植物源抗氧化活性肽研究进展

天然抗氧化活性肽因具有较强抗氧化活性和很高安全性,近年来已成为各国的研究重点。综述了几种植物源抗氧化活性肽的研究概况、应用前景,并提出了研究展望,以期为植物源抗氧化活性肽的开发研究提供可借鉴的信息。     

Physical properties of wood in thinned Scots pines (Pinus sylvestris L.) from plantations in northern Spain

? The physical properties of wood and the associated variations within and between trees were evaluated by analysing 770 small specimens of clear wood from 11 Pinus sylvestris L. trees thinned from 3 plantations.

? Within-tree variations in basic density or volumetric shrinkage increased with cambial age and decreased with increasing ring width. The effect of the height in the stem on wood properties was considered indirect and height was not included as an explanatory variable in the mixed models proposed to estimate basic density and volumetric shrinkage.

? The models had random components for the intercept parameter and explained 52.5% of the total variance in basic density and 56% of the total variance in volumetric shrinkage. Linear shrinkage in the direction of the grain was extremely variable.

? Between-tree variation and between-plot variation in the physical properties of wood were high, considering that all trees sampled were growing in similar sites and stands. It would then be desirable to predict physical properties of wood on living trees in order to use the quality of wood as a criterion for timber tree selection in thinnings.

     

去年我国木窗、木门出口有增 进口略减

2007年,我国的木窗、木门进出口贸易的发展状况是与我国的经济形势的变化,以及国家对于属于原材料高耗费的此类全木质产品生产、消费和出口进行一系列政策调控同步同行的。这种变化从国家海关最近公布的数据能够清晰地显示出来。     

从日本市场看中国蔬菜的国际竞争力

中国蔬菜的第一大出口去向是日本,但是近年来中国对日本的蔬菜出口出现了波动现象。本研究为了分析中国蔬菜在日本市场上的竞争力,首先运用市场占有率等指标分析法进行了分析。然后通过构建蔬菜进口函数模型并进行联立方程估计,对日本蔬菜主要进口来源国中国、美国和新西兰进行了相互比较。结果表明：总体上中国产蔬菜在日本进口蔬菜中具有较大的竞争力。进口国家的两两对比发现,日本从美国进口蔬菜的增加会促进从中国进口蔬菜的增加．而从新西兰进口蔬菜的增加,会导致从中国进口蔬菜的减少。     

辽东林区人工诱导红松阔叶混交林群落结构与动态变化

采用样带网格调查法和分层株数法,初步研究了辽东林区退化天然次生林经40余年人工诱导形成的红松阔叶混交林群落结构及动态变化趋势,定量地评价了不同恢复措施对其群落结构及动态的影响,探讨了辽东林区退化天然林恢复技术及优化模式。结果表明:不同透光方式(未透光、半透光和全透光)对群落组成结构和径级分布具有较大的影响,即随着透光强度的增加,红松在群落中的地位(重要值依次为49.3%、75.8%和100.0%)呈现出逐渐加强的变化规律,而阔叶树种则逐渐下降;未透光林分以中、小径材占优势(94.8%),半透光林分以中径材占优势(88.9%),而全透光林分则以大、中径材占优势(100%)。立地条件(坡位)对群落结构也具有一定的影响,即沿着自下而上的坡面环境梯度,半透光林分中红松的重要值在中上部坡位呈现增加趋势(61.5%、74.5%和75.8%),阔叶树种呈现出有规律的更替;半透光林分大径材比例呈下降趋势;全透光林分的中径材质量有所下降。半透光林分与全透光林分均呈现出更新层和演替层数量较多,主林层数量较少的分布格局,且均呈现出进展演替趋势——红松阔叶混交林。     

Assessing benefits of irrigation and nutrient management practices on a southeast Florida royal palm (Roystonea elata) field nursery

Many of the best management practices (BMPs) that are recommended for agricultural producers have not been scientifically evaluated for their conservation benefits considering the soil, climate, and hydrology of the proposed application location. The goal of this study was to compare royal palm (Roystonea elata) production in south Florida, USA, using tensiometer automated irrigation and reduced soil applications of nitrogen (N) and phosphorus (P), to that of traditional grower practices considering water savings, nutrient inputs, crop yield, crop nutrient status, soil nutrient status, and economic analyses. The study consisted of six treatments: (1) control (i.e., a grower irrigation rate and N and P fertilizer rates); (2) irrigation system automated to irrigate when soil water suction exceeded 5 kPa and the grower N and P rates; (3) irrigation system automated to irrigate when soil water suction exceeded 15 kPa and the grower N and P rates; (4) irrigation system automated to irrigate when soil water suction exceeded 15 kPa and 50% of the grower N and P rates; (5) the grower irrigation rate and 75% of the grower N and P rates; and (6) the grower irrigation rate and 50% of the grower N and P rates. Irrigation water volume applied, plant diameters, and plant heights were measured periodically throughout the study and plant tissue samples and soil samples were collected periodically for analysis of N and P content. Significant differences among treatments were only observed for the irrigation water volume applied. Automating the irrigation system to irrigate at soil suction exceeding 5 and 15 kPa resulted in 75 and 96% less water applied, respectively, than traditional irrigation scheduling practices used by a grower. Economic analyses suggested that all treatments would result in financial savings ranging from 7 to 34% per ha considering a 5-year, 2 ha investment. Thus, automating irrigation based on soil water suction for palm production in southern Florida, USA and similar locations will result in more sustainable agricultural production systems by benefiting the environment (less nutrients and water applied) and the grower (lower cost).     

油气混输泵抗气阻稳压器的设计

对油气混输泵中普遍存在的气阻现象进行了详细分析,为解决气阻现象,设计了抗气阻稳压器;通过理论分析和实际运行验汪,总结归纳了抗气阻稳压器具体结构的设计方法.设计制造的样机产品经实际运行考核,能够较好地满足现场恶劣使用条件的需求.     

四川乐山市竹林主要病虫害调查初报

将四川乐山竹林区分为6个不同的生态区域,2006~2008年调查研究了乐山竹林的主要病虫害及其发生特点,调查结果表明,乐山竹林区主要虫害10种,以长足大竹象危害最为严重,主要病害4种,以竹基腐病危害最重,且面积逐年增加;随着竹林面积的增加,竹类病虫害呈现上升趋势,防治一虫(长足大竹象)一病(竹基腐病)并加强竹林病虫的预测预报对提高竹林产量、促进竹产业发展具有十分重要的作用。     

新旧勘测定界规程的几点比较

勘测定界工作是一项非常重要的日常测绘工作,随着《土地勘测定界规程》的颁布实施,使得此项工作的开展更加规范有序。本文对新旧勘测定界规程进行了比较解读,阐述了新规程的几点完善之处。     

淮北市农产品加工业现状与发展对策

分析淮北市农产品加工业的基础现状,并根据自身的资源优势和存在问题,提出发展思路及对策。