bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ecophysiology of germination in the aromatic plants thyme, savory and oregano (Labiatae)
Authors: Thanos Costas A. , Kadis Costas C. , Skarou Flora 
Published: September 2008

AbstractEcophysiological aspects of seed germination were investigated in the widely distributed Mediterranean-endemic, aromatic plants thyme (Coridothymus capitatus), savory (Satureja thymbra) and oregano (Origanum vulgaresubsp.hirtum). Thyme seed germination is light indifferent, whereas oregano seeds have an absolute light requirement; their germination can be promoted even by green safelight or far-red light. In savory, a portion of the seeds germinates in the dark and germination can be either increased or decreased by the appropriate illumination. All three species show more germination at a relatively low temperature range, a Mediterranean characteristic, with an optimum around 15–20°C. The rate of germination is considerably higher in the tiny seeds of thyme and oregano than in the larger seeds of savory. In the latter species, germination is also dependent upon the age of the seeds; old seeds germinate to a higher percentage than fresh ones, as already observed by Theophrastus, possibly as a result of the volatilization of the essential oils present on the nutlet coat. Seeds of thyme, savory and oregano are dispersed within the persistent fruiting calyces and the seeds eventually germinate within it. Essential oils in the calyx strongly inhibit germination of the enclosed seeds; germination is much suppressed in thyme and to a lesser extent in savory and oregano. This diaspore dormancy caused by essential oils apparently is overcome under natural conditions by leaching of the inhibitors with rainwater. It is suggested that this dormancy operates as an adaptation strategy that delays germination by acting as a rain gauge. In this way, seed germination and subsequent seedling establishment are prevented during the early phase of the rainy period, which is usually interrupted by drought spells in the Mediterranean climate.
Molecular studies on osmoprimed seeds of cauliflower: a partial amino acid sequence of a vigour-related protein and osmopriming-enhanced expression of putative aspartic protease
Authors: Fujikura Yuzo , Karssen Cees M. 
Published: September 2008

AbstractA partial amino acid sequence of a vigour-related protein, V-1, from cauliflower (Brassica oleracea L.) seeds was obtained, after isolation by two-dimensional gel electrophoresis and gas-phase micro-sequencing. The sequence was found to have high homology to soybean seed maturation proteins. However, the position of the sequence in the V-1 polypeptide suggests that the V-1 and soybean proteins have different polypeptide structures. An osmoprimed seeds cDNA library was constructed and has been screened by a cDNA probe derived from the V-1 sequence. Two cDNA clones with high homology to aspartic protease (EC 3.4.23) from barley grain were isolated. The expression of putative aspartic protease mRNA was found to be enhanced by osmopriming, however the clones were found to have no significant sequence homology to the V-1.
Protease activities and elongation growth of excised cotton seed axes during the first 24 hours of imbibition
Authors: Vigil Eugene L. , Fang Tung K. 
Published: September 2008

AbstractExcised axes from cotton (Gossypium hirsutumL. cv. M-8, a double haploid) were imbibedin vitrofor 3,6,9,12,18 and 24 h. Data for length, fresh and dry weight and percentage water showed that excised axes undergo a triphasic pattern of growth: an initial burst, a short lag phase and then protracted rapid growth. Analysis of protein content with SDS-PAGE, and of activities of amino-, carboxy- and endopeptidases provided data indicating a direct correlation between major axis elongation growth between 12 and 24 h and enzymatic breakdown of storage proteins (especially those of 48 kDa) by carboxy- and endopeptidase. Data for axes imbibed at 30°C and 0–5°C for 12, 18 and 24 h indicated that a reduction in length and percentage moisture in the cold occurred in parallel with reductions in carboxy- and endopeptidase activities but not in ami-nopeptidase activity. The tentative conclusion is that carboxy- and endopeptidase are probably synthesizedde novoin the axis during imbibition and are important in initial breakdown of storage proteins for axial elongation growth.
Interactions of temperature and dormancy-relieving compounds on the germination of weed seeds
Authors: Carmona R. , Murdoch A.J. 
Published: September 2008

