Mobilisation of the raffinose family oligosaccharides and galactomannan in germinating seeds of Sesbania marginata Benth. (Leguminosae-Faboideae)

Buckeridge, Marcos Silveira; Dietrich, Sônia M. C.

doi:10.1016/0168-9452(96)04410-x

Cited by 66 publications

(97 citation statements)

References 22 publications

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“…Indeed, transitory starch has been observed previously in seeds that mobilize galactomannan (Reid, 1971;McCleary, 1983;Buckeridge and Dietrich, 1996), and this has been proposed as an important step in the regulation of carbon flow in leaves (Ludewig et al, 1998). It is thought that transitory starch is synthesized as a response to the production of large amounts of carbon during storage cell wall polysaccharide mobilization .…”

Section: Discussionmentioning

confidence: 90%

The Control of Storage Xyloglucan Mobilization in Cotyledons of Hymenaea courbaril

et al. 2004

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Hymenaea courbaril is a leguminous tree species from the neotropical rain forests. Its cotyledons are largely enriched with a storage cell wall polysaccharide (xyloglucan). Studies of cell wall storage polymers have been focused mostly on the mechanisms of their disassembly, whereas the control of their mobilization and the relationship between their metabolism and seedling development is not well understood. Here, we show that xyloglucan mobilization is strictly controlled by the development of first leaves of the seedling, with the start of its degradation occurring after the beginning of eophyll (first leaves) expansion. During the period of storage mobilization, an increase in the levels of xyloglucan hydrolases, starch, and free sugars were observed in the cotyledons. Xyloglucan mobilization was inhibited by shoot excision, darkness, and by treatment with the auxin-transport inhibitor N-1-naphthylphthalamic acid. Analyses of endogenous indole-3-acetic acid in the cotyledons revealed that its increase in concentration is followed by the rise in xyloglucan hydrolase activities, indicating that auxin is directly related to xyloglucan mobilization. Cotyledons detached during xyloglucan mobilization and treated with 2,4-dichlorophenoxyacetic acid showed a similar mobilization rate as in attached cotyledons. This hormonal control is probably essential for the ecophysiological performance of this species in their natural environment since it is the main factor responsible for promoting synchronism between shoot growth and reserve degradation. This is likely to increase the efficiency of carbon reserves utilization by the growing seedling in the understorey light conditions of the rain forest.

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Section: Discussionmentioning

confidence: 90%

The Control of Storage Xyloglucan Mobilization in Cotyledons of Hymenaea courbaril

et al. 2004

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“…On the other hand, when seedling growth was evaluated by measurement of radicle length, a significant inhibition was observed (figure 1B) even after 96 h. As this is a more accurate form of evaluation of the effect of ABA on early growth than radicle protrusion alone, it can be concluded that ABA has a permanent (rather than retardation only) effect on seedling growth. Morphology of seeds -As a typical legume seed from the subfamily Faboideae, Sesbania virgata possesses an endosperm, which completely surrounds the embryo (figure 2A, see also Buckeridge & Dietrich 1996). Under larger magnification (figure 2B), it can be seen that the seed coat presents a layer of osteosclereids as well as a parenchyma layer.…”

Section: Resultsmentioning

confidence: 98%

“…When constant weight was attained (after approximately 48 h) the dry mass was recorded. As it has been calculated that 50% of dry mass of the endosperm plus seed coat correspond to galactomannan (Buckeridge & Dietrich 1996), the loss of half of the dry mass of endosperm was considered as 100% of degradation. Using the general procedure described above, several parameters were evaluated every 24 h in the following way: (W) seeds maintained in water from 0 to 144 h; (W/A) seeds maintained in water from 0 to17 h and transferred to 10 -4 M ABA until 144 h; (A/W) seeds maintained 10 -4 M ABA from 0 to 17 h and transferred to water until 144 h; (A) seeds maintained in 10 -4 M ABA from 0 to 144 h. Galactomannan extraction -Galactomannan was extracted from powdered endosperm plus seed coat with hot water (80 ºC, 0.1 g.ml -1…”

Section: Methodsmentioning

confidence: 99%

“…These polymers are broken down after germination, producing free galactose and mannose which serve as a source of carbon and energy for the growing seedling (Reid 1971, McCleary & Matheson 1974, Buckeridge & Dietrich 1996. Galactomannan has therefore been considered as a storage polysaccharide (Reid 1985).…”

