Control by External and Internal Factors Over the Mobilization of Reserve Carbohydrates in Higher Plants

Halmer, P.; Bewley, J. Derek

doi:10.1007/978-3-642-68275-9_21

Cited by 14 publications

(9 citation statements)

References 165 publications

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“…Alternatively, GA3 may alter the chemical partitioning of carbon in leaves by decreasing the ratio of starch to soluble sugars (3,(6)(7)(8). Such an effect could increase the amount of sucrose available for export, therefore increasing mass flow in the phloem.…”

Section: Resultsmentioning

confidence: 99%

Enhancement of [¹⁴C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid

Aloni

Daie²,

Wyse³

1986

Plant Physiol.

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The effect of gibberellic acid (GA3) on sucrose export from source leaves was studied in broad bean (Viciafaba L.) plants trimmed of all but one source and one sink leaf. GA3 (10 micromolar) applied to the source leaf, enhanced export of ['4qsucrose (generated by '4C02 fixation) to the root and to the sink leaf. Enhanced export was observed with GA treatments as short as 35 minutes. When GA3 was applied 24 hours prior to the '4CO2 pulse, the enhancement of sucrose transport toward the root was abolished but transport toward the upper sink leaf was unchanged. The enhanced sucrose export was not due to increased photosynthetic rate or to changes in the starch/sucrose ratio within the source leaf; rather, GA3 increased the proportion of sucrose exported. After a 10-min exposure to 1'4qGA,, radioactivity was found only in the source leaf. Following a 2 hour exposure to I'4qGA3, radioactivity was distributed along the entire stem and was present in both the roots and sink leaf.Extraction and partitioning of GA metabolites by thin layer chromatography indicated that there was a decline in I'4CjGA3 in the lower stem and root, but not in the upper stem. This pattern of metabolism is consistent with the disappearance of the GA3 effect in the lower stem with time after treatment. We conclude that in the short term, GA3 enhances assimilate export from source leaves by increasing phloem loading. In the long term (24 hours), the effect of GA3 is outside the source leaf. GA3 accumulates in the apical region resulting in enhanced growth and thus greater sink strength. Conversely, GA3 is rapidly metabolized in the lower stem thus attenuating any GA effect. and more direct short term effects on transport and carbon metabolism.Based on the evidence in the literature, it is believed that GA and IAA enhance and ABA inhibits phloem loading of sucrose (4, 5). Gibberellin and kinetin influence assimilate transport at the site of hormone application (11,(13)(14)(15) With the exception of work by Daie et al. (4), most evidence on the hormonal regulation ofphloem loading has been obtained in vitro. In the present study we investigated the effect of GA3 on movement of 14C assimilates from the source leaf to remote sinks (root and young sink leaves) in vivo. The results indicate that a short-term effect ofGA3 may be enhanced phloem loading.The observation is consistent with our combined in vitro and in vivo studies in celery (5), supporting a direct role for GA and IAA in phloem loading. MATERIALS AND METHODSHormones are believed to play an important role in the regulation of assimilate partitioning and translocation in plants (2, 11, 12 and references therein). In the source-path-sink continuum, phloem loading of organic solutes is a crucial step subject to regulation by phytohormones (3,13,16). However, the mechanism by which each hormone influences these processes is not well understood. In general, a distinction must be made between the indirect effect ofhormones through their influence on growth Plant Material. Broad bea...

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Section: Resultsmentioning

confidence: 99%

Enhancement of [¹⁴C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid

Aloni

Daie²,

Wyse³

1986

Plant Physiol.

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“…In general, cold-treatment, energy sources and other essential nutrients are required for growth and development of not only storage organs such as bulbs, tubers and corms, but also their daughter organs such as bulblets and plantlets (Bach 1992, Fernie and Willmitzer 2001, Fosket 1994, Halmer and Bewley 1982, Xu et al 1998. From our results, one characteristic point is why the cold-pretreated bulbs on medium without sucrose are more effective in growth and development of the bulblets as compared with other treatments.…”

Section: Resultsmentioning

confidence: 58%

“…The reports also provided evidence that when the storage organs began to regenerate, they used the reserved starch as an energy source, which had been accumulated during their formation (Fernie and Willmitzer 2001, Jenner 1982, Xu et al 1998. Accordingly, it is thought that the phenomenon on the decrease in the reserve starch is a general pattern in their energy utilization during development of the bulblets (Halmer and Bewley 1982). Other interesting point is that why a rapid transient decrease of starch by temperature pretreatment occurred and why the degree of starch decrease was higher at 20 than at 4 °C ( Fig.…”