AbstractDormant weed seeds were germinated at constant and alternating temperatures using five chemicals. Germination ofChenopodium albumwhen expressed in normal equivalent deviates, increased linearly with the logarithm of chemical dose up to an optimal concentration. Ethephon (2-chloroethyl phosphonic acid) and sodium azide slightly stimulated germination ofC. albumseeds at 20°C while potassium nitrate, thiourea and azide each interacted positively with alternating temperatures (5°/25°C). Relief ofAvena fatuadormancy by azide exhibited a positive interaction with cool constant temperatures (3–10°C), and chemicals had smaller or no effects at higher and alternating temperatures. No chemical mixture, including that of nitrate, thlourea, ethephon, azide and hydrogen peroxide, promoted more germination than azide on its own inA. fatuaor nitrate together with ethephon inC. album. InC. album, this result arose largely because nitrate and azide antagonized each other in the presence of ethephon. Peroxide and thiourea together relieved this antagonism so that the fourth order interaction was positive. The negative interaction of nitrate, azide and ethephon inC. albumwas avoided in a sequential treatment with nitrate plus ethephon for seven days followed by sodium azide. Relief of dormancy by nitrate and ethephon was optimized at 67 mM nitrate with 1.4 mM ethephon forC. albumat 20°C and 20 mM nitrate with 1.4 mM ethephon forA. fatuaat 15°C. None of the chemicals used in this investigation stimulated the germination ofRumex crispusseeds. The results are discussed with respect to chemical control of soil seed banks.
Dormancy in white spruce (Picea glauca[Moench.] Voss.) seeds is imposed by tissues surrounding the embryo
Authors: Downie Bruce , Bewley J. Derek 
Published: September 2008

AbstractThe germination of intact, moist-chilled white spruce (Picea glauca[Moench.] Voss.) seeds and liquid–nitrogen–decoated (LN2), unchilled seeds is significantly more than of intact, unchilled seeds and intact, unchilled seeds exposed to LN2. The testa is largely responsible for imposition of dormancy in these seeds, although the megagametophyte and/or nucellus also play a role. One or both of these tissues undergoes significant weakening during moist chilling. Excised embryos from dormant and nondormant white spruce seeds elongate when placed on solid Murashige and Skoog minimal organics medium supplemented with a carbon source (sucrose, glucose or galactose), but elongate very little on medium without sugar. They are not killed by rapid imbibition on unsupplemented media. Thus, embryos of white spruce do not exhibit innate dormancy, but are dependent on a carbon source for elongation, and have dormancy imposed on them by their surrounding structures.
Comparative cytological and biochemical analysis of protein storage vacuoles from cotyledons and radicles of cotton seeds
Authors: Vigil E.L. , Fleming A.L. , Fang T. , Chaney N. , Wergin W. P. 
Published: September 2008

AbstractProtein storage vacuoles (PSVs) from radicles and cotyledons of dry cotton seeds were isolated by differential centrifugation following homogenization in glycerol. Protein complement analysis of isolated PSVs with one dimensional SDS-PAGE gels revealed similar major storage proteins, viz. 53 and 48 kDa, with differences in lower molecular mass proteins. Radicle PSVs have apparently more 35-kDa and less 22-kDa storage protein than do cotyledon PSVs. The mineral composition of whole radicles, cotyledons and isolated PSVs from radicles and cotyledons was determined by atomic absorption spectroscopy and colorimetric elemental analyses. The concentration of calcium (Ca), magnesium (Mg), potassium (K) and phosphate (P) was lower in isolated PSVs from radicles than from cotyledons, resulting in a marked difference in the Mg/Ca and (Mg+Ca)/K ratios in PSVs from these two sources. Analysis of radicle and cotyledon tissue from dry seeds for mineral distribution with EDX and scanning electron microscopy revealed major concentrations of Mg, K and P in PSVs. These observations indicate that PSVs in radicles are similar in protein and mineral composition to PSVs in cotyledons. PSVs in radicles have the potential function as storage organelles to provide minerals and nutrients for radicle growth during imbibition and germination.
Very low fluence and low fluence response in the induction and inhibition of seed germination in Celosia argentea
Authors: Dixit Sanjay , Amritphale Dilip 
Published: September 2008

