遮陰對十八種適用綠籬植物葉片壽命之影響

Effect of Shading on Leaf Longevity of 18 Hedge Plants

本研究是以不遮陰、遮陰30%、50%、80%及90%五種遮陰程度，處理18種具有成為綠籬植物潛力之植物，以葉片壽命作為指標測試其耐陰度。十八種植物間及遮陰處理，對平均葉片壽命有極顯著之影響。將遮陰後葉片壽命之改變，轉換成葉片壽命增減率後，顯示18種植物之葉片壽命對遮陰之反應不一，不同遮陰度影響供試植物之葉片增減率之排序，其排序之改變足以顯示其耐陰度。再將供試植物處理後，葉片壽命與遮陰度間做迴歸分析，則兩者之間大多呈現顯著之二次相關。將迴歸分析與遮陰後植物葉片壽命增減率排序兩項結果綜合後，大致可將供試植物分為五群，即1.遮陰後葉片壽命隨遮陰度增加而減少，如：小芽新木薑子（Neolitsea parvigemma）、金平氏冬青（Ilex triflora var. Kanehirai）、臺灣白蠟樹（Fraxinus formosana）、九重葛（Bougainvillea spp.）、台灣樹蘭（Aglaia formosana）；2.遮陰後葉片壽命隨遮陰度增加而增加，如：月橘（Murraya paniculata）、春不老（Ardisia squamulosa）、蚊母樹（Distylium racemosum）、蘭嶼柿（Diospyros kotoensis）；3.輕度遮陰可增加葉片壽命，如：台灣海桐（Pittosporum pentandrum）、馬櫻丹（Lantana camara）、鐵冬青（Ilex rotunda）；4.中度遮陰可增加葉片壽命，如：台東火刺木（Pyracantha koidzumii）、紅豆杉（Taxus sumatrana）、蘭嶼樹杞（Ardisia elliptica）及5.葉片壽命不受遮陰度之影響，如白樹仔（Gelonium aequoreum）、魯花樹（Scolopia oldhamii）、楓港柿（Diospyros vaccinioides）。 This study used leaf longevity as indicator to test shading tolerance of 18 hedge plants by an shading experiment, which included non-shading, 30% shading, 50% shading, 80% shading and 90% shading. Not only plant species but also shading rate had significant influence to average leaf longevity. In most of plants, leaf-longevity was significantly quadric correlated to shading rate. After change leaf-longevity to variation-of-leaf-longevity and arrange them by the order of variation-of-leaf-longevity, we found that the responses of shading on leaf-longevity could significantly show the shading tolerance of the plants. According to the order of variation-of-leaf-longevity and correlation between leaf-longevity and shading rate, the plants could divide into five groups. Group Ⅰ. Non-shading tolerance, include Neolitsea parvigemma, Ilex triflora var. Kanehirai, Fraxinus formosana, Bougainvillea spp. and Aglaia formosana. Group Ⅱ. High shading tolerance, include Murraya paniculata, Ardisia squamulosa, Distylium racemosum and Diospyros kotoensis. Group Ⅲ. Slight shading tolerance, include Pittosporum pentandrum, Lantana camara and Ilex rotunda. Group Ⅳ. Middle shading tolerance, include Pyracantha koidzumii, Taxus sumatrana and Ardisia elliptica. Group Ⅴ. Non response, included Gelonium aequoreum, Scolopia oldhamii and Diospyros vaccinioides.