The breakdown of lipid reserves in the endosperm of germinating castor beans

Marriott, K M; Northcote, D. H.

doi:10.1042/bj1480139

Cited by 36 publications

(26 citation statements)

References 37 publications

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“…The newly synthesized diglycerides contain no ricinoleate (6). However, this activity does not -significantly alter the composition of the storage lipid (11).…”

Section: Discussionmentioning

confidence: 99%

“…After 6 days germination when most of the storage lipid has been degraded (11,13) several new lipid classes become apparent ( Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

“…1) (11,14). Triricinolein (TR3), the most prominent component in castor bean, is the most polar triglyceride.…”

Section: Resultsmentioning

confidence: 99%

“…The net disappearance of the storage lipid, consisting mainly of triricinolein, occurs later, coincidentally with the development of glyoxysomal alkaline lipase, /3 oxidation, and the glyoxylate cycle enzymes (12,13). It has been supposed that the storage lipid is converted to sucrose without the accumulation of free ricinoleic acid (1,3,11,13). The possible occurrence of free ricinoleate has not been examined directly.…”

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confidence: 99%

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Accumulation of Free Ricinoleic Acid in Germinating Castor Bean Endosperm

Donaldson

1977

Plant Physiol.

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Lipids from the endosperm of germinating castor bean (Ricinus communis var. Hale) were separated by thin layer chromatography and quantitated by gas chromatography. During the later stages of lipid breakdown (4-6 days germination at 30 C), several lipid classes were found in addition to the storage triglycerides, which are triricinoleins for the most part. One was identified as free ricinoleic acid, the proportion of which increased as germination progressed. After 6 days germination, ricinoleic acid comprised more than 30% of the total lipid. The appearance of this fatty acid implies that lipase activity (lipolysis) is not strictly coordinated with g3 oxidation in this tissue.

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“…The newly synthesized diglycerides contain no ricinoleate (6). However, this activity does not -significantly alter the composition of the storage lipid (11).…”

Section: Discussionmentioning

confidence: 99%

“…After 6 days germination when most of the storage lipid has been degraded (11,13) several new lipid classes become apparent ( Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

“…1) (11,14). Triricinolein (TR3), the most prominent component in castor bean, is the most polar triglyceride.…”

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Accumulation of Free Ricinoleic Acid in Germinating Castor Bean Endosperm

Donaldson

1977

Plant Physiol.

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“…This suggests that accumulation of these three enzymes was dependent on GA action. Marriott and Northcote (1975) showed that GAs stimulate the induction of isocitrate lyase activity during germination. Moreover, a TAACAAA sequence analogous to the GARE is present in position Ϫ1403 and Ϫ233 of the genes encoding isocitrate lyase and phosphoglyceromutase, respectively.…”

Section: Mobilization Of Stored Lipid Seed Reservesmentioning

confidence: 99%

Proteomics of Arabidopsis Seed Germination. A Comparative Study of Wild-Type and Gibberellin-Deficient Seeds

et al. 2002

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We examined the role of gibberellins (GAs) in germination of Arabidopsis seeds by a proteomic approach. For that purpose, we used two systems. The first system consisted of seeds of the GA-deficient ga1 mutant, and the second corresponded to wild-type seeds incubated in paclobutrazol, a specific GA biosynthesis inhibitor. With both systems, radicle protrusion was strictly dependent on exogenous GAs. The proteomic analysis indicated that GAs do not participate in many processes involved in germination sensu stricto (prior to radicle protrusion), as, for example, the initial mobilization of seed protein and lipid reserves. Out of 46 protein changes detected during germination sensu stricto (1 d of incubation on water), only one, corresponding to the cytoskeleton component ␣-2,4 tubulin, appeared to depend on the action of GAs. An increase in this protein spot was noted for the wild-type seeds but not for the ga1 seeds incubated for 1 d on water. In contrast, GAs appeared to be involved, directly or indirectly, in controlling the abundance of several proteins associated with radicle protrusion. This is the case for two isoforms of S-adenosyl-methionine (Ado-Met) synthetase, which catalyzes the formation of Ado-Met from Met and ATP. Owing to the housekeeping functions of Ado-Met, this event is presumably required for germination and seedling establishment, and might represent a major metabolic control of seedling establishment. GAs can also play a role in controlling the abundance of a ␤-glucosidase, which might be involved in the embryo cell wall loosening needed for cell elongation and radicle extension.Maturation drying is the normal terminal event in the vast majority of seeds, after which they pass into a metabolically quiescent state where they may remain for many years and still retain their viability (Hoekstra et al., 2001). Upon hydration under suitable conditions, the seed, if not dormant, reactivates its metabolism and commences germination, giving rise to a new plant.Seed germination can be divided into three phases, imbibition, increased metabolic activity, and initiation of growth, which loosely parallel the triphasic water uptake of dry mature seeds. Morphologically, initiation of growth corresponds to radicle emergence; subsequent growth is generally defined as seedling growth. By definition, germination sensu stricto incorporates those events that start with the uptake of water by the quiescent dry seed and terminate with the protrusion of the radicle and the elongation of the embryonic axis (Bewley, 1997). From physiological studies on a wide variety of species, including a number of mutants, it appears that gibberellins (GAs) play a key role in late stages of seed germination Karssen, 1988, 1992;Karssen et al., 1989;Hilhorst and Toorop, 1997; Yamaguchi et al., 1998; Richards et al., 2001). Thus, in plant species such as Arabidopsis and tomato (Lycopersicon esculentum), the strong alleles of GA-deficient mutants are unable to complete germination without exogenous GAs (Koornneef and van der Veen,...

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The action of exogenous gibberellic acid on protein and mRNA in germinating castor bean seeds

Martin

Northcote

1982

Planta

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Gibberellic acid (GA3) stimulates water uptake in castor beans and increases the activity of certain enzymes associated with lipid mobilisation.The effect of the GA3 on the enzymes is possibly due to a general effect of the growth substance on protein synthesis. Gibberellic acid advanced the appearance of rRNA and poly (A(+))RNA in castor bean endosperms without specifically stimulating the synthesis of particular mRNA species. Thus these increased levels of mRNA and rRNA may act synergistically to affect the rate of a predetermined pattern of protein synthesis.

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The breakdown of lipid reserves in the endosperm of germinating castor beans

Cited by 36 publications

References 37 publications

Accumulation of Free Ricinoleic Acid in Germinating Castor Bean Endosperm

Accumulation of Free Ricinoleic Acid in Germinating Castor Bean Endosperm

Proteomics of Arabidopsis Seed Germination. A Comparative Study of Wild-Type and Gibberellin-Deficient Seeds

The action of exogenous gibberellic acid on protein and mRNA in germinating castor bean seeds

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