干旱区矿区不同立地类型土壤种子库特征

矿区的自然或人工植被恢复是维持生物多样性及生态系统稳定的重要途径。通过室外萌发法对金昌镍铜矿区7种不同立地生境土壤种子库的研究表明:该区域土壤中物种丰富度较高,包括16科47属,共56种植物,分别为:藜科(Chenopodiaceae)、禾本科(Gramineae)、菊科(Compositae)、柽柳科(Tamaricaceae)、苋科(Amaranthaceae)、马齿苋科(Portulacaceae)、豆科(Leguminosae)、十字花科(Cruciferae)、车前科(Plantaginaceae)、胡颓子科(Elaeagnaceae)、蒺藜科(Zygophyllaceae)、莎草科(Cyperaceae)、大戟科(Euphorbiaceae)、紫草科(Boraginaceae)、蔷薇科(Rosaceae)、茄科(Solanaceae);植物组成以一年生草本植物占绝对优势(89.3%),多年生草本植物次之(7.54%),灌木种最少(2.59%)。土壤种子平均储量412粒·m~(-2),不同立地类型土壤种子库储量差异显著,与其他荒漠地区比较,土壤种子库储量偏低;土壤种子库物种Simpson多样性指数为:新尾矿周边自然植被区龙首矿自然植被区龙首矿开采废弃地供暖公司柽柳林地。     

寒地多年生麦草新种质的形态学分析与细胞学检测

为丰富北方寒地牧草品种,选育适合北方寒冷地区种植的优势牧草,以八倍体小偃麦(Trititrigia)与中间偃麦草(Thinopyrum intermedium)杂交后代选育的10份寒地多年生麦草新种质为材料,借助我国东北哈尔滨地区的气候特点,对其进行形态学分析和细胞学鉴定。结果表明:10份材料田间自然生长年限超过3a,均具有抗寒性和多年生特性,可在哈尔滨地区-30℃环境下安全过冬;根系发达,除2个株系8LF2 1-1-4和11LF3 1-1-4外,其他株系具有地下茎。植株生长繁茂,有5个株系总分孽数超过40,2个株系穗长超过24cm。株系11LF3 1-1-4和11LF4 1-18-1结实率平均值在80%以上,远高于亲本中间偃麦草;10份材料种子发芽率在60%~90%;株系5Q10L1-18-1茎秆干重可达1.7kg·m~(-2)。10个株系根尖体细胞染色体为42条,遗传稳定,植株均表现抗旱、抗寒,抗病等特性。本研究可为北方寒地的牧草选育提供理论和材料基础。     

Leaf chlorophyll content as a possible diagnostic mean for the evaluation of plant nitrogen uptake from the soil

The influence of temperature, irradiance, and soil humidity on the nitrogen (N) concentration in some organs, chlorophyll in the leaves, N uptake and accumulation of dry matter in plants of winter wheat was investigated. In the plants grown under equal initial N supplement but in contrasting conditions of the evironment, the correlation between concentration of total N and chlorophyll in the leaves was absent. No interrelationship was found between concentration of total N in the leaves and accumulation of N and dry matter in the whole plants. There is a close correlation between chlorophyll in the leaves, accumulation of total N, and dry matter of the whole plant. It was concluded that chlorophyll is a more stable informative parameter for the estimation of the N uptake from the soil under different growth conditions than leaf N concentration.     

提高黔东南生态文明建设实验区生态效率的对策研究——基于生态足迹模型法

利用生态足迹方法计算分析了黔东南生态文明实验区生态环境消耗的类型和生态效率状况,结果显示其生态效率低,并且指出：生态效率低的原因是落后的经济及区域经济增长对生态环境资源消耗大。并在此基础上提出了提高生态效率对策。     

Comparative Performance of Rice with System of Rice Intensification (SRI) and Conventional Management using Different Plant Spacings

