Induction of tetraploidy in meristematically active seeds of Japanese barberry (Berberis thunbergii var. atropurpurea) through exposure to colchicine and oryzalin

Japanese barberry (Berberis thunbergii DC) is an invasive shrub, widely naturalized across the United States, whose numerous cultivars remain an important horticultural commodity. Maintaining this crop for the future necessitates the development of sterile clones. Exposure to the mitotic inhibitors colchicine and oryzalin is a traditional method for inducing tetraploidy in breeding lines as a precursor to creating sterile genotypes. Treatments utilized pre-germinated B. t. var. atropurpurea seeds with emerged radicles. Seeds were immersed in aqueous solutions of colchicine (.02%, .05%, .1% and .2%) and oryzalin (.002%, .005%, .01% and .02%) dissolved in 1% DMSO for 6, 12 and 24 h durations. Seedling ploidy level was determined via flow cytometry following 6 and 52 weeks of growth in the greenhouse. Both anti-mitotic chemicals proved effective at inducing tetraploidy and produced comparable efficiency rates. The survival rate of treated seeds decreased in response to both increased mitotic inhibitor concentration and longer exposure duration. While exposure to oryzalin produced greater seed mortality than colchicine, most seedlings that survived had altered ploidy levels. The most efficient oryzalin concentration was 0.002% with a rating of 28%, while the most efficient colchicine concentrations were in the range from 0.05% to 0.2%. Duration of exposure to mitotic inhibitor was not a significant factor over the range from 6 to 24 h. Reversion of tetraploid plants to the diploid state occurred at a low frequency following a dormancy period. Some tetraploid seedlings derived from exposure to both chemicals displayed foliar abnormalities including irregular leaf margins and mottled lamina. The primary advantage of colchicine was low seedling toxicity, while oryzalin was notable for its ability to induce tetraploidy at low concentrations.     

驻马店市蔷薇科观赏植物资源调查研究

驻马店观赏植物种类32科59属120种,其中蔷薇科植物17属33种.对蔷薇科植物进行了分类、对其特征特性作了简要描述,对应用现状进行了分析.     

观赏番茄观赏茄子双向嫁接研究

利用观赏茄子的一个分枝作砧木,观赏番茄作接穗;观赏番茄的一个侧枝作砧木,观赏茄子作接穗进行观赏番茄观赏茄子双向嫁接研究。试验结果表明,观赏番茄作接穗时嫁接成活率明显高于观赏茄子作接穗时的嫁接成活率,能否嫁接成活与嫁接时的砧木、接穗的茎粗有一定的关系,本试验中观赏番茄、观赏茄子茎粗在0.5 cm时嫁接成活率最高。     

2个锦鲤人工养殖群体遗传多样性的微卫星标记分析

采用13对微卫星引物,对2个锦鲤(Ornamental carp)人工养殖群体的遗传多样性进行了研究.结果表明,锦鲤群体的遗传多样性水平较高;其平均等位基因数(A)为7.86和8.37;2个群体的平均观测杂合度(Ho)为0.7911和0.7928,平均期望杂合度(He)为0.6735和0.6792,平均多态信息含量为0.7145和0.7192.群体间的遗传距离为0.1057,遗传相似度为0.9011.13个微卫星位点可用于锦鲤群体的遗传学研究.     

FlorTree: A unifying modelling framework for estimating the species-specific pollution removal by individual trees and shrubs

Atmospheric pollution is a threatening problem around the world, with tropospheric ozone (O₃), nitrogen dioxide (NO₂) and particulate matter (PM₁₀) among the most harmful pollutants for citizens’ health. Nature-based solutions such as urban trees can cut down air concentrations of these pollutants thanks to stomatal uptake and dry deposition on their canopies and, in addition, uptake carbon dioxide (CO₂) and store carbon in their tissues. Unfortunately, some species emit biogenic Volatile Organic Compounds (bVOCs) that are O₃-precursors leading to air quality deterioration. As a proper selection of species is essential for urban greening, we developed an innovative single-tree model (FlorTree) to estimate the maximum flux of air pollutants. FlorTree considered species-specific parameters, such as tree morphology (height and crown leaf area), leaf/shoot structure, leaf habit (deciduous/evergreen) and eco-physiological responses to environmental factors, for 221 urban tree and shrub species. We applied the FlorTree model to examine i) which are the best species for air pollution removal in the case study of Florence (Italy) and ii) whether the species-specific removal performance is affected by different climate and air pollution conditions in other cities, namely Bucharest (Romania) and Tokyo (Japan). Results suggested that 24 tall trees (mainly broadleaves belonging to Tilia, Acer and Fraxinus genus) may be recommended for Florence due to their large crowns at maturity (50 years old), relatively high stomatal conductance and no bVOCs release. These general characteristics, however, were affected by climatic and pollutant conditions, suggesting that FlorTree must be applied to the local conditions. Therefore, our results demonstrated that FlorTree can be applied in any city for maximizing the air quality improvement by urban trees.     

