Metabolism of raffinose in cotton seeds

Shiroya, Tsugio

doi:10.1016/s0031-9422(00)88014-0

Cited by 43 publications

(32 citation statements)

References 28 publications

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“…It has been found that a-galactosidase activity was detectable in dry seeds of cotton (16). Invertase activity is also present in dry seeds, but its activity is at least 5 to 10 times less than that 'Research supported in part by the International Board for Plant Genetic Resources and in part by the Institute for International Education.…”

Section: Methodsmentioning

confidence: 99%

Changes in Soluble Carbohydrates during Seed Storage

Bernal-Lugo¹,

Leopold²

1992

Plant Physiol.

119

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The soluble sugars present in the maize (Zea mays L.) embryo may serve as important components of protection or may contnbute to the deteriorative changes occurring during seed storage. Examination of the changes in sugars during accelerated aging of maize seeds indicates that the decline in vigor is associated with a marked decline in monosaccharides and in raffinose. Sucrose content remains relatively stable. The depletion of raffinose may have special relevance to the decline in seed vigor.shown by a-galactosidase. These facts reinforce the expectation that changes in sugars may occur during seed storage.We have carried out experiments on the sugar contents of maize seeds as a function of accelerated aging, with the intent to examine the possible relation of carbohydrate changes to the deterioration of vigor, and then to the loss of germinability. MATERIALS AND METHODSThe decline of seed quality during storage is expressed first as a decrease in the growth rate of the germinating axis (vigor) and subsequently as a loss of actual germinability. Changes in the soluble carbohydrate contents could contribute to both the declines of vigor and of germinability of the seeds. It is known that soluble carbohydrates generally decline with seed aging (15), and this decline might result in limited availability of respiratory substrates for germination (9). Another possibility is that depletions of disaccharides may lessen the protective effects of sugars on structural integrity of membranes (7) or may limit the ability of the seeds to maintain the vitrified state, a noncrystalline liquid state of high viscosity (3,20). Finally, the presence of reducing sugars may lead to deterioration of protein components through Amadori and Maillard reactions. These are nonenzymatic carbonyl-amine reactions that take place preferentially in dry systems (11). They may contribute to seed deterioration (19).In quiescent seeds, the main soluble embryonic carbohydrate reserves are sucrose, usually associated with lesser amounts of the oligosaccharides, raffinose, stachyose, and/or verbascose (1). Sucrose is exceptionally effective in protecting membrane integrity in dry systems (6), as well as being one of the best vitrifying sugars (12). Raffinose is known to enhance the protective effects of sucrose by limiting crystalization (5).Interconversion of sugars may occur in dry seeds. It has been found that a-galactosidase activity was detectable in dry seeds of cotton (16). Invertase activity is also present in dry seeds, but its activity is at least 5 to 10 times less than that 'Research supported in part by the International Board for Plant Genetic Resources and in part by the Institute for International Education. Plant MaterialMaize seeds (Zea mays L.) NYCO 11 3XNYPA33 (C2) were obtained from the New York Seed Improvement Cooperative, Ithaca, NY. Before storage, the seeds were surface-sterilized with 3.5% sodium hypochlorite twice, for 3 min, and each time, they were rinsed with sterilized deionized water and blotted dry. All manip...

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Section: Methodsmentioning

confidence: 99%

Changes in Soluble Carbohydrates during Seed Storage

Bernal-Lugo¹,

Leopold²

1992

Plant Physiol.

119

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“…Germination of several species is accompanied by a decrease in raffinose content (19,25,26). One of the first changes in enzyme activity during imbibition is an increase in galactosidase activity (12,25).…”

Section: Metabolism Of Seeds During Water Stressmentioning

confidence: 99%

“…One of the first changes in enzyme activity during imbibition is an increase in galactosidase activity (12,25). Hydrolysis of the trisaccharide raffinose probably provides galactose required for cell wall and cell membrane synthesis and sucrose which could be utilized as respiratory substrate (4,17).…”

Section: Metabolism Of Seeds During Water Stressmentioning

confidence: 99%

Effect of Water Stress on the Carbohydrate Metabolism of Citrullus lanatus Seeds during Germination

Botha

Small²

1985

Plant Physiol.

