肥料配方及固定與分期營養管理對紅花朵麗蝶蘭開花之影響

Effects of Fertilizer Formulae and Invariable and Gradational Nutrition Management on the Flowering of Doritaenopsis I-Hsin Madame

臺灣蘭花生產者，慣用低氮高磷比例肥料（10N-30P2O5-20K2O），調配營養液以管理朵麗蝶蘭之開花生長。據前人報導，鉀充裕情況下，提高養液磷濃度對蝴蝶蘭抽梗及開花並無顯著助益，而適當提高養液氮濃度將有益開花。因此，本研究以不同氮磷比例肥料配方，採固定營養管理（invariable nutrition management）試驗或分期營養管理（gradational nutrition management）試驗，探討不同肥料處理對紅花朵麗蝶蘭花梗誘導及花梗花序發育之影響。結果顯示固定營養管理下，灌溉水及5N-20P2O5-20K2O（代號分別為IR及5-20-20）之處理對植株初期之花梗誘導率最高，而5-20-20處理植株之花梗長度最長。另外，10N-30P2O5-20K2O及20N-20P2O5-20K2O（代號分別為10-30-20及20-20-20）處理植株，花苞開放所需時間顯著長於IR及5-20-20之處理。肥料鉀比例相同，提高氮比例，有利於植株花梗萌發後之生長、提高側生花序發生率、促進晚抽花梗萌發及增加植株總花數。但是，氮比例最高之30N-10P2O5-20K2O（代號為30-10-20）處理，其花朵寬度則減小。適當增加氮至50mg•L^(-1)，雖可提高植株總花朵鮮乾重。但是，再增加氮至100-300mg•L^(-1)，對提高植株總花朵鮮乾重，效果有限。相較於固定營養管理，分期營養管理的給肥模式可促進植株催花前期之抽梗率及花梗生長速率，進而縮短10-30-20及20-20-20兩處理植株花苞開放所需時間。 A compound fertilizer (10N-30P2O5-20K2O) is commonly used by growers to manipulate the flowering of Doritaenopsis. However, previous reports showed that an increase in P application did not stimulate spike induction and flowering of Phalaenopsis when K application was sufficient, whereas an increase in N application promoted flowering. The objectives of this study were to determine the effects of the fertilizer formulae with invariable or gradational nutrition management on the flowering of Dtps. I-Hsin Madame. The irrigation water without fertilizer and 5N-20P2O5-20K2O treatments resulted in the highest emergence rate of earlier spikes in the invariable nutrition management, while the plants with 5-20-20 treatment had the longest earlier spikes. The plants in the 10-30-20 and 20-20-20 treatments took longer to anthesis than those in water only and 5-20-20 treatments. Under the same level of K conditions, higher N increased the emergence and growth of flowering spikes, the lateral inflorescence, and the total flower number. However, the 30-10-20 treatment decreased the flower width. Appropriate supply of N at 50 mg•L^(-1) increased the fresh and dry weights of flowers, but a further increase in N to 100-300 mg•L^(-1) was not effective. As compared with the invariable nutrition management, the plants had higher spike emergence rate and faster growth rate of flowering spikes in the gradational nutrition management, and the plants with 10-20-20 and 20-20-20 treatments had an earlier anthesis.