鳳梨植株本身條件與催花處理效果關係之研究

Study on the Relation between the Condition of Pineapple Plant and Its Effect Inducing Flowers

本研究利用生物測定法，測定不同時期，時間或特殊天候下之鳳梨植株生長點及幼葉基部之Auxin含量，並測定晝夜間呼吸作用變化之情形，同時進行電石及NAA處理，以探求鳳梨植株本身之條件與鳳梨催花處理效果之關係。鳳梨莖生長點之IAA含量於下午3時最多，上午9時最少，幼葉基部之IAA含量亦於下午3時最多，但淩晨3時最少，而抑制物質則莖生長點與幼葉基部，均在夜間較晝間為多，尤其淩晨3時最多，莖生長點及幼葉基部Auxin含量均於6~11月間較高，12~5月間較低，其中以8~10月間最高3月最低。施後15~20天時為最高，此後則逐漸降低。晴天時之Auxin含量，其間比夜間為高，陰天則晝夜間之差異甚微，而陰雨天則日變化甚為不規則。鳳梨電石處理之效果，夜間處理者較晝間處理者為佳，尤其淩晨3時處理之效果最佳。在2~5月間NAA處理之效果佳而安定，8~11月間效果差。電石處理後，生長點之生長物質減少，而抑制物質急激增加，由此亦可推知生長物質之減少及抑制物質之增加為誘導鳳梨花芽分化之主要原因之一。葉片夜間呼吸量比晝間大，與電石處理效果有影響。

The purpose of this study was to measure the auxin content on the basal parts of young leaves and the growing point of pineapple plants under the condition of particular weather or different period by using bioassay method and also measure the respiratory changes between day and night time and to find the relation between the condition of pineapple plant and the effect of flower-inducing by treating calcium carbide and NAA as the base of improving flower-inducing method to raise the yield of pineapple. The results were summarized as follows; 1 The IAA content of the growing point of pineapple stem was the highest at 3 am, and the lowest 9 am. The IAA content of basal parts of young leaves was also the highest at 3 am, and the lowest at 3 am. However the inhibitor of stem growing point and basal part of young leaves was more in night than daytime, especially the highest at 3 am. 2 The auxin contents both in the basal parts of young leaves and the growing point of pineapple stems were hi her during the period of June to November, and lower during the period of December to May, especially the highest in August to October and the lowest in March. 3 The auxin content of basal part of young leaves and the growing point of stem would be increased gradually after applying fertilizer on pineapple plants and would reach the highest on 15-20th day after fertilizer application and then decreased radually. 4 The weather conditions would directly affect the auxin content of pineapple plant. Usually the dail changes between day and night time of auxin content were re ualr and higher in daytime than night on fine day little change on cloudy day and irregular on rainyday. 5 The effect of calcium carbide was greater in night time than day time treatment. The treatment at 3 am was the most effective because of found between and larger fruit. However, no significant difference was found between the effect of NAA treatment and time of treatmet. 6 The effect of NAA treatment was good and stable during February to May, however, the effect was poor and unstable during August to November. 7 After calcium carbide treatment the growing substances at the stem growing point of pineapple plant would be decreased and the inhibitor would be rapidly increased. Hence, the decrement of growing substances and increment of inhibitor might be a major reason for inducing pineapple flower differentiation. 8 Based on the result, the auxin contents around the growing point of pineapple plant seemed to be associated with inducing flower differentiation by calcium carbide treatment especially, the content of inhibitor seemed to be more important than IAA content. 9 Although the respiration rates of various parts of pineapple leafblade were different, the respiration rate at night were greater than in daytime. This might be associated with the opening of stomata and the effect of calcium carbide carbide treatment.