潮汐灌溉下之營養液、介質與遮光對火鶴花'粉冠軍'生長及開花之影響

Abstract

火鶴花 (Anthurium andraeanum Lind.) 為世界重要的花卉作物之一，近二十年來歐美等國已改採養液循環之潮汐灌溉系統栽培盆花，不僅可以省水省肥，亦可避免養液流失而汙染環境。本研究探討潮汐灌溉下之營養液、介質與遮光對火鶴盆花‘粉冠軍’生長及開花之影響，期供業者生產之參考。 以潮汐灌溉或傳統澆灌搭配五種強生氏營養液 (Johnson’s solution) 濃度處理六個月，結果顯示兩種灌溉方式皆以施用25% (營養液EC值為0.5 dS•m-1) 者具較佳之葉片及花朵生長情形，其中潮汐灌溉處理之花朵乾重質量比 (花朵乾重/全株乾重) 較大。施用50%至100% (營養液EC值為1至2 dS•m-1) 營養液使葉片尖端邊緣出現點狀壞疽及佛焰苞耳部褪色，且隨營養液濃度提高情況漸趨嚴重。葉片之氮、磷、鉀、鈣濃度隨施用營養液濃度提高而增加，而葉片鎂濃度隨施用養液濃度提高而下降，施用50%即可使總葉片之巨量元素含量達飽和。施用75% (營養液EC值為1.5 dS•m-1) 或100%處理時，潮汐灌溉栽培之上層介質EC值為3.0 dS•m-1顯著高於傳統澆灌者 (介質EC值為1.5 dS•m-1)，而中下層介質EC值則無顯著差異，均為0.8-1.5 dS•m-1。 以泥炭苔及椰纖混合介質栽種，並比較五種氮濃度處理六個月對火鶴花生長之影響。結果顯示每週肥灌一次時，施用4或8 mM N可使火鶴花‘粉冠軍’生長良好，且兩種混合介質處理之生長差異不顯著。於16 mM N處理，以椰纖混合介質栽種之葉片及花朵乾重顯著低於以泥炭苔混合介質栽種者；以泥炭苔混合介質栽種且施用0和4 mM N之處理介質pH值分別為6.0和5.7，pH值隨施用氮濃度提高而下降；但椰粉混合介質之pH值皆降至3.4-4.6。 以五種NH4＋:NO3－比例 (0:100、25:75、50:50、75:25及100:0) 處理五個月後，調查對火鶴花生長之影響。結果顯示氮型態比例對葉片及花朵生長無顯著影響，但黃斑及壞疽葉片數與佛焰苞耳部褪色及壞疽之花朵數隨施用NH4-N濃度提高而增加。施用NH4＋:NO3－為75:25及100:0之處理，植株淨光合作用速率、氣孔導度及蒸散作用速率皆顯著降低。單獨施用NH4-N處理之葉片磷濃度最高，而鈣濃度最低，錳及鋅濃度隨施用NH4-N濃度提高而增加。隨施用銨態氮比例提高，介質EC值由0.8 dS•m-1增至3.1 dS•m-1，介質pH值則由6.5降至3.3。 以椰纖混合介質栽種火鶴花‘粉冠軍’，以NO3-N較NH4-N處理生長佳。單獨施用NH4-N之處理，每公升介質需添加9 g苦土石灰，以維持介質pH值介於5.2-6.2。添加9 g•L-1之苦土石灰可減緩因施用NH4-N而造成的介質酸化問題使根部生長較佳。 於臺灣北部冬季栽種火鶴花‘粉冠軍’，搭設80%之黑色遮陰網 (76 µmol•m-2•s-1 PPF) 會使新生葉片及花朵數較少，葉柄及花梗徒長，過度遮光使葉片及佛焰苞較細長。隨施用營養液濃度由25%至100%，植株生長情形愈佳。於冬季以50%或60%之遮光程度 (分別為178和129 µmol•m-2•s-1 PPF) 並施用50%之營養液濃度，可使火鶴花‘粉冠軍’生長良好。

Anthurium andraeanum Lind. is one of the most important floricultural crops in the world. European and American countries have used ebb-and-flow (E-F) irrigation system for potted plants production. Recycle nutrition in E-F can reduce water and fertilizer usage and avoid fertilizer leaching and water pollution. Although anthuriums have been produced commercially using E-F, related scientific reports are limited. The objectives of this study were to investigate the nutrient solution, media, and shading on growth and flowering of Anthurium ‘Pink Champion’ under E-F system. Five concentrations of Johnson’s solution were applied under E-F or hand-watering irrigation system. For both irrigation methods, the best leaf and flower growth occurred in plants with 25%. The ratio of flower dry weight to total dry weight was higher in E-F than in hand-watering. Higher nutrient concentrations (50% to 100%) led to salt-injury symptoms, with marginal necrosis of the leaf tip and discolored spathe lobe. The symptoms were expressed more as the nutrition concentration increased. Leaf N, P, K and Ca concentrations increased, leaf Mg decreased, as solution concentration increased. Leaf macro-element contents were saturated in plants with 50% or higher concentrations. When applied with 75% or 100%, E-F had higher electrical conductivity (EC) of the upper portion of the medium than hand-watering. However, the EC of middle and bottom portions did not differ between two irrigation methods. Five nitrogen concentrations were applied to anthurium plants cultivated in peat- or coir-based medium. Maximum growth was obtained in plants grown in peat- or coir-based medium with 4 and 8 mM N. Plant growth did not differ between peat- and coir-based media. Under 16 mM N, leaf and flower dry weight were lower in coir-based medium than in peat-based medium. The medium pH was 6.0 and 5.7 when applying 0 and 4 mM N in peat-based medium, respectively, while pH decreased to 3.4 to 4.6 in coir-based medium. Five NH4＋:NO3－ ratios (0:100, 25:75, 50:50, 75:25, and 100:0) did not significantly affect on leaf and flower growth. However, the numbers of chlorotic spot and/or necrotic leaves, discolored spathes, and necrotic flowers increased as NH4-N ratio increased in the nutrient solution. Applying NH4＋:NO3－=75:25 and 100:0 reduced net photosynthesis rate, stomatal conductance, and transpiration rate. Plants treated with NH4-N alone had the highest leaf phosphorus and the lowest leaf calcium concentrations. The concentrations of manganese and zinc in leaves increased as NH4-N ratio increased. When NH4-N ratio increased, the medium EC increased from 0.8 dS•m-1 to 3.1 dS•m-1, while medium pH decreased from 6.5 to 3.3. In coir-based medium, plants grew better with NO3-N than NH4-N. When applying NH4-N, dolomite (9 g•L-1) should be added to coir-based medium to maintain the medium pH between 5.2 and 6.2 for better root growth. Plants with NH4-N required a supplementary 9 g•L-1 dolomite to coir-based medium to grow equally well with those with NO3-N. Anthurium ‘Pink Champion’ had fewer new-grown leaves and flowers, and slender petioles and peduncles when grown under 80% shade (76 µmol•m-2•s-1 PPF) than 50% or 60% shade (178 and 129 µmol•m-2•s-1 PPF, respectively) in winter. The 80% shading resulted in decreased leaf and spathe width. Plants grew better under 50% to 60% shading and 50% than those under 80% shading with 25% or 100% treatments.