bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detecting and overcoming water-impermeable barriers in prickly sida (Sida spinosaL.) seeds
Authors: Egley G. H. , Paul R. N. 
Published: September 2008

AbstractBarriers to water permeability in prickly sida seeds were characterized using solvents and water-soluble salts. The seeds imbibed water when barriers in the chalazal area broke down. The major barrier was in the distal region of the palisade layer bordered internally by the light line. Soaking dormant seeds in certain organic solvents overcame the barrier and enabled the seeds to imbibe water. The most active were non-polar solvents with dielectric constants between 3.7 and 18.5, and with a high ability to hydrate and swell cellulosic materials. We concluded that the most active solvents (pyridine, diethylamine) overcame the major barrier, entered the proximal portion of the palisade layer and caused the swelling of cellulosic cell components. The cellular expansion created stresses that broke thin walls of the underlying subpalisade cells in the chalazal area. The breakage resulted in separation of the cell layers and rapid entry of water into the seed. Highly non-polar or highly polar solvents had little or no activity. Some solvents overcame the barrier but did not cause swelling and disruption of the cell layers. We propose that the natural breakdown of impermeability in prickly sida seeds was due to the gradual seepage of water past the barrier in the distal portion of the coat in the chalazal area and into the inner portions where swelling of hygroscopic components triggered the breakage of subpalisade cell walls resulting in cell layer separation.
Rapid and efficient purification of seed messenger RNA without phenol:chloroform extraction
Authors: Pramanik S. K. , Reynolds T. L. , Maclsaac S. A. , Bewley J. D. 
Published: September 2008

AbstractA novel method has been devised to extract poly (A+)RNA from seed tissues. The advantages of this technique include the speed of extraction and the elimination of the hazardous phenol:chloroform extraction step which usually precedes oligo (dT)-cellulose column chromatography. Instead, the crude supernatant, containing a high concentration of SDS and salts to effectively inhibit RNase activity, is passed directly over the oligo (dT)-cellulose column. The resultant isolated poly (A+)RNA is of high yield and purity and is suitable for in vitro translation and Northern blot analysis.
X-ray studies on changes in embryo and endosperm morphology during priming and imbibition of tomato seeds
Authors: Liu Y. , van der Burg W. J. , Aartse J. W. , van Zwol R. A. , Jalink H. , Bino R. J. 
Published: September 2008

AbstractMorphological changes in tomato (Lycopersicon esculentumMill. cv. Moneymaker) seed during osmopriming and imbibition (‘hydropriming’) were followed using X-ray photographs. Embryo, endosperm and free space areas were measured. Both osmopriming and hydropriming resulted in free space development (+ 8.1% and + 10.8% of the whole seed planar area, respectively), almost all at the cost of the endosperm area. Planar dimensions of whole seeds were relatively constant and the dimension perpendicular to the planar surface, the thickness, could account for the volume increase of primed seeds reported in the literature. In dead seeds, only a small amount of free space developed while the planar area of the seed remained the same. In the imbibing viable seeds no deterioration of endosperm could be detected until the moment of root protrusion.Seeds which were osmoprimed directly after harvest, i.e. in the fresh state, did not showthe induction of any free space, while free space developed normally after dehydration and a second priming treatment. Apparently, a dehydration step prior to the priming treatments is required for the development of free space in osmo- or hydroprimed seed.X-ray photographs of hydroprimed seeds showed that the radicle tip adhered tightly to theendosperm cap. This results in various forms of damage to the root tips upon redrying. Priming did not introduce cotyledon abnormalities.
The effect of aerated hydration on DNA synthesis in embryos of Brassica oleracea L.
Authors: Thornton J. M. , Collins A. R. S. , Powell A. A. 
Published: September 2008