AbstractSeeds of Celosia argentea L. displayed an absolute requirement for light for germination. Germination could be induced by far-red light as well as red light, and therefore, the effect of red light was not completely reversible by far-red light. A considerable proportion of the seed population was sensitive to red light within the range 0.01–0.1 μmol m−2, which suggested that phytochrome was operating in the very low fluence response mode. Seeds showed a gradual increase in germination in response to red light with an increasing duration of previous dark imbibition. Interruption of the dark imbibition period with very low fluence (10−4−10–1 μmol m−2) or low fluence (1–103 μmol m−2) red light prevented germination subsequent to a terminal, saturating red light irradiation. Increasing responsiveness to red light with increase in imbibition temperature and inhibition of development of photosensitivity by cycloheximide suggested that phytochrome synthesis occurred during the dark imbibition period. An absolute requirement for light for seed germination, inhibition of seed germination on interrupting the dark imbibition period with very low fluence or low fluence red light, and the recovery from photoinhibition of seeds in darkness are consistent with the hypothesis that PhyA is the principal phytochrome involved in the photoregulation of seed germination in C. argentea.
Effects of osmotic priming on dormancy and storability of tomato (Lycopersicon esculentumMill.) seeds
Authors: Liu Yongqing , Bino R. J. , van der Burg W. J. , Groot S. P. C. , Hilhorst H. W. M. 
Published: September 2008

AbstractFreshly harvested tomato (Lycopersicon esculentumMill, cv. Moneymaker) seeds were osmotically primed for 8 d in −1.0 MPa PEG-6000 solution and dried to about 6% water content for storage. Such so–called ‘fresh PEG priming’ enhanced seed germination and improved seedling performance as compared with the untreated control. Fresh PEG priming neither alleviated seed dormancy nor promoted DNA replication as was the case when seeds were dried upon harvest and subsequently primed in PEG (normal PEG priming). However, the addition of 10 μM GA4+7to the osmotic priming solution triggered replicative DNA synthesis of fresh-priming seeds and further enhanced the germination process. After 5 months of storage in ambient temperature conditions, fresh PEG-primed seeds maintained more positive effects gained from priming, whereas, normal PEG-primed seeds had lost the promoting effects on germination. Normal PEG-primed seeds were much more susceptible to controlled deterioration than fresh PEG-primed seeds. It is suggested that the advancement of germination is negatively correlated with seed storability. The mechanisms of seed priming in relation to nuclear replication activities and physical changes are discussed.
Partial predispersal seed predation in Lotus corniculatus L. (Fabaceae)
Authors: Ollerton Jeff , Lack Andrew 
Published: September 2008

AbstractPredispersal seed predation may have implications for plant population dynamics and the evolution of plant traits, but assessing the level of seed predation for an individual plant is not always straightforward. Seeds of Lotus corniculatus (Fabaceae) are often only partially eaten by a weevil seed predator, Apion loti. Samples of these seeds were tested for viability and subsequent seedling vigour. A large proportion of these damaged seeds were viable, and the resulting seedlings almost as vigorous as those from undamaged seeds. The ubiquity of these findings, and their ecological significance, is discussed.
Presence of dehydrin-like proteins and levels of abscisic acid in recalcitrant (desiccation sensitive) seeds may be related to habitat
Authors: Farrant Jill M. , Pammenter Norman W. , Berjak Patricia , Farnsworth Elizabeth J. , Vertucci Christina W. 
Published: September 2008

AbstractThe presence of dehydrins could not be demonstrated in axes of mature, undried recalcitrant seeds of the tropical wetland species Avicennia marina, Barringtonia racemosa, Bruguiera exaristata, Bruguiera cylindrica, Bruguiera gymnorrhiza, Ceriops tagal, Rhizophora apiculata, Rhizophora mucronata and Rhizophora stylosa, but were present in the temperate species Acer saccharinum, Aesculus hippocastanum, Araucaria angustifolia, Camellia sinensis, Castanea sativa, Poncirus trifoliata and Zizania palustris. They were also present in axes of Castanospermum australe (of tropical origin) seeds which underwent development in a temperate climate, and were produced in response to drying in axes of Barringtonia racemosa but not Avicennia marina. The presence of dehydrins was associated with high abscisic acid contents. These proteins may provide protection against low temperatures in temperate seeds and against water loss to which the seeds may be naturally exposed. The presence of dehydrins was unrelated to the evolutionary status of the families studied.
Observation of unique structures between the endosperm and embryo in seeds ofGlycine max
Authors: Yaklich R. W. , Wergin W. P. , Erbe E. F. 
Published: September 2008

