Effects of Soil Moisture and Chemical Application on Low Temperature Stress of Cucumber (Cucumis sativus L.) Seedling

This study was conducted to investigate the effects of chemical application and amout of soil moisture on low temperature stress of cucumber seedling under the greenhouse conditions. When chilling treatments ($2^{\circ}C$) were begun at 07:00AM, survival rates of seedlings of two conditions; -0.3 bar and -5.5 bar were 28.3% and 83.3% respectively. But when chilling treatments were begun at 6:00PM - even the soil moisture condition was -0.3 bar - the survival rate was above the 87%. When reducing the soil moisture from -0.3 bar to -9.0 bar, ABA content in leaf was inc.eased by 6.5fo1d. Spraying of abscisc acid (ABA) before or after the chilling significantly increased the survival rates of seedlings, decreased the amounts of leaking electrolytes and prevented the yield reductions. ABA application on the soil before the chilling appeared to be more effective than the application after the chilling with foliar spray. Spraying of ABA ($10^{-5}M$), urea (0.2%) or $KH_2PO_4$ was effective in counteracting the low temperature, which causes growth deterioration and yield reduction in cucumbers.

토양수분조건 및 화학물질처리가 오이묘의 저온장해에 미치는 영향

오이묘가 저온피해를 입기 전, 후 토양수분조건과 몇 가지의 화학물질처리가 오이묘의 냉해 경감에 미치는 영향을 연구한 결과 토양수분 -0.3bar 적습상태에서 07:00시에 $2^{\circ}C$로 저온처리를 했을 때, 생존율은 28.3%이었으나 -5.5bar에서는 83.3%로 높아져 토양수분이 건조하면 저온피해가 감소되었다. 그러나 18:00시에 저온처리하면 -0.3bar에서도 생존율은 87% 이상이었다. 토양수분이 건조하면 엽신의 ABA함량은 크게 증가되었다. 저온처리 전, 후 ABA의 토양 및 엽면처리는 오이묘의 생존율을 유의하게 증가시켰고 세포의 전해질 누출량도 현저하게 감소시켰으며, 수량의 감소를 경감시켰다. 또한 ABA 처리는 저온처리 후보다는 저온처리 전에, 엽면처리보다는 토양에 처리하는 것이 보다 효과적이었다. ABA($10^{-5}M$)와 더불어 요소(0.2%)와 $KH_2PO_4$의 엽면살포는 오이의 생장과 수량에 미치는 저온피해를 경감시키는데 효과적이었다.