Seed Germination Behavior Research Articles

Seed germination of Caragana species from different regions is strongly driven by environmental cues and not phylogenetic signals

Seed germination behavior is an important factor in the distribution of species. Many studies have shown that germination is controlled by phylogenetic constraints, however, it is not clear whether phylogenetic constraints or environmental cues explain seed germination of a genus from a common ancestor. In this study, seed germination under different temperature- and water-regimes [induced by different osmotic potentials of polyethylene glycol (PEG)] was investigated in the phylogenetically-related Caragana species that thrive in arid, semiarid, semihumid and humid environments. The results showed that the final percentage germination (FPG) decreased from 95% in species from arid habitats to 0% in species from humid habitats, but with no significant phylogenetic signal. Rather, the response of seed germination to temperature and PEG varied greatly with species from arid to humid habitats and was tightly linked to the ecological niche of the species, their seed coat structure and abscisic acid concentration. The findings are not consistent with the hypothesis that within a family or a genus, seed germination strategies can be a stable evolutionary trait, thus constraining interspecific variation, but the results clearly show that seed germination of Caragana species distributed across a range of habitats has adapted to the environment of that habitat.

Canalization of Seasonal Phenology in the Presence of Developmental Variation: Seed Dormancy Cycling in an Annual Weed.

Variation in the developmental timing in one life stage may ramify within and across generations to disrupt optimal phenology of other life stages. By focusing on a common mechanism of developmental arrest in plants-seed dormancy-we investigated how variation in flowering time influenced seed germination behavior and identified potential processes that can lead to canalized germination behavior despite variation in reproductive timing. We quantified effects of reproductive timing on dormancy cycling by experimentally manipulating the temperature during seed maturation and the seasonal timing of seed dispersal/burial, and by assessing temperature-dependent germination of un-earthed seeds over a seasonal cycle. We found that reproductive timing, via both seed-maturation temperature and the timing of dispersal, strongly influenced germination behavior in the weeks immediately following seed burial. However, buried seeds subsequently canalized their germination behavior, after losing primary dormancy and experiencing natural temperature and moisture conditions in the field. After the complete loss of primary dormancy, germination behavior was similar across seed-maturation and dispersal treatments, even when secondary dormancy was induced. Maternal effects themselves may contribute to the canalization of germination: first, by inducing stronger dormancy in autumn-matured seeds, and second by modifying the responses of those seeds to their ambient environment. Genotypes differed in dormancy cycling, with functional alleles of known dormancy genes necessary for the suppression of germination at warm temperatures in autumn through spring across multiple years. Loss of function of dormancy genes abolished almost all dormancy cycling. In summary, effects of reproductive phenology on dormancy cycling of buried seeds were apparent only as long as seeds retained primary dormancy, and a combination of genetically imposed seed dormancy, maternally induced seed dormancy, and secondary dormancy can mitigate variation in germination behavior imposed by variation in reproductive phenology.

Impacts of Host Trees and Sowing Conditions on Germination Success and a Simple Ex Situ Approach to Generate Symbiotic Seedlings of a Rare Epiphytic Orchid Endemic to Hainan Island, China

For species relying on seeds for population regeneration, knowledge on seed germination behaviors in relation to environmental factors is critical in designing species recovery strategy. Dendrobium sinense is an orchid endemic to Hainan Island of China and listed as Endangered by the IUCN Redlist. It reproduces primarily via seeds in its natural habitat. However, how germination is impacted by major environmental factors is poorly known. This study aimed to examine germination success of D. sinense seeds using two approaches, i.e. in situ and ex situ, using host tree barks as germination media. The latter was intended to generate symbiotic seedlings in a simple and economic approach which could be used for reintroduction efforts. In addition, three factors of in situ symbiotic seed germination success, including different sowing time, location (distance from an adult plant), and host tree were investigated. Our results showed that seeds sown ex situ and in situ in July had the highest rates of germination. Seed germination was significantly higher ex situ using bark as medium than in situ. Seeds sown directly on Rhododendron moulmainense, the most common host tree, with naturally occurring conspecific orchids had the highest rate of germination. In contrast, ex situ seeds sown on the bark of Cyclobalanopsis blakeii, a non-host species, had the highest rate of seed germination. In situ a positive correlation was found between the seed germination rate and the distance of the seeds from the adult D. sinense. Based on these results, it is likely seedling recruitments are determined by host tree species, the presence of and the distance from an adult conspecific orchid, which imply the importance of the mycorrhizal fungi, which were not reported here. This study provided important information on the optimal environmental conditions for population augmentation and reintroduction, which can be used as part of the species recovery strategy.

