棉花[AGD]三种杂种核型分析

对棉花三种杂种进行了细胞水平的核型分析,得出结论:三种杂种[A2×G1]×[AD]1的染色体数目为2n=4x=52,核型公式为2n=4x=52=2M+44m(2SAT)+6sm(2SAT),核型类型为1B。三种杂种[A2×G1]×[AD]2的染色体数目为2n=4x=52,核型公式为2n=4x=52=44m(2SAT)+8sm(2SAT),核型类型为2B。     

贸易便利化评价指标体系研究及其应用

从口岸效率、关税环境、基础设施及服务、信息和通信技术、商务环境五个方面遴选若干指标,运用德尔菲法和层次分析法构建了对贸易便利化进行科学测评的综合指标体系,并合理确定了各指标的权重指数,将贸易便利化指标作为自变量导入传统贸易引力模型,对原模型进行修正。采用我国的25个主要贸易伙伴的数据,对模型进行了实证检验。回归结果表明,包括贸易便利化指标在内的自变量很好地解释了我国出口贸易的情况。同时,这个结果也反证了本文提出的模型贸易便利化测评指标体系构建合理,有较强的说服力。     

人力资源管理系统与研发人员留职意愿——工作家庭促进与工作家庭冲突的中介效应

面对激烈的市场竞争,研发人员日益成为企业可持续发展的支柱力量。在既有研究的基础上重构了基于研发人员的双元（dual-concern model）人力资源管理模型（维持导向与绩效导向人力资源管理子系统）,探索了绩效与维持导向人力资源管理子系统通过工作家庭促进与工作家庭冲突中介影响留职意愿的作用机制。     

Agricultural landscape modification increases the abundance of an important food resource: Mistletoes, birds and brigalow

Agricultural landuse alters landscape pattern, with important consequences for native species. Complex responses to changes in landscape pattern may be observed for species with strong inter-specific relationships. We investigate how the abundance of an ecologically important food resource, the grey mistletoe (Amyema quandang), is influenced by the interactive influences of human-modified landscape pattern, bird disperser abundance and host condition. Mistletoe abundance was estimated in brigalow (Acacia harpophylla) dominated remnants in three separate study areas with differing landscape patterns. Negative binomial generalised linear models of mistletoe abundance were tested with combinations of seven explanatory variables: study area, landscape connectivity and edge contrast, patch shape, bird disperser abundance, brigalow foliage cover and basal area of standing dead trees. Ranking of model averaged parameter estimates showed that study area, bird disperser abundance, patch shape, dead trees and connectivity had the strongest influence on A. quandang abundance. Mistletoe abundance apparently increased with landscape modification, particularly in narrow linear patches, but may be limited by the availability of seed dispersers and host condition. Given high landscape modification and ongoing degradation, management should be targeted towards maintaining brigalow remnant condition to ensure bird and mistletoe populations can be supported in the long-term.     

苹果园种植牧草对幼树生长及15N–尿素吸收、利用的影响

以两年生红富士/平邑甜茶为试材,采用田间小区试验及15N同位素标记示踪法,研究了低氮（50 kg ? hm-2）和中氮（100 kg ? hm-2）条件下分别种植3种牧草（白三叶、黑麦草和鼠茅草）对苹果幼树生长及15N–尿素吸收、利用的影响。结果表明,春梢停长期,与单作苹果相比,种植牧草后苹果植株生物量、吸氮量及15N肥料利用率显著降低,这在低氮处理下尤为明显;而到秋梢停长期,与单作苹果相比,种植牧草后苹果植株生物量、吸氮量、15N肥料利用率及根系活力显著提高。至秋梢停长期,0 ~ 20 cm土层15N丰度及总氮含量为种植白三叶 > 种植鼠茅草 > 种植黑麦草 > 单作苹果,而在20 ~ 40 cm及40 ~ 60 cm土层15N丰度及总氮含量为单作苹果 > 种植黑麦草 > 种植鼠茅草 > 种植白三叶,表明种植白三叶、黑麦草和鼠茅草降低了氮素的淋溶损失,有利于氮肥的保持,从而提高氮肥利用率,促进苹果幼树的生长。     

Restoration of degraded ecosystems in the Afromontane highlands of Ethiopia: comparison of plantations and natural regeneration§

The scale of deforestation in sub-Saharan Africa underscores the need for forest restoration. Information is scarce for evidence-based restoration options. Sown Senna didymobotrya, planted Ficus thonningii cuttings, sown S. didymobotrya and planted F. thonningii combined, and previously occurring native non-browse shrubs (NNS) were compared for their effect on selected plant nutrients and occurrence of Olea europaea subsp. cuspidata in north-west Ethiopia. The treatments were applied to experimental units established on previous grazing land. At the end of the fourth year, 60% of planted F. thonningii stakes survived. The leaf biomass production was encouraging. Senna didymobotrya attained close to 1 m height and crown width. Natural regeneration of O. europaea was observed only under previously occurring shrubs. Six previously occurring NNS species were identified. Soils immediately under these shrubs were richer in nutrients than between shrubs in the open spaces. Our results suggest that vegetative stakes and NNS could be promising tools for ecological restoration of decimated ecosystems in the highlands of Ethiopia. Management interventions, which aim at steering succession close to pre-disturbance forest community structure by facilitation, should be selective of the shrub species.     

