해송의 종자 발아 및 유묘 생장에 대한 오존저항성의 개체간 차이

Abstract

본 연구에서는 종자생산, 발아와 유묘 발달에 대한 오존 저항성의 개체간 차이를 비교하였다. 대기오염지역에서 12년간 자란 해송 중에서 가시적 피해와 생장을 기준으로 건전목과 피해목을 선정한 후, 구과분석, 종자발아, 지질과산화, 항산화효소 활성을 측정하였다. 구과분석 후, 종자와 유묘를 대상으로 대조구, 150, 300ppb 농도의 오존 처리를 실시하였다. 피해목 종자의 발아율은 건전목 종자보다 발아율이 21.6% 낮았다. 건전목과 피해목 종자의 발아율은 300ppb 오존처리시 대조구에 비해 각각 10, 19% 감소하였다. 종자의 SOD, GR, CAT 활성도 건전목 종자가 높았다. 오존처리 시 GR, APX와 CAT 활성은 두 종류의 종자 모두에서 감소하였고 MDA 함량은은 종자에 따른 차이가 없었다. 유묘 생육은 침엽 길이, 줄기와 뿌리의 길이 및 무게에서 종자에 따른 차이는 없었으나 300ppb의 오존 처리 시 침엽과 줄기의 길이 및 무게는 감소 되었다. 피해목 유묘의 SOD, APX, CAT 활성과 MDA 함량은 건전목 유묘보다 높았고, 오존처리 시피해목 유묘에서 유의하게 감소하였다. 결론적으로, 오염지역의 건전목과 피해목은 종자 발아 특성과 유묘의 항산화 능력 차이가 뚜렷하며, 그들의 종자의 발아 특성과 유묘 생장은 오존농도 증가에 민감하게 반응하므로 조림을 위한 개체 선정 시 고려해야 한다. Individual differences of ozone (<TEX>$O_3$</TEX>) resistance for seed production, seed germination and seedling development were examined in this study. Five in each healthy and damaged trees of Pinus thunbergii growing in air polluted area for 12 years were chosen based on visible foliar injury and growth. The cones of P. thunbergii, which were collected from healthy and damaged trees, were analyzed for physical characteristics and seeds from the cones were used to test germination percentage under <TEX>$O_3$</TEX> treatment. The germinated seeds were continuously exposed to <TEX>$O_3$</TEX> treatment and the lipid peroxidation and activities of antioxidative enzymes were determined for both seeds and seedlings. The <TEX>$O_3$</TEX> treatment for seed germination and seedling development were conducted at three conditions: control, 150 ppb and 300 ppb of <TEX>$O_3$</TEX>. The non-treated seeds from the damaged trees showed 21.6% lower germination than those from the healthy ones. On the <TEX>$O_3$</TEX> treatment of 300 ppb, seed germination decreased approximately 10% for the healthy trees and 19% for the damaged trees compared to that on the control. The seeds from the healthy trees showed significantly higher activities of superoxide dismutase (SOD), glutathione reductase (GR), and catalase (CAT) than those from the damaged trees. The activities of GR, ascorbate peroxidase (APX), and CAT decreased along with the increasing <TEX>$O_3$</TEX> concentration in two tree grades. Malondialdehyde (MDA) content of seeds was not influenced by <TEX>$O_3$</TEX> treatment for two tree grades. In seedling development, there were no significant differences for length and biomass of needle and root of two tree grades at both the control and 150 ppb of <TEX>$O_3$</TEX>. At 300 ppb of <TEX>$O_3$</TEX> treatment, however, the length and biomass of needle and stem decreased for two tree grades but no significant differences was detected in root. The seedlings from the damaged trees were more sensitive to the <TEX>$O_3$</TEX> treatment, showing higher activities of SOD, APX, and CAT and content of MDA compared to those from the healthy tree seedlings. Our results indicate that seed germination and seedling development are vulnerable to increasing <TEX>$O_3$</TEX> concentrations and that attention must be paid to the individual selection of tree species for reforestation.