AbstractAgeing causes a delay in the onset of DNA replication in seeds. Aerated hydration for 8 h, a treatment to invigorate seeds, resulted in a reduction of about 12 h in the time difference in the onset of DNA synthesis between unaged and aged embryos of brassica seed. This effect is consistent with a recovery process occurring during aerated hydration of the seed involving the repair of accumulated DNA damage. The occurrence of hydroxyurea-resistant 3H-thymidine incorporation in aged Brussels sprouts embryos during the period 16–32 h from the start of hydration supports this interpretation.
The mechanisms of desiccation tolerance in developing seeds
Authors: Leprince O. , Hendry G. A. F. , McKersie B. D. 
Published: September 2008

AbstractDesiccation tolerance is one of the most fundamental properties of seeds. It is acquired late in seed development and is considered necessary for the completion of the plant's life cycle, as an adaptive strategy to enable seed survival during storage or environmental stress, and to ensure better dissemination of the species. The role of water status in desiccated tissues and problems related to testing tolerance in seeds are reviewed. The molecular mechanisms of desiccation tolerance has received extensive consideration only during this past decade. There is a general consensus that desiccation tolerance involves the protection of cellular membranes from the deleterious effect of water removal and the resultant necessity to maintain the bilayer structure in the absence of an aqueous environment. Therefore, some aspects of desiccation-induced membrane injury are described. Several strategies for coping with cellular desiccation have been identified the presence of high amounts of non-reducing sugars, the efficiency of free radical-scavenging systems and the expression of desiccation- and/or ABA-regulated genes. These molecular mechanisms allowing cellular protection are reviewed together with their respective role in dessication tolerance. It is concluded that desiccation tolerance is not likely to be ascribed to a single mechanism but rather to a multifactorial property in which each component is equally critical.
Release of dormancy in sunflower embryos by dry storage: involvement of gibberellins and abscisic acid
Authors: Bianco J. , Garello G. , Le Page-Degivry M. T. 
Published: September 2008

AbstractExcised Helianthus annuus L. embryos became dormant during the third week after anthesis. At this stage a short drying treatment (3 d) led to a slight improvement in germination but a 6-week dry storage caused a complete release from dormancy. The short drying treatment, however, elicited the embryos' response to an exogenous concentration of GAs which was unable to promote germination of fresh embryos. It therefore appeared that a short drying treatment changed the sensitivity to GAs but was not capable of directing embryo metabolism completely towards a germinative mode. Moreover, this drying treatment reduced considerably the ABA content in both the axis and the embryo. Nevertheless, no correlation could be established between germinability and the ABA content since the amount of ABA was not modified by the 6-week dry storage. The key step for predisposing the seeds to germinate is the suppression of the capacity for ABA synthesis in the axis, a suppression which takes place during 6-week dry storage.
The fluorescence assay for Maillard product accumulation does not correlate with seed viability
Authors: Baker Ellen H. , Bradford Kent J. 
Published: September 2008

AbstractA recent hypothesis states that the accumulation of amino-carbonyl reaction products of reducing sugars with proteins (Maillard products) is related to the loss of seed vigour and viability during ageing. Since Maillard products are biochemical end products, their accumulation should provide an index of seed deterioration. A simple fluorescence assay has been used to estimate the quantity of Maillard products in aqueous seed extracts. We tested whether an accumulation of fluorescent compounds correlates with the loss of seed viability during ageing. Fluorescence of extracts from lettuce (Lactuca sativa) embryonic axes increased after controlled deterioration, but was not correlated with ageing period. Fluorescence of extracts from whole broccoli (Brassica oleracea var. italica) seeds was either unchanged or declined during controlled deterioration. Extracts from naturally aged whole seeds of carrot (Daucus carota), tomato (Lycopersicon esculentum), and cauliflower (B. oleracea var. botrytis) had higher fluorescence than controls, but there was no consistent increase in fluorescence in proportion to the loss of viability. Extracts of naturally aged onion (Allium cepa) seeds exhibited less fluorescence than extracts from seeds with higher viability. We conclude that the fluorescence assay does not have general utility as an index of seed deterioration.
Cellular and metabolic damage induced by desiccation in recalcitrant Araucaria angustifolia embryos
Authors: Espindola L. Salmen , Noin M. , Corbineau F. , Côme D. 
Published: September 2008

