溫度對東方梨花芽分化及休眠之影響

Abstract

種植於低海拔地區之梨高溫期過長，易造成花芽敗育，且需克服休眠解除之問題，因此利用修剪及溫度試驗探討解決之道。試驗一是利用高接後新興梨(‘Shinko’ Pyrus pyrifolia)新生的枝條，於2015年秋季(8-10月)修剪，並分別施予4%(稀釋25倍)與2%(稀釋50倍)氰滿素(商品名：春雷，含49%氰胺)，使修剪後之腋芽能萌發，觀察萌發之新梢營養生長、花芽分化、休眠狀態等。處理後，以8月修剪後催芽有較佳萌芽率，達75.9±9.7%，處理時間越晚萌芽率越低。在8-10月處理後新梢可花芽分化，但是枝條快速停止生長，枝條最長者為8月處理，枝條長度平均8.9±1.3公分左右，長度不足以作為隔年梨穗之使用。由氣象紀錄資料可知2015年卓蘭地區秋季仍處在高溫期，推測可能為枝條快速停止生長之誘導因子。試驗二為探討溫度對梨休眠之影響。鳥梨(bird pear P. lindleyi)、橫山梨(‘Heng-Shan’ P. pyrifolia)與新興梨(‘Shinko’ P. pyrifolia)盆栽於2015年3月6日起分別置於為日夜溫30/25℃、25/20℃、20/15℃、15/13℃之環境中，光週為自然日長，觀察新生枝條長度、生長停止時間、花芽形成、休眠狀態。鳥梨於30/25℃、25/20℃環境中60-75天後停止營養生長；20/15℃處理者於處理120天後生長停止，15/13℃處理者至180天調查結束時枝條仍持續生長。橫山梨植株於30/25℃、25/20℃環境中，30-60天後停止營養生長，兩處理植株在生長停止後形成頂芽；20/15℃處理者於處理120天後生長停止並形成頂芽，15/13℃處理者至180天仍顯示持續生長，無頂芽出現。新興梨在所有溫度處理下，於45-60天後枝條生長皆停止。受試3種梨皆於30/25℃環境中具有花芽形成能力。處理180天後(9月)修剪，受試3種梨在各溫度中皆能重新抽梢，芽體似仍處在相對休眠與生理休眠之間。以卓蘭田間6-9月枝條單芽扦插，其萌芽率最高為7月60.4±5.40%，9月後萌芽率大幅下降，降至39.2±8.90%。且枝條內80%乙醇可溶性醣於9月亦有下降情形，而澱粉於9月後開始大量增加，推斷卓蘭低海拔地區於9月後已進入生理休眠。

The long high temperature period makes flower bud abortion. In this study, pruning and 49% cynamide applcaition were used to let new lateral shoot growth in autumn (August to October) and the shoot length, flower formation, and dormancy were investigated in ‘Shinko’ (Pyrus pyrifolia) in Zhou-Lan. The highest percentage of bud break occurred in August, and it decreased in October as the dormancy development. Flower buds could be found during August to October, but the new shoot length was only 10 cm, and the growth ceased after a short time. These kind of shoots are not good enough to be the pear scion next year. Temperature is the key point to bud dormancy. Three Asian pear, bird pear (P. lindleyi), ‘Heng-Shan’ (P. pyrifolia), and ‘Shinko’ (P. pyrifolia) were put into 15/13℃, 25/20℃, 25/20℃, and 30/25℃, respectively, for 180 days. The vegetative growth of bird pear in 30/25℃, 25/20℃ ceased after 60-75 days. The shoots growth in 20/15℃ stopped after 120 days. However, the vegetative growth last for 180 days in 15/13℃. The vegetative growth of ‘Heng-Shan’ in 30/25℃ and 25/20℃ ceased after 45-60 days. The shoots growth in 20/15℃ stopped after 120 days. However, the vegetative growth also last for 180 days in 15/13℃. The vegetative growth of ‘Shinko’ stopped after 45-60 days in all temperature treatments. The floral formation could be investigated in all 3 varieties in 30/25℃. Three shoots were cut per month after July (after 120-day investigation) in every variety in all treatment. The percentage of bud break were above 33% during July to September in three varieties. It suggests the dormancy stage may be between paradormancy and endodormancy stage in September. However, comparing the bud break ratio of the shoots from Zhou-Lan dereased from 60% to 38% during July to September. Analyzing the carbohydrates and nitrogen contents in the shoots from Zhou-Lan during July to November. The total soluble solid decreased and the starch increased to the highest level after September. It suggests the dormancy stage would be into endodormancy in September.