Reversal of ethylene action on cocklebur seed germination in relation to duration of pre‐treatment soaking and temperature

Esashi, Yohji; Saijoh, Yukio; Ishida, Satoko; Oota, Hiroshi; Isizawa, Kimiharu

doi:10.1111/j.1365-3040.1986.tb01574.x

Cited by 7 publications

(1 citation statement)

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“…The upper cocklebur seeds which require red light for germination were capable of germinating in response to far red light or in darkness when subjected to lower temperatures during the presoaking period (11). The germination of this seed responds positively to C2H4 at 23°C, but is strongly inhibited by C2H4 at higher temperatures above 27°C when they were presoaked over several hours at 23°C (14). These facts suggest that the sequence of the CO2-and C2H4-sensitive phases in cocklebur seed germination could be changed by seed conditioning.…”

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Interrelations between Carbon Dioxide and Ethylene on the Stimulation of Cocklebur Seed Germination

Esashi¹,

Kawabe²,

Isuzugawa³

et al. 1988

Plant Physiol.

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Interrelations between CO2 and C2H4 on promotion of seed germination were examined in more detail at 23°C with presoaked upper seeds of Xawthium penlsylvanicum WaUr. The germination-promoting effect of C2H, decreased gradually as its application time was delayed during a soaking period, whereas CO2 was most promotive in application at 5 days of soaking, then its effect declined. CO2 and C2I4 were additive in earlier soaking periods and synergistic in later periods. Such ing upon the preconditioning of the seeds during soaking. The upper cocklebur seeds which require red light for germination were capable of germinating in response to far red light or in darkness when subjected to lower temperatures during the presoaking period (11). The germination of this seed responds positively to C2H4 at 23°C, but is strongly inhibited by C2H4 at higher temperatures above 27°C when they were presoaked over several hours at 23°C (14). These facts suggest that the sequence of the CO2-and C2H4-sensitive phases in cocklebur seed germination could be changed by seed conditioning. Negm et al. (22) have reported that C2H4 requires a minimum endogenous level of CO2 for overcoming the high temperatureinduced secondary dormancy oflettuce seeds. On the other hand, in cocklebur seeds, the respiration activity and C2H4 production decrease with the development of secondary dormancy (10) (21,27). On the other hand, we have reported that CO2 promotes seed germination by dual manners: first by enhancing the production of C2H4 which stimulates seed germination (13,19), and second, by increasing the initial growth of seed tissues by CO2 itself( 1-3). These imply that the difference in phase sequence may come from the different dependency of germinating seed species upon C2H4. Thus, if the germination of some seeds depends greatly upon the endogenous C2H4, the production of which is controlled by CO2, then CO2 would be required before C2H4 in the induction of their germination. Conversely, if the endogenous C2H4 level has been sufficiently attained, the C02-sensitive phase is not required to be preceded by the C2H4-sensitive phase.We have previously described that the responsiveness of seeds to various germination-controlling factors varies widely, depend- MATERIALS AND METHODSPost-ripened upper seeds of cocklebur (Xanthium pennsylvanicum Wallr.) harvested in November 1984 were used throughout this study. Prior to gas treatments, seeds were soaked at 23°C on a water substratum in 15-cm Petri dishes for described periods.Germination Test. Presoaked seeds were placed on 2 discs of filter paper wetted with 4 ml distilled water in 125-ml flasks in which the small glass tubes containing 0.5 ml of 2.5 M NaOH, a CO2 absorbent, and/or 0.2 ml of 0.25 M Hg(C104)2, a C2H4 absorbent, were included. The flasks were sealed with a skirted rubber stopper and the necessary volumes of C2H4 and/or CO2 were injected with a syringe. Needle perforations on the rubber stoppers were covered with a piece of adhesive vinyl tape. Triplicates of 18 to 22 seeds ...

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confidence: 77%