Metabolism of Germinating Seeds

Mayer, Alfred M.; Poljakoff‐Mayber, A.

doi:10.1016/b978-0-08-028853-6.50012-7

Cited by 20 publications

(10 citation statements)

References 135 publications

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“…It has been reported that an increment in the seed water content results in an increase of hydrolytic enzymatic activity, i.e. amylase, protease, phytase, o~-glucosidase [35]. These enzymes are inactivated at 50 to 70 ~ Therefore, below this range of temperature, during DSC analysis, the hydrolases would be active.…”

Section: Resultsmentioning

confidence: 98%

Cotyledon thermal behavior and pectic solubility as related to cooking quality in common beans

Bernal-Lugo

Parra

Portilla

et al. 1997

Plant Food Hum Nutr

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The characteristic of proteins, starch and pectic substances in cotyledons of two bean cultivars varying in cooking time were determined to investigate their possible contribution to bean cooking quality. Both cultivars showed the same enthalpies of starch gelatinization but different protein denaturation enthalpies. The proportion of hot water soluble pectins was higher in Michigan, the cultivar with the lower cooking time, than in Ojo de Cabra, the cultivar with the higher cooking time. These results were not due to differences in pectin methylation or in the ratio of monovalent to divalent cations in the tissue, suggesting that in fresh beans the beta-elimination reaction is not the sole or predominant route of thermal pectin degradation. Overall, this study indicates that varietal differences in bean cooking quality may be reflections of the rate of pectin loss during soaking/heating and that the thermal properties of starch and protein fractions seem to have a minor contribution. Researchers involved in this study propose that in fresh beans, the thermal pectin loss results from a two step mechanism: pectin enzymic breakdown during the bean soaking followed by thermal solubilization rather than beta-elimination during the bean heating.

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Section: Resultsmentioning

confidence: 98%

Cotyledon thermal behavior and pectic solubility as related to cooking quality in common beans

Bernal-Lugo

Parra

Portilla

et al. 1997

Plant Food Hum Nutr

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“…ASC is not only the substrate of the enzyme, but it also controls the expression of the enzyme (De ). On the contrary, orthodox seeds need neither ASC nor ASC peroxidase, because they are dry with a low oxidative metabolic activity and consequently a poor hydrogen peroxide production (Mayer andPoljakoff-Mayber 1982, Puntarulo et al 1988).…”

Section: Discussionmentioning

confidence: 99%

The ascorbate system in recalcitrant and orthodox seeds

Tommasi

Paciolla

Arrigoni

1999

Physiologia Plantarum

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Recalcitrant seeds of Ginkgo biloba L,, Quercus cer I is L,, Aesculus hippocastanum L, and Cycas revoluta Thunb, are shed bgl the plant at a high moisture content, contain a large amount of ascorbic acid (ASA) and maintain high ascorbate (ASC) peroxidase (EC 1.11.1.11) activity. Three proteins showing ASC peroxidase activity are present in G, biloba seeds. Conversely, dry orthodox seeds (Vicia faba L,, Avena sativa L,, Pinus pinea L.) are completely devoid of ASA and ASC peroxidase. Experimentally induced rapid variations of the mater Iel el in both recalcitrant and orthodox seeds do not affect the ASC peroxidase; slow dehydration affects the ASC peroxidase activity moderately in recalcitrant seeds, but provokes a complete loss of germinability. Another peculiar difference between orthodox and recalcitrant seeds concerns the ascorbate recycling enzymes, ascorbate free radical (AFR) reductase (EC 1.6.5.4) and dehydroascorbate (DHA) reductase (EC 1.8.5.1), The DHA reduction capability is lo in recalcitrant seeds, but is high in the orthodox ones. In contrast, AFR reductase activity is high in recalcitrant seeds and low in the orthodox ones. Data reported here concerning the ASC system appear to contribute to better understanding the recalcitrance. The presence of three different proteins showing ASC peroxidase activity in the archaic seed-bearing plant G. biloba and its involvement in the spermatophyte evolution is discusse

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“…Other mineral elements can also be remobilized from vegetative or seed covering tissues (Garnett and Graham 2005;Gregersen et al 2008;MasclauxDaubresse et al 2010;Naeve and Shibles 2005;Suna-rpi and Anderson 1996;Waters and Sankaran 2011). Likewise, cotyledons and endosperm tissues can be important sources of remobilized minerals for developing seedling growth, such as S (Sunarpi and Anderson 1995), Zn (Sudia and Green 1972), Fe (Ambler and Brown 1974;Tiffin et al 1973), N and P (Bewley and Black 1985;Dalling and Bhalla 1984;Mayer and Poljakoff-Mayber 1982). An increased understanding of genes involved in remobilization from seed reserves or vegetative tissues could lead to strategies to increase internal Fe use efficiency.…”

Section: Introductionmentioning

confidence: 99%