Section: Introductionmentioning

confidence: 99%

“…Pers. was followed during and after germination, the enzymes α-galactosidase, endo-ß-mannanase and exo-mannanase being the principal enzymes involved (Buckeridge & Dietrich 1996). S. virgata (published by our group under the synonym of Sesbania marginata Benth.)…”

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confidence: 99%

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Effect of abscisic acid on the mobilisation of galactomannan and embryo development of Sesbania virgata (Cav.) Pers. (Leguminosae - Faboideae)

Potomati

Buckeridge

2002

Rev. bras. Bot.

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-(Effect of abscisic acid on the mobilisation of galactomannan and embryo development of Sesbania virgata (Cav.) Pers. (Leguminosae -Faboideae)). Galactomannans (GM) are storage cell wall polysaccharides present in endospermic seeds of legumes. They are thought to be storage polymers, since it has been observed for a few species (among them Sesbania virgata) that they are completely broken down after germination and their products are transferred to the growing embryo. We examined the effect of 10 -4 M abscisic acid (ABA) on the degradation of galactomannan in isolated endosperms and intact seeds of S. virgata. We found that after seed germination the initial embryo growth was retarded. Ultrastructural analysis showed that the embryo is completely surrounded by an endosperm which displays very thick galactomannan-containing cell walls. Although an inhibitory effect has been observed on the increase of fresh mass of the embryo, the effect of ABA on the dry mass was weaker and transitory (from 48 to 96 h). Endosperm dry mass and galactomannan degradation were significantly inhibited and the activity of α-galactosidase was strongly affected. The addition of ABA before and/or after the start of mobilisation in intact seeds or isolated endosperms, showed that whereas addition before mobilisation did not affect dry mass decrease in intact seeds, it was strongly affected in isolated endosperms. On the other hand, whereas it affected embryo fresh mass increase in intact seeds, but not in isolated embryos, no significant effect was observed on dry mass. These results suggest that ABA affects galactomannan degradation and by doing so, prevents water absorption by the embryo, rather than affect its dry mass. As ABA has been detected in the endosperm of seeds of S. virgata, it is proposed that it probably acts as a modulator of galactomannan mobilisation and consequently synchronises it with early growth of the embryo.RESUMO -(Efeito do ácido abscísico sobre a mobilização de galactomanano e desenvolvimento do embrião de Sesbania virgata (Cav.) Pers. (Leguminosae -Faboideae)). As sementes de Sesbania virgata (Leguminosae -Faboideae) acumulam galactomanano no endosperma, o qual é degradado após a germinação e seus produtos de degradação são transferidos para o embrião em crescimento. Neste trabalho verificou-se que o ácido abscísico (ABA 10 -4 M) retarda a germinação de sementes de S. virgata e inibe o crescimento do embrião. Sobre as massas fresca e seca deste, o ABA teve efeito transitório sobre o segundo e efeito drástico sobre o primeiro, sugerindo que sua ação seja na absorção de água pelo embrião em crescimento. Um efeito parcial do ABA foi verificado sobre a degradação do galactomanano e sobre a atividade de uma das enzimas de degradação, a α-galactosidase. O ABA atuou sobre a mobilização quando aplicado antes ou durante o período experimental e menos quando aplicado depois. O efeitos sobre a massa fresca do embrião foram similares aos observados para o endosperma, porém, não houve efeito sobre a massa seca do...

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Lettuce Seed Germination

Cantliffe

Sung

Nascimento

1999

Horticultural Reviews

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Mobilisation of the raffinose family oligosaccharides and galactomannan in germinating seeds of Sesbania marginata Benth. (Leguminosae-Faboideae)

Cited by 66 publications

References 22 publications

The Control of Storage Xyloglucan Mobilization in Cotyledons of Hymenaea courbaril

The Control of Storage Xyloglucan Mobilization in Cotyledons of Hymenaea courbaril

Effect of abscisic acid on the mobilisation of galactomannan and embryo development of Sesbania virgata (Cav.) Pers. (Leguminosae - Faboideae)

Lettuce Seed Germination

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