The System of Rice Intensification (SRI) reportedly enhances the yields of rice (Oryza sativa L.) through synergy among several agronomic management practices. This study was conducted to investigate the effects on rice plant characteristics and yield by comparing the plants grown with different methods of cultivation – SRI vs. recommended management practices (RMP) focusing on the impact of different plant spacings. Performance of individual hills was significantly improved with wider spacing compared with closer‐spaced hills in terms of root growth and xylem exudation rates, leaf number and leaf sizes, canopy angle, tiller and panicle number, panicle length and grain number per panicle, grain filling and 1000‐grain weight and straw weight, irrespective of whether SRI or RMP was employed. Both sets of practices gave their highest grain yield with the spacing of 20 × 20 cm; however, SRI yielded 40 % more than the recommended practice. At this spacing, canopies also had the highest leaf area index (LAI) and light interception during flowering stage. The lowest yield was recorded at 30 × 30 cm spacing under both the practices, as a result of less plant population (11 m^?2), despite improved hill performance. During the ripening stage, hills with wider spacing had larger root dry weight, produced greater xylem exudates, and transported these towards shoot at faster rates. These features contributed to the maintenance of higher chlorophyll levels, enhanced fluorescence and photosynthesis rates of leaves and supported more favourable yield attributes and grain yield in individual hills than in closely‐spaced plants. Moreover, these parameters further improved in SRI, apart from the enhanced percentage of effective tillers and showed substantial and positive impacts on grain yield (17 %) compared with recommended practice. In conclusion, wide spacing beyond optimum plant density, however, does not give higher grain yield on an area basis and for achieving this, a combination of improved hills with optimum plant population must be worked out for SRI.     

陕西省宁东森林公园景区划分与景点等级评价

在实地调查基础上,对陕西省宁东森林公园进行了景区划分和景点等级评价,结果为:宁东森林公园可划分为平河梁、旬阳坝、响潭沟和蒿沟脑等4个景区,53个景点,其中森林景点13个,自然景点33个,人文景点7个;景点等级评判分值为5.3～9.1,其中Ⅰ级景点16个,Ⅱ级景点28个,Ⅲ级景点9个。     

城市化与“三农”问题及云南的路径选择

通过阐述城市化和"三农"问题的特点以及城市化对"三农"的影响进行分析探讨,并结合云南"三农"发展现状提出了云南城市化是解决"三农"问题的重要途径,提出了建设五级核心城市带动辐射周边的城市化发展思路和重点加大农村小城镇建设对促进云南农业、农村、农民发展的建议。     

内蒙农牧交错带家畜品种改良可行性分析——以克什克腾旗经棚镇为例

引入外来品种改良牲畜被作为干旱半干旱地区发展畜牧业的重要手段,但对其在生产基础差、严重依赖自然资源的小农户生产系统中的适用性却缺乏分析,因而,盲目推广改良可能危及牧民生计,进而导致生态破坏。以位于农牧交错带的内蒙古赤峰市克旗的家畜改良为案例,通过入户访谈,在识别其畜牧业生产系统约束条件的基础上,分析了家畜改良的效果、可行性条件及存在的问题。研究表明:在小农户生产系统中,家畜品种改良并不能提高限制性资源的生产率,而且增加了农户面临的生态风险和市场风险,改良是否可行取决于外部环境能否有效地改善其对限制性资源的利用及平衡风险,尤其是提供稳定的饲料和畜产品市场,以及良好的基础设施、技术及金融保障。     

不同氮磷配比对旱作土壤养分和油葵产量的影响

采用调查分析、田间试验等方法,研究了旱作土壤条件下油用向日葵氮磷肥的吸肥特性和对氮磷肥的吸收规律。结果表明:不同厚度(0～20cm)和(20～40cm)的土壤对养分的吸收呈现动态的变化特点,施氮270.0kg/hm2时吸收氮素分别为47.5和35.7mg/kg,相差24.8%;油葵产量为2 604.0kg/hm2,施磷100.05kg/hm2时吸收磷素分别为28.4和21.5mg/kg,相差24.2%,油葵产量为3 199.5kg/hm2。     

《红楼梦》大观园中的园林植物初考

《红楼梦》中“大观园”是小说主要人物生活的场所,大观园中的园林植物是其园林中的重要组成部分,书中提及种植在大观园中的园林植物经初略统计和考证较确切的共有31科39属48种及种下分类单位。笔者对每种植物给予简单描述,并对植物配植和栽种方式进行归纳,以期对目前园林植物的应用和配置提供借鉴。