AbstractOpenings are present on the inside surface of the endosperm cell wall adjacent to the developing cotyledon. The objective of this study was to determine if the openings were present during seed growth, maturation and imbibition by observing the inside surface of the endosperm with low temperature scanning electron microscopy. The openings were found to be present throughout seed development, maturation and imbibition. The openings were not formed by attachment to the cotyledon surface. However, the inner surface of the endosperm was occasionally attached to the surface of the embryo. At seed maturity, outgrowths on the cotyledon cell wall surface were embedded in the cell wall of the inside surface of the endosperm. These structures were also observed in the imbibing seed. These points of contact between the endosperm and embryo of soybean seeds may align the embryo, endosperm and seed coat during growth, desiccation and imbibition.
Germination characteristics of seeds differing in mass
Authors: Milberg P. , Andersson L. , Elfverson C. , Regnér S. 
Published: September 2008

AbstractGerminability and the rate of germination were related to seed mass inLithospermum arvenseL. andAnchusa arvensis(L.) Bieb. Prior to germination experiments, seeds from two populations of each species had been sorted into nine similarly sized groups according to their seed mass. Germinability varied greatly among the different seed-mass fractions inL. arvense, while differences were smaller inA. arvensis. Germination rate varied with seed mass in some cases. However, in many cases where clear patterns in the relationship between germination characteristics and seed mass were found, these patterns differed both between species and between populations. Furthermore, the character of the relationship varied depending on the experimental conditions used. It is hard to identify the cause of these relations since within- and between-plant variability can affect both seed mass and germination characteristics independently. It is concluded that the results of a germination test can differ depending on the seed mass fractions used, but that the magnitude and direction of such differences are difficult to foresee. Therefore, seed batches should be prepared with care, and experiments designed with awareness of the importance of the germination conditions chosen.
Effect of sowing date and harvest time on longevity of rice seeds
Authors: Rao N. Kameswara , Jackson M. T. 
Published: September 2008

AbstractChanges in germination ability and longevity were monitored during seed development in three japonica rice cultivars and one indica rice cultivar sown on three different dates, 14 October 1993, 24 November 1993 and 5 January 1994 at Los Baños, Philippines. Germinability of the seeds varied among cultivars in the early stages of development, but it was generally similar across sowing dates. The estimates of potential longevity (determined by storage at 40°C and 15% moisture and quantified by the values of the seed lot constant K1 of the viability equation) differed among cultivars and sowing dates. While the maximum potential longevity attained across different sowing dates was similar in the japonica cultivars Ju ku and Chianan 8, it was significantly higher in the first sowing than in the second or third sowings in cv. Akihikari. In the indica cultivar IR 58, maximum potential longevity attained in the second and third sowings was significantly greater than that in the first sowing. The mean potential longevity, averaged over cultivars and sowing dates, was marginally higher in the first sowing (K1=3.81) than in the second (3.65) and third (3.63); and averaged over cultivars and harvest times it was greatest at 34.8 days after flowering (DAF) in the first sowing, 31.8 DAF in the second and 28.3 DAF in the third. These results suggest that sowing in mid-October to allow seed ripening to coincide with the cooler and drier segment of the Los Baños dry season, and harvesting 35 DAF can improve the potential longevity of some japonica cultivars.
Role of the pigmented seed coat of proso millet (Panicum miliaceumL.) in imbibition, germination and seed persistence
Authors: Khan Mumtaz , Cavers Paul B. , Kane Marguerite , Thompson Ken 
Published: September 2008

AbstractProso millet (Panicum miliaceumL.) is both a crop and a weed in many parts of the world. The weedy biotypes exhibit a wide range of seed colours, but the strains with the most persistent seeds are distinguished by darker seeds. This paper compares the seed biology of a range of biotypes from Canada and demonstrates that darker seeds have heavier seed coats, imbibe and germinate more slowly, and suffer less imbibition damage (measured as electrolyte leakage). It is concluded that all these attributes contribute to the increased persistence in the soil of the dark-seeded weedy biotypes. Imbibition damage is widely implicated in poor emergence and low vigour of crop seeds, but has not previously been considered in the context of weed seed persistence.
The development of desiccation-sensitive seeds in Quercus robur L.: Reserve accumulation and plant growth regulators
Authors: Finch-Savage W. E. , Farrant Jill M. 
Published: September 2008