An overview of magnetic field exposure on germination behavior of seeds under saline stress

An overview of magnetic field exposure on germination behavior of seeds under saline stress

Managing glyphosate-resistant common ragweed (Ambrosia artemisiifolia): effect of glyphosate-phenoxy tank mixes on growth, fecundity, and seed viability

Common ragweed is one of the most important weeds in the soybean-producing areas of the United States and Canada. Recently, glyphosate-resistant (GR) biotypes have been reported in 15 states and one Canadian province. Reducing the proliferation of GR common ragweed biotypes is complicated by the high fecundity and complex seed germination behavior exhibited by this species. An experiment was conducted to evaluate the efficacy of late herbicide applications for reducing seed production, seed weight, and seed viability of a GR common ragweed biotype. Herbicide treatments included: water control, glyphosate, 2,4-D, dicamba, 2,4-D plus glyphosate, and dicamba plus glyphosate. Treatments were applied at the appearance of male flower buds (Biologische Bundesanstalt, Bundessortenamt and Chemical industry scale [BBCH] 51) or at the early female flowering stage (BBCH 61 to 63). At BBCH 51, 2,4-D or dicamba applied alone or in a tank mix with glyphosate reduced seed production by an average of 80%. Conversely, seed production following these same treatments applied at BBCH 61 to 63 was not significantly different from when glyphosate was applied alone. At this stage of development, all herbicide treatments reduced seed viability relative to the control; however, treatments containing 2,4-D or dicamba resulted in significantly lower viability than when glyphosate was applied alone. These results suggest that the application of tank mixes containing 2,4-D or dicamba have the potential to limit seed production of GR common ragweed when applied on or before BBCH 51. The development of new technologies that facilitate the in-crop application of tank mixes containing 2,4-D or dicamba may therefore be an effective option for limiting population establishment, seedbank replenishment, and future spread of glyphosate-resistant alleles.

Impact of fertilizer priming on seed germination behavior and vigor of maize

Laboratory experiments were conducted to examine the efficacy of fertilizer priming on seed germination behavior and vigor of two maize cultivars “Azam and Phari” at Agronomy Research Laboratory, University of Agriculture, Peshawar- Pakistan during 2015. Studied treatments include hydropriming (distilled water) and osmopriming with Calcium Ammonium Nitrate (CAN) at 0.5% for 24 hours. Non primed seed were used as control. Data were recorded on germination and vigor parameters according to standard procedures. Results showed that both hydro and osmo-priming significantly improved germination %, mean germination time, germination index, plumule and radical length, seedling fresh and dry weight of both cultivars as compared to control treatment. Cultivar Azam performed better in all germination and vigor attributes than Phari. It was concluded that both hydro and osmopriming with Calcium Ammonium Nitrate (CAN) at 0.5% for 24 hours are practical approaches for improving growth and vigor of maize crop under harsh environment.

Effects of environmental stress on seed germination and seedling growth of Salsola ferganica (Chenopodiaceae)

Plant growth and development are usually influenced by salt, drought, high or low temperature, strong illumination and other adverse factors, which may finally threaten the settlement and propagation of the species. Studies on seed germination behavior and seedling growth of annual halophyte plant living in harsh environment can help us to thoroughly understand the tolerance mechanism of desert plants. Salsola ferganica, an annual halophyte living in extreme desert habitat, has special morphological structure and characteristics in tolerance of stress. In the present study, we discussed the effects of different stress conditions, such as light, day/night temperature variation, salt (NaCl) and drought (PEG 6000), etc. on seed germination (SG) and seedling growth (SGr) of S. ferganica. Results showed that: (1) Light had a positive effect, while darkness had a negative effect on SG, which indicates that seed germination of S. ferganica depends on and is sensitive to light. (2) Monthly examination of SG from 2014 to 2015 showed that SG of seed without winged perianth (NWP) was apparently higher than seed with winged perianth (WWP) stored at room temperature (RT) or 4°C. For WWP seeds, SG in light was significantly higher than that in darkness; SG also varied among seasons: in Spring, SG of seeds stored at RT was the lowest and so did it in summer with seeds stored at 4°C. SG of seeds stored at both temperatures had no significant difference at the same month. Seed vigor agreed with SG behavior partly and there was no obvious difference between months. (3) The day/night temperature variation (D/NTV) applied significant effect on SG and SGr. SG decreased at lower D/NTV (e.g. 5°C/15°C) but increased at middle and higher D/NTV (e.g. 10°C/20°C, 15°C/25°C, 20°C/30°C) in light. In darkness, the SG decreased at higher D/NTV (e.g. 15°C/25°C, 20°C/30°C) but increased at lower and middle D/NTV (e.g. 5°C/15°C, 10°C/20°C). 10°C/20°C D/NTV had positive effect on SG in both light and darkness; germination rate was promoted at higher D/NTV in both light and darkness. SGr was promoted at lower D/NTV while inhibited at higher D/NTV. (4) SG at lower concentration of NaCl (<100mmolL−1, osmotic pressure (OP)≥−500kPa) and PEG (<150gL−1, OP≥−300kPa) was similar to the control (OP 0kPa); however SG at higher concentration of NaCl (≥500mmolL−1, OP<−2478kPa) and PEG (≥200gL−1, OP<−300kPa) significantly decreased but still exceeded 35%, indicating that S. ferganica is salt- and drought-tolerant. When considered of the SG between NaCl and PEG treatment at the same level of OP, which was much better with NaCl than that with PEG. Taken together, we speculate that S. ferganica should employ ‘cautious strategy’ in germination, which means that under favorable conditions with light, temperature, water, etc., S. ferganica can germinate actively and get enough seedlings developing into adult plants; whereas under unfavorable conditions, the seeds may not germinate or germinate in a small amount to replenish soil seed bank.

