Effective plant-mutation method using heavy-ion beam, 2

Abstract

It was found that accelerated heavy-ion beams were effective tools for the mutagenesis of plants under a particular condition of the fertilization cycle. The effect of heavy-ion beams on various tissue of tobacco has been examined. The applicability of this new technique for screening the herbicide-resistant mutants was discussed. Anthers from the tobacco flower-buds were cultured in a medium for four to ten days, after that anthers were irradiated by the heavy-ion beams of N-14 or Ne-20 at 135 MeV/u. One month after the irradiation, the number of the pollen germination was counted. Effect of the anther treatment with ion beams on the pollen germination was shown in a figure. It was found that the high-dose irradiation caused a decrease of the germination. The resistance test against a herbicide inhibiting a key enzyme in the chlorophyll biosynthesis at chloroplasts has been carried out. It was proved that the decrease of the chlorophyll contents of the tolerant plant was less than that of the control plant.

加速重イオンビームは特定の発育サイクル条件下における植物の突然変異誘発に対して有効なツールであることが分かった。種々のタバコ組織に及ぼす重イオンビームの効果を調べた。除草剤耐性変種のスクリーニングに対するこの新規手法の適用可能性を論じた。タバコの花の蕾からとった葯を培養基中で4?10日間培養し、その後、135MeV/uのN-14あるいはNe-20の重イオンビームで照射した。照射後1か月における花粉発芽数を計数した。花粉発芽に及ぼすイオンビームによる葯処理の効果を図示した。高線量が発芽の低下を引き起こすことが分かった。葉緑体におけるクロロフィルの生合成の際の重要な酵素を抑制する除草剤に対する耐性試験を行った。耐性植物のクロロフィル含有率低下は対照標準植物のクロロフィル低下よりも少ないことが分かった。