Physiology of Oil Seeds

Ketring, D. L.; Morgan, Page W.

doi:10.1104/pp.45.3.268

Cited by 35 publications

(28 citation statements)

References 25 publications

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“…It remains uncertain whether, as this hypothesis requires, the level of endogenously formed ethylene reaches a sufficient concentration at its site of action within the seeds to have a significant influence on germination. However, this seems probable in view of previous reports which suggest that ethylene is an essential prerequisite of germination in lettuce and other seeds (3,4,(6)(7)(8)11). …”

Section: Discussionmentioning

confidence: 41%

Antagonistic Effects of High and Low Temperature Pretreatments on the Germination and Pregermination Ethylene Synthesis of Lettuce Seeds

Burdett

1972

Plant Physiol.

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Red light-induced germination of Grand Rapids lettuce seeds (Lactuca sativa L.) incubated at 20 C was inhibited if the seeds were first imbibed at 30 C for 36 hours. This effect was counteracted by exogenous ethylene and associated with a reduction in the rate at which the seeds produced ethylene throughout the pregermination period. A chilling treatment reversed the effect of a prior imbibition at 30 C on both germination and ethylene production. The possibility that the pretreatments influence germination through their effects on ethylene production is discussed.Other evidence presented indicates that the inability of seeds to germinate at supraoptimal temperature is not due either to a rapid loss of far red-absorbing phytochrome or to an inadequate capacity for ethylene synthesis. It was also shown that a chilling treatment potentiated germination at high temperature without affecting the ethylene synthetic capacity of the seeds.A number of the effects of temperature on the germination of Grand Rapids lettuce seeds have been attributed to the temperature-sensitivity of Pfr decay (5,9,10,12). Among these is the inhibitory effect of a short imbibition at a temperature which is supraoptimal for germination on the capacity of the seeds to germinate when subsequently incubated at a lower temperature (5, 10). However, other inhibitory effects have been inferred to account for the dormancy of seeds subjected to longer pretreatments at high temperature (5, 10). In the present study it was found that dormancy induced in this way was broken by ethylene. The possibility that this and other effects of temperature on the germination of lettuce seeds are mediated by regulatory effects on endogenous ethylene synthesis was, therefore, examined. MATERIALS AND METHODSSeeds (Lactuca sativa L. cv. Grand Rapids) harvested in 1970 were purchased in December of that year and stored for 10 months in airtight containers at -20 C before use. For the 'The research was supported in part by Canadian National Research Council Grant A2908. experiments described, seeds were selected for freedom from damage and uniformity of color and size.The seed pretreatments referred to below were carried out as follows. Lots of 50 or 135 seeds were spread over 4.25-cm filter circles. The latter were placed on a glass plate covered with two layers of filter paper. In turn, the glass plate rested on 1.5 cm high supports standing in an enameled dish. The filter paper covering the plate was folded down at the edges so that it was in contact with the bottom of the dish. Imbibition of the seeds was started by adding water to the dish which was then covered with another glass plate and incubated in the dark at the temperature, and for the period, required.All the light treatments consisted of a 1-min exposure to a red or far red filtered light source with maximum energy at 660 or 731 nm respectively (half peak height bandwidth 10 nm) and an irradiance of 6 X 10-J cm-2 sec-1.To determine the effects of exogenous ethylene on the germination of pretreated...

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Section: Discussionmentioning

confidence: 41%

Antagonistic Effects of High and Low Temperature Pretreatments on the Germination and Pregermination Ethylene Synthesis of Lettuce Seeds

Burdett

1972

Plant Physiol.

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“…Auxins (3) and gibberellic acid (10,17) are known to stimulate ethylene formation in plant tissues, but in our preliminary observation neither 5 x 1 0' M gibberellic acid nor 1 X 10"-M IAA accelerated germination of aged seeds. In this study, however, the exposure of aged seeds to the gas enhanced their germination and growth.…”

Section: Discussionmentioning

confidence: 82%

“…With (9); it also breaks the dormancy of seed of various species (4,9,10,18,19). Stewart and Freebaim (17) showed that heat-treated lettuce seed which became insensitive to gibberellic acid germinated well subsequent to treatment with exogenous ethylene.…”

Section: Introductionmentioning

confidence: 99%

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Enhancement of Germination Rate of Aged Seeds by Ethylene

Takayanagi¹,

Harrington²

1971

Plant Physiol.

