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牡丹组织培养技术研究综述 总被引:1,自引:1,他引:0
从外植体类型、培养条件、培养基种类、生根培养方法、组培苗移栽驯化几方面综述了牡丹组织培养技术的研究现状,分析了目前牡丹组织培养中存在的问题,提出了今后的发展方向。 相似文献
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Plant species exert strong effects on ecosystem functions and one of the emerging, and difficult to test hypotheses, is that plants alter soil functions through changing the community structure of soil microorganisms. We tested the hypothesis for atmospheric CH4 oxidation by using soil samples from a Siberian afforestation experiment and exposing them to 13C-CH4. We determined the activity of the soil methanotrophs under different tree species at three levels of initial CH4 concentration (30, 200 and 1000 ppm) thus distinguishing the activities of low- and high-affinity methanotrophs. Half of the samples were incubated with 13C-enriched CH4 (99.9%) and half with 12C-CH4. This allowed an estimation of the amount of 13C incorporated into individual PLFAs and determination of PLFAs of methanotrophs involved in CH4 oxidation at the different CH4 concentrations. Tree species strongly altered the activity of atmospheric CH4 oxidation without appearing to change the composition of high-affinity methanotrophs as evidenced by PLFA 13C labeling. The low diversity of atmospheric CH4 oxidizers, presumably belonging to the UCSα group, may explain the lack of tree species effects on the composition of soil methanotrophs. We submit that the observed tree species effects on atmospheric CH4 oxidation indicate an effect on biomass or cell-specific activities rather than by a community change and this may be related to the impact of the tree species on soil N cycling. 相似文献
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Apart from influencing the amount of leaf-deposited particles, tree crown morphology will influence the local distribution of atmospheric particles. Nevertheless, tree crowns are often represented very rudimentary in three-dimensional air quality models. Therefore, the influence of tree crown representation on the local ambient PM10 concentration and resulting leaf-deposited PM10 mass was evaluated, using the three-dimensional computational fluid dynamics (CFD) model ENVI-met® and ground-based LiDAR imaging. The modelled leaf-deposited PM10 mass was compared to gravimetric results within three different particle size fractions (0.2–3, 3–10 and >10 μm), obtained at 20 locations within the tree crown. Modelling of the LiDAR-derived tree crown resulted in altered atmospheric PM10 concentrations in the vicinity of the tree crown. Although this model study was limited to a single tree and model configuration, our results demonstrate that improving tree crown characteristics (shape, dimensions and LAD) affects the resulting local PM10 distribution in ENVI-met. An accurate tree crown representation seems, therefore, of great importance when aiming at modelling the local PM distribution. 相似文献
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Application of Grey System Theory to tree growth prediction 总被引:1,自引:0,他引:1
IntroductionDahurian larch plantations were planted affer the1950's in Heilongjiang Province. Some of them areless than 40 years old. There lack permanent plots oflong-term. Sometimes, statistical models for predicting tree growth are not always desirable. The GreySystem is a new branch of mathematics founded byProf. Deng Julong in 1982 (Deng 1985). In contrast tostatistic models, which need a lot of measured data,the Grey System only need a f6w data for setting upmodels. In recent years… 相似文献
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通过分析农副产品销售系统中树形视图各列表项的构成层次,提出了一种调用insertitemlast()函数实现列表项动态构建的新方法,并给出了基于此方法的农副产品销售系统实例。 相似文献