AbstractEmbryos of Araucaria angustifolia seeds showed no dormancy; they germinated easily at temperatures ranging from 10° to 30°C, and the thermal optimum was about 25–30°C; they were recalcitrant. At harvest, their mean moisture content (dry weight basis) was about 120% and they completely lost viability when their moisture content fell to about 30%. The cotyledons were more sensitive to dehydration than the radicle. Dehydration induced deterioration of cell membranes as indicated by a high increase in leakage of solutes. It also resulted in damage in the nuclei, which was not repaired upon rehydration. During desiccation, respiratory activity decreased; however, O2 uptake was not an indication of germination ability, since it was significantly affected only when embryo moisture content reached the critical value of 30%. The decrease in the capacity to convert 1-aminocyclopropane 1-carboxylic acid to ethylene, which was observed at 30–60 min of dehydration, was a very early indicator of deterioration in embryos. Desiccation resulted also in a rapid decrease in the ability for protein synthesis as measured by [35S]methionine incorporation into total protein; 50% inhibition was observed after 30–60 min of desiccation for both axis and cotyledons.
Physical properties of water in Zizania embryos in relation to maturity status, water content and temperature
Authors: Vertucci C. W. , Crane J. , Porter R. A. , Oelke E. A. 
Published: September 2008

AbstractChanges in the properties of water in excised embryos were measured during the late stages of grain development in two cultivars of Zizania palustris and a population of the endangered species Z. texana. The relationships between water content and water activity were determined from water sorption isotherms, measured at temperatures between 35 and 5°C and then derived for lower temperatures. The freezing and melting behaviour of water in embryos at different water contents was determined using differential scanning calorimetry. The moisture content of embryos at high water activities decreased with maturation, as did the moisture content at which freezing transitions were not observed. While the temperatures of freezing and melting transitions decreased as the moisture content of embryos decreased, there were no discernible differences among embryos at different developmental stages. The properties of water measured in maturing Zizania embryos approached those for orthodox seeds as determined from the strength of water sorption, the enthalpy of the melting transition and the moisture content at which water is unfreezable. From these data we conclude that the properties of water in recalcitrant Zizania embryos change with development to resemble those of embryos of desiccation-tolerant seeds, but that the seeds never achieve the orthodox condition. The effects of interactions between moisture content and temperature on desiccation damage, freezing damage and germination in Zizania are predicted, based on the physical properties of water reported here and the correspondence of these properties with physiological function reported for other species. The resulting ‘phase diagram’ defines possible combinations of moisture content and temperature for storage under equilibrium conditions.
Two-dimensional protein patterns of tomato (Lycopersicon esculentum Mill.) seeds; effects of isolation procedure and imbibition
Authors: Bergervoet J. H. W. , Kraak H. L. , De Vos C. H. R. , Bino R. J. 
Published: September 2008

AbstractA computer-aided comparison of tomato (Lycopersicon esculentum Mill.) seed protein patterns, obtained after two-dimensional gel electrophoresis, was made for three different extraction procedures: TCA acetone/lysis buffer, lysis buffer only and modified Laemmli/lysis buffer. Comparison of the isolation methods showed that about half of the amount of proteins detected was common in each method. Also, proteins specific to some isolation methods were detected. Protein synthesis during imbibition was monitored using 35S-methionine. After labelling the proteins were extracted using TCA acetone/lysis buffer. Following two-dimensional gel electrophoresis the gels were first silver stained, to give a general picture of all proteins present in the seed, then the gels were exposed to a film for autoradiography. Comparison of the in vivo-synthesized protein patterns and the silver-stained proteins revealed that from day 0 to day 1 the protein pattern was changed but the total number of different spots was similar. After 1 day of imbibition, the number of protein spots increased greatly and the protein pattern changed again.
Wheat seed ageing and embryo protein degradation
Authors: Dell'Aquila A. 
Published: September 2008

