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Barrero JM, Jacobsen JV, Talbot MJ, White RG, Swain SM, Garvin DF, Gubler F. Grain dormancy and light quality effects on germination in the model grass Brachypodium distachyon. THE NEW PHYTOLOGIST 2012; 193:376-86. [PMID: 22039925 DOI: 10.1111/j.1469-8137.2011.03938.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
• Lack of grain dormancy in cereal crops such as barley and wheat is a common problem affecting farming areas around the world, causing losses in yield and quality because of preharvest sprouting. Control of seed or grain dormancy has been investigated extensively using various approaches in different species, including Arabidopsis and cereals. However, the use of a monocot model plant such as Brachypodium distachyon presents opportunities for the discovery of new genes related to grain dormancy that are not present in modern commercial crops. • In this work we present an anatomical description of the Brachypodium caryopsis, and we describe the dormancy behaviour of six common diploid Brachypodium inbred genotypes. We also study the effect of light quality (blue, red and far-red) on germination, and analyse changes in abscisic acid levels and gene expression between a dormant and a non-dormant Brachypodium genotype. • Our results indicate that different genotypes display high natural variability in grain dormancy and that the characteristics of dormancy and germination are similar to those found in other cereals. • We propose that Brachypodium is an ideal model for studies of grain dormancy in grasses and can be used to identify new strategies for increasing grain dormancy in crop species.
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Barrero JM, Talbot MJ, White RG, Jacobsen JV, Gubler F. Anatomical and transcriptomic studies of the coleorhiza reveal the importance of this tissue in regulating dormancy in barley. PLANT PHYSIOLOGY 2009; 150:1006-21. [PMID: 19386806 PMCID: PMC2689963 DOI: 10.1104/pp.109.137901] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Accepted: 04/17/2009] [Indexed: 05/19/2023]
Abstract
The decay of seed dormancy during after-ripening is not well understood, but elucidation of the mechanisms involved may be important for developing strategies for modifying dormancy in crop species and, for example, addressing the problem of preharvest sprouting in cereals. We have studied the germination characteristics of barley (Hordeum vulgare 'Betzes') embryos, including a description of anatomical changes in the coleorhiza and the enclosed seminal roots. The changes that occur correlate with abscisic acid (ABA) contents of embryo tissues. To understand the molecular mechanisms involved in dormancy loss, we compared the transcriptome of dormant and after-ripened barley embryos using a tissue-specific microarray approach. Our results indicate that in the coleorhiza, ABA catabolism is promoted and ABA sensitivity is reduced and that this is associated with differential regulation by after-ripening of ABA 8'-hydroxylase and of the LIPID PHOSPHATE PHOSPHATASE gene family and ABI3-INTERACTING PROTEIN2, respectively. We also identified other processes, including jasmonate responses, cell wall modification, nitrate and nitrite reduction, mRNA stability, and blue light sensitivity, that were affected by after-ripening in the coleorhiza that may be downstream of ABA signaling. Based on these results, we propose that the coleorhiza plays a major role in causing dormancy by acting as a barrier to root emergence and that after-ripening potentiates molecular changes related to ABA metabolism and sensitivity that ultimately lead to degradation of the coleorhiza, root emergence, and germination.
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Affiliation(s)
- José M Barrero
- Plant Industry, Commonwealth Scientific and Industrial Research Organisation, Canberra, Australian Capital Territory 2601, Australia
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A freeze-fracture study of mesophyll cell membranes in the embryonic Phaseolus leaf, in the dry seed and during the initial stages of germination. Tissue Cell 1994; 26:133-42. [DOI: 10.1016/0040-8166(94)90089-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/1993] [Accepted: 10/26/1993] [Indexed: 11/19/2022]
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Zlatanova JS, Ivanov PV, Stoilov LM, Chimshirova KV, Stanchev BS. DNA repair precedes replicative synthesis during early germination in maize. PLANT MOLECULAR BIOLOGY 1987; 10:139-144. [PMID: 24277499 DOI: 10.1007/bf00016151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/1987] [Accepted: 10/12/1987] [Indexed: 06/02/2023]
Abstract
DNA synthesis was studied during germination by following the rate of incorporation of radioactive thymidine into high molecular weight DNA. A peak of DNA synthesis was observed between the 8th and the 12th hour, i.e. before the beginning of the semi-conservative replication of genomic DNA, accompanied by an increase in the DNA content of the embryo. By the use of nucleoid sedimentation and nick-translation it was shown that, during the first hours of germination, extensive repair occurs of the DNA single-strand breaks present in the dry embryo. As a result, the DNA of the 16-h-germinated embryo acquires the conformation typical of that of the root meristemic cells active in transcription and replication.In addition we have shown that cytoplasmic organelle (most probably mitochondrial) DNA synthesis is very active during the prereplicative state which confirms earlier microscopic data on mitochondrial biogenesis during early germination.
