(61(3):250-257)Evaluating Biodegradable Materials as Phalaenopsis Growing Media

水苔 (sphagnum moss) 為台灣蝴蝶蘭主要栽培介質，近年來因過度開採導致產量減少，成本提高，品質穩定度不一，影響高品質蝴蝶蘭的生產。聚乳酸(polylactic acid) 為一種生物可分解聚合物，近年來已廣泛地被應用。本研究評估聚乳酸作為替代水苔為蝴蝶蘭栽培介質之可行性，同時比較水苔及以樹皮椰纖和泥炭土等傳統成分組成的混合介質，進行蝴蝶蘭 (Phalaenopsis Sogo Yukidian) 栽培試驗，分析介質之酸鹼度、導電度與對植株生長之影響。研究結果顯示，泥炭土混合介質對蝴蝶蘭植株生長與開花性狀之表現與天然水苔處理者無顯著差異 (P > 0.05)。以中性的聚乳酸介質栽培蝴蝶蘭，植株葉片之生長表現與天然水苔間有顯著性差異；於自然花期均能順利抽梗開花，平均抽梗數約為 1 梗，處理間無顯著差異，但開花性狀表現則不如水苔處理組，後者花梗長度 117.2 cm，長粒柱狀聚乳酸及片狀聚乳酸等處理組，分別只有 89.7 cm 及 91.7 cm，並影響平均著生花朵數，分別為 13.4 及 12.6 朵，較水苔處理組植株減少約 2–4 朵。 Sphagnum moss is the main growing medium for cultivation of phalaenopsis in Taiwan. In recent years, over-exploitation of sphagnum moss, resulting in increased costs and unstable quality, affected the quality of orchids. Polylactic acid, one of the biodegradable polymers, has been developed for many years and was the most widely used material. The objective of this study was to investigate if the polylactic acid could substitute for sphagnum moss. The coconut fiber and peat moss were also compared. The pH and EC of the different media were measured and the effects on the growth of phalaenopsis were studied. The results showed that polylactic acid was a neutral medium; there were significant differences in the leaf growth between polyactic acid and sphagnum moss treatments. All the plants produced one spike successfully in natural flowering season with one spike, no significant difference among treatments. Spike lengths of polylactic acid granules (P1) and pieces (P2) treatments were 89.7 and 91.7 cm, respectively, significantly shorter than that of the sphagnum moss treatment (117.2 cm). The average number of flowers per spike of P1 and P2 were 13.4 and 12.6, respectively, 2–4 flowers less then that of the sphagnum moss treatment