陕西省关中地区大棚蔬菜低温冻害预报服务方法

通过比较系统的大棚蔬菜温度观测,建立了不同天气类型下棚内外最低温度的回归模式,确定了大棚蔬菜低温冻害的气象预报指标,以泾阳为代表分析了关中地区大棚蔬菜低温冻害的时间分布特点,并提出了不同低温冻害等级下的防御对策建议.     

两栖类结冰耐受机制及其研究策略

综述了近年来美洲林蛙的研究进展,总结了两栖类动物结冰耐受的主要机制,并提出该领域研究的新方向。     

蔬菜冷冻贮藏营养成分变化的研究

对蔬菜冷冻贮藏营养成分变化的研究表明，随着冷冻贮藏时间的延长和温度的升高，蔬菜中４种维生素的损失率均不同程度地增加，损失规律基本一致。除杀菁瓠瓜外，低温处理使杀菁豇豆和未杀菁马齿苋中氨基酸态氮含量先升后降。低温处理有利于控制蔬菜中硝态氮的含量，但对可溶性总糖含量的影响却较小。     

Colonist farmers' perceptions of fertility and the frontier environment in eastern Amazonia

Colonists, unlike indigenous peoples, are often assumed tohave little knowledge of their environment. However, their perceptions of the environment and their knowledgeof natural resource systems have a significant impact on their farming practices. Farmers in the frontier regionof Marabá, Eastern Amazonia, understand nutrient cycling and the links between different components in farmingsystems. Diagrams drawn by farmers show very diversified systems, and farmers' knowledge of soilcharacteristics, including sub-surface features, and distribution in their localities is very detailed in comparison to pedologicalclassifications. However, knowledge about nutrient cycling is very uneven, even between farmers from the same area.Generally, farmers were found to have very detailed knowledge of environmental resources, but very patchyknowledge of processes and functions underlying systems, and this conforms to evolutionary models of ecologicalknowledge. Perceptions of change in soil fertility are related to the length of settlement, and are closelylinked to the presence of forest. Overall, the majority of farmers believe they will not be able to sustain cropping in thefuture, and as forest and fallow become scarce the most feasible option will be for them to move to other areas.Farmers are more optimistic about pasture, which is viewed as a more stable system, with the key to long-termsustainability being weed control. These findings imply that a high degree of information sharing between farmers andscientists is required to establish resource management strategies and social institutions to supportsustainable development strategies at the frontier.     

苹果梨冻害观察研究

明确了苹果梨冻害发生的主要部位 ,发生原因及其时期。花芽冻害不是小花原始体而是花轴维管束受冻。枝条受冻是次生韧皮部而不是形成层。盛果期树体冻害重 ,初果期冻害轻。冻害发生原因与第一年气候异常 ,当年低温以及化冻急等多因子有密切关系。冻害发生在仲冬至早春 ,但冻害致死在早春     

中华结缕草成熟胚再生影响因素研究

以中华结缕草(Zoysia sinica Hance)成熟胚为外植体,研究了培养基、水解酪蛋白(CH)、水解乳蛋白(LH)、植物生长调节剂等对愈伤组织诱导及其生长的影响,以及不同继代周期对愈伤组织分化及植株再生的影响。结果表明:2,4-D是影响愈伤组织诱导的关键因素;MS无机成分及有机成分含量对愈伤组织生长影响不显著,附加CH 500mg/L利于愈伤组织生长;继代培养次数直接影响胚性愈伤组织的诱导及植株再生;不经继代培养转入分化培养基的愈伤组织植株再生率最高达34.2%,随继代次数的增加,再生率明显下降,继代培养3次的愈伤组织再生率低于10%。     

垂榆冻害调查及其影响因素的分析

对长春市4个不同地点(路段)栽植垂榆的受冻害状况进行了调查与分析,结果表明:4个调查地点垂榆的冻害率分别为67.0%、31.0%、72.0%和92.0%,平均值为65.5%;冻害指数分别为31.0、11.4、49.2和64.9,平均值为39.1。2009~2010年冬春季节持续低温的累积作用是导致发生冻害的主要因素,老龄植株生长后期的嫁接不亲和作用与砧木个体抗寒能力的遗传差异亦是影响因素之一。     

