為建立試管內抗旱水稻篩選技術,探討以聚乙二醇(polyethylene glycol; PEG)為篩選劑,以癒傷組織、種子與幼苗做為篩選材料之可行性。首先,探討以癒傷組織為篩選材料之篩選技術,取台稉九號水稻種子誘導之癒傷組織培養於含10% PEG與不含PEG之CS-1培養基進行抗旱篩選及植株再生培養。為檢測再生植株之抗旱性,將再生植株分別移入含13% PEG之CS-1培養基培養42天,結果於含10% PEG之CS-1培養基中再生之植株之存活率(約57%)與植株生長狀況均較不含PEG培養基中再生之植株優。探討以種子為篩選材料之篩選技術,將水稻種子分別培養於含0-50% PEG之CS-1培養基培養14天。為確認未發芽種子是否全數死亡,將未發芽之種子(40-50% PEG處理者)分別移入不含PEG之CS-1培養基中14天,結果其發芽率均達97%以上,顯示40-50% PEG可抑制種子發芽,但無法造成種子死亡。探討水稻幼苗為篩選材料之篩選技術,將13天株齡幼苗移入含0-50% PEG之CS-1培養基培養30天,結果於含40-50% PEG之CS-1培養基培養之幼苗均枯死;繼以13天株齡幼苗行切除莖葉後為篩選材料,分別移入含0-50% PEG之CS-1培養基培養7天後,再移植至不含PEG之CS-1培養基培養6天,結果也以40-50% PEG之CS-1培養基培養之幼苗均枯死。顯示,40-50% PEG為水稻幼苗之致死濃度。探討以萌芽期水稻幼苗為篩選材料之篩選技術,將發芽後2天株齡幼苗分別培養於含0-50% PEG之CS-1培養基培養3天後,再移入不含PEG之培養基培養。結果於含50% PEG之CS-1培養基培養之幼苗存活率約48%,顯示50% PEG可致52% 萌芽期幼苗枯死。上述結果顯示,PEG做為抗旱篩選劑對癒傷組織、種子與幼苗之致死濃度差異極大。其中,對癒傷組織致死濃度最低。若考量變異體存在率、篩選效率、經濟性及方便性,則以癒傷組織或萌芽期幼苗為篩選材料較佳。
In order to establish the in vitro selection techniques of draught-resistant variety in rice, we evaluated the feasibilities of PEG offered as the selection agent on callus, seed and seedling. First to evaluate callus as the material for selection. The callus, induced from the seed of Oryza sativa var. japonicaTaiken 9, cultured on CS-1 medium containing 10% PEG or PEG-free to proceed drought-resistant selection and plantlet regeneration culture, then the regenerated plantlets transplanted on CS-1 medium containing 13% PEG for 42 days to detect drought resistibility of the regenerated plants. The result indicated that the regenerated plantlets cultured on CS-1 medium containing 10% PEG were significantly better than cultured on PEG-free in survival rate (about 57%) of regenerated plantlet and growth condition. In the seed selection, the seeds cultured in CS-1 liquid medium containing 0-50% PEG for 14 days, then transplanted the ungerminated seeds (treated with 40-50% PEG) in CS-1 liquid medium without PEG for 14 days to confirm whether all of the ungerminated seeds have died,all seeds showed germination rates above 97%. This result showed that PEG could inhibit the seed germination, but couldn’t cause death of the seed. In the seedling selection, 13-day-old seedlings were transplanted in CS-1 liquid medium containing 0-50% PEG for 30 days, all the seedlings cultured in CS-1 medium containing 40-50 PEG were wilted. Further, when 13-day-old seedlings, cut out the shoots as the materials for selection, transplanted on CS-1 medium containing 0-50% PEG for 7 days and transplanted on PEG-free of CS-1 medium for 6 days. All the seedlings wilted while cultured in CS-1 medium containing 40-50 PEG, that is, 40-50% PEG was the lethal dose in rice seedling. The seedling in embryonic stage as the material for selection, 2-day-old seedlings cultured in CS-1 medium containing 0-50% PEG for 3 days and transplanted in PEG-free of CS-1 medium. The survival rate of seedlings was 48% while cultured in CS-1 medium containing 50% PEG. The result indicated that 50% PEG could cause 52% germinated seedling withered. Summarize the above results, it indicated that there were great differences of lethal dose on of callus, seed, and seedling using PEG as the selection agent for drought-resistance. The callus was the lowest in lethal dose. However, while consider the incident rate of variant, selection efficiency, economy and convenience, callus or seedlings in embryonic stage were better materials for selection.