Gibberellin-induced dormancy in bulbils of Dioscorea

Okagami, Nobuo; Nagao, Masayuki

doi:10.1007/bf00387694

Cited by 24 publications

(18 citation statements)

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“…In contrast, the most characterized physiological features in Chinese yam are that dormancy of tubers and bulbils is induced by the application of gibberellin (Okagami and Nagao, 1971). It means that high endogenous gibberellin level is necessary for the dormancy of the bulbils of Chinese yam.…”

Section: Discussionmentioning

confidence: 99%

“…By contrast, in some plants gibberellins also induces dormancy. One of the most characteristic physiological features of Chinese yam is that dormancy of tubers and bulbils is induced by application of gibberellin (Okagami and Nagao, 1971). The sprouting of aerial tubers (bulbils) of Begonia evansiana (Nagao and Mitsui, 1959), like that of resting buds of some woody plants (Brian et al, 1959;Weaver, 1959), is delayed by gibberellin treatment, while exogenous gibberellins (GAs) have a dormancy-breaking effect in most plants.…”

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Endogenous Gibberellins in Bulbils of Chinese Yam during Growth and Storage

Kim

Shon

Park

et al. 2005

Plant Production Science

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Endogenous Gibberellins in Bulbils of Chinese Yam during Growth and Storage

Kim

Shon

Park

et al. 2005

Plant Production Science

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“…However, in bulbils of Begonia evansiana (2,(4)(5)(6)(7)9) and also bulbils and subterranean dormant organs of some species in the genus Dioscorea (8,10), dormancy is induced by endogenous and exogenous gibberellin. Sprouting in winter buds of some woody plants is also retarded by applied gibberellin (1,12).…”

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Dormancy in Dioscorea

Okagami

Kawai²

1977

Plant Physiol.

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Effects of Light and gibberellic acid (GA3) application on the germination of Dioscorea tokoro Makino and Dioscorea tenuipes Franch. et Savat. were observed. For complete germination, seeds of both species required prechilling in moist condition before incubation at a higher temperture. Red Ught irradiation during the incubation after the prechilling promoted germination; blue, green, or far red light markedly inhibited the germination of both species.Application of GA3 induced complicated changes in the germination of both species in relation to light quality. In the germination of D. tokoro, GA3 inhibited in the dark and red; however, i promoted germination in blue and far red light. GA3 promoted germination of D. tenuipes in the dark and in blue, green, or far red lght. These phenomena are explainable by assuming two counteractive reactions (germination-promoting and germination-inhibiting) which are both activated by applied GA3.Gibberellin is well known to break dormancy of seeds and buds in many plants (3,11). However, in bulbils of Begonia evansiana (2,(4)(5)(6)(7)9) and also bulbils and subterranean dormant organs of some species in the genus Dioscorea (8, 10), dormancy is induced by endogenous and exogenous gibberellin. Sprouting in winter buds of some woody plants is also retarded by applied gibberellin (1, 12). In seeds, however, no information about the germination-inhibiting effect of gibberellin seems to have been published.We have studied comparative physiology in dormancy of seeds and buds of many species of the genus Dioscorea, perennial monocotyledonous herbaceous plants, which range from the tropics to the cold temperate zones. In the present paper, we tested light and temperature effect on germination and GA3-induced germination inhibition in seeds of Dioscorea tokoro and Prefecture) of Japan, dried at room temperature, and then stored in a desiccator containing silica gel until used. In germination experiments, 40 to 70 seeds were placed in a 9-cm Petri dish on a thin layer of absorbent cotton moistened with distilled H20 or aqueous solutions of GA3 (gift from Kyowa Fermentation Industries, Tokyo) and allowed to stand under various light conditions at 25 or 26 C in D. tokoro and 20 C in D. tenuipes. In some experiments, prior to incubation at the above conditions, the seeds were placed under 5 C in the dark in a Petri dish on a thin layer of absorbent cotton moistened with distilled H20 (prechilling).White light of 1,500 lux was obtained from real daylight (40-D-SDL, Toshiba, Tokyo) fluorescent lamps. Blue, green, and red light were obtained by filtering the radiations from colored fluorescent lamps (FL-20BF, FL-20GF, and FL-20RF, respectively, Mitsubishi, Tokyo) through a 1-mm thickness of blue, green, and red vinyl resin plates, respectively. For far red irradiation, light from medical IR incandescent lamps (Toshiba) was filtered through 10-cm of distilled H20 and a 1-mm thickness of red and blue vinyl resin plates. Approximate wavelength of peak and half-bandwidth of colored light...