Optimization of Freeze-drying Protective Agents for Lactobacillus plantarum KLDS1.0391 by Response Surface Methodology

In this study, the Single Factor Test(SFT) was used to optimize the pre-freezing conditions of L. plantarum KLDS1.0391(KLDS1.0391). Further, the Freeze-Drying Protective Agents(FDPA) of KLDS1.0391 was optimized by Response Surface Methodology(RSM). The optimum pretreatment conditions were as the follows: initial concentration of KLDS1.0391 was 1011 CFU · m L~(-1) and KLDS1.0391 was pre-freezed at –80℃ for 8 h to achieve the survival rate of 46.21%. The main components of FDPA were skim milk, sucrose, sodium glutamate and Tween-80. And the influence of four factors on the survival rate of KLDS1.0391 in freeze-drying was in order as the follows: skim milksucroseTween-80sodium glutamate. The optimal FDPA composition was skim milk 11.3%, sucrose 9.8%, sodium glutamate 5.1% and Tween-80 0.2%. Under the above conditions, the survival rate of the cells was 82.98%. Comparing the predicted values, the relative error was 0.37% and the difference was not significant, which indicated that the established model could effectively reflect the actual protection of FDPA to KLDS1.0391.     

Microbial hotspots and hot moments in soil: Concept & review

Soils are the most heterogeneous parts of the biosphere, with an extremely high differentiation of properties and processes within nano- to macroscales. The spatial and temporal heterogeneity of input of labile organics by plants creates microbial hotspots over short periods of time – the hot moments. We define microbial hotspots as small soil volumes with much faster process rates and much more intensive interactions compared to the average soil conditions. Such hotspots are found in the rhizosphere, detritusphere, biopores (including drilosphere) and on aggregate surfaces, but hotspots are frequently of mixed origin. Hot moments are short-term events or sequences of events inducing accelerated process rates as compared to the average rates. Thus, hotspots and hot moments are defined by dynamic characteristics, i.e. by process rates.For this hotspot concept we extensively reviewed and examined the localization and size of hotspots, spatial distribution and visualization approaches, transport of labile C to and from hotspots, lifetime and process intensities, with a special focus on process rates and microbial activities. The fraction of active microorganisms in hotspots is 2–20 times higher than in the bulk soil, and their specific activities (i.e. respiration, microbial growth, mineralization potential, enzyme activities, RNA/DNA ratio) may also be much higher. The duration of hot moments in the rhizosphere is limited and is controlled by the length of the input of labile organics. It can last a few hours up to a few days. In the detritusphere, however, the duration of hot moments is regulated by the output – by decomposition rates of litter – and lasts for weeks and months. Hot moments induce succession in microbial communities and intense intra- and interspecific competition affecting C use efficiency, microbial growth and turnover. The faster turnover and lower C use efficiency in hotspots counterbalances the high C inputs, leading to the absence of strong increases in C stocks. Consequently, the intensification of fluxes is much stronger than the increase of pools. Maintenance of stoichiometric ratios by accelerated microbial growth in hotspots requires additional nutrients (e.g. N and P), causing their microbial mining from soil organic matter, i.e. priming effects. Consequently, priming effects are localized in microbial hotspots and are consequences of hot moments. We estimated the contribution of the hotspots to the whole soil profile and suggested that, irrespective of their volume, the hotspots are mainly responsible for the ecologically relevant processes in soil. By this review, we raised the importance of concepts and ecological theory of distribution and functioning of microorganisms in soil.     

漠大线多年冻土沼泽区管道融沉防治及温度监测

漠大线管道自投产以来,全年均为正温输送,且输送温度远高于设计预期温度,因而加速了管道周围冻土区的融化,管道容易发生融沉,安全性面临极大考验。结合漠大线投产后的实际运行情况,参考冻土区工程建设经验,设计了热棒与粗颗粒土换填相结合的多年冻土沼泽区域管道融沉防治方案,并在漠大线K305处完成了100 m示范段建设,并在示范段管道周围土壤中安装了温度监测系统,通过近一年的温度监测数据分析了目前示范段的融沉防治情况。结果表明：热棒的安装降低了管道地基的温度,增加了土壤的冷储量,起到了稳定地基的作用,而管道底部换填的粗颗粒土可以保障热棒的制冷作用不会引发管道冻胀灾害。