Abstract
This study was conducted to investigate sensitivity of tree seedlings to $SO_2$. Visible injury symptoms and changes of ethylene production were investigated in tree seedlings with the fumigation of $SO_2$ in gas chamber 4 hours a day for six days. The symptoms of visible injury did not appear below 0.5ppm level of $SO_2$ exposure but a change of visible injury with the passage of time appeared at 1.5 and 2.5ppm in all seedlings. With the higher the concentration and/or the longer exposure of $SO_2$ the visible injury symptoms on leaves increased in all seedlings. The sensitivity of seedlings to $SO_2$ was the highest in Liriodendron tulipifera followed by Pinus strobus, Ginkgo biloba, Pinus densiflora and Pinus koraiensis. The amount of ethylene production was more at 1.5 and 2.5ppm of $SO_2$ exposure than at 0.5ppm and the peak time of it came faster at higher levels. The amount of ethylene production was significantly different among tree seedlings. It showed a higher at production of ethylene in Liriodendron tulipifera compared to Ginkgo biloba and the ethylene production of Pinus trees to $SO_2$ were the highest in Pinus strobus followed by Pinus densiflora and Pinus koraiensis. In needle of Pinus strobus the ethylene production increased with the increasing rate of visible injury until the injury rate of 40-50% and than decreased with the increasing rate of visible injury since the rate of 50%.
$SO_2$에 의한 조경수목(造景樹木)들의 피해(被害)의 감수성(感受性)을 조사하기 위하여 무처리(無處理), 0.5, 1.5 및 2.5ppm의 $SO_2$ 가스를 각각 하루에 4시간(時間)씩 6일간(日間) 처리(處理)하면서 가시피해율(可視被害率)과 내생(內生) ethylene 발생량(發生量)을 측정(測定), 분석(分析)하였다. $SO_2$ 농도(濃度)에 따른 묘목(苗木)들의 가시피해율(可視被害率)은 0.5ppm 이하에서는 조사대상(調査對象) 수종(樹種) 모두 피해증상(被害症狀)이 없었으며, 1.5와 2.5ppm 수준(水準)에서 경시적(經時的)으로 변화(變化)가 나타났는데, 고농도(高濃度) 일수록 피해율(被害率)이 높았으며, 평균(平均) 피해율(被害率)은 튜립나무가 가장 높았고 다음으로 스트로브잣나무, 은행나무, 소나무, 잣나무의 순(順)이었다. $SO_2$ 처리(處理)에 의한 내생(內生) ethylene의 발생량(發生量)을 보면, 고농도(高濃度) 처리구(處理區)에서는 저농도(低濃度)에 서보다 ethylene의 발생량(發生量)이 많았으며, 발생량(發生量) 최대점(最大點)에 도달되는 시간(時間)도 빨랐다. Ethylene 발생량(發生量)은 튜립나무가 은행나무에서보다 많았으며, 침엽수류에서는 스트로브잣나무, 소나무, 잣나무 순(順)으로 많았다. 특히 가시피해율(可視被害率)이 80% 이상(以上)이었던 스트로브잣나무는 가시피해율(可視被害率)이 증가(增加)함에 따라 ethylene 발생량(發生量)도 직선적(直線的)으로 증가(增加)하다가 가시피해율(可視被害率)이 40-50% 이상에 도달한 이후 ethylene 발생(發生)이 오히려 감소(減少)하는 경향(傾向)을 나타내었다.