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Affiliation(s)
- J S Zlatanova
- Molecular Genetics Lab., Institute of Genetics, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
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Wharton DA, Barrett J. Ultrastructural changes during recovery from anabiosis in the plant parasitic nematode, Ditylenchus. Tissue Cell 1985; 17:79-96. [PMID: 4002213 DOI: 10.1016/0040-8166(85)90017-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Ultrastructural changes after desiccation and rehydration of the anabiotic fourth-stage juveniles of the plant parasitic nematode Ditylenchus dipsaci (Kuhn) Filipjev are described and quantified. Anabiotic juveniles retain their structural integrity, although the cuticle decreases in thickness and the muscle cell sarcoplasm condenses. In contrast the structure of the non-anabiotic nematode Panagrellus silusae is completely disorganized by desiccation. Following rehydration of D. dipsaci there is a lag phase of 2-3 hr before the nematodes become active. During this period the juveniles undergo an ordered series of morphological changes. The lipid droplets within the intestinal cells coalesce and the cuticle increases in thickness. The muscle cell sarcoplasm expands, the spacing of the thick myofilaments increases and the mitochondria swell before recovering a more normal appearance. These morphological changes, together with earlier metabolic studies, indicate that repair occurs during the lag phase prior to recovery. This may involve membrane repair and the re-establishment of the ionic gradients essential for normal muscle and nerve function.
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Crèvecoeur M, Deltour R, Bronchart R. Quantitative freeze-fracture study of plasmalemma and nuclear envelope of Zea mays root cells during early germination. JOURNAL OF ULTRASTRUCTURE RESEARCH 1982; 80:1-11. [PMID: 7097841 DOI: 10.1016/s0022-5320(82)80027-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Vanderzee D, Kennedy RA. Plastid development in seedlings of Echinochloa crus-galli var. oryzicola under anoxic germination conditions. PLANTA 1982; 155:1-7. [PMID: 24271619 DOI: 10.1007/bf00402924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/1980] [Accepted: 11/20/1981] [Indexed: 06/02/2023]
Abstract
Plastid development in the primary leaf of Echinochloa crus-galli (L.) Beauv. var. oryzicola (Vasing.) Ohwi was followed during 5 d of anoxic germination and growth. Plastids develop slowly from simple spheroidal proplastids into larger pleomorphic plastids with several stromal membranes and many peripheral membrane vesicles. A small prolamellar body is present at 96 h with perforated (pro)thylakoids extending into the stroma. Changes in starch grains and plastoglobuli are evidence of carbohydrate and lipid metabolism. Plastid division is indicated by dumbbell plastid profiles after 4 d of anoxia. These results demonstrate that plastids not only maintain their integrity during anaerobic germination but also show developmental changes involving an increase in internal membrane complexity, although to a lesser extent than in etiolated shoots.
