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Pengaruh Teknik Skarifikasi Fisik dan Media Perkecambahan terhadap Daya Berkecambah Benih Pala (Myristica fragrans) Texte intégral
2015
Febriyan, Dwi Gery | Widajati, Eny
<em>The objective of this experiment is studying the effect of physical scarification of nutmeg seed coat and germination media to accelerating germination rate and enhancing nutmeg seed viability. This experiment was conducted in December 2013 until May 2014 at Leuwikopo Experimental Field’s green house and Seed Laboratory of Agronomy and Horticulture Department, Faculty of Agriculture, Bogor Agricultural University. This experiment was using factorial randomize complete block design with 3 replications. The first factor was physical scarification on the seed coat with three levels: without scarification, one hole scarification on seed’s base, and two holes scarifications on seed’s base. The Second factor was the seed germination substrate that consist of sand, charcoal of husk rice, and mixture of sand and compost 1:1 (v/v). The results showed that two holes physical scarification could enhance germination process according to the earlier appearance of roots and shoot. Sand as the germinating substrate was observed as a better substrate according to the parameters of germinating potency and shoot height. Two holes physical scarification treatment which was sowed in sand substrate showed the increase of lateral root number into 6 lateral roots. Nutmeg seedling growth from sand substrate seedling showed a better growth than the charcoal of husk rice substrate seedling by evaluating these parameters on stem diameter, seedling’s height, amount of leaves, canopy’s width, and leaves colour.</em>
Afficher plus [+] Moins [-]Pengaruh Teknik Skarifikasi Fisik dan Media Perkecambahan terhadap Daya Berkecambah Benih Pala (Myristica fragrans) Texte intégral
2015
Febriyan, Dwi Gery | Widajati, Eny
The objective of this experiment is studying the effect of physical scarification of nutmeg seed coat and germination media to accelerating germination rate and enhancing nutmeg seed viability. This experiment was conducted in December 2013 until May 2014 at Leuwikopo Experimental Field’s green house and Seed Laboratory of Agronomy and Horticulture Department, Faculty of Agriculture, Bogor Agricultural University. This experiment was using factorial randomize complete block design with 3 replications. The first factor was physical scarification on the seed coat with three levels: without scarification, one hole scarification on seed’s base, and two holes scarifications on seed’s base. The Second factor was the seed germination substrate that consist of sand, charcoal of husk rice, and mixture of sand and compost 1:1 (v/v). The results showed that two holes physical scarification could enhance germination process according to the earlier appearance of roots and shoot. Sand as the germinating substrate was observed as a better substrate according to the parameters of germinating potency and shoot height. Two holes physical scarification treatment which was sowed in sand substrate showed the increase of lateral root number into 6 lateral roots. Nutmeg seedling growth from sand substrate seedling showed a better growth than the charcoal of husk rice substrate seedling by evaluating these parameters on stem diameter, seedling’s height, amount of leaves, canopy’s width, and leaves colour.
Afficher plus [+] Moins [-]Pericarp structure of Glebionis coronaria (L.) Cass. ex Spach (Asteraceae) cypselae controls water uptake during germination Texte intégral
2015
Puglia, Giuseppe | Grimaldi, Simona | Carta, Angelino | Pavone, Pietro | Toorop, Peter
Glebionis coronaria (L.) Cass. ex Spach is a common Mediterranean weed producing distinctive central and peripheral dormant cypselae with a hard fruit coat, which was previously hypothesized to impose physical dormancy. Analysis of water uptake in cypselae and in naked seeds showed that it preferentially takes place at the basal end of the fruit; however, seeds within an intact pericarp do not fully imbibe when compared with naked seeds. Germination was not significantly different between the two heteromorphs, and afterripening or cold stratification did not increase germination, while warm stratification at 35/20°C, as revealed by logistic regression, resulted in a significant improvement. However, loss of viability was also rapid at these high temperatures. Central and peripheral cypselae generally showed very low germination. In both heteromorphs, faster and higher germination (60–70%) was reached only after extensive scarification of pericarp tissue, and full germination was observed only after complete removal of pericarp tissue. Although the pericarp significantly reduced water uptake, no palisade layer(s) of macrosclereids could be observed. Xylem-vessel elements were found running through the basal end of the pericarp and forming the main point of water entry. We reject the hypothesis that G. coronaria cypselae have physical dormancy. Instead, water uptake and germination are impeded by: (1) directed water uptake, mainly through a pericarp-spanning channel-like structure; and (2) mechanical constraint on embryo growth exerted by the hard pericarp. The channel-like structure forms the principal system for controlling seed germination.
