盆栽黛粉葉之地上部與根系及介質移除甲醛之效率評估

Assessment of Formaldehyde Removal Efficiency of Shoots and Medium-Root Zones of Potted Dieffenbachia maculata

甲醛為室內常見之揮發性有機物質，且為人類致癌物。利用植栽可減少甲醛，但移除甲醛之效率因植株部位及介質而異。本研究將黛粉葉‘白玉’[Dieffenbachia maculata（Lodd.）G. Don 'Camilla']之地上部、全株帶介質、根系帶介質及高溫高壓處理後之根系與介質，置於含甲醛濃度為1±0.01μL•L^(-1)之密閉熏氣箱（0.128立方公尺）內每日8小時，連續7天，以測試各部位之甲醛移除能力。結果以平均葉面積為416至536平方公分之地上部與全株帶介質處理者之移除能力最好，單盆每天皆可移除熏氣箱內0.8至0.9μL•L^(-1)之甲醛。換算單位葉面積甲醛移除效率，以全株帶介質處理者最佳；於7天內每日移除熏氣箱中一半甲醛濃度之時間均介於13至19分鐘。於甲醛處理7天內地上部及全株帶介質兩處理之葉片淨光合作用速率、葉綠素計讀值與葉綠素螢光值，皆無下降。而根系帶介質處理者，於7天之甲醛處理期間，每天亦可移除熏氣箱內約60%之甲醛。高溫121℃處理根系及介質後，其移除能力隨試驗天數增加而上升，至第7天與未經高溫高壓處理者差異不顯著。 Formaldehyde is one of the common indoor volatile organic compounds and it has been classified as a human carcinogen. Plants are known to remove formaldehyde, but the efficiency varies with plant parts and growing media. In this study, we measured formaldehyde removing capacity of the shoot, whole plant-medium, medium-root zone, and sterilized medium-root zone of Dieffenbachia maculata (Lodd.) G. Don 'Camilla'. Each of these test materials was exposed to 1±0.01μL•L^(-1) formaldehyde in airtight chambers (0.128 m^3) at 8 h•d^(-1) for seven days and the formaldehyde removal rate measured daily. Shoot and whole plant- medium of Dieffenbachia maculata 'Camilla' had the highest formaldehyde absorption rate, 0.8 to 0.9μL•L^(-1) formaldehyde removed per pot (leaf area 416 to 536 cm^2) per day. When calculated on a leaf area basis, the whole plant-medium treatment had the shortest time (13 to 19 min) to reduce 50% of initial formaldehyde concentration in the chamber. Exposure to formaldehyde did not alter net photosynthetic rate, SPAD-502 value and Fv/Fm of the recently fully developed leaves of growing Dieffenbachia plants. Medium-root zone removed 60% of formaldehyde in the chamber each day for seven successive days. Sterilized medium-root zone lost its ability to absorb formaldehyde temporarily, but gradually recovered and reached the same level as non-sterilized one on day 7.