聚乙二醇對百香果花粉體外發芽之影響

The Effect of Polyethylene Glycol on Pollen in Vitro Germination of Passion Fruits

百香果花粉於體外（in vitro）狀況下很難發芽，使用適合於多數作物花粉之培養基（B&K培養基，1963），發芽率在0至6%之間。若於培養基中添加PEG10%或15%，或再加入低濃度0.1%洋菜，皆可改善發芽率及促進花粉管伸長。紫百香果（Passiflora edulis Sims）花粉，發芽率即可高達68.7%。PEG對其他雜交種或相關種P.alata及P.caerulea，亦顯示促進花粉發芽效果。PEG與蔗糖具協力作用，兩者可能藉由調整膜的滲透性和物理狀態來影響發芽。適合百香果花粉發芽的滲透壓值在-24.39至-12.68 bar之間。然而利用蔗糖與甘露醇（mannitol）或山梨醣醇（sorbitol）之組合來調節滲透壓，無法取代外在滲透壓調節劑PEG促進發芽之效果。PEG人工培養基中再添加柱頭組織，可提高發芽率，紫果種可達89%，但在P.caerulea則呈抑制反應。柱頭組織所含發芽誘導因素，對花粉體外發芽呈抑制或促進效應，仍受不親和性系統之影響。

The pollen germinability of passion fruit and related species lays between 0 to 6% in B & K medium. The addition of polyethylene glycol revealed pronounced effect on pollen germination and tube elongation. As in the case of purple passion fruit, germination was obtained 68.7% supplying 10% PEG、20% sucrose and 0.1% agar. The optimum osmotic pressure for pollen germination was assessed in the range of -24.39 to -12.68 bar, that could be approached by the combination of 10 -20% sucrose and 10-15% PEG, but the effect of PEG osmoticum on external osmotic regulation and membrane permeability could not substituted by mannitol or sorbitol. In the presence of PEG, the germinability was largely improved by stigmatic tissue of purple passion fruit, but inhibited by self stigmatic tissue of P. careulea.