之一，宜春市委、市政府十分重视毛竹产业发展工作，特别是集体林权制度改革后，产业发展走在全省的前列。但在发展过程中存在诸多问题，毛竹产业发展潜力和自身优势还未得到充分发挥。通过分析产业现状，查找问题，对加快全市毛竹产业发展提出总体思路与对策建议。     

热处理对竹基纤维复合材料性能的影响

为拓展竹基纤维复合材料的应用领域,对慈竹纤维化单板进行热处理,探讨蒸汽压力和热处理时间对竹基纤维复合材料性能的影响.结果表明:经过热处理,竹基纤维复合材料的尺寸稳定性改善；随着蒸汽压力的增大和热处理时间的延长,材料的静曲强度和水平剪切强度显著降低,弹性模量则呈现先增后减的趋势.在保证材料性能的前提下,建议根据产品需求来选择适宜的热处理工艺.     

甘薯苗期茎尖多酚含量对其 DPPH?清除反应的影响

研究了25个甘薯品种苗期茎尖乙醇提取物多酚含量（PC）及其对1，1二苯基2三硝基苯肼（DPPH? ， 1，1‐diphenyl 2 picrylhydrazyl）清除反应的清除量（QS ）和反应速率（RS ）的影响，以期为甘薯茎尖抗氧化活性DPPH?评定法提供科学依据．结果表明，在特定的DPPH?清除反应体系中， PC在0.83～41.01μg／mL线性范围内， PC与QS极显著正相关，与0～1 min RS极显著正相关；反应80 min以后的QS与 RS达到稳定平衡阶段．因此，DPPH?清除反应制约于多酚和DPPH?两种底物浓度，并受反应时间影响．当 PC增加到一定程度和经过一定的反应时间， PC与其 QS ，RS存在非线性相关．利用DPPH?清除法评价甘薯茎尖抗氧化活性时，由于品种间 PC存在显著差异，因此应研究特定反应体系下茎尖 PC及其与 QS ，RS的线性相关区域，确定适宜的茎尖质量浓度范围和反应时间．     

楠竹播种育苗造林主要技术

通过试验、研究、推广,即边推广应用,边扩大辐射,总结出实生苗造林与母竹造林不同的成套技术措施。     

竹材加工剩余物苯甲基化改性试验

以竹子开条、开片或拉丝加工过程产生的长条状剩余物为研究对象,采用低温碱液润胀、苄化处理试验,系统研究了预处理及苄化反应条件对竹材增重率(苄化率)的影响;并借助FTIR、X-射线、SEM、DSC等现代分析手段研究分析了苄化竹材的微观结构、化学结构特征及热熔特征的变化规律。试验结果表明:碱液润胀工艺对竹材苄化增重率的影响最大,苄化试剂用量与反应时间对竹材苄化也有不同程度的作用。在试验范围内较佳的工艺条件为:碱液浓度22.5%、润胀时间10 h、苄化试剂用量50 mL、反应时间1 h。苄化增重率不同,苄化竹材的玻璃化转变温度有显著差异。将苄化增重率45%～50%的变性竹材按同纤维方向重组,可在温度为140℃、单位压力2.0MPa的条件下热压熔接成板。     

福建省笋竹加工现状调查及发展研究

福建是全国竹子的重点产区，近年来，随着竹林资源的不断发展，竹笋、竹材产量显著提高，笋，竹产品市场供大于求的矛盾逐渐突出。为拓宽笋、竹市场、发展深加工、扩大社会需求量、切实保护竹农培育竹林的积极性，推进竹产业化进程，福建省林业厅于１９９８年８月￣１９９９年４月组织开展了笋竹产品市场，加工现状调查。本文根据调查数据，分析福建省笋竹加工现状，存在问题，提出今后的发展对策。