Effect of Light Condition before and after Chilling Treatment on the Survival and Physiological Responses of Cucumber (Cucumis sativus L.) Seedlings

냉온처리 전후의 광환경 조건이 오이 묘의 생존율에 미치는 영향

This study was conducted to investigate the influence of light condition before and after chilling treatment started at different times of a day on the survival and physiological responses of cucumber seedlings grown in a greenhouse. Percent survival of cucumber seedling exposed to a chilling temperature of 2$^{\circ}C$ for 48 hours varied considerably depending upon the initiation time of chilling treatment. Seedlings exposed to chilling treatment from 7:00 o clock, the end of a dark period, showed considerably lower % survival of 30.6% as compared to 90.2% in those exposed to the same treatment starting from 18:00 o clock, the end of a photoperiod. This difference in % survival was found to be closely associated with content of photosynthetic assimilates in seedlings. Relative amount of electrolyte leakage was 57.1% in seedlings chilled from 7:00 o clock and 25.9% in seedlings chilled from 18:00 o clock. Among the ions found in the electrolyte leakage, content of $K^{+}$ was the greatest, followed by that of N $a^{+}$, $Mg^{+}$ and $Ca^{+2}$. Light illumination for 2 hours or longer shortly before chilling treatment during the dark period was effective in increasing % survival of seedlings, probably because of increased photosynthetic assimilates in seedlings. Light illumination during a 48 hour chilling treatment at 3$^{\circ}C$ significantly reduced % survival to 43.3% as compared to 92.0% in seedlings kept continuously in darkness.ess.s.

겨울철 시설내에서 정전 등으로 인하여 수시간 동안 작물체가 생육한계 온도로 경과시 오이묘에 나타나는 피해와 피해발생의 생리적 요인 및 피해 경감대책을 구명하기 위하여 저온처리 전후의 광환경 조건이 오이 묘의 생존율 및 생육반응에 미치는 영향을 조사하였다. 냉온처리(2$^{\circ}C$, 48시간)에 따른 오이묘의 생존율은 암기말인 07:00시 처리에서 30.6%이었고, 암기 개시기인 18:00시 처리에서는 92.2%로 높았다. 세포의 전해질 누출은 07:00시 처리에서(72시간) 57.1%, 18:00시 처리에서는 25.9%로 낮았다. 누출액중 무기이온 함량은 $K^{+}$ 이온이 가장 많았고, $Na^{+}$, $Mg^{+2}$ , $Ca^{+2}$ 순으로 적었다. 냉온처리전 야간에 광을 조사하면 생존율이 광 무처리에 비해 56% 더 높아졌으며, 광조사는 2시간 처리로 충분한 효과가 있었다. 광 조사에 의하여 생존율이 높아지는 것은 광합성에 의한 당함량의 증가 때문인 것으로 해석 되었다. 냉온처리(3$^{\circ}C$, 48시간) 기간중 광을 조사하면, 생존율이 43.3%로 낮아진 반면, 암조건에두면 92%로 높았다.