Section: Effect Of Storage Temperatures and Sucrose On Change Of Starmentioning

confidence: 93%

“…Consequently, many attempts to improve their multiplication have been made by applying various treatments such as low temperatures, different sucrose concentrations, different plant growth regulators (Bach 1992, Le Nard and De Hertogh 1993, Kim and De Hertogh 1997, Yi et al 2002. Some workers (Halmer and Bewley 1982, Heidema et al 1985, Lian et al 2003, Stimart and Ascher l981, Takayama and Misawa 1980 showed that cold pre-treatment and sucrose concentrations have great influence on the initiation and growth of the bulblets or plantlets from the bulb explants of some bulb ornamental plants such as tulips, Lilium, hyacinth and gladioli. To understand the relation among storage temperature, sucrose and the bulblet development in hyacinth, we have examined some changes in amount of starch stored in the bulb scale segment, and in protein contents and their profiles.…”

Section: Introductionmentioning

confidence: 99%

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Effects of storage temperature and sucrose on bulblet growth, starch and protein contents in in vitro cultures of Hyacinthus orientalis

Chung¹,

Chung²,

Yang³

et al. 2006

Biologia plant.

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The scale segments of the bulblets of Hyacinthus orientalis L. cv. Anna Marie were examined to improve their growth and development with cold-pretreatment and sucrose. The cold-pretreated (4 °C for 4 months) segments showed higher growth and better development of the bulblets on medium without sucrose than ones stored at 20 °C. A rapid decrease in starch content of bulb pieces was found during the first 2 weeks in all cultures and thereafter the content decreased gradually. A scanning electron microscopic observation during the bulblet growth and development showed a gradual decreasing trend of the starch granules from 2 to 16 weeks of the cultures. SDS-PAGE electrophoresis revealed the presence of a characteristic polypeptide of approximately 45 kD, which is assumed to be a major storage protein in the bulblets.

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“…Starch mobilization and the activity of starch hydro-Jyzing enzymes in the cotyledons of germinating pea seeds have been the objective of several studies, and this subject has been reviewed recently (Halmer and Bewley 1982). However, comparatively little attention has been paid to the nature and the fate of the products of starch mobilization.…”

Section: Introductionmentioning

confidence: 99%

Sugar and starch changes in pea cotyledons during germination

Monerri

García-Luis

Guardiola

1986

Physiologia Plantarum

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J. L. 1986. Sugar and starch changes in pea cotyledons during germination. -Physiol. Plant. 67: 49-54.Changes in starch and sugar contents in the cotyledons during germination have been compared in a smooth (cv. Alaska) and a wrinkled (cv. Progress) cultivar of the garden pea (Pisum sativum L.). In both cultivars there was an initial accumulation of sucrose due to the hydrolysis of sucrosyl oligosaccharides, but galactose did not accumulate in the cotyledons. Starch mobilization in the Progress pea was linear with time and started before the rise in a-amylase (EC 3.2.1.1) activity in the cotyledons; sucrose was synthesized in the cotyledons, and their excision from the axis resulted in an additional accumulation of this sugar. In the Alaska pea, the onset of starch hydrolysis coincided with the rise in a-amylase activity; no accumulation of sucrose was found in excised cotyledons, whilst the sucrose content decreased continuously in attached cotyledons. The same sugars were found in the cotyledons of both cultivars, suggesting a common pathway for starch breakdown. Maltose, maltotriose and linear malto-dextrins were not present and only trace amounts of glucose were detected, suggesting a degradation of starch by phosphorylase after an initial attack by a-amylase. Q-Amylase activity in the cotyledons was higher in the presence of the axis, but was influenced by the water content of the cotyledons. Transient changes in a-amylase activity correlated well with changes in the rate of starch hydrolysis, but after 2-3 days starch mobilization was reduced in excised cotyledons probably due to the resynthesis of starch.Additional key words -Alaska pea, a-amylase, Pisum sativum. Progress pea, sucrose, sucrosyl oligosaccharides.

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Control by External and Internal Factors Over the Mobilization of Reserve Carbohydrates in Higher Plants

Cited by 14 publications

References 165 publications

Enhancement of [¹⁴C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid

Enhancement of [¹⁴C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid

Effects of storage temperature and sucrose on bulblet growth, starch and protein contents in in vitro cultures of Hyacinthus orientalis

Sugar and starch changes in pea cotyledons during germination

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Control by External and Internal Factors Over the Mobilization of Reserve Carbohydrates in Higher Plants

Cited by 14 publications

References 165 publications

Enhancement of [14C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid

Enhancement of [14C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid

Effects of storage temperature and sucrose on bulblet growth, starch and protein contents in in vitro cultures of Hyacinthus orientalis

Sugar and starch changes in pea cotyledons during germination

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Enhancement of [¹⁴C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid

Enhancement of [¹⁴C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid