摘要：Current arable land and increasing food demand necessitates the practice of double and multiple cropping systems with inclusion of ultra-fast maize hybrids, which are characterized by smaller size, fewer leaves per plant, lower leaf area and fewer self-shading problems, under irrigation. In this context, a field experiment was conducted for two successive cropping seasons 2008/2009 to 2009/2010 at Kenilworth Experimental Station to evaluate the effect of row spacings and plant density on growth. Three row spacing （0.225, 0.45 and 0.90 m） and five plant densities （5, 7.5, 10, 12.5 and 15 plants m^-2） were used. Treatments were combined in a factorial combination and laid out in a completely randomized design with replications consisting of five single plants randomly selected from each treatment for destructive sampling. Growth factors reacted differently to row spacing by plant density. At crop establishment, growth indicators were not significantly affected by either main effects or a combination thereof. However, at the end of the vegetative phase, almost all growth indicators reached a maximum and were significantly affected by treatment interactions. Growth analysis showed that there was an interaction effect of row spacing by plant density on plant height, dry matter （DM） accumulation, leaf area index （LAI）, crop growth rate （CGR） and net assimilation rate （NAR） of maize. Therefore, the current investigation demonstrated that a row spacing of 0.45 m or 0.90 m with a plant density of 10 plants m^-2 was optimum for the selected ultra-fast maize hybrid under irrigation.

摘要：A field experiment was conducted at Kpongu in the Upper West region of Ghana to determine the added benefits in grain yield of maize derived from the concurrent use of manure and mineral fertilizer, and their cost effectiveness. Factorial combinations of cattle manure and mineral fertilizer each at 0, 50 and 100% of their recommended rates were evaluated in both the field and the laboratory studies. The treatments were applied in a randomized complete block design with three replications on the field. The same treatments were applied in the incubation study in a completely randomized design. The use of 100% NPK （Nitrogen, Phosphorus, Potassium） ＋ 5 t manure gave the highest grain yield of 4,678 kg·ha^-1. Synergistic interactions resulting in added benefits in grain yield were observed in all the combined nutrient inputs except 50% NPK ＋ 2.5 t manure which accrued an added disadvantage of 44 kg·ha^-1. Economic analysis proved that 100% NPK ＋ 2.5 t manure and 50% NPK ＋ 5 t manure were the most economically viable combined treatments in terms of grain yield. Based on the results from this study, resource poor farmers in the Upper West region of Ghana may reduce mineral fertilizer recommended rates by 50% and supplement it with 5 t quality （N 〉2.5%） cattle manure without compromising yield and profit.

摘要：The long atmospheric residence time of CO2 creates an urgent need to add atmospheric carbon drawdown to CO2 regulatory *** and systems biology(SSB),which enables manipulation of cellular phenotypes,offers a powerful approach to amplifying and adding new possibilities to current land management practices aimed at reducing atmospheric *** participants(in attendance:Christina Agapakis,George Annas,Adam Arkin,George Church,Robert Cook-Deegan,Charles DeLisi,Dan Drell,Sheldon Glashow,Steve Hamburg,Henry Jacoby,Henry Kelly,Mark Kon,Todd Kuiken,Mary Lidstrom,Mike MacCracken,June Medford,Jerry Melillo,Ron Milo,Pilar Ossorio,Ari Patrinos,Keith Paustian,Kristala Jones Prather,Kent Redford,David Resnik,John Reilly,Richard ***,Daniel Segre,Susan Solomon,Elizabeth Strychalski,Chris Voigt,Dominic Woolf,Stan Wullschleger,and Xiaohan Yang)identified a range of possibilities by which SSB might help reduce greenhouse gas concentrations and which might also contribute to environmental sustainability and *** include,among other possibilities,engineering plants to convert CO2 produced by respiration into a stable carbonate,designing plants with an increased root-to-shoot ratio,and creating plants with the ability to self-fertilize.A number of serious ecological and societal challenges must,however,be confronted and resolved before any such application can be fully assessed,realized,and deployed.

摘要：Plants are complex systems hierarchically organized and composed of various cell *** understand the molecular underpinnings of complex plant systems,single-cell RNA sequencing(scRNA-seq)has emerged as a powerful tool for revealing high resolution of gene expression patterns at the cellular level and investigating the cell-type ***,scRNA-seq analysis of plant biosystems has great potential for generating new knowledge to inform plant biosystems design and synthetic biology,which aims to modify plants genetically/epigenetically through genome editing,engineering,or re-writing based on rational design for increasing crop yield and quality,promoting the bioeconomy and enhancing environmental *** particular,data from scRNA-seq studies can be utilized to facilitate the development of high-precision Build-Design-Test-Learn capabilities for maximizing the targeted performance of engineered plant biosystems while minimizing unintended side *** date,scRNA-seq has been demonstrated in a limited number of plant species,including model plants(e.g.,Arabidopsis thaliana),agricultural crops(e.g.,Oryza sativa),and bioenergy crops(e.g.,Populus spp.).It is expected that future technical advancements will reduce the cost of scRNA-seq and consequently accelerate the application of this emerging technology in *** this review,we summarize current technical advancements in plant scRNA-seq,including sample preparation,sequencing,and data analysis,to provide guidance on how to choose the appropriate scRNA-seq methods for different types of plant *** then highlight various applications of scRNA-seq in both plant systems biology and plant synthetic biology ***,we discuss the challenges and opportunities for the application of scRNA-seq in plants.