Seed priming improves seedling emergence and reduces oxidative stress in Nigella sativa under soil moisture stress

Nigella sativa seeds have multiple industrial and pharmaceutical uses for the diseases treatment such as bronchitis, rheumatism, high blood pressure, cough, eczema, inflammation, and influenza. Although semi-arid areas are suitable for production of annual medicinal plants because they receive favorable amounts of solar radiations, the establishment of these plants' seedling requires frequent irrigations because their seeds are small and the climate is hot at the time of planting. When the irrigation sources are limited, poor establishment and inadequate production will result. Therefore, in order to improve nitrogen (N) in N. sativa seedling establishment, different effects of seed priming treatments were evaluated under drought stress. Different levels of soil moisture (irrigation after 11, 22, 33, and 44 mm of evaporation as no water stress, mild water stress, moderate water stress, and severe water stress, respectively) and seed priming treatments [no priming, potassium nitrate (KNO₃), zinc sulfate (ZnSO₄), polyethylene glycol 6000, and gibberellic acid (GA)] were evaluated as the main plot and subplot factors, respectively. The results showed that under mild water stress condition, seed priming significantly increased proline content and the highest percentage of emergence was obtained with ZnSO₄. Furthermore, the highest amount of soluble protein was observed in the KNO₃ treatment and the catalase enzyme content increased in all priming treatments, except polyethylene glycol treatment. Under moderate water stress condition, the KNO₃ treatment raised the rate and percentage of emergence and the seedling length. However, under severe water stress condition, the highest percentage of emergence was achieved by GA and ZnSO₄ treatments. Moreover, hydropriming and GA produced the highest proline content and seedling dry weight. Under moderate and severe water stress conditions, the hydropriming and ZnSO₄ treatments showed a significant increase in catalase activity. It can be concluded that priming of N. sativa seeds with ZnSO₄ and GA can alleviate drought stress in the early stages of seedling growth by increasing the antioxidants in the seedlings. Farmers in semi-arid regions can prime N. sativa seeds with these compounds before planting to increase production of this valuable medicinal plant and reduce water consumption.     

Implementation analysis of transfer of development rights for conserving privately owned built heritage in Hong Kong: A transactions costs perspective

Transfer of development rights (TDR) programs are introduced as an alternative institutional innovation to the traditional regulatory instruments for land development. They meet the demand for development and conservation while balancing the conflicts between public and private interests with minimal use of public funds. Most TDR literature is about nature conservation and there is little focus on the complicated process and diverse stakeholders’ interests of urban land use in dealing with built heritage conservation. Previous studies show that the success of TDR programs depends on various elements, especially policy design and implementation approaches. The design and implementation of TDR programs involves transaction costs that can reduce the efficiency and effectiveness of these programs. This paper aims at developing a framework for analyzing TDR programs. This proposed framework not only takes transactions costs into account, but also provides a basis for decision makers to decipher the process of informal TDR. Using Hong Kong as a case study, three TDR implementation modes are selected to examine how different informal institutional arrangements have resulted in specific transaction costs in practice and hindered TDR projects. Our findings, which are informed by transactions costs economics, provide practical insights in order to improving the efficiency and effectiveness of TDR programs, particularly in informal contexts.     

Dynamics of soil protozoa using a direct count method

We adapted a direct count method for obtaining counts of active protozoa that was not overly time consuming. Soil samples from an agricultural field were examined at 1- to 3-day intervals three times through the year. The three sampling periods represented different weather conditions. At each sampling event, fresh soil samples were extracted upon return to the laboratory for protozoa. These were enumerated at the microscope without prior culture, in soil–water suspension dilutions. We describe a procedure that allowed all samples to be processed in a few hours. Our results suggest there is good reproducibility and agreement between samples collected on the same day. Our data resolve differences between days as soil conditions changed slowly with drying or wetting. This procedure is suitable for describing species active at the time of sampling. Unlike the ‘most probable number’ procedure that relies on cultivable species, it is less prone to enumerating excysting individuals, and it provides better resolution between sampling dates, with a relatively low number of samples.     

