Germination response in wheat grains to dihydroactinidiolide, a germination inhibitor in wheat husks, and related compounds.
On the basis of our recent findings that the germination of intact wheat grains with glumes (husks) belonging to dormant varieties was restrained as compared with that of dehusked grains, we have explored the identities of germination inhibitors in the glumes, resulting in the characterization of dihydroactinidiolide (1) and some aromatic compounds. A related natural product, tetrahydroactinidiolide (2), showed similar activity. The present study has demonstrated that the sensitivity in inhibition response of germination of the grains to 1 and 2 declined during after-ripening, in parallel with changes in germinability; the sprouting of after-ripened seeds on a whole spike was preventable by exogenous application of 2 in laboratory conditions, and germination of after-ripened grains was delayed by more than two weeks by the action of 1 or 2. The term "pseudodormancy" is proposed for the phenomenon of delay of germination caused by the inhibitor. After accumulation of additional evidence on inhibition response of actinidiolide-type natural products, structurally related to inhibitor 1, a mechanism concerning germination inhibition by 1 or 2 is proposed on the basis of the concept of nonbonding interaction with the inhibitors at an active site of an acceptor.
Kato
Tadahiro
T
Department of Chemistry, Faculty of Science, Science University of Tokyo, 1-3 Kagurazaka, Shinjuku ku, Tokyo 162-8601, Japan. tkato1936@cc.e-mansion.com
Imai
Takahito
T
Kashimura
Kaori
K
Saito
Naoko
N
Masaya
Kengo
K
D001572:Benzofurans / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D018525:Germination / Q000187:drug effects*; D012639:Seeds / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development; D014908:Triticum / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development*
D001572:Benzofurans; C010711:dihydroactinidiolide