Abstract: 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.

Key words: Rhododendron fortunei Lindl., pH regime, growth index, chemical analysis of substrate, mineral element content, alkali tolerance