AbstractThe fruits of Quercus robur are shed containing seeds at high moisture contents which remain desiccation sensitive and exhibit recalcitrant storage behaviour. Little is known of the control of seed development in these and other recalcitrant seeds. In the present work the changing concentrations of four plant growth regulators during seed reserve accumulation was studied over five years on seeds from the same tree. The pattern of reserve accumulation and changing ABA content in seeds differed between years. Although ABA content in the cotyledons increased in line with increasing dry weight to different contents at shedding, similar concentrations existed in cotyledons in each year. Thus ABA did not appear to be influencing dry weight accumulation. However, unlike orthodox seeds the decline in ABA concentration prior to shedding was limited and consistent with a continuing role for ABA in preventing precocious germination. An earlier peak in ABA concentration was associated with greater desiccation tolerance at shedding across years. The concentrations of zeatin and zeatin riboside in cotyledons were similar in each year and declined during reserve accumulation in a similar fashion to that reported for orthodox seeds. By contrast, IAA concentration increased in both the cotyledons and axes in the latter stages of seed development, opposite to that reported for orthodox seeds. It is possible that the increasing IAA concentration in cotyledons and axes and the stable concentration of zeatin and zeatin riboside throughout the latter stages of development in the axes of Q. robur are linked to the maintenance of active metabolism for the rapid initiation of germination upon shedding observed in seeds of this species.
The effect of the initial rate of drying on the subsequent ability of immature seeds of Norway maple (Acer platanoidesL.) to survive rapid desiccation
Authors: Hong T. D. , Ellis R. H. 
Published: September 2008

AbstractThe viability of Norway maple seeds harvested at mass maturity (57.3% moisture content) was reduced from 100% to only 38% if dried rapidly (at 15% RH and 15°C for 3 days) to 4.7% moisture content. In contrast, slow drying for 32 days (the optimum duration of several investigated) to 29.9% moisture content enabled 93% of the seeds to survive subsequent rapid desiccation to 3.5% moisture content. This is similar to the 95% viability shown by seeds harvested 40 days after mass maturity and then dried rapidly to 4.4% moisture content. However, fruits or seeds harvested at mass maturity and then held moist for 21 days also showed 94 and 91% viability after subsequent rapid desiccation to 3.8 and 3.3% moisture content, respectively. Thus a post-ovule-abscission programme is required before Norway maple seeds are able to tolerate rapid enforced desiccation to low moisture contents, but loss in moisture during this period is not essential to the development of desiccation tolerance.
Oligosaccharides and galactosyl cyclitols in seed desiccation tolerance
Authors: Obendorf Ralph L. 
Published: September 2008

AbstractSoluble carbohydrates are one of multiple components required for the acquisition of desiccation tolerance during seed development and maturation. Sucrose and the raffinose series of oligosaccharides have been extensively studied in relation to seed desiccation tolerance. These galactosyl sucrose oligosaccharides are present in viable tissues of many edible seeds, especially the legumes, and contribute to flatulence after ingestion. A reduction in oligosaccharides of the raffinose series is desired by nutritionists but, if present at less than a threshold level, this this may result in reduced desiccation tolerance and storability of seeds. Some seeds that have very low amounts of raffinose and stachyose accumulate galactosyl cyclitols and small amounts of free cyclitols. Galactosyl cyclitols present in various seeds include galactosyl or methyl derivatives ofmyo-inositol, D-pinitol, D-chiro-inositol, D-ononitol, andscyllo-inositol. Castor bean seeds accumulate galactinol and buck-wheat seeds accumulate fagopyritol in addition to sucrose. Fagopyritol accumulation is associated with the acquisition of desiccation tolerance in buckwheat seeds. The galactosyl sucrose and galactosyl cyclitol soluble carbohydrates in maturing seeds have been proposed to have various roles in desiccation tolerance including non-toxic and non-reducing forms of seed storage products and intracellular osmotic agents contributing to the structural stability of organelles, membranes, enzymes and proteins, other macromolecules, and the glassy state. Ether derivatives of cyclitols may form liquid crystals. Methyl ether derivatives of cyclitols may have roles as cryoprotectants, desiccation protectants, and hydroxyl radical scavengers.