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Overcoming seed dormancy of mooseer (Allium hirtifolium) through cold stratification, gibberellic acid, and acid scarification Полный текст
2012
Dashti, Farshad | Ghahremani-Majd, Hojat | Esna-Ashari, Mahmood
Mooseer (Allium hirtifolium Boiss.) is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we evaluated four treatments: sulfuric acid scarification, sandpaper scarification, cold stratification, and gibberellic acid (GA₃) application. In the second experiment, we evaluated combinations of these treatments. All treatments in the first experiment had no effect on seed germination, suggesting that mooseer seeds have physical and physiological dormancy. In the second experiment, the highest germination percentage (86.6%) was observed after five minutes scarification with sulfuric acid (75% v/v), followed by 60 days of cold stratification. Duration of sulfuric acid scarification (5, 10, and 20 min) did not affect germination rates, but increasing duration of cold stratification (from 15 to 60 days), increased germination from 28.3% to 86.6%. Our study showed that mooseer seeds have both physical and physiological dormancy.
Показать больше [+] Меньше [-]Farmers' Seed Sources and Seed Quality: 1. Physical and Physiological Quality Полный текст
2012
Bishaw, Z. (Zewdie) | Struik, P. C. | Gastel, A. J. G. van
Understanding farmers' seed quality problem will enable farmers to devise strategies to improve quality at the farm level. The study was conducted to assess the quality of seed used by farmers from different sources and regions. A total of 304 wheat (Trticium aestivum L. and T. durum L.) seed samples from Ethiopia and 206 wheat and 200 barley (Hordeum vulgare L.) seed samples from Syria were collected from major wheat and barley growing regions to investigate the quality of seed obtained from various sources and regions and planted by farmers. A 1 kg sample was drawn from seed lots intended for planting from each farmer. A detailed questionnaire was used to collect information on seed selection and management practices and farmers' perception of seed quality. The physical and physiological quality of seed samples was analyzed using standard testing procedures. In Ethiopia, the mean physical purity and germination of wheat seed was 98.92% and 96%, respectively, and the majority of samples (93%; n = 303) met the minimum purity and germination standards for certified seed 2. Certified seed from the formal sector seed had the highest analytical purity (99.4%), but this was not significantly different from other seed sources, such as neighbors/other farmers (98.8%), local traders/markets (98.6%), or own saved seed (98.9%). However, the mean germination for certified seed (96%) showed a weak significant difference from seed obtained from other sources (94%). In Syria, mean physical purity and germination for wheat was 97.6% and 88%, respectively, and for barley 95.5% and 86%, respectively. Seed quality was better in wheat than in barley. The majority of wheat seed samples, i.e., 70.4% (n = 206) for physical purity and 78.2% for germination, met the minimum seed quality requirements of certified seed 2. In barley, only 10% of samples for physical purity and 72% of samples for germination met this standard. Contamination with weed seeds appeared to be the major constraint for seed samples not meeting the standard of formal sector. There was no significant difference in physical and physiological quality of wheat seed samples obtained from different sources. In barley, germination from different sources was significantly different. Highly significant differences in seed quality were observed for seed samples collected from different regions and districts for wheat and barley crops in both countries. Vigor indices showed significant differences among wheat and barley seed samples from different regions and districts, but not among different sources. Simple correlation coefficients showed significant relationships among vigor tests. The standard germination, speed of germination, and seedling root length were well correlated with field emergence in wheat and barley in both countries. Farmers used local seed management practices, such as seed selection, cleaning, treatment, or separate storage to improve or maintain seed quality. A large number of seed samples managed differently by farmers met the minimum physical purity and germination standard for certified seed 2, producing seed comparable to those from the formal sector. It is imperative that national seed polices equally recognize the role of both formal and informal sectors and provide support to create an integrated seed system catering to the needs of a diverse group of farmers.
Показать больше [+] Меньше [-]Effects of Pinus pinea litter on seed germination and seedling performance of three Mediterranean shrub species Полный текст
2012
Valera-Burgos, Javier | Díaz-Barradas, Mari Cruz | Zunzunegui, María
Pinus pinea L. is a coniferous tree inhabiting the Mediterranean Basin, which appears widely distributed in the Iberian Peninsula, frequently associated to Mediterranean shrub species, such as Cistus salvifolius L., C. libanotis L. and Halimium halimifolium (L.) Willk. (Cistaceae). This study investigated the effects (chemical and physical) of P. pinea needles on the seed germination and early growth of these three shrub species. Laboratory experiments were carried out in order to assess an expected negative effect by using different treatments to seeds (physical layer and two aqueous extracts concentrations). Seed germination of all species was inhibited when treated with aqueous extracts and the degree of inhibition was higher when using the extract with the highest concentration, while no effect was observed with the physical layer treatment. Seedling performance was also sensitive to the different treatments, showing the most stressed values with the high concentration extract. The results from this study highlight the importance of allelopathy of P. pinea needles as a mechanism for controlling seed germination and seedling performance of some Mediterranean shrub species.
