57(P-25) コムギ種子殻の発芽抑制物質の構造と、抑制物質による種子休眠の再現および穂発芽抑制(ポスター発表の部)

概要

論文の詳細を見る
Preharvest sprouting is one of the main problems encountered in cereal grains production, particularly when grain maturation takes place under damp conditions. Although it is known that embryo maturation is regulated and precocious germination is prevented by abscisic acid (ABA) in many species, including wheat, during grain development, involvement of ABA in dormancy after maturation and desiccation of grains is uncertain. Based on our findings that the germinations of intact wheat grains with husks belonging to dormancy varieties are restrained as compared with those of the dehusked grains (Table 1), we have explored the germination inhibitors in the husks, resulting in the characterization of the active compounds summarized in Fig. 1, all of which showed clear inhibition of germination in mature wheat grains at 500ppm in aqueous solution (Table 2). The related compounds, 1-phenylethyl alcohol (1-PEA) 5 and tetrahydroactinidiolide (TAL) 6 were as active as 2-PEA 1 and DAL 4 whereas no noticeable difference in activity was observed among both enantiomers and the dl-form of compounds 4, 5, and 6. In addition, clear synergistic relations (Fig. 2) were disclosed between DAL 4 and 2-PEA 1 and also DAL 4 and MVP 3, suggesting that the characterized active compounds become synergistically operative as sprouting inhibitors. In addition, we demonstrate that germination of grains on a whole spike, corresponding to the pre-harvest sprouting, was prevented in response to the employed aqueous solution of TAL 6/1-PEA 5 in laboratory conditions (photo), presumably due to regeneration of dormancy of dormancy released grains (Fig. 4). It was also revealed that the decrease of susceptibility toward the present active compounds occurred in the dormancy-released grains depending on the storage conditions (Fig. 3). In order to get insight into the structure-activity relation of DAL(TAL), the inhibition activity of related compounds in Fig. 5 were examined. The most interesting feature of the activities is that loliolides 11 and 12 possess almost no activity as shown in Fig. 6. The germination inhibition mechanism was speculated, in which the manifestation of germination inhibition of dormancy-released wheat grains may be caused by taking TAL (DAL) into an acceptor existing at the growing point of the embryo of the grain. The level of germination inhibition is clearly correlated with the concentration of TAL (DAL), suggesting the existence of equilibrium (eq. 1) between associated and dissociated forms among the grains and TAL (DAL) in an aqueous solution. The former causes the inhibition while the germination takes place from the latter, in which the grains exist free from TAL (DAL). The high concentration of TAL (DAL) enriches the associated form in aqueous solution and hence prevents the germination.
2002-09-01

57(P-25) コムギ種子殻の発芽抑制物質の構造と、抑制物質による種子休眠の再現および穂発芽抑制(ポスター発表の部)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク