生長調節劑與除花梗對文心蘭生育及開花之影響

Abstract

文心蘭為台灣重要外銷切花之一，然切花生產時具產期集中之問題，本研究首先探討生長調節劑(細胞分裂素(Cytokinins, CTKs)與激勃素(Gibberellin, GAs))及不同季節除花梗對文心蘭Gower Ramsey 生育與開花之影響，以期提早或延後花期，使產期分散。此外，文心蘭盆花具花型、花色豐富之特性，有發展潛力，而觀賞壽命為盆花品質之重要因素，因此本研究亦探討文心蘭盆花(Colmanara Wildcat ‘Golden Fairy’)花朵老化因子及施用生長調節劑延長花朵壽命之效果。 在CTKs 與GAs 影響文心蘭切花生育與開花方面，無論於抽梗前或後處理0.2、0.4 及0.8 mM 6-benzyladeninepurine (BA)皆可增加植株營養芽數。抽梗前處理0.8mM BA 會延後抽梗、第一朵花開及採收時間，且花徑較小；抽梗後處理0.8 mM BA則完全抑制開花。處理0.2 mM 及0.4 mM BA 之採收天數也較對照組晚。其次，於夏季之簡易溫室下進行不同種類的CTKs (0.2、0.4、0.6 mM 的BA 及Kinetin)、GAs(0.3、0.9、2.7 mM 的GA3 及GA4+7)與兩者複合處理，顯示GAs 可促提早抽梗，但對至第一朵花開及採收天數則沒有影響，低濃度GAs (0.3 mM)抽梗率較高，但處理後有老葉黃化現象。CTKs 中僅BA 可提高營養芽萌發率、促進營養芽生長且營養芽數較多，但明顯抑制開花或降低開花率。BA 與GAs 之複合處理可提早花梗抽出及營養芽萌發。 在不同季節除花梗方面，於2008 年3 月、7 月與8 月剪除已伸長至5-13 cm 之花梗，以3 月份除花梗的營養芽數較未除花梗者多，但當代再抽梗率低(0%-16.7%)，子代於10 月左右開花，未能錯開9-11 月的產期。7 月與8 月剪除花梗者，營養芽數與對照組無顯著差異，而當代再抽梗率較3 月處理者高(8.3%-41.7%)。達產調目的之處理有，1) 8 月剪除5 cm 花梗之第二花莖採收日為12 月中旬，較未剪除者延後60 天；2) 7 月剪除5-13 cm 花梗後，抽梗時間較對照組提早98-113 天，採收時間為隔年3 月中旬至4 月上旬。分析再抽花梗與否和假球莖大小之相關性，顯示再抽花梗之植株其假球莖較未再抽花梗者瘦且薄。 在延長文心蘭盆花(Colm. Wildcat ‘Golden Fairy’)花朵壽命方面，花朵於老化過程中乙稀釋放量極低(＜0.003 nL·g-1FW·h-1)，且處理0.8 μL·L-1 1-MCP 6 小時或1.5mM STS 之乙烯作用抑制劑無法延長花朵壽命，顯示自然老化過程中，乙烯非主要影響因子，但如外施10 ppm 低濃度Ethephon 仍會降低花序壽命，且主要影響完全展開之小花。處理25、50、100 μM Fluridone (ABA 抑制劑)可有效延緩花朵老化，顯示ABA 可能為影響Colm. Wildcat ‘Golden Fairy’花朵壽命之重要因子，然而於綠色花苞期處理Fluridone 會降低花瓣黃色度。此外，BA(0.1、0.2、0.4 mM)處理在花序開花階段以較高濃度(0.4 mM)有延長花朵壽命之效果，花苞階段則以0.2 mM 較為有效。至於單朵小花壽命方面，無論於小花完全展開、小花半開或半轉色花苞階段處理，皆以高濃度BA (0.4 mM)延長壽命效果較佳。