Response of root traits of Reaumuria soongorica and Salsola passerina to facilitation

C3 plant Reaumuria soongorica and C4 plant Salsola passerina are super xerophytes and coexist in a mixed community in either isolated or associated growth, and interspecific facilitation occurs in associated growth. In the present study, the root traits including root distribution, root length(RL), root surface area(RSA), root weight(RW) and specific root length(SRL) of both species in two growth forms were investigated to clarify their response to facilitation in associated growth. Six isolated plants of each species, as well as six associated plants similar in size and development were selected during the plant growing season, and their roots were excavated at 0–10, 10–20, 20–30, 30–40 and 40–50 cm soil depths at the end of the growing season. All the roots of each plant were separated into the two categories of fine roots(2 mm diameter) and coarse roots(≥2 mm diameter). Root traits such as RL and RSA in the fine and coarse roots were obtained by the root analyzing system WinRHIZO. Most of the coarse roots in R. soongorica and S. passerina were distributed in the top 10 cm of the soil in both growth forms, whereas the fine roots of the two plant species were found mainly in the 10–20 and 20–30 cm soil depths in isolated growth, respectively. However, the fine roots of both species were mostly overlapped in 10–20 cm soil depth in associated growth. The root/canopy ratios of both species reduced, whereas the ratios of their fine roots to coarse roots in RL increased, and both species had an increased SRL in the fine roots in associated growth. In addition, there was the increase in RL of fine roots and content of root N for S. passerina in associated growth. Taken together, the root growth of S. passerina was facilitated for water and nutrient exploration under the interaction of the overlapped roots in both species in associated growth, and higher SRL allowed both species to more effectively adapt to the infertile soil in the desert ecosystem.     

花椰菜和小白菜种间杂种子房培养研究

以小白菜雄性不育系h08015为母本,以花椰菜自交系082005、082009、082010、082063为父本进行种间杂种离体子房培养。结果表明：离体培养时杂种子房发育天数、接种方式、激素水平及父本基因型对杂交种子发芽率均有明显影响。授粉后6 d的子房培养能获得较好的效果;4 d后剥取种子继续培养,获得的种子发芽率高于其他接种方式;不加激素的MS培养基好于添加6-BA及NAA的MS培养基;不同父本基因型最适取材时间不同,多数基因型最佳培养时间为授粉后6 d的子房,个别基因型则是授粉后10 d的子房。     

Collective action in watershed management -- experiences from the Andean hillsides

Watersheds constitute a special case of multiple-use common pool resources (CPRs). In a textual sense, watersheds tend to be mosaics of privately owned and managed patches of land. At the same time, however, watersheds are also ecosystems in which multiple resources and people interact through an infinity of bio-physical processes. Through such interaction, new watershed-level qualities emerge that, together with other factors, condition watershed users' continued resource use and access. In this perspective, watersheds become common-pool resources. Hence, watershed users do not only manage their individual plots, crops, forests, etc., knowingly or not, they manage landscape patterns and bio-physical processes that transcend their private property. In this context, drawing on experiences gained through participatory action research in a micro-watershed in the Andean hillsides of southern Colombia, this paper describes a process aimed at fostering collective watershed management. The paper illustrates the importance of platforms as a mechanism for negotiating and coordinating collective action by multiple users and discusses the issues of representation on such platforms as well as the importance of third party facilitation.     

Effect of Organic and Synthetic Fertilizers on the Crop Yield and Macronutrients Contents in Soil and Pepper

Nowadays farmers are interested in moving to organic cultivation. The purpose of this experiment was to compare two organic, with or without effective microorganisms (EM), and one conventional greenhouse pepper cropping systems. We focused on the study of the macronutrients nitrogen, phosphorus, and potassium (N, P, K) concentrations in leaves plants, soil, and soil solution during the full production cycle to detect any plant nutrient deficiencies and differences in crop yield for the three different treatments. Foliar analyses showed good concentrations of nutrients with conventional treatment, but P was low with organic ones. However, P content in soil was high, because this element is easily precipitated in carbonated soil. Pepper yield was higher in conventional treatment and no differences in productivity were found between the two organic treatments. The role of EM was not clear on the development of plants and fruits; however it seems to influence the N mineralization in organic treatments.