Versatile physiological functions of the Nudix hydrolase family in berry development and stress response in grapevine

Nudix hydrolases are widely distributed across all classes of organisms and provide the potential capacity to hydrolyze a wide range of organic pyrophosphates. Although Nudix hydrolases are involved in plant detoxification processes in response to abiotic and biotic stresses, the biological functions of Nudix hydrolases remain largely unclear in grapevine.In the present study, a total of 25 putative grapevine Nudix hydrolases(VvNUDXs) were identified by bioinformatics analysis and classified int...     

不结球白菜维生素C和可溶性糖含量的遗传分析

采用主基因—多基因混合遗传模型分析方法,对不结球白菜乌塌菜×矮脚黄、雪克青×矮脚黄两个组合的维生素Ｃ、可溶性糖含量进行单世代和联合世代遗传分析。结果表明,两组合中维生素Ｃ含量遗传符合一个主基因和多基因的混合遗传模型,主基因遗传率为５２６８％～７４１２％。可溶性糖在雪克青×矮脚黄组合中也符合主基因—多基因遗传模型,主基因遗传率为８９７３％～８９７９％。维生素Ｃ和可溶性糖主基因效应均以加性效应为主,在乌塌菜×矮脚黄组合中,两性状主基因有较明显的负向显性效应,在雪克青×矮脚黄组合中,显性效应不明显。育种实践中应注重对主基因加性效应的利用。     

Soil saturation effects on forest dynamics: scaling across a southern boreal/northern hardwood landscape

Patch modeling can be used to scale-up processes to portray landscape-level dynamics. Via direct extrapolation, a heterogeneous landscape is divided into its constituent patches; dynamics are simulated on each representative patch and are weighted and aggregated to formulate the higher level response. Further extrapolation may be attained by coarsening the resolution of or lumping environmental data (e.g., climatic, edaphic, hydrologic, topographic) used to delimit a patch.Forest patterns at the southern boreal/northern hardwood transition zone are often defined by soil heterogeneity, determined primarily by the extent and duration of soil saturation. To determine how landscape-level dynamics predicted from direct extrapolation compare when coarsening soil parameters, we simulated forest dynamics for soil series representing a range of drainage classes from east- central Maine. Responses were aggregated according to the distribution of soil associations comprising a 600 ha area based on local- (1:12,000), county- (1:120,000) and state- (1:250,000) scale soil maps. At the patch level, simulated aboveground biomass accumulated more slowly in poorer draining soils. Different soil series yielded different communities comprised of species with various tolerances for soil saturation. When aggregated, removal of waterlogging caused a 20–60% increase in biomass accumulation during the first 50 years of simulation. However, this early successional increase and the maximum level of biomass accumulation over a 200 year period varied by as much as 40% depending on the geospatial data. This marked discrepancy suggests caution when extrapolating with forest patch models by coarsening parameters and demonstrates how rules used to rescale environmental data need to be evaluated for consistency.     

我国海岛旅游开发模式创新研究 ——以舟山群岛为例

我国海岛资源丰富,旅游开发潜力巨大.舟山群岛作为我国第一大群岛,由于缺乏科学的开发模式和管理机制,舟山群岛一些岛屿的旅游开发效果并不理想,富有吸引力的旅游岛很少.文章采用SWOT分析法,剖析了舟山群岛旅游开发的优劣势和存在的主要问题,论述了要把舟山群岛建成特色鲜明、在海内外具有较强吸引力的国际性亚热带群岛型海洋休闲旅游目的地,就必须在开发理念、开发与管理体制和模式等方面实行创新,在旅游发展空间布局上突出"一体两翼三大中心",在旅游产品开发方面重点塑造"海天佛国渔都港城-中国舟山群岛"整体旅游形象品牌,突出海洋文化和海洋休闲两个主题,精心打造海洋观光、海洋文化、海洋休闲、海鲜美食等九大旅游产品,开发好一片特色无居民海岛.     

Model uncertainty in the ecosystem approach to fisheries

Fisheries scientists habitually consider uncertainty in parameter values, but often neglect uncertainty about model structure, an issue of increasing importance as ecosystem models are devised to support the move to an ecosystem approach to fisheries (EAF). This paper sets out pragmatic approaches with which to account for uncertainties in model structure and we review current ways of dealing with this issue in fisheries and other disciplines. All involve considering a set of alternative models representing different structural assumptions, but differ in how those models are used. The models can be asked to identify bounds on possible outcomes, find management actions that will perform adequately irrespective of the true model, find management actions that best achieve one or more objectives given weights assigned to each model, or formalize hypotheses for evaluation through experimentation. Data availability is likely to limit the use of approaches that involve weighting alternative models in an ecosystem setting, and the cost of experimentation is likely to limit its use. Practical implementation of an EAF should therefore be based on management approaches that acknowledge the uncertainty inherent in model predictions and are robust to it. Model results must be presented in ways that represent the risks and trade‐offs associated with alternative actions and the degree of uncertainty in predictions. This presentation should not disguise the fact that, in many cases, estimates of model uncertainty may be based on subjective criteria. The problem of model uncertainty is far from unique to fisheries, and a dialogue among fisheries modellers and modellers from other scientific communities will therefore be helpful.     