Effect of reduced oxygen concentration on the germination behavior of vegetable seeds

Oxygen (O2) in the soil is necessary for the germination of seeds, but it can be reduced by excessive water contents, compaction, compression, and hard surfaces. Reduced O2 concentrations may change the germination success (proportion of seeds germinated; d) and speed (time to reach 50% germination; t 50) of seeds. Independent laboratory experiments tested the germination of nine economically valuable vegetable species at five O2 concentrations (20.9, 15, 10, 5, and 2.5%). Members of the Asteraceae (butterhead lettuce and iceberg lettuce) and Brassicaceae (broccoli and white cabbage) families germinated best at 20.9% O2 and 15% O2, but were also able to germinate at 5-2.5% O2. Members of the Apiaceae (carrot, celeriac, and parsley) were sensitive to 5-2.5% O2 concentrations, which reduced their d and increased their t50. The germination rate of Swiss chard (Amaranthaceae) consistently declined as O2 concentrations reduced from 20.9% O2 to 2.5% O2. There was a slight variation in the germination response to O2 concentration between the morphotypes of Brassica oleracea, (white cabbage, broccoli and cauliflower), although it was unclear whether this was related to seed age, genetic variation, or the conditions experienced during seed production or storage. The seeds of the Brassicaceae (broccoli and white cabbage) and Asteraceae (butterhead lettuce and iceberg lettuce) were less sensitive to reduced O2 concentrations and therefore may be more suitable for soils suffering from low O2 concentrations, such as compacted soils with hard surfaces or waterlogged soils.

Ecotype-correlated variations in germination and seedling growth of Zataria multiflora

Zataria multiflora Boiss. is a rare aromatic species endemic to the southern and southwestern regions of Iran. It is a species that is not under cultivation anywhere else in the world and is only gathered from the wild by amateur collectors. Its cultivation and domestication is very limited. Hence, we investigated the seed germination behaviour and seedling growth of different ecotypes of Z. multiflora collected from 6 sites in Iran (Jam, Ab-garm, Layzangan, Dashte-khak, Kooh-namak, and Chehel-cheshmeh) in late spring. The experiment was carried out at College of Agriculture, Shiraz University, Shiraz, Iran, in 2012. The statistical differences among the ecotypes were determined through variance analysis (ANOVA). The results of the pot experiment showed that ecotype had a significant difference for the total germination percentage, number of leaves per plant, plant height, fresh mass, dry mass, relative water content, and antioxidant enzyme activity. Differences in growth performance were also noted in relation to the altitude of the six test populations: ecotypes at a higher altitude exhibited lower germination rates and plant height. This study is significant for land managers and conservation agencies with an interest in optimizing the germination of arid-zone seeds for rehabilitation of this threatened species.

Gentiana lutea L. subsp. lutea seed germination: natural versus controlled conditions

Gentiana lutea L. subsp. lutea is a geophyte that occurs in the central-southern European mountains. We investigated its germination ecophysiology with the main aim of evaluating seed germination behaviour under controlled and natural conditions. Seeds from four natural sites were tested for germination requirements under a range of different temperatures, and by comparing the results with those obtained under both cold stratification at 5 °C and treatment with GA3. We simultaneously carried out germination tests at each collecting site, and soil temperatures were recorded. Our results indicate that germination under controlled conditions is limited by high temperatures (25 °C), below which GA3 has a remarkable effect on germination percentages. Cold stratification did not have an influence on the germination response, thus suggesting that a temperature of 5 °C is not sufficient to break seed dormancy; this result was supported by soil temperatures. Gentiana lutea created a short-term persistent seed bank, and seeds mainly germinated in their first year. The germination under controlled conditions was similar in all accessions, while different responses were found in the field, where a potential influence of the aspect was observed. These findings underscore the importance of understanding germination behaviour in the field to define the real thermal requirements of a taxon.