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Naturally and artificially aged seeds of rape, Brassica napus L., produced less ethylene than freshly harvested seed during the early stage of germination. With (9); it also breaks the dormancy of seed of various species (4,9,10,18,19). Stewart and Freebaim (17) showed that heat-treated lettuce seed which became insensitive to gibberellic acid germinated well subsequent to treatment with exogenous ethylene. Ruge (15) showed earlier that ethylene enhanced the percentage germination of aged oat seed. In the present paper, the pattern of ethylene production by rape seedlings in the early stage of germination and the stimulation of the germination of aged seeds by exogenous ethylene were studied. MATERIALS AND METHODSMaterials used in the experiments were the seeds of rape, Brassica napus L., variety Chisaya-natane, harvested in 1965 and seeds were sealed in tin cans and were put with the other seed at 3 C until the experiment was started.A germination test of the seeds was conducted with three replications (100 seeds X 3) on December 10, 1969. The blotter method at 25 C was used. The first count was on the 3rd day, and the final count was on the 7th day. The number of normal seedlings, abnormal seedlings, and slowly germinating seeds was counted.For observing ethylene production by seedlings and effects of exogenous ethylene on aged seeds, all experiments were conducted in Erlenmeyer flasks equipped with rubber serum stoppers. To prevent mold growth, the flasks, stoppers, and seeds were sterilized at the start of the experiment. Flasks containing filter paper or agar media were autoclaved at 15 psi for 20 min. The rubber stoppers were immersed in 95% ethanol and dried under sterile conditions. The seeds were treated with 95% ethanol for 5 sec, rinsed with sterile water, sterilized with 0.1% sodium hypochlorite for 30 min, and washed three times with sterile water. Seedlings were germinated and grown under continuous fluorescent light in a room maintained at 25 C. Samples of ethylene given off from seedlings in a flask were withdrawn with a 1-ml syringe through the rubber stopper. The amount of ethylene was determined by gas chromatography, using an alumina column maintained at 50 C and a flame ionization detector. Each experiment was replicated three times.The first two experiments were conducted to follow the trend of ethylene production during germination. In the first trial, the seeds were maintained in a closed system in 25-ml Erlenmeyer flasks containing two layers of wet filter paper. A 1-ml gas sample was withdrawn daily for 9 days from each flask for ethylene determination. In the second trial, the seeds were transferred aseptically to 125-ml Erlenmeyer flasks containing 25 ml of 1% agar. In contrast to the first trial, a 1-ml gas sample was taken every 6 or 12 hr for ethylene analysis, after which the gaseous content of the flask was flushed with fresh ethylene-free air. This trial was conducted for 120 hr.In the third experiment, ethylene was introduced into the flask containing aged seeds t...

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“…On the other hand, the presence cf high levels of ethylene prevents bud growth; the inhibition of internode elongation and leaf expansion play a primary role. Burg and Burg 4 have shown that nodal regions of pea plants produced more ethylene than internodal ones, and that the inhibition of lateral bud break by apical applica.ion of auxin was due to the increased ethylene production associated with the application of high levels of auxin. The extent to which endogenous ethylene production controls bud dormancy remains to be shown.…”

Section: Bud Dormancymentioning

confidence: 99%

The Role of Ethylene in Plant Growth and Development

Abeles¹

1971

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Physiology of Oil Seeds

Cited by 35 publications

References 25 publications

Antagonistic Effects of High and Low Temperature Pretreatments on the Germination and Pregermination Ethylene Synthesis of Lettuce Seeds

Antagonistic Effects of High and Low Temperature Pretreatments on the Germination and Pregermination Ethylene Synthesis of Lettuce Seeds

Enhancement of Germination Rate of Aged Seeds by Ethylene

The Role of Ethylene in Plant Growth and Development

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