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Affiliation(s)
- D Vanderzee
- Department of Horticulture and Landscape Architecture, Washington State University, 99164, Pullman, WA, USA
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Bouvier-Durand M, Dereuddre J, Côme D. Ultrastructural changes in the endoplasmic reticulum during dormancy release of apple embryos (Pyrus malus L.). PLANTA 1981; 151:6-14. [PMID: 24301664 DOI: 10.1007/bf00384231] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/1980] [Accepted: 08/28/1980] [Indexed: 06/02/2023]
Abstract
Apple embryos were treated by cold (0°C) within the fruits, to break their dormancy; the controls were treated at 12°C or at 20°C. Ultrastructural features of meristematic cells in the embryonic axis were compared for each treatment. The organization of the cells of dormant embryos was described: Endoplasmic reticulum consisted in some short rough cisternae; lipid droplets regularly arranged near the plasmalemma constituted a kind of shell; mitochondria had a few cristae; and dictyosomes were rarely observed. All these features are typical of dry seeds. After cold treatments, the only evolution observed was in the endoplasmic reticulum, where highly organized stacks appeared progressively as a function of time at 0°C. An intermediate temperature (12°C) induced similar formations in the reticulum but they were rarely observed and their degree of organization was lower than that obtained at 0°C. At 20°C, endoplasmic reticulum resembled that of the dormant embryo cells. The relation between the appearance of these structures in the reticulum and the disappearance of dormancy induced by cold is discussed.
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Affiliation(s)
- M Bouvier-Durand
- Laboratoire de Physiologie Végétale Appliquée, Université Pierre et Marie Curie (Paris VI), Tour 53, 4 Place Jussieu, F-75230, Paris Cedex 05, France
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Cuming AC, Osborne DJ. Membrane turnover in imbibed dormant embryos of the wild oat (Avena fatua L.) : II. Phospholipid turnover and membrane replacement. PLANTA 1978; 139:219-226. [PMID: 24414263 DOI: 10.1007/bf00388633] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/1977] [Accepted: 12/29/1977] [Indexed: 06/03/2023]
Abstract
Germinating non-dormant (ND) embryos of wild oat incorporate [(3)H]glycerol into phospholipid, and a 250% increase in total extractable phospholipid occurs within 72 h. During germination, leveles of phosphatidyl inositol showed the greatest change, increasing approximately 5-fold.Imbibed dormant (D) embryos of the wild oat also incorporate [(3)H]gycerol into phospholipids, but there is no net synthesis. A continuous turnover of membrane phospholipids could be demonstrated in pulse chase experiments, and although the proportions of most phospholipids does not change, there was a decrease of 50% in phosphatidyl serine.The half-life of [(3)H]glycerol in the extracted phospholipids of D and ND embryos varies between 35 and 57 h, and in membrane fractions separated on sucrose density gradients the half-lives vary between 26 and 56 h.D embryos induced to germinate with GA and ND embryos in which germination is repressed by ABA show similar phospholipid changes to ND and D embryos respectively, with the exception that the proportion of phosphatidyl serine remained unchanged in the ND-ABA embryos.It is concluded that the continual turnover of membranes of imbibed dormant embryos is consistent with the maintenance of cellular integrity determining the longevity of the seed under natural conditions.
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Affiliation(s)
- A C Cuming
- Agricultural Research Council Unit of Developmental Botany, 181A Huntingdon Road, CB3 ODY, Cambridge, UK
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Peumans WJ, Carlier AR, Caers LI. Sedimentation properties of preformed messenger particles in dry rye embryo extracts. PLANTA 1978; 140:171-176. [PMID: 24414474 DOI: 10.1007/bf00384917] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/1977] [Accepted: 02/13/1978] [Indexed: 06/03/2023]
Abstract
Two classes of messenger containing particles can be distinguished in cell-free extracts from dry rye (Secale cereale, L.; var. Celestijner) embryos. A part of the endogenous template activity is associated with large structures, even during in vitro translation. Treatment with detergents results in a partial solubilization of the messenger particles from the large, presumably membranous structures. The sedimentation behavior of the "soluble" mRNP particles (about 75% of the total endogenous template activity) is strongly influenced by the composition of the homogenization medium. At high Mg(2+) or Ca(2+) concentrations, and at low pH, the soluble mRNP particles form aggregates sedimenting at low centrifugal forces. This peculiar behavior is of partical interest with respect to the preparation of cell-free extracts with low endogenous template activity.
