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471.
472.
Soil is the foundation for sustainable food production and environmental protection. Created by unsustainable land management practices and a range of social, economic and environmental drivers, soil degradation and pollution have been an ongoing threat to international food security and environmental quality. Soil degradation and pollution assessments are, however, often focused on the soil itself with little scope to devise new soil management approaches that match food production systems and/or environmental protection. This study draws lessons from an Australia-China Joint Research Center Program, Healthy Soils for Sustainable Food Production and Environmental Quality: a research platform that has brought together multi-disciplinary approaches from world-renowned universities and research organizations in Australia and China. To this end, a framework is presented for future soil management in a new way that combines excellence in research, industry and policymakers in a partnership that will ensure not only the right focus of the research but also that high-quality outputs will be transferable to industry and end-users.  相似文献   
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This study provides a very first report on the use of a sprayable formulation of 1-MCP, HarvistaTM, on ornamental plant species. Individual florets of Phalaenopsis and inflorescences of Kalanchoë blossfeldiana were sprayed with 1, 2, 4, or 6% HarvistaTM and this was compared to the commonly used 1-MCP formulation, SmartFreshTM, which is administered as a powder releasing gas. HarvistaTM treatments for Kalanchoë were in addition also compared to plants treated with an alternative ethylene receptor blocker, STS, as well as with transgenic plants expressing the etr1-1 mutant gene of Arabidopsis thaliana.

In the presence of ethylene, HarvistaTM at all concentrations (except 1% for Kalanchoë), as well as the conventional SmartFreshTM treatment, prevented wilting of florets and significantly extended their display life compared to that of control treatments: up to twofold for Kalanchoë and up to fourfold for Phalaenopsis. For Kalanchoë the best display life was, however, presented by etr1-1 transgenic plants. The efficacy and suitability of using HarvistaTM, a sprayable formulation of 1-MCP, was compared to using the gaseous application of SmartFreshTM, or the environmental hazardous silver treatment, against having to consider expensive and lengthy genetic modification with etr1-1 as commercial alternatives to achieve protection against the detrimental effects of ethylene.

Abbreviations: 1-MCP, 1-methylcyclopropene; STS, silver thiosulfate  相似文献   

475.
The green mussel, Perna viridis is known to have the ability to selectively ingest certain suspended particles from water. However, the preferential ingestion of specific phytoplankton taxa by P. viridis under different environmental conditions is not well understood. A study was undertaken to identify the phytoplankton taxa that are preferentially ingested and rejected by P. viridis in different environmental conditions at Marudu Bay, Malaysia. Phytoplankton abundance and composition in stomach and surrounding waters were determined microscopically. The gonad development stages of P. viridis and various environmental parameters of the bay including temperature, salinity, dissolved oxygen, current speed, pH, visibility, chlorophyll a, nutrients concentration and suspended particles were also determined. Results of current study demonstrated that selective ingestion in P. viridis was mainly influenced by seston concentration, phytoplankton abundance and composition. At high seston concentration with low phytoplankton abundance, P. viridis selectively ingested Coscinodiscus spp. In contrast, P. viridis was found to ingest wider range of phytoplankton at low seston concentration and high phytoplankton abundance. Interestingly, Chaetoceros spp. and Bacteriastrum spp. were selectively rejected by P. viridis in both high and low seston conditions. Nevertheless, no selective ingestion behaviour was evidenced in low seston with low phytoplankton conditions. Besides phytoplankton, zooplankton has also contributed significantly in the diet of P. viridis, where high numbers of copepod and bivalve larvae were found in the stomach. The findings of current study can be useful in determining potential farming sites for green mussel in future.  相似文献   
476.
综述了蚜虫较典型的3种嗅觉行为即报警信息素反应、植物挥发物对蚜虫的引诱行为和驱避行为以及嗅觉在寄主定位中的作用,结合由G蛋白介导的昆虫嗅觉信号转导途径的研究现状,从一个全新的角度总结了近年来针对蚜虫嗅觉反应及其机制的研究进展。文章还就麦蚜嗅觉信号转导途径研究的可行性及意义进行了讨论。  相似文献   
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  目的  九龙山榧Torreya jiulongshanensis为浙江特有的古老孑遗植物,数量极少,为国家Ⅱ级重点保护野生植物,也被列为浙江省极小种群保护植物。系统观测九龙山榧大、小孢子的发生和雌、雄配子体的发育过程,有助于发现其配子是否发育异常及导致结籽率低下的原因。  方法  以九龙山榧模式产地的雌、雄植株为研究对象,通过定期观测和取样,采用石蜡切片法对其大、小孢子的发生,雌、雄配子体的发育过程进行切片、染色和观察。  结果  ①小孢子叶球于8月中旬开始分化,8月下旬分化形成次生造孢细胞,11月中旬形成小孢子母细胞,翌年2月下旬进入减数分裂期,3月中旬形成游离小孢子细胞,于3月末逐渐成熟;成熟花粉粒为双核,无气囊。小孢子囊的发育类型为基本型,孢质分裂方式为同时型,四分体有四面体形和左右对称形。②雄配子体从3月中下旬开始发生,到7月底形成精子,整个过程历时约4个月。③翌年3月下旬,大孢子叶球每个苞叶的叶腋基部直立着生2枚胚珠;大孢子母细胞于4月下旬经过减数分裂Ⅰ和减数分裂Ⅱ形成4个直列大孢子,5月中旬珠孔端的3个大孢子退化,合点端的大孢子最终发育成为雌配子体。④九龙山榧有2个单生型椭圆形的颈卵器,从传粉到受精历时约7个月。  结论  九龙山榧雌雄生殖系统发育的周期均较红豆杉科Taxaceae其他种更长,其冗长的生殖周期、复杂的生殖过程和雌性生殖系统发育明显滞后于雄性生殖系统,加之种群个体数量极度稀少(1雌株、2雄株)是造成结籽率低下、自然更新困难的主要原因。图3表1参34  相似文献   
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