Growth Characteristics and Nutrient Uptake of Kalanchoe Plants (Kalanchoe blossfeldiana 'Marlene') at Different Light Intensities and Nutrient Strengths in Ebb and Flow Subirrigation Systems

The objective of this study was to determine the effects of light intensity and electrical conductivity (EC) of nutrient solution on the growth and nutrient uptake of potted kalanchoe plants (Kalanchoe blossfeldiana 'Marlene') with growth stage in ebb and flow subirrigation systems. The plants were grown at four ECs of 0.5, 1.0, 1.5, and 2.0 $dS{\cdot}m^{-1}$ for seedling stage and four ECs of 1.0, 1.5, 2.0, and 3.0 $dS{\cdot}m^{-1}$ for short day stage under three daily photosynthetic photon flux (PPF) of 6.5, 10.3, 18.2 $mol{\cdot}m^{-2}{\cdot}d^{-1}$. At seedling stage, plant height was the longest under the lowest light intensity, and particularly dry weights and leaf areas were the highest at PPF 10.3 $mol{\cdot}m^{-2}{\cdot}d^{-1}$. Dry weights and leaf areas were the highest at EC 1.5 $dS{\cdot}m^{-1}$ regardless of light intensity. At short day exposure, plant height was the longest under the lowest light intensity. Dry weights, leaf areas, and number of pedicels of the plants significantly increased as light intensity increased. Under all light intensity conditions, dry weights, leaf areas, and number of pedicles increased until EC becomes to 1.0 - 2.0 $dS{\cdot}m^{-1}$. And after reached the highest at EC 2.0 $dS{\cdot}m^{-1}$, they decreased at EC 3.0 $dS{\cdot}m^{-1}$. By comparing the ion uptakes at EC 1.5 $dS{\cdot}m^{-1}$ of seedling stage and EC 2.0 $dS{\cdot}m^{-1}$ of short day stage in which the plants grew better, we confirmed that ion balance of nutrient solution among $NO_3{^-}$-N, $H_2PO_4{^-}$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were significantly changed at short day stage compared to seedling stage. For better growth of the plants, both ion balance and EC of nutrient solution should be considered under different light intensities at short day stage while control of EC is enough at seedling stage.

Ebb and Flow 저면관수 시스템에서 광강도와 양액농도에 따른 칼랑코에(Kalanchoe blossfeldiana 'Marlene') 생육 및 양분흡수 특성

광강도와 배양액 농도에 따른 칼랑코에(Kalanchoe blossfeldiana 'Marlene')의 생육단계별 양수분 흡수율과 작물생육을 조사하였다. 광강도는 일적산 광합성유효광양자속(PPF)이 6.5, 10.3, $18.2mol{\cdot}m^{-2}{\cdot}d^{-1}$의 3수준으로, 배양액의 농도는 유묘기 EC 0.5, 1.0, 1.5, $2.0dS{\cdot}m^{-1}$의 4수준, 단일처리 후 EC 1.0, 1.5, 2.0, $3.0dS{\cdot}m^{-1}$의 4수준으로 처리하였다. 유묘기 초장은 저광 조건에서 가장 길었고, 엽면적과 건물중은 PPF $10.3mol{\cdot}m^{-2}{\cdot}d^{-1}$에서 가장 높았다. 유묘기 모든 광조건에서 EC $1.5dS{\cdot}m^{-1}$일 경우에 최대 건물중과 엽면적이 나타났다. 단일처리기 초장 역시 저광 조건에서 길었고, 엽면적, 건물 중, 분지수는 광강도가 증가함에 따라 현저하게 증가하였다. 모든 광조건에서 엽면적, 건물중, 분지수는 배양액농도가 EC 1.0-$2.0dS{\cdot}m^{-1}$까지 증가하다가 EC $3.0dS{\cdot}m^{-1}$에서 현저히 감소하였고, EC $2.0dS{\cdot}m^{-1}$에서 가장 높았다. 생육이 양호하였던 EC 처리구(유묘기 EC $1.5dS{\cdot}m^{-1}$, 단일처리기 EC $2.0dS{\cdot}m^{-1}$)의 $NO_3$-N, $H_2PO_4{^-}$, $K^+$, $Ca^{2+}$, $Mg^{2+}$ 이온간의 상호간 비율을 분석한 결과 육묘단계에서는 광강도에 따라 큰 차이가 없었지만, 단일처리기에서는 큰 차이가 확인되었다. 따라서 작물의 최적의 생장을 위해 유묘기에는 광도 별 EC 조절로 충분하지만, 단일처리기에는 광강도에 따른 배양액 조성과 EC조절이 필요하다.