암모니아가스에 의한 난과 식물의 피해증상

Injury Symptoms of Some orchids by Ammonia Gases

This study was conducted to determine injury symptoms of orchids by ammonia gases, four ordhid plants(Phalaenopis, Cymbidim, Dendrobium phalaenopsis, Oncidium) were exposed to ammonia gases in an enclosed growth chambers. The gas treatments consist of six different ammonia gas concentrations(0, 30, 60, 100, 300, and 400mg ㆍL⁻¹) and plant exposure of 15 hours with 26±1.9℃ air temperature and 82.4±11.2% relative humidity. The effect of time to gas exposure in a day was also evaluated by treating the plants with 200mgㆍL⁻¹ammonia gas every 2.4 hours for Oncidium(sensitive to NH₃). Phalaenopis leaves showed symptoms of injury at >300mgㆍL⁻¹ ammoniagas. Cymbidim, Oncidium, Dendrobium phalaenopsis, leaves showed symptoms of injury at >100mg{br}L⁻¹. Oncidium was especially sensitive to ammonia gas. As the gas concentration increased, the rate of injury increased and reached up to 83.4% when the gas concentration was at 400mgㆍL⁻¹. Also maximum quantum yield of photo-system II(Fv/Fm) were decreased. The injury to ammonia gas exposure in a day was recorded during the period 6 am - 6 pm wherein the most severe were noted during the time 10 am -4 pm. Major leaf injury symptoms was dried rapidly, rolled the edge of a leaf then drying or changing light yellowish brown color.