洋桔梗根系生長對植株抽莖之影響

Abstract

本試驗使用洋桔梗’EX-Rosa Green’、’EX-Rosa Pink Flash’和’EX-Rosa Blue’三品種，調查不同季節育苗對地上部與地下部生長生長之影響。秋季育苗之植株在播種後第八週開始抽莖，而夏季育苗植株延至播種後第十八週才開始抽莖。植株抽莖時，根系活性會出現明顯上昇的趨勢。抽莖植株與簇生植株的差異也反應在根系生長上；抽莖苗的根數較簇生苗根數多，且根系活性也較佳，其中以第三、四級根之差異最明顯。 從抽莖株花蕾著生期和開花期取得的單節培殖體，所繁殖之苗株較多，抽苔率也較高，初代培養即可獲得6.9~9.8個芽體。芽體繼代三次後，增殖能力下降，每次繼代僅剩2.8～3.4個芽體再生。移植前發根培養時，NAA 0.1, 0.25及0.5 mg/L能誘導培殖體提早發根，產生的根數多且根系總活性最高，但簇生葉數較多，抽莖較為延遲；IAA 0.5, 1及2 mg/L與IBA 0.5, 1 mg/L能提升培殖體抽莖率，且IAA 0.5, 1 mg/L能維持’EX-Rosa Green’培殖體的抽莖率至繼代第三次，但根系生長較緩慢，根數少，根系總活性較低。’EX-Rosa Green’本身的抽苔率明顯較’EX-Rosa Pink Flash’容易，且抽莖速度也較快， IAA和IBA可使培殖體在瓶內快速抽莖，導致出瓶後植株莖部過細，營養生長不足，因此對’EX-Rosa Green’而言，NAA 0.1, 0.25 mg/L的濃度較能兼顧植株抽莖與出瓶後的生長勢，而’EX-Rosa Pink Flash’則是以IAA和IBA的效果較佳。瓶內抽莖之培殖體出瓶後，’EX-Rosa Green’ 植株最終抽莖率達100%，但’EX-Rosa Pink Flash’植株抽莖率僅88%。 穀胱甘肽(Glutathione；GSH)能促進瓶內簇生化之培殖體抽莖。GSH 10 mg/L，可提升’EX-Rosa Green’繼代三次後之培殖體抽莖率達92%。’EX-Rosa Pink Flash’ 經GSH培養後對抽莖的提升效果較差，雖GSH 50 mg/L效果較佳，但抽莖率僅42.6%。 繼代三次之’EX-Rosa Pink Flash’培殖體經ZnSO4．7H2O 17.2 mg/L處理2週之培殖體，移至含有NAA 0.5 mg/L的MS培養基中，雖發根率無顯著提升， 但ZnSO4．7H2O能有效增加根長和根數，且抽莖率提高至60.6%。

This study investigated in the effect of sowing season on the growth of shoot and root of three Eustoma grandiflorum cultivars, 'EX-Rosa Green', ' EX-Rosa Pink Flash' and ' EX-Rosa Blue' .In autumn, seedlings bolted at the 8th week after sowing, but the bolting in summer delayed until the 18th wk after sowing. The root activity obviously increased when the seedlings start bolted in both seasons. The bolting explants produced more lateral roots than rosetting seedlings produced, in addition the bolting seedlings expressed more active in root activity, especially shown in the 3rd and 4th levels of lateral roots. To propagate Eustoma grandiflorum in vitro, the nodal initial explants obtained at the stage of bolting or flowering proliferated more shoots with higher bolting potency. About 6.9 to 9.8 shoots proliferated from initial cultured, but only 2.8 to 3.4 shoots obtained after 3 times of subcultured. In pretrans planting, NAA (α-naphthalene acetic acid) 0.1, 0.25 or 0.5 mg/L enhanced both root number and activity, but delated bolting and increased the rosetted leaves. IAA (Indole-3-acetic acid) 0.5, 1 or 2 mg/L and IBA (Indole-3-butyric acid) 0.5, 1 mg/L obviously increased the bolting frequency until the 3rd subculture. However, roots grew slowly, poorly, and lower activity in IAA and IBA treatment. The bolting frequency of ' EX- Rosa Green' is more higher than ' EX-Rosa Pink Flash'. Therefore, ' EX-Rosa Green' was optimal with addition of NAA at concentration of 0.1~ 0.5 mg/L, and ' EX-Rosa Pink Flash' was greater in IAA 0.5~2 mg/L or IBA 0.5~1 mg/L. Medium in addition of Glutathione (GSH) induced bolting of in vitro explants, 92% of bolting rate was achieved by adding GSH 10 mg/L in growing media before the thrice multiplied explants of ' EX-Rosa Green' transplanted to rooting media. The highest bolting rate of ' EX-Rosa Pink Flash' were 42.6%, by applying GSH 50 mg/L in media. Root length and root number on thrice multiplied explants of ' EX-Rosa Pink Flash' promoted by NAA 0.5 mg/L treatment and was further promoted by addition of ZnSO4．7H2O 17.2 mg/L, although there was no significant increase in total rooting percentage, the bolting rate was raised by the treatment of ZnSO4．7H2O.