云锦杜鹃的耐碱反应

 在循环型底面潮水式灌施营养液栽培系统中，对云锦杜鹃3年生实生苗进行了营养液pH4.5，5.5，6.5，7.5和8.5处理。结果表明，以植株地上和地下部干、鲜样质量为指标，营养液pH7.5的环境较为适合，而pH8.5处理不适宜云锦杜鹃的营养物质积累，即干、鲜样质量偏低，在其它的低pH处理中该指标均表现为中等水平；叶片叶绿素含量和光合效率随pH值的升高呈现出较不明显的下降趋势；根系与叶片的营养元素含量没有明显变化，除P之外，所有被测定的矿质营养元素在5个不同的pH处理中均而无明显差异。云锦杜鹃有一定的耐碱性，而且对微量元素没有特别的要求。

Alkali Tolerance of Rhododendron fortunei in Subirrigated Ebb & Flow Bench Systems with Hydroponics

In a closed ebb &; flow subirrigation bench system, plant growth response and nutrient element analysis of Rhododendron fortunei in 5 different pH regimes (pH4.5, 5.5, 6.5, 7.5, and 8.5) were conducted and the results indicated that pH 7.5 environment adapted preferably R. fortunei growth and development, in return, the higher pH 8.5 regime was not suitable for its growth in terms of dry and fresh mass of shoot and root, whereas the lower pH treatments stood at medium. It preferred lower pH treatments to higher pH environments on basis of leaf chlorophyll contents and adapted to the conditions of climate and soil in Seoul based on plant growth, leaf chlorophyll content and photosynthesis rates. It appeared that R. fortunei was little affected by the pH variation of media, even if an acidic or an alkaline root environment, e.g. in pH 4.5 and 8.5 regimes. R. fortunei needed less micronutrients, no special demands for mineral nutrients as any other plants. Most of the mineral nutrient elements except for P were unexpectedly showed a flat variation among 5 different pH treatments which proved furthermore that plant growth responses, especially, nutrient contents of R. fortunei were insensitive to pH changes. Therefore, R. fortunei would be a promising gene resource for application and breeding as lime-tolerant rhododendrons.