Показать больше [+] Меньше [-]In vitro zygotic embryo culture of Pinus peuce Gris.: optimization of culture conditions affecting germination and early seedling growth Полный текст
2012
Stojičić, D., Faculty of Sciences and Mathematics, Niš (Serbia) | Janošević, D., Faculty of Biology, Belgrade (Serbia). Institute of Botany and Botanical Garden Jevremovac | Uzelac, B., Institute for Biological Research Siniša Stanković, Belgrade (Serbia) | Čokeša, V., Institute of Forestry, Belgrade (Serbia) | Budimir, S., Institute for Biological Research Siniša Stanković, Belgrade (Serbia)
This study reports a protocol for the germination and early seedling growth of Pinus peuce Gris. using zygotic embryo culture. In order to overcome seed dormancy and optimize organogenesis, the effect of nutritional, plant growth regulatory and physical factors on in vitro germination and growth of isolated mature zygotic embryos of Pinus peuce were investigated.
Показать больше [+] Меньше [-]In vitro zygotic embryo culture of Pinus peuce Gris.: Optimization of culture conditions affecting germination and early seedling growth Полный текст
2012
Stojičić Dragana | Janošević Dušica | Uzelac Branka | Čokeša V. | Budimir Snežana
This study reports a protocol for the germination and early seedling growth of Pinus peuce Gris. using zygotic embryo culture. In order to overcome seed dormancy and optimize organogenesis, the effect of nutritional, plant growth regulatory and physical factors on in vitro germination and growth of isolated mature zygotic embryos of P. peuce were investigated.
Показать больше [+] Меньше [-]Distillery Spentwash as an Effective Liquid Fertilizer and Alternative Irrigation Medium in Floriculture Полный текст
2012
S. Chandraju | C. Thejovathi | C. S. Chidan Kumar
Germination growth and yields of Aster (Asteraceae) and Daisies (Asteraceae)flowering plants were made by irrigated with distillery spentwash of different concentrations.Diluted spentwash (1:1, 1:2, and 1:3) were analyzed for plant nutrients such as nitrogen,phosphorous, potassium and other physical and chemical characteristics. Experimental soil wastested for its chemical and physical parameters. Aster and Daisies seeds were sowed indifferent pots and irrigated with raw water (RW), 1:1, 1:2 and 1:3 spentwash. The nature ofgermination growth and yields of seeds was studied. It was found that, the germination growthand yields was very good (100%) in 1:3 SW irrigation, while very poor (25%) in 1:1 SW,moderate (80%) in 1:2 SW and 95% in RW irrigation.
Показать больше [+] Меньше [-]Water absorption and dormancy-breaking requirements of physically dormant seeds of Schizolobium parahyba (Fabaceae – Caesalpinioideae) Полный текст
2012
de Souza, Thaysi Ventura | Voltolini, Caroline Heinig | Santos, Marisa | Silveira Paulilo, Maria Terezinha
Physical dormancy refers to seeds that are water impermeable. Within the Fabaceae, the structure associated with the breaking of dormancy is usually the lens. This study verified the role of the lens in physical dormancy of seeds of Schizolobium parahyba, a gap species of Fabaceae from the Atlantic Forest of Brazil. The lens in S. parahyba seeds appeared as a subtle depression near the hilum and opposite the micropyle. After treatment of the seeds with hot water, the lens detached from the coat. Blocking water from contacting the lens inhibited water absorption in hot-water-treated seeds. High constant (30°C) and alternating (20/30°C) temperatures promoted the breaking of physical dormancy and germination in non-scarified seeds. Maximum percentage of germination occurred earlier for seeds incubated at 20/30°C than for those incubated at 30°C. Seeds with a blocked lens did not germinate at alternating or high temperatures. This study suggests that alternating temperatures are probably the cause of physical dormancy break of seeds of S. parahyba in gaps in the forest.
Показать больше [+] Меньше [-]Tanned or burned: The role of fire in shaping physical seed dormancy Полный текст
2012
Moreira, Bruno | Pausas, J. G.
