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Possible involvement of volatile compounds in the after‐ripening of cocklebur seeds
Author(s) -
Esashi Yohji,
Zhang Ming,
Segawa Kazuya,
Furihata Taiei,
Nakaya Minoru,
Maeda Yutaka
Publication year - 1994
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1994.tb08817.x
Subject(s) - xanthium , ripening , dormancy , acetaldehyde , chemistry , germination , alcohol dehydrogenase , ethanol , botany , horticulture , biology , food science , biochemistry
The mechanism of emergence from primary dormancy, the process of after‐ripening, in cocklebur (Xanthium pennsylvanicum) seeds was examined in relation to the involvement of volatile compounds and to the relative humidity (RH) in which the seeds were stored. The after‐ripening of these seeds proceeds only at water contents between 7 and 14% which are conditioned under RHs of 33% to 53% and are identified with water‐binding region II. After‐ripening of cocklebur seeds occurred even in water‐binding region I. imposed by 12% RH. when exposed to HCN gas during the storage period. Exposure of dormant seeds to acetaldehyde (ethanal) retarded after‐ripening. even in water‐binding region II. thus decreasing germinability. This decrease of germinability by ethanal was found also in the after‐ripened seeds, suggesting that ethanal accelerates seed deterioration rather than retarding the after‐ripening. The contents of ethanal. ethanal and HCN were high only in the dormant seeds held at 12% RH. Regardless of RH. a possible conversion of ethanal to ethanol. perhaps via alcohol dehydrogenase. was far larger in dormant than in non‐dormant seeds. In contrast, the reverse conversion of ethanol to ethanal was more profound in non‐dormant seeds. Pre‐exposure of both types of seeds to HCN reduced the contents of both ethanal and ethanol at 12% RH. The contents of various adenylales including ATP in seed tissues were higher in dormant seeds stored at 12% RH than in non‐dormant seeds after‐ripened at 44% RH. It is suggested that emergence of cocklebur seeds from primary dormancy by HCN treatment at 12% RH may result from the reduction in the contents of ethanal via an unknown mechanism incurring the consumption of ATP. This implies involvement of volatile compound metabolism at the water‐binding region II in the after‐ripening process of cocklebur seeds.