Temperature-dependent stock-recruitment model for walleye pollock (Theragra chalcogramma) around northern Japan

Changes in fish year‐class strength have been attributed to year‐to‐year variability in environmental conditions and spawning stock biomass (SSB). In particular, sea temperature has been shown to be linked to fish recruitment. In the present study, I examined the relationship between sea surface temperature (SST), SSB and recruitment for two stocks of walleye pollock (Theragra chalcogramma) around northern Japan [Japanese Pacific stock (JPS) and northern Japan Sea stock (JSS)] using a temperature‐dependent stock‐recruitment model (TDSRM). The recruitment fluctuation of JPS was successfully reproduced by the TDSRM with February and April SSTs, and February SST was a better environmental predictor than April SST. In addition, the JPS recruitment was positively related to February SST and negatively to April SST. The JSS recruitment modeled by the TDSRM incorporating February SST was also consistent with the observation, whereas the relationship between recruitment and February SST was negative, that is the opposite trend to JPS. These findings suggest that SST in February is important as a predictor of recruitment for both stocks, and that higher and lower SSTs in February act favorably on the recruitment of JPS and JSS respectively. Furthermore, Ricker‐type TDSRM was not selected for either of the stocks, suggesting that the strong density‐dependent effect as in the Ricker model does not exist for JPS and JSS. I formulate hypotheses to explain the links between SST and recruitment, and note that these relationships should be considered in any future attempts to understand the recruitment dynamics of JPS and JSS.     

全子叶生物活性豆腐凝胶特性的研究

通过因子筛选实验,确定了接种量、微生物转谷氨酰胺酶(MTG)用量和水豆比是影响全子叶生物活性豆腐凝胶特性的关键因子。在此基础上,采用响应曲面法(Response SurfaceMethodology,RSM)分别建立了豆腐硬度和持水率的二次多项数学模型,验证了模型的有效性并探讨了上述3个因子的交互作用。从产品成本和凝胶特性综合考虑,选择出最佳配比,即乳酸菌接种量为105cfu/mL,MTG用量为347 U/L,水豆比为8.5,其硬度和持水率实测值分别为44.8g和89.2%,可生产出富含乳酸菌和几乎全部大豆营养的健康豆腐。     

现阶段宁夏农民合作经济组织的发展思考

农民合作经济组织是在农村经济体制改革中兴起的,以其独特的组织形式、灵活的机制、广泛的适应性,在提高农业产业化经营水平及提高农民收入方面发挥了巨大的作用.为了更好地促进农民合作经济组织的发展,通过调查分析得出农民合作经济组织的运作经验为:扶持龙头企业,提高带动能力,围绕特色建协会,力争政策和资金支持,以利益联结、股份合作、提高科学技术服务于农民.提出了加快农村制度改革,科学定位,法律保障,提供公共支持,建立农工贸一体化生产经营体系的发展对策.     

基于水量平衡原理的畦灌水流推进简化解析模型研究

畦灌水流推进过程计算模型对确定灌水技术要素、田间平均入渗率和糙率有十分重要的作用。该文依据水量平衡模型,分析畦灌下渗水形状系数、地表储水形状系数的变化规律,结果表明下渗水形状系数受地表水推进过程中的推进距离和时间的幂指数影响很小,可用一个稳定值代替,由此建立了基于水量平衡原理的畦灌水流推进简化解析模型。结合已有文献资料和田间试验对模型进行检验,表明该模型具有计算求解方便、精度较高的优点,可用于畦灌合理灌水技术指标的确定。     

深松旋耕组合作业机的研制与试验研究

根据国内中等功率拖拉机配套农机具的研究现状,以机组匹配理论为依据,研制了与中型拖拉机配套的深松旋耕组合作业机,并进行了单独深松、单独旋耕和组合工况的试验。试验表明所研制的机具在作业时能充分发挥拖拉机的动力性,减少拖拉机的功率消耗。机具配置的深松铲和旋耕刀片排列合理,深松扰动影响宽度和旋耕宽度相匹配,作业时波动范围较小,偏牵矩对拖拉机方向的稳定性基本没有影响。机具的研制也为与大功率拖拉机配套新型农机具的开发提供了借鉴。