Afficher plus [+] Moins [-]Inter- and intra-specific variability in seed dormancy loss and germination requirements in the Lavatera triloba aggregate (Malvaceae) Texte intégral
2015
Santo,Andrea | Mattana,Efisio | Bacchetta,Gianluigi
Background and aims – The genus Lavatera is comprised of perennial and annual species that grow in different ecosystems such as coastal cliffs, plains, endorheic lagoons and ditches. In this study, we compared the seed germination ecology of three phylogenetically related taxa: L. agrigentina, L. triloba subsp. pallescens and L. triloba subsp. triloba, all of which belong to the L. triloba aggregate (section Glandulosae ) and grow on chalky plains, limestone cliffs and endorheic lagoons with clayey sediments. Methods – For each taxon, the effects of seed scarification and dry after-ripening (90 days at 25°C) on seed dormancy loss and of light and temperature (constant 5 to 25°C and alternating 25/10°C) on seed germination were evaluated. Key results – Scarification allowed water imbibition and subsequent seed germination, indicating physical dormancy (PY) for all three investigated taxa. In addition, dry after-ripening positively affected seed germination in L. agrigentina, thus, seeds of this species have combinational dormancy [physical (PY) + physiological (PD)]. Light did not affect the final germination in any of the taxa. The germination response to incubation temperatures varied among the taxa, suggesting ecological adaptations, with the highest germination in the range of 10–20°C for L . agrigentina and L. triloba and 5–15°C for L. pallescens . Interpopulation variability in final germination was detected for both L. agrigentina and L. triloba subsp. triloba and in germination rate only for L. agrigentina . Conclusions – The three Lavatera taxa differed in their germination requirements, and these could be related to the habitat/ecology of each taxon. Our results suggest that seeds of the three taxa can germinate in the field from autumn to spring, when conditions are favourable for seedling establishment in the Mediterranean climate.
Afficher plus [+] Moins [-]Hot water treatment for improving germination in Melochia corchorifolia Texte intégral
2015
Pandey, Chitra Devi | Pandey, Sushil
Melochia corchorifolia seeds collected from Odisha were tested for germination before conserving in genebank, exhibited physical dormancy due to hard seededness. In order to determine the most suitable method to reduce the hard seeds and promote rapid and uniform germination, seeds were subjected to hot water treatment at different temperatures and duration. Soaking seeds in water at 70°C for 10 min. was found most effective in breaking dormancy and on an average, germination increased from 7 to 96% in two genotypes. Besides germination, seedling vigour, vigour index and electrolyte leakage were also noticed significantly higher in the treated seeds than in untreated seeds.
Afficher plus [+] Moins [-]Germination of selected African leafy vegetables in response to different dormancy pre-sowing treatments Texte intégral
2015
Slabbert, M. M. | Motsa, M. | Van Averbeke, W.
When the cultivation of weedy species is being considered, knowledge of seed dormancy is important, because dormancy impedes timing and extent of seed germination. In this study the effect of dormancy on seed germination of eight selected African leafy vegetables was investigated. The objective was to determine whether these vegetables had any form of seed dormancy and if so, whether pre-sowing treatments could break seed dormancy. The different factors associated with seed dormancy that were investigated included:- 1) physical barriers, such as hardness of the seed coat; (2) physiological dormancy, such as the effect of temperature (thermodormancy) and light (photodormancy) on embryo differentiation and development; and (3) chemical dormancy, such as the presence of chemical inhibitors in the seed cotyledons. Fresh, mature seeds of Amaranthus cruentus, Brassica rapa subsp. chinensis, Citrulus lanatus, Cleome gynandra, Corchorus olitorius, Cucurbita maxima, Solanum retroflexum and Vigna unguiculata were studied, whilst Beta vulgaris var. cicla served as the reference crop. The findings showed that A. cruentus, B. rapa subsp. chinensis, C. gynandra and S. retroflexum exhibited some form of physical, embryo or physiological dormancy within their seed. Scarification improved onset and final germination of A. cruentus and B. rapa subsp. chinensis seed, whilst pre-chilling improved the germination of A. cruentus. Soaking seed in KNO3 improved both onset and final germination of B. rapa subsp. chinensis and S. retroflexum.
Afficher plus [+] Moins [-]Seed storage-mediated dormancy alleviation in Fabaceae from campo rupestre Texte intégral
2015
Naïla Nativel | Elise Buisson | Fernando Augusto Oliveira Silveira
ABSTRACTWe studied the effects of seed storage on germination and dormancy alleviation in three species of Fabaceae endemic to campo rupestrein southeastern Brazil. Fresh seeds of Collaea cipoensis, Mimosa maguirei and Mimosa foliolosawere set to germinate and germination of seeds after four, five and 13 years of storage was tested. Seed viability was maintained for all species after the full storage period. Seed storage significantly increased germination percentage and decreased germination time for C. cipoensisand M. foliolosa, suggesting the alleviation of physical dormancy with storage. However, we did not find evidence of dormancy alleviation in M. maguirei since stored seeds showed a decrease in germination in comparison to that of fresh seeds. Our data indicate species-specific storage-mediated dormancy alleviation, which will have important implications for restoration of campo rupestre.