AbstractWheat seed lots of different viability were obtained by an accelerated ageing technique in which seeds were hydrated up to 12.5–14.5% on a fresh weight basis and stored at 35°C. Ageing was accompanied by a progressive delay of the onset of germination and a decrease of [35S]-methionine uptake and incorporation into soluble proteins of the imbibing embryos. A detailed analysis of newly synthesized proteins by two-dimensional polyacrylamide gel electrophoresis showed that normal protein patterns during the germination process were impaired by ageing. Only two groups of polypeptides with molecular masses of 84.9–69.5 and 66.6–60.2 kDa, respectively, were actively produced while most proteins decreased or were definitely degraded. Our results suggest that the biochemical changes required for germination are gradually opposed by a deterioration process and that some newly-synthesized polypeptides can be taken as markers in assessing seed survival of ageing stress.
Gene expression during maize kernel development
Authors: Doehlert Douglas C. , Smith Leslie J. , Duke Edwin R. 
Published: September 2008

AbstractRelationships have been investigated between gene transcript abundance, enzyme activities and storage product accumulation in developing maize (Zea maysL.) kernels from 10 to 55 days postpollination (DPP). At the early stages of kernel development, there was very little increase in dry weight but kernels accumulated high concentrations of sugars and amino acids. At the end of this ‘lag’ phase (at 15 DPP), many transcripts appeared with little evidence of their translation. The initiation of the kernel-fill period at 20 DPP was characterized by a sudden rise in total RNA, increases in enzyme activities, and the initiation of storage product accumulation. Zein accumulation during this phase was highly correlated with α-zein transcript abundance. Starch accumulation was correlated with both the activity of ADP-GIc pyrophosphorylase and the abundance of gene transcripts encoding this enzyme (Shrunken-2andBrittle-2). DNA content of kernels increased linearly up to 30 DPP as a result of endoreplication, but had no apparent relationship to gene expression. DNA may accumulate as a storage product. Kernel-fill terminated when the moisture content fell below 36% and was marked by a decline of transcripts and a reduction of enzyme activities.
Seed quality as cause for differences in longevity behaviour after seed pretreatment in wheat (Triticum aestivumL.)
Authors: Hofmann P. , Steiner A. M. 
Published: September 2008

AbstractHydration-dehydration seed pretreatments are well-known to improve germination rate, germination and vigour. However, contradictory results have been reported concerning the effect of a pretreatment on longevity. The present paper shows that the effect of a seed pretreatment on longevity is largely dependent on the quality of the seed at the time of pretreatment. Pretreating wheat seeds of high quality increased the rate of viability loss during subsequent storage. On the other hand, pretreating wheat seeds of relatively low quality decreased the rate of seed deterioration during subsequent storage. In the light of these findings, hitherto contradictory results in the literature could be explained.
Changes in the synthesis of some proteins during breaking of secondarily induced thermodormancy by respiration inhibitors (cyanide, azide) and BAP in embryos ofAgrostemma githagoL. seeds
Authors: Bernhardt D. , Gerth U. 
Published: September 2008

AbstractSecondary dormancy (thermodormancy) inAgrostemma githagoL. seeds, caused by imbibing the seeds for 4 d at 35°C in the dark, is broken under the influence of cyanide (10 mM), azide (1 mM or BAP (0.44 mM). Both respiration inhibitors (cyanide and azide) and BAP increase the synthesis of five specific soluble proteins in the embryo axes and cotyledons. The activity of β-cyanoalanine synthase (β-CAS, EC 4.4.1.9.), which is able to detoxify cyanide, decreased in response to cyanide and azide. The relevance of these findings to the breaking of thermodormancy is discussed.
Increase of the content of QP47 (a desiccation-associated nuclear protein) in embryo cells during maturation of pea seeds
Authors: Chiatante Donato , Brusa Paola 
Published: September 2008

AbstractA nuclear protein (QP47) is synthesized during the last stage of seed maturation when the embryo cells start to dehydrate and enter a condition of metabolic quiescence. This protein is localized in the nucleoplasm surrounding the chromosomes. The correlation existing between the synthesis of QP47 and arrest of cell proliferation, suggests that the presence of this protein in the nucleus could influence its metabolic activities. This hypothesis is supported by the fact that degradation of this protein precedes resumption of cell proliferation during the early stage of radicle elongation.
Maize seed response to successive imbibition/dryback cycles: viability and vigour
Authors: Davidson K. G. V. , Sowa S. , Moore F. D. , Roos E. E. 
Published: September 2008