8 páginas, 3 figuras, 3 tablas. | Plant species with physical seed dormancy are common in mediterranean fire-prone ecosystems. Because fire breaks seed dormancy and enhances the recruitment of many species, this trait might be considered adaptive in fire-prone environments. However, to what extent the temperature thresholds that break physical seed dormancy have been shaped by fire (i.e., for post-fire recruitment) or by summer temperatures in the bare soil (i.e., for recruitment in fire-independent gaps) remains unknown. Our hypothesis is that the temperature thresholds that break physical seed dormancy have been shaped by fire and thus we predict higher dormancy lost in response to fire than in response to summer temperatures. We tested this hypothesis in six woody species with physical seed dormancy occurring in fire-prone areas across the Mediterranean Basin. Seeds from different populations of each species were subject to heat treatments simulating fire (i.e., a single high temperature peak of 100uC, 120uC or 150uC for 5 minutes) and heat treatments simulating summer (i.e., temperature fluctuations; 30 daily cycles of 3 hours at 31uC, 4 hours at 43uC, 3 hours at 33uC and 14 hours at 18uC). Fire treatments broke dormancy and stimulated germination in all populations of all species. In contrast, summer treatments had no effect over the seed dormancy for most species and only enhanced the germination in Ulex parviflorus, although less than the fire treatments. Our results suggest that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as a response to summer temperatures. The high level of dormancy release by the heat produced by fire might enforce most recruitment to be capitalized into a single post-fire pulse when the most favorable conditions occur. This supports the important role of fire in shaping seed traits. | We thank the authorities from the Parque Natural del Carrascal de la Font Roja and Fundación Caja Castellón-Bancaja (Barranc dels Horts, Ares del Maestrat) for permission to collect seeds in these areas. We also thank C¸ . Tavsanoglu for his collaboration in the seed collection and germination experiment and J. Baeza for providing soil temperature data for the Ayora site (Fig. 1). | Peer reviewed
Показать больше [+] Меньше [-]FENOLOGIA, MORFOLOGIA E ANÁLISE DE SEMENTES DE Apuleia leiocarpa (Vogel) J. F. Macbr. Полный текст
2012
Marciele Felippi | Charles Rodrigo Belmonte Maffra | Edison Bisognin Cantarelli | Maristela Machado Araújo | Solon Jonas Longhi
In order to add knowledge regarding to Apuleia leiocarpa (Vogel) J. F. Macbr., it was analyzed its time offlowering and fruiting, fruit morphology, seed germination, seedling and changes, as well as its physical characteristics, germination and emergence of seeds of different trees. From the selectionof20 mother trees, observations were made monthly in order to ascertain the presence of flowers and fruits After maturation, the fruits were collected, the seeds extracted from fruits, processed and separated by matrix, from which samples were taken for the determination of weight, moisture content, germination tests and emergency conditions in laboratory and nursery. Copies of fruits and seeds were stored in 70 % ethanol for the latermorphological description. The greater presence of Apuleia leiocarpa flowers occurred fromSeptember to October and fruits from January to March, with a variation in the time and frequency of mother trees i both clones as well as the estimated amount of fruits and seeds in each year. Morphologically, the fruit is simple, indehiscent pod and dry, with 1-2 seeds, which are brown in color with visible linear scar, micropyleand raphe undeveloped near the hilum. Internally, the seed is albuminous, with axial embryo, spatulate,occupying three quarters of the inner region, with large and foliaceous cotyledons. The germination is epigeal and the seedling phanerocotyledonal. The fruit length ranged from 1.45 to 3.01 cm, width from 1.20to 2.07 cm and thickness from 0.20 to 0.30 cm. For the seeds, 1.2 to 2.1 cm long, 0.6 to 0.95 cm wide and 0.1 to 0.2 cm thick. There were differences between the parent trees for the physical and physiological tests, where the number of seeds per kilogram ranged from 8,713 to 11,197, the moisturecontent from 12.43 to 27. 97 % germination 13 to 96 % and the emergengc from 26 to 88 %. It was concludedthat seeds from individuals of the same population have significant physical and physiological variations, either because of environmental or genetic factors or due to the micro habitat. Thus, although providing better genetic representation, they reduce the homogeneity of the seed lots.
Показать больше [+] Меньше [-]Effect of storage temperature and dormancy-breaking treatments on seed germination, moisture content and seed vigor in gum karaya (Sterculia urens Roxb.) Полный текст
2012
Subhashini Devi, P. | Satyanarayana, B. | Arundhati, A. | Raghava Rao, T.
Sterculia urens is a commercially important tree with wide applications. Although it reproduces by seed, its germination requirements are not known. The seed also suffers with dormancy. The present study is an attempt to understand the proper storage conditions and also the type of dormancy in seeds of Sterculia urens . The optimum temperature for storage of seeds was found to be 0–4°C in a polythene bag which retained the required moisture content of seed for germination. The treatment with phytohormones showed maximum increase in germination percentage followed by acid and mechanical scarification, suggesting both physical and physiological dormancy in seeds of Sterculia urens .
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