电感耦合等离子体质谱法（ICP-MS）同时测定土壤中多种元素

为优化ICP-MS法同时测定土壤中多种元素的测定条件,采用在线加入内标的方法,探讨同时测定元素Li、Be、Sc、Ge﹑Mo、Sb、W、Tl、Bi、Th、U的参数条件,并对优化后的条件进行质量水平评价。试验结果表明：元素检出限为0.003～0.450μg/L;Δlgc〈0.04;RSD%〈10（n=12）;加标回收率在98%～108%之间。     

Genetic Diversity Among <Emphasis Type="Italic">Juglans Regia</Emphasis> Genotypes Based on Morphological Characters of Nut

Walnut germplasm from three different sites in Oltenia region, located in the southwestern part of Romania, was evaluated to determine the variability and to identify promising types. A total of 64 genotypes were evaluated using morphological characteristics of nuts. Considerable genetic variation in the measured traits was found in native trees which were of seedling origin. Variability found was between 7.62–20.90?g in nut weight, between 31.17 and 53.60?mm in nut length, between 24.81 and 37.48?mm in nut diameter I, and between 23.64 and 36.18?mm in nut diameter II. Separation of the three areas in multivariate space was assessed by calculating the Mahalanobis distance. The highest inter-populations value was observed between Bechet and Ostroveni population (1.83), followed by Sadova and Ostroveni population (1.08), which indicates a wide genetic distance between these populations. Cluster analyses showed a considerable diversity within the same germplasm population. The results indicated that most of genotypes were suitable in terms of morphological traits of nut. These data demonstrated large phenotypic diversity of nut among the selected genotypes that can be considered as a valuable gene stock for breeding programs.     

Vegetative propagation of Vitellaria paradoxa by grafting

Vitellaria paradoxa or karité is a wild fruit-bearing tree species of sudano-sahelian parklands that plays an important socio-economic role in Sub-Saharan Africa due to the commercial and domestic value of the fruits. Principal constraints of karité fruit production are: long juvenile phase, slow growth, genetic variability and lack of knowledge regarding the cultivation of the species. To address these constraints and to enhance productivity and quality, five methods of grafting (side cleft, top cleft, tongue, chip budding and side veneer), two methods of pre-treatment of scions and rootstocks (washing with 10% sodium hypochlorite to wash off latex and sterilise and a control without washing), and two methods of protection of grafts against desiccation (covering with white plastic sheet and aluminium foil) were tested. The results showed decreasing success of survival of grafts 16 weeks after grafting for the five grafting techniques: side cleft (86.1%), tongue (80.9%), top cleft (78.1%), chip budding (38.1%) and side veneer (20.7%) grafting methods. The results also showed May to be the optimum time for grafting, with high rates of shoot growth and survival of grafts. The average annual growth rate of grafts was 12.6 cm. The pre-treatment of scions with 10% sodium hypochlorite, however, had no significant effect on survival of scions. There was also no significant difference in survival of scions between the two methods of protection of grafts against desiccation (aluminium foil and plastic sheet). Two grafts produced fruits two years after grafting using side veneer grafting.This revised version was published online in November 2005 with corrections to the Cover Date.     

Phenological and pomological properties of promising walnut (Juglans regia L.) genotype with cluster fruiting from selected native population in Oltenia,Romania

Genetic Resources and Crop Evolution - Lateral fruiting in walnut is an important feature and many breeding programs follow this criterion. Following the evaluation of walnut genotypes from Padea...     

中美农产品贸易对中国农业发展影响的实证分析

根据1993—2011年中美两国农产品贸易总额和中国农业总产值的数据,采用协整分析、Granger因果关系检验和误差修正模型对中美农产品贸易与中国农业发展的关系进行了实证分析。结果表明,中美农产品贸易与中国农业发展存在长期的均衡关系;中美农产品贸易总额是中国农业发展的Granger原因;从短期来看,当短期波动偏离长期均衡时,误差修正项以0.371的力度作反向修正,将非均衡状态恢复到均衡状态。