Afficher plus [+] Moins [-]GERMINAÇÃO E MORFOLOGIA DE SEMENTES E PLÂNTULAS DE Albizia edwallii (Hoehne) Barneby & J. W. Grimes Texte intégral
2015
MANOELA MENDES DUARTE | JAÇANAN ELOÍSA DE FREITAS MILANI | CHRISTOPHER THOMAS BLUM | ANTONIO CARLOS NOGUEIRA
This study aimed to characterize the morphology of seeds and seedlings and evaluate the germination of seeds of Albizia edwallii submitted to different substrates and temperatures. In physical characterization were evaluated thousand seed weight, the number of seeds per kilogram and moisture content. To determine the morphological characteristics, it was evaluated the biometry of 50 seeds, as well as its internal and external characteristics. Germination was conducted at three temperatures (20 ° C, 25 ° C and 30 ° C) and three substrates (sand, vermiculite and blotting paper) with five replications of 40 seeds per treatment, in a factorial 3 x 3 and completely randomized design. The variables were germination percentage, germination rate index, mean germination time, and synchronization index. The thousand seed weight was 47.7 g, while the number of seeds per kilo was 20.964 for the moisture content of 13.1%. The seeds have an elliptical shape, no endosperm and have persistent funiculus. Germination is epigeal, and the seedling is phanerocotylar being fully formed at 15 days. Temperatures of 20 ° C and 25 ° C provide the highest germination rates, 42 and 38%, respectively, and germination speed index (GSI). The use of sand as a substrate provided better germination percentage than the other substrates. Thus, it is recommended to use sand as a substrate and temperatures of 20 ° C and 25 ° C in A. edwalli germination tests.
Afficher plus [+] Moins [-]Profile of the contents of different forms of soybean isoflavones and the effect of germination time on these compounds and the physical parameters in soybean sprouts Texte intégral
2015
Quinhone, A. | Ida, E.I.
The aim of this study was to evaluate the profile of the contents of different forms of soybean isoflavones and the effect of germination time on these compounds and the physical parameters in BRS 284 soybean sprouts. Soybean seeds were germinated for 168h, and the sprouts were collected every 24h. The physical parameters and contents of different forms of isoflavones of the seeds and soybean sprouts were evaluated, and the data were subjected to regression analysis. The soybean seeds contained 26.0% β-glucosides, 72.9% malonylglucosides and 1.2% aglycones. The yield of soybean sprouts was 632.4%. The effect of germination time was quadratic on the length, moisture and on the daidzin, genistin and genistein content; linear on the fresh weight and on the malonyldaidzin content. The dry matter and malonylglycitin content was constant, and glycitin and glycitein were not detected in the soybean sprouts.
Afficher plus [+] Moins [-]Geobacillus stearothermophilus ATCC 7953 spore chemical germination mechanisms in model systems Texte intégral
2015
Georget, Erika | Kushman, Asel | Callanan, Michael | Ananta, Edwin | Heinz, Volker | Mathys, Alexander
Bacterial endospores through their strong resistance to both chemical and physical hurdles constitute a risk for food industry. Inactivation strategies are based on thermal and/or chemical treatments but rely on incomplete knowledge of the mechanisms of inactivation. Alternative strategies were suggested to achieve food safety while improving product quality. One of them relies on the successive germination and inactivation by pasteurization of bacterial spores. However, to date, a gap of knowledge on bacterial spore germination remains and hinders such an application for food sterilization. Geobacillus stearothermophilus ATCC 7953 spore germination mechanisms were investigated by in situ fluorometry combined with plate counts. G. stearothermophilus spores' inner membrane was stained with Laurdan fluorescent dye. While nutrient pathways showed no strong germination with the combinations tested, successful germination up to 3 log10 could be achieved using 60 mmol l−1 calcium-dipicolinic acid (CaDPA) at 55 °C for 2 h. A model for the CaDPA germination mechanism in two phases could be derived which suggested a potential key role of cortex fragments in the germination path, before completion of the cortex degradation. Additionally, it was confirmed that the germination potential of CaDPA, which does not rely on nutrient receptors, is a widespread germination trigger across spore formers. Understanding germination mechanisms and the limitations of different germination paths is important for the development of multi-hurdle approaches to achieve commercial sterility with reduced thermal load.
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