光週、溫度及化學疏除藥劑對麗格秋海棠盆花生產的影響

Abstract

麗格秋海棠是台灣秋冬季盆花市場中熱門花卉之一，台灣地區主要於夏末秋初開始生產，秋冬季販售。本研究首先探討電照方式對麗格秋海棠花期之影響；其次探討台灣地區現行麗格秋海棠品種的扦插繁殖及生長適溫；最後探討化學疏除藥劑ethephon及NAA對延後花期的影響及運用在花期調節上的可行性。 電照處理方面，麗格秋海棠‘Netja Dark’以鎢絲燈電照處理，延長日長至12、14、16小時，或於暗期中央電照2或4小時，或在暗期兩端電照4小時。延長日長至14小時，總葉片數從15.7片增加到19.4片；側枝葉片數自5.6片增加到9.1片；側枝數及乾重亦隨之增加。延長日長至12、16小時效果與14小時相似，均促進營養生長。於暗期中央電照2或4小時，其總葉片數、側枝葉片數、側枝數和乾重均增加，與延長日長相似。所有暗中斷處理組之株高均明顯較矮。開花方面，所有延長日長處理均無法有效延後開花，到花日數與對照組相近。暗中斷處理均造成開花延後，暗期中央電照4小時處理，花下節數自5.4個增加到5.9個；在暗期中央或兩端電照4小時也均造成始花期延後，到花日數自31天增加到65天。 溫度試驗方面，麗格秋海棠‘Netja Dark’插穗分別在日夜溫30/25、25/20、20/15及15/13℃四個溫度下扦插繁殖。以30/25℃處理組在所有參試植株中表現最好，根系發育完整、根數多、根長長；25/20℃處理者之表現與30/25℃組相近，發根亦良好；然20/15及15/13℃處理組之植株根部發育明顯較差。’Netja Dark’栽培於30/25℃自然光照環境，小苗發育到成株開花速度最快，到花日數43.2天；25/20℃需50.7天次之；20/15及15/13℃到花延遲，分別需要77.3及89.3天，且植株開花不整齊。花朵數、花瓣數及總葉片數隨溫度下降而減少，又以20/15及15/13℃最為明顯。30/25℃組之到花快速且總葉片數、花朵數和花瓣數均較多，但花徑明顯較其他溫度縮小10 mm。‘Netja Dark’小苗栽培於30/25及28/22℃之生長箱中，始花及盛花時間無明顯差異，於28/22℃者株高、花苞數、花朵數、乾、鮮重及節位大於3節以上的側枝數表現均較佳，盆型也較飽滿。28/22℃處理組之觀賞品質良好且後續維持情況亦較佳，達等級4或5的植株佔70％，30/25℃處理組僅佔30％。‘Barcos’在30/25℃及25/20℃之自然光照環境下表現最好，到花快速、花朵數及總葉片數多。 藥劑試驗方面，麗格秋海棠‘Clara’具可見花苞之成株噴施ethephon一週後，明顯造成最大花苞直徑小於0.5公分及大於1公分兩生育階段植株可見花苞掉落。且經ethephon 400、800 mg•L-1處理其盛花時間較對照組延遲18-23天，效果最佳；1,600、3,200 mg•L-1則觀察到藥害，造成花朵持續脫落而無法達到盛花狀態。Ethephon處理後，節間數、葉片數、花梗數等較對照組多，且節間較短、葉面積較小、花梗較細，但不影響盆花觀賞品質。噴施NAA 10及20 mg•L-1未造成可見花苞脫落，且僅有NAA 10 mg•L-1能使花苞直徑小於0.5公分之植株盛花延遲9天。麗格秋海棠‘Natja Dark’已具花苞之小苗，經單次施用ethephon 400、800 、1,200、1,600 mg•L-1及施以兩次 ethephon 400、800、1,200 mg•L-1處理，均無法造成一致性的疏花，雖均能延後開花但後續開花不整齊。其中單次施用ethephon 400、800 mg•L-1效果最好，雖未能造成一致性的疏花，但花期略為延後且後續開花率達100％，對株高及花朵數的影響也較小。但欲應用ethephon在麗格秋海棠‘Natja Dark’已具花苞之小苗疏花上，仍有待進一步探討。