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Section: Introductionmentioning

confidence: 99%

“…(our unpublished data). Therefore, it is most likely that endogenous GAs are involved in induction and maintenance of dormancy of seeds (10), bulbils (11,12), and subterranean tubers (12,13) in the genus Dioscorea.Investigation of the dynamics of endogenous GAs in dormant organs is important for understanding the roles of GAs in both dormancy inducing or maintaining and dormancy breaking. However, there has been no literature concerning GA dynamics in dormant organs whose dormancy was induced either naturally, presumably by endogenous GAs, or by GA3 application.…”

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Identification of Endogenous Gibberellins in Dormant Bulbils of Chinese Yam, Dioscorea opposita

Tanno¹,

Yokota²,

Abe³

et al. 1992

Plant Physiol.

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It is known that dormancy of the genus Dioscorea is induced by application of gibberellin (GA) A3. To understand the role of GAs in dormancy induction, endogenous GAs have been identified by Kovats retention indices and full mass spectra from capillary gas chromatography-mass spectrometry analysis of purified extract from dormant bulbils of Dioscorea opposita Thunb. These include GA4, GA9, GA12, GA19, GA20, GA24, GA36, and GA53; their presence suggests the occurrence of two biosynthetic pathways in D. opposita bulbils, the early 13-hydroxylation pathway and the non-13-hydroxylation pathway.It is well known that dormancy of many plant species (15) can be broken by application of GAs'. Endogenous GAs are believed to be a group of plant hormones that break dormancy and initiate germination and sprouting. In contrast, application of GA3 strengthens or deepens the dormancy of seeds or buds of several species (3-5, 8, 10-14, 17). Among these species, promotion of sprouting of half-dormant bulbils and subterranean tubers by inhibitors of GA biosynthesis, such as N-dimethylaminosuccinamic acid, 2-chloroethyl-trimethyl ammonium chloride, and AMO 1618 was observed in some species in the genus Dioscorea (11,12). This is also the effect of uniconazole, a triazole-type growth retardant, on bulbils of Dioscorea spp. (our unpublished data). Therefore, it is most likely that endogenous GAs are involved in induction and maintenance of dormancy of seeds (10), bulbils (11,12), and subterranean tubers (12,13) in the genus Dioscorea.Investigation of the dynamics of endogenous GAs in dormant organs is important for understanding the roles of GAs in both dormancy inducing or maintaining and dormancy breaking. However, there has been no literature concerning GA dynamics in dormant organs whose dormancy was induced either naturally, presumably by endogenous GAs, or by GA3 application. To get information necessary for understanding natural or GA-induced dormancy, we analyzed endogenous GAs in dormant bulbils of D. opposita and identified several GAs. MATERIALS AND METHODS Extraction and PurificationDormant, mature bulbils of Chinese yam, Dioscorea opposita Thunb., which naturally shed from the cultivated mother plants, were collected in November 1988 and immediately stored at -400C until extracted. As much as 51.2 kg of the bulbils were extracted three times using 200 L of acetone. The acetone was evaporated, and the resultant aqueous phase was adjusted with HCl to pH 2.4 and partitioned five times against 3.6 L of EtOAc, which was concentrated in vacuo to brown gum (26 g). This was dissolved in 500 mL of 0.1 M phosphate buffer (pH 8.0) and then loaded onto a column of polyvinylpolypyrrolidone (500 g; Tokyo Kasei Co., Tokyo, Japan). The buffer eluate (4 L) was acidified and partitioned four times against 2 L of EtOAc. The organic phases were concentrated in vacuo to 5.34 g of brown oil. This oil was dissolved in 40 mL of 70% MeOH (0.1% HOAc), loaded onto a column of ODS (100 g; Senshu Scientific Co., Ltd., Tokyo, Japan), and elu...

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Gibberellin-induced dormancy in bulbils of Dioscorea

Abstract: The sprouting of bulbils of some plants in genus Dioscorea was inhibited by gibberellin (GA) treatment and was promoted by treatment with growth retardants. The results suggest that endogenous GAs in some manner induce and maintain the dormant state in these bulbils.

Cited by 24 publications

References 4 publications

Endogenous Gibberellins in Bulbils of Chinese Yam during Growth and Storage

Endogenous Gibberellins in Bulbils of Chinese Yam during Growth and Storage

Dormancy in Dioscorea

Identification of Endogenous Gibberellins in Dormant Bulbils of Chinese Yam, Dioscorea opposita

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