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Gluconeogenesis in Citrullus lanatus seeds is a post germinative event. Increases in isocitrate lyase activity and incorporation of radioactivity from 12-'4Clacetate into sugars occur only after radicle emergence. During germination, the seeds appear to rely on carbohydrate as the respiratory substrate. At this time, glycolysis, the pentose phosphate pathway, and the tricarbocyclic acid cycle seem to be functional. Utilization of raffinose during germination appears to be important.Water stress, which completely inhibits germination, has a marked effect on carbohydrate metabolism. The rate of 'C02 release from 12-14Cjacetate, 1l-14Cglucose, and 16-'4Clucose is lower in the stressed seeds than the control seeds during the respiratory lag phase. However, in the stressed seeds neither glycolysis, the pentose phosphate pathway, nor the tricarboxylic acid cycle is completely inhibited. In contrast to the control seeds in which raffnose content sharply declines after 12 h of incubation, raffmose content in the stressed seeds remains fairly constant.The respiratory lag phase of the control seeds coincides with a lower reducing substance content, glucose content, and fructose content than in the stressed seeds during the corresponding incubation period.Germination of Citrullus lanatus seeds can be completely inhibited by moderate water stress (6). We (7) have previously shown that such stress has a marked effect on the pattern of respiration and on the development of cyanide-sensitive respiratory component in these seeds. The RQ values of the seeds during germination were greater than one. This suggests that lipid was unlikely to be the major respiratory substrate. In contrast, water-stressed seeds exhibited much lower RQ values.Previous work on the metabolism of lipid-rich seeds has generally not distinguished between germination and early seedling establishment (9,14,21,23,27). Germination is the series of steps normally occurring prior to the emergence of the radicle from the seed coat (16,23). The little that is known suggests that in several species gluconeogenesis is a postgerminative event (1,10,17,27). In Cucurbita pepo (a species closely related to C. lanatus), gluconeogenesis is limited for the first 2 d (27). During this time, glycolysis and the PP pathway2 are thought to predominate (27,28). However, the available data are limited to measurements made at 0 and 48 h, by which time germination is complete. The data provide little information on changes in metabolism during germination. To investigate the effects of

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“…Hattori and Shiroya (1951)^ studying germination in the Japanese black pine, reported that the concentration of raffinose decreased to zero by the time the radicle protruded the seed coat. Shiroya (1963) observed a rapid decline in the concentration of raffinose in the germinating cotton seed and an accompanying increase in the amounts of sucrose and free hexoses. In non-germinable seeds that were allowed to imbibe stachyose, raffinose and sucrose levels remained unchanged and there was no increase in the level of free hexoses.…”

Section: Raffinose and Stachyosementioning

confidence: 92%

“…Stachyose and raffinose decrease rapidly and disappear altogether during germination (Âbrahamsen and Sudia, 1966;Hattori and Shiroya, 1951;Pazur et al, 1962;Sasaki, 1933;and Shiroya, 1963). Hattori and Shiroya (1951)^ studying germination in the Japanese black pine, reported that the concentration of raffinose decreased to zero by the time the radicle protruded the seed coat.…”

Section: Raffinose and Stachyosementioning

confidence: 99%

Dry matter changes and carbohydrate metabolism of germinating soybeans

Wahab

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Metabolism of raffinose in cotton seeds

Cited by 43 publications

References 28 publications

Changes in Soluble Carbohydrates during Seed Storage

Changes in Soluble Carbohydrates during Seed Storage

Effect of Water Stress on the Carbohydrate Metabolism of Citrullus lanatus Seeds during Germination

Dry matter changes and carbohydrate metabolism of germinating soybeans

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