AbstractElectroconductivity tests are currently used for seed vigour assessment. They are rapid and simple and after further development, they may yet provide the seed industry with a non-destructive alternative to the standard germination test, which is thoroughly destructive to the sample, time consuming, and expensive. Seed injury, a result of soaking required by the electroconductivity test, was evaluated using high qualityZea maysL. seeds responding to successive imbibition/dryback cycles. If the soaking time is brief, injury to the seeds should be minimal, thus permitting successive tests on the same sample. We tested 5 imbibition/dryback cycles (C) and 5 imbibition periods, or cycle durations (CD) of 2, 4, 6, 7 and 8 h. Dryback periods lasted 5–7 d at room temperature. Seeds were permitted to dry back to 10% moisture. Electroconductivity readings were obtained at the end of each CD for each C. Each treatment (C × CD) sample, n=100 seeds, was germinated at 25°C for 7 d; radicle lengths were measured after 3 d. The experiment was repeated yielding a total of 50 observations. Viability and vigour losses were measured in response to successive C and increasing CD. Five cycles of 6 h each resulted in only a 10% loss of viability, but a 20% loss of relative vigour, confirming that vigour is more sensitive to the testing procedure. Cycles had the greatest effect on loss of seed quality since 45% of the readily leachable electrolytes were lost from the seeds during the first soaking period. There was no interaction between C and CD.
Observations on the survival of seeds of Agathis spp. stored at low moisture contents and temperatures
Authors: Dickie J. B. , Smith R. D. 
Published: September 2008

AbstractThree seedlots of Agathis australis (Lambert) Steud. (kauri pine) were stored hermetically at moisture contents of 1.5–15.5% and at temperatures from −20° to 42°C; and one seedlot of Agathis macrophylla was stored at 7%, 9% or 13% moisture content and at 26°, 6° or −13°C. Seeds of A. australis showed orthodox storage behaviour; except that viability was progressively reduced with drying below about 5% moisture content, and, depending on seedlot, subsequent storage longevities were reduced at all temperatures. Seeds of A. macrophylla again showed essentially orthodox characteristics at 9 and 13% moisture content; but drying to 7% moisture content reduced viability significantly, and of those seeds surviving, a further proportion died as a result of transfer to −13°C, and the remainder survived for 2500 d with little further viability loss. Seeds of neither species conformed fully to orthodox characterisics, nor to those of the intermediate category. The results are discussed in relation to possible causes of this ‘sub-orthodox’ behaviour, especially current seed-harvesting methods, and the limits put upon ex situ conservation of these species in seed banks by their predicted comparatively short storage lives.
Survival of Zizania embryos in relation to water content, temperature and maturity status
Authors: Vertucci Christina W. , Crane Jennifer , Porter Raymond A. , Oelke Ervin A. 
Published: September 2008

AbstractThe interactions between water content and temperature on freezing and desiccation damage were examined for Zizania (wild rice) embryos at several stages of maturity. The water content of excised embryos was manipulated by flash drying at 35°C or room temperature to between 2.5 g H2O/g dw and 0.05 g/g. Embryos were then exposed to temperatures ranging from 5 to −50°C. Viability following the drying and cooling treatments was assayed by leakage of electrolytes and germination in culture. Viability of embryos decreased when embryos were dried below a critical water content. The critical water content was greatest for the least mature embryos. Critical water contents were also temperature dependent and increased with decreasing temperature. Even though the critical water content varied with developmental status and temperature, the water activity corresponding to the critical water content appeared to be constant at 0.90. The most mature embryos survived temperatures as low as −50°C while the least mature embryos survived only to −18°C. These trends were predicted by ‘phase diagrams’ based on the physical properties of water in embryos at different stages of maturity (Vertucci et al., 1994a). Our results confirm the earlier prediction that long term preservation of Zizania grains is possible at −20°C and the degree of success will be related to the maturity status of the embryos.