The cut flower of Oncidium Gower Ramsey is one of the most important export flowers in Taiwan, but cut flower has problem of intensive production period. First, this study aimed to investigat the effect of plant growth regulators (cytokinins(CTKs)、gibberellins(GAs)) and removing flower stalks in different seasons on growth and flowering of Oncidium Gower Ramsey, in order to hasten or delay flowering period. Potted flower varieties of Oncidium bear attractive flowers with patterns and colors that have potential in the future, and flower longevity is an important factor on potted flower quality. Therefore, the study aimed to investigate the factors contributing to Colmanara Wildcat‘Golden Fairy’flower senescence and extend flower longevity by plant growth regulators. Experiment on effect of plant growth regulators (CTKs and GAs) on growth and flowering of Oncidium showed that treatment with 0.2、0.4 or 0.8 mM BA increased the number of vegetative buds either applied before or after flower stalk emergence. Treatment with 0.8 mM BA before flower stalk emergence, postponed the time of flower stalk emergence, anthesis and harvest and reduced the floret diameter. Treatment with 0.8 mM BA after flower stalk emergence did not flower and treatments with 0.2 and 0.4 mM BA delayed harvest. Meanwhile, treatments with different kind of CTKs (0.2, 0.4, or 0.6 mM BA or Kinetin), GAs (0.3, 0.9 or 2.7 mM GA3 or GA4+7) or their combination during summer under plastic tunnel greenhouses. The results showed that GAs treatments hastened the days to inflorescence emergence, but did not affect the days to anthesis and inflorescence harvest, and the percentage of flower stalk emergence was higher with lower GAs concentration (0.3 mM). However, the older leaves turned chlorosis after GAs treatments. Among CTKs treatments, only BA treatments promoted the percentage of vegetative bud emergence, vegetative bud growth and increased the number of vegetative buds per plant. BA treatments inhibited flowering percentage significantly. BA combinated with GAs treatments promoted inflorescence and vegetative bud emergence. In seasonal flower stalk removing, five- to thirteen-cm flower stalks were removed on March, July and August. March-removing treatments had more vegetative buds than control treatments, but the percentage of current shoot with second inflorescence is low (0%-16.7%). Flowering date of daughter shoots in March-removing treatments was around October, and did not shift the flowering period away from September to November. Flower stalk removing on July and August did not increase the number of vegetative buds, but the percentage of current shoot with secondary inflorescence (8.3%-41.7%) is higher than March-removing treatments. The results showed that two treatments achieved the ambition: 1) Removing 5-cm flower stalk on August, the time of second flower stalk harvest delayed 60 days than control plants, and the period of harvest was during mid December. 2) Removing 5- to 13-cm flower stalk on July, the flower stalk emergence date of daughter shoots was 98-113 days earlier than control plants, and the period of harvest was from mid-March to early-April. Size of pseudobulb with second flower stalk was narrower and thinner than plants without second flower stalk. In extending Colm. Wildcat ‘Golden Fairy’ flower longevity, ethylene production of floret was extreme low during senescence (＜0.003 nL·g-1·h-1). Treatment with 0.8μL·L-1 1-MCP for 6 hr and 1.5 mM STS (ethylene action inhibitor) did not extend flower longevity. The result showed that ethylene is not a major factor during senescence. But it still reduces inflorescence longevity with lower ethephon dosage (10 ppm), especially affects full-opened florets. Treatments with 25, 50, or 100 μM fluridone (abscisic acid synthetic inhibitor) delayed flower senescence, thus showed that abscisic acid other than ethylene may be more important factors on Colm. Wildcat ‘Golden Fairy’ flower longevity. However, the yellow coloration of florets reduced when fluridone was applied at green floral bud stage. In BA treatment (0.1, 0.2, 0.4 mM), flower longevity was improved when higher concentration (0.4 mM) applied at blooming stage was prolonged with 0.2 mM BA at bud stage. Treatment with 0.4 mM BA prolonged individual floret longevity among applied at the stages of full-opened floret, half-opened floret and half-colored floral bud.