Begonia × hiemalis Fotsch is one of the popular flowering potted plants in Taiwan during fall and winter, the production generally beginning in late summer and early fall, and sales during fall and winter. One of the aims of this study is investigate the application of lamp for day-extension lighting or night interruption (NI), to create a long day environment, in order to inhibit reproductive growth. Another aim is investigate the opportunity temperature of Begonia × hiemalis Fotsch cultivars in Taiwan and the effect of temperature on growth. This study also investigate the effect of plant growth regulators (PGRs)— ethephon and NAA on growth and flowering of Begonia × hiemalis Fotsch. To evaluate the practicability of using PGRs for flowering control, and try to solve the problem of flowering plantlets. For lighting treatment, plants of ‘Netja Dark’ were treated by tungsten lamp to investigate the effect of lighting treatment on flowering and growth. Treatments included day-extension lighting to 12-, 14-, and 16-h daylength; 2- or 4- h lighting in the middle of night; and 4-h lighting in the mid or in the terminal of night. Of total leaves number was significantly increase from 15.7 up to 19.4, by day-extension lighting treatment to 14-h daylength, and leaves no. of lateral shoots was also up to 9.1 from 5.6. Number of lateral shoots and dry weight were increase, too. Results of day-extension lighting to 12-h and 16-h were similar to 14-h daylength, which also enhance vegetative growth. 2- or 4-h lighting in the middle of night increased no. of total leaves, lateral shoot leaves, lateral shoots, and dry weight of plants, as well as day-extension lighting. Day-extension treatments couldn’t inhibit flowering efficiently; days to flowering were same with the untreated control. Plants treated by NI, would be inhibited significantly in plant height, and delay in flowering. Numbers of node counted at first flower were increased by 4-h lighting in the middle of night. 4-h lighting in the middle and in the terminal of night, both decrease the days to first flower, from 65 days to 31 days. For temperature experiences, roots of ‘Netja Dark’ cuttings development completely, and had most root no. and longest roots under 30/25℃. Under 25/20℃ was similar to 30/25℃, however, cuttings grew weakly and slowly at 20/15℃and 15/13℃. Plantlets of ’Netja Dark’ grew fast at 30/25℃, it coasted only 43.2 days to first flower; the second is 30/25℃ to 50.7 days; significantly laggard at 20/15 and 15/13℃ to 77.3 and 89.3 days. Besides, plants flowering at 30/25 and25/20℃ were identical, but not identical at 20/15 and 15/13℃. Nnmbers of flower, petal and total leaves were decreased with the drop of temperature, especially in 20/15℃and 15/13℃. They had more flowers, leaves, and decreased days to flowering, but flower diameter reduced about 10 mm at 30/25℃. In the growth chamber, plantlets of ‘Netja Dark’ grew better at 28/22℃ than 30/25℃ on plant height, no. of flowers and flower buds, total fresh and dry weight, and no. of later shoots (>3 nodes). The quality and maintainability were significant better at 28/22℃. Plantlets of ‘Barcos’ grew fast to flowering at 30/25℃ and 25/20℃. For plant growth regulators experiences, plant of ‘Clara’ treated with ethephon 400、800、1600 and 3200 mg•L-1 lead to flower abscission one week after treatments. Ethephon sprayed on all plants which flower bud small than 1.5 cm, 400 and 800 mg•L-1 let the days to first flower increase about 18 to 23 days, effectively delay flowering. Treatment of ethephon 1600 and 3200 mg•L-1 made continuous flower abscission. After ethephon treatments, number of nodes, leaves and inflorescence of plants were increased. Although internodes got shorter, leaf area became smaller, and inflorescences looked thinner, but didn’t affect plant quality. Treated with NAA didn’t make flower abscission, but delay flowering on plants which biggest flower buds less than 0.5 cm for 9 days at NAA 10 mg•L-1. Flowering plantlets of ‘Netja Dark’ were sprayed ethephon 400、800、1200、1600 mg•L-1once, or twice of ethephon 400、800、1200 mg•L-1. All ethephon treatments did flowering delay but flower abscission and newly flowering not identical. In all treatments, plantlets sprayed with ethephon 400 or 800 mg•L-1 once were best than the others, those treatments could delay flowering slightly and get to 100% flowering percentage on plant height and no. of flowers. Therefore, base on our achievements, it would be more investigated to the application of ethephon on flowering plantlets.