高原地区多年生与一年生禾本科牧草混播效果

在高原地区退耕还草示范种植中,利用牧区广泛种植的一年生禾本科牧草燕麦Avena sativa与进口的多年生禾本科牧草细茎冰草Efymus trachycaulum混播。结果表明：燕麦和细茎冰草混播既能克服单一种植多年生禾本科牧草时的杂草危害问题,也能使退耕当年就获得较好的经济效益,解决了种植当年的收成问题,使项目建设的效益及早得到体现。第1年燕麦开花期鲜草产量为2.49 kg/m2, 细茎冰草第2年能够良好生长,第2年细茎冰草开花期鲜草产量为1.48 kg/m2,生长后期鲜草产量为1.76 kg/m2。     

Divergent effects of defoliation intensity and frequency on tiller growth and production dynamics of Pascopyrum smithii and Hesperostipa comata

Rotational stocking theoretically enables regrazing of regrowth, but regrowth may be limited in xerophytic vegetation. We tested the hypothesis that regrowth would be slow and fixed in Hesperostipa comata (a caespitose, drought‐tolerant grass), while growth would be flexible in Pascopyrum smithii (a rhizomatous, less drought‐tolerant grass) under increasing defoliation and moisture, by assessing tiller growth rates, population dynamics and plant yield on marked plants in a Dry Mixed Grass prairie. Plots were clipped in late summer to simulate a deferred control, or intermittently during the growing season (May–August) at high intensity–low frequency (HILF), low intensity–high frequency (LIHF) or high intensity–high frequency and crossed with two water treatments (ambient and addition) in both a xeric upland and a mesic lowland. Growing season defoliation increased tiller growth rates of P. smithii in the upland, whereas HILF and LIHF reduced growth in the lowland. All defoliation regimes increased tiller growth for H. comata. Tiller populations of H. comata increased with frequent defoliation, while tiller populations of P. smithii decreased regardless of defoliation regime. Frequent defoliation, regardless of intensity, reduced yield relative to the deferred control for both grasses. While water addition consistently increased growth rates and reduced differences in tiller number among defoliation treatments, the regrowth of both grasses remained similar under varied defoliation with ambient moisture. High moisture conditions also promoted regrowth more in P. smithii compared to H. comata. In summary, neither grass species displayed an inherently fixed or flexible tiller or plant yield response in response to defoliation or moisture.     

Interacting effects of soil degradation and precipitation on plant productivity in NE Patagonia,Argentina

Our objective was to examine the effects of inter-annual variation of precipitation on productivity of two dominant species (Chuquiraga avellanedae, an evergreen shrub, and Nassella tenuis, a perennial grass) in two communities of contrasting soil degradation: a herbaceous steppe with shrubs (HSS) and a degraded shrub steppe (SS). Data were collected during two consecutive years with different annual precipitation. Aboveground productivity was determined nondestructively using a double sampling approach. The number of inflorescences per plant was recorded too. Perennial grass productivity was lower in SS than in HSS in both years, while shrub productivity was lower in SS only during the year of below average precipitation. With rising precipitation the perennial grass increased the number of inflorescences while the evergreen shrub augmented vegetative biomass. In summary, the effects of precipitation on plant productivity are community dependent; abiotic factors, such as superficial and sub-superficial soil characteristics, and biotic factors, such as leaf area index (LAI) or tussock sizes, may interact to influence the responses of species to precipitation. Our results suggest that if precipitation increased, this would favor the dominance of shrubs over grasses.     

紫茉莉品系观赏性状与遗传多样性的AFLP分析

[目的]紫茉莉(Mirabilis jalapa Linn)是中国传统乡土花卉,研究不同种质的观赏性状,对利用这些资源进行杂交育种筛选后代、提高育种的针对性和加快育种进程具有重要的意义.[方法]本研究对具代表性的9个紫茉莉品系进行了株高、花型、花色、童期等观赏性状的比较,并利用扩增片段长度多态性(amplified fragment length polymorphism,AFLP)分子标记技术进行分析.[结果]紫茉莉的观赏性状主要包括株高、花型、花色、童期等,传统分类法可分为高株系统和矮株系统,花型为重瓣和单瓣,其花色有白色、粉色共9种颜色,多样性丰富.通过AFLP技术,采用8对引物组合共扩增出2 569条谱带,其中多态性条带2 488条,多态性条带比率为96.85％,平均每对引物扩增出321个位点,311个多态性位点.9个品系的相似性系数在0.2357～0.6493之问,平均值为0.4425,每个位点的有效等位基因数为1.2044,平均多样性指数为0.2127,遗传相似性系数最高的是5号和8号,达到0.6493,最低的是3和7,为0.2357.[结论]根据遗传相似性系数进行聚类分析,可将紫茉莉品系分为矮株型Ⅰ类和高株型Ⅱ类,分子聚类结果与表型性状特征分类结果较为一致,而在每一类中具体的观赏性状聚类存在一定差异.通过形态性状与分子标记为紫茉莉品系的研究,为进一步育种利用提供参考.     

观赏桃植物空间营造探析

植物空间营造是植物造景的重要组成部分。笔者以观赏桃为研究对象,介绍了观赏桃的不同树形与品种,并将观赏桃的空间形态限定要素概括为基面、竖向分隔面及覆盖面,进而从空间体量与尺度、空间形状与比例、空间通透度、空间实体景观的艺术处理4个方面研究观赏桃空间营造手法。详细探讨了观赏桃适宜的空间尺度、观赏距离和植物高度比值,全围合、半围合和焦点型观赏桃植物空间的围合方式,以及高低错落、疏密有致的观赏桃空间立面设计思路,最后从主从与重点、对比与协调、均衡与稳定、比例与尺度、韵律与节奏5个方面总结了观赏桃多样统一的空间实体景观艺术处理手法,以期为其他植物景观的营造提供参考。