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Affiliation(s)
- W J Peumans
- Laboratorium voor Plantenbiochemie, Katholieke Universiteit Leuven, Vaartstraat 24, B-3000, Leuven, Belgium
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Hecker M, Köhler KH, Wiedmann M. Reactivation of Ribonucleic Acid Synthesis during Early Germination of Agrostemma githago Embryos. ACTA ACUST UNITED AC 1977. [DOI: 10.1016/s0015-3796(17)30329-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Bray CM, Chow TY. Lesions in post-ribosomal supernatant fractions associated with loss of viability in pea (Pisum arvense) seed. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 442:1-13. [PMID: 952997 DOI: 10.1016/0005-2787(76)90169-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
RNA synthesis and protein synthesis in viable pea embryonic axis tissue commences during the first hour of water imbibition whilst DNA synthesis commences after 8 h of imbibition. Neither DNA synthesis nor protein synthesis could be detected in non-viable axis tissue during the first 24 h of imbibition but some RNA synthesis is detectable during this period. Both post-ribosomal supernatant and ribosomal fractions from imbibed non-viable embryonic axis tissue were impaired in their ability to support polyphenylalanine synthesis in a cell-free protein-synthesising system, yet the same fractions isolated from unimbibed non-viable axis tissue were as efficient as equivalent fractions from unimbibed viable axis tissue in the support of polyphenylalanine synthesis in the cell-free system. A major lesion in elongation factor 1 activity and additional lesions in elongation factor 2 and phenylalanyl-tRNA synthetase activities were detected in the post-ribosomal supernatants isolated from non-viable embryonic axis tissue.
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Hecker M. [Studies on stable and during early imbibition phases synthesized poly(A)-RNA of Agrostemma githago embryos (author's transl)]. EXPERIENTIA 1976; 32:50-3. [PMID: 1248588 DOI: 10.1007/bf01932618] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
RNA isolated from dry embryos of Agrostemma githago seeds contains poly(A)-sequences, but in very small amounts. In the early phase of imbibition, an intensive synthesis of poly(A)-containing RNA is brought about. The importance of this synthesis of poly(A)-RNA is discussed.
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Hallam ND, Roberts BE, Osborne DJ. Embryogenesis and germination in rye (Secale cereale L.) : III. Fine structure and biochemistry of the non-viable embryo. PLANTA 1973; 110:279-290. [PMID: 24474457 DOI: 10.1007/bf00387056] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/1972] [Indexed: 06/03/2023]
Abstract
Fine structural investigations of non-viable rye grains indicate recognisible abnormalities in the plasmalemma and mitochondrial membranes of the unimbibed embryo. Once such grains are wetted there is rapid and progressive disorganisation of the tissue. Biochemical studies show a reduced uptake of water, lack of respiratory activity and a failure in nucleic acid and protein synthesis. Whereas total DNA, RNA and protein levels are unchanged on loss of viability, the integrity of DNA and RNA is impaired and ribosomal RNA and soluble protein levels are reduced.
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Affiliation(s)
- N D Hallam
- Agricultural Research Council Unit of Developmental Botany, 181A Huntingdon Road, CB3 0DY, Cambridge, UK
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Stoddart JL, Thomas H, Robertson A. Protein synthesis patterns in barley embryos during germination. PLANTA 1973; 112:309-321. [PMID: 24468811 DOI: 10.1007/bf00390304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/1973] [Indexed: 06/03/2023]
Abstract
The incorporation pattern of [(14)C] amino-acid into protein during the first 8 h of germination in isolated barley embryos (Hordeum vulgare) is described. Two maxima were recognised. The first, at 4 h, was entirely accounted for by scutellum activity and the second, at 8 h, coincided with active radicle elongation. An intervening minimum was situated at 5.5 h. The first peak was insensitive to actinomycin-D but the second showed a partial inhibition by this compound. Only slight changes in enzyme activity were associated with these periods of increased synthesis. Incorporation of [17-(14)C] kaurenoic acid into compounds co-chromatographing with gibberellins was followed over the same period in both embryos and scutella and high activity was found after only 2-4 h. It is concluded that, on the basis of protein synthetic activity, the scutellum is the most probable source of the initial gibberellin stimulus.
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Affiliation(s)
- J L Stoddart
- Welsh Plant Breeding Station, SY 23-3 EB, Aberystwyth, UK
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