Seed germination studies on Gymnacranthera canarica (King) Warb. - a Vulnerable tree species of a highly threatened Myristica swamp ecosystem

Gymnacranthera canarica (King) Warb. is an exclusive Myristica swamp species endemic to the Western Ghats. The Myristica swamp is a Critically Endangered ecosystem. Studies were carried out to assess the viability, germination and storage behaviour of Gymnacranthera canarica seeds. In the present study, it was observed that seeds have shown an initiation of germination after two weeks. A maximum of 90% germination was recorded when the initial moisture content was 38.04 ± 1.75 %. A decreased percentage (3%) was observed when the moisture content reached 14.26 ± 2.3 after 70 days of storage. Seeds failed to germinate beyond this moisture level. A desiccation study showed recalcitrant behaviour and seeds can be stored in lab conditions for up to two and half months.

Morphological and genetic diversity and seed germination behavior of a snow lotus (Saussurea involucrata, Asteraceae) from the Mongolian Altay Mountains, Western Mongolia

Different conservation measures including domestication approaches are needed to preserve rare and extensively used plant species and to satisfy future market demands. Snow lotus (a common name used for a number of high altitude species in central Asia) species in Mongolia are important medicinal plants, mostly endangered at the regional level due to the extensive use for medicinal purposes and naturally limited distribution ranges. In order to develop effective conservation and cultivation approaches we studied the morphological and genetic diversity as well as the seed germination behavior of three populations of Saussurea involucrata in the Altay Mountains of Western Mongolia. Plant height and leaf length were measured on 41–53 randomly selected individuals in each population. Enhancement of seed germination was studied using either mechanical or chemical scarification with potassium nitrate and gibberellic acid. Genetic diversity within and among three populations of the species was analyzed using Amplified Fragment Length Polymorphisms. Plants in three populations differed in height and leaf length (P < 0.001). Plant size tended to be negatively correlated with habitat altitude. Seed germination rate was low and increased with seed soaking in gibberellic acid. However, the response of seeds to different treatments was rather population-specific. Most treatments did not significantly affect mean days to germination and the ratio of shoot to root dry weight of 2-weeks old seedlings. The level of genetic diversity in the studied populations was lower than the average value for other long-lived perennial herbs. Analysis of molecular variance revealed a high differentiation within populations (92 % of total variation) indicating sufficient gene flow among populations.

Seed anatomical studies on dormancy and germination in Chamaecrista absus

Present study was conducted to analyze the anatomical structure of seed to study the dormancy behaviour in Chamaecrista absus. Seed germination behaviour was also studied after breaking the seed dormancy by artificial seed treatments. The anotamical studies revealed that seed has apical hilar region and seed coat has four layers consisting of outer cuticle, sub cuticle, palisade layer and inner tegma leading to physical dormancy. Outer cuticle and sub cuticle layers are very hard to break naturally and hence seeds possess hard seed coat dormancy. This physically hard seed coat should be made soft to enhance germination. Studies to break dormancy were conducted involving treatments like hot water, hormones and in combinations of both. The results revealed that seeds dipped in boiling water made inner layers permeable for water absorption in hilar region and thus germination enhanced. In specific seeds treated with boiling water for 5 minutes recorded higher germination (82 %) over untreated control (26 %). . Other artificial treatments with hormones gibberellic acid (33 % ) and ethrel (34 % ) did not enhanced the germination significantly over control. C. absus has hard coat dormancy and can be overcame by treating seeds with boiling water treatment.

Variabilidad germinativa en semillas de diferentes poblaciones de cuatro especies de gramíneas nativas de Patagonia: Un estudio de caso en el noroeste de Chubut.

En este estudio se analizó la calidad y el comportamiento germinativo de semillas de diferentes poblaciones localizadas en un gradiente de precipitación anual oeste-este (500 a 150 mm) en cuatro especies de gramíneas forrajeras nativas (Bromus setifolius, Hordeum comosum, Festuca pallescens y Poa ligularis), del NO de Chubut. Se estimó el peso y el porcentaje de semillas llenas a nivel inter- e intra-específico. Las semillas fueron sembradas en un ambiente común y se calculó el porcentaje de germinación y la velocidad de emergencia para las especies y las poblaciones. En este trabajo se presentan datos relacionados a la germinación de semillas recolectadas en un año en particular (2015) de estas cuatro especies y se discuten principalmente los resultados obtenidos para P. ligularis, la especie que presentó mayor variabilidad entre las poblaciones analizadas. En P. ligularis un gran porcentaje de semillas de la población del sitio más árido germinaron/emergieron en menos días. Esta característica podría estar asociada a adaptaciones fisiológicas de las plantas para germinar, emerger y establecerse rápidamente ante la escasa disponibilidad de agua en este sitio. Los genotipos de esta población particular podrían ser utilizados para programas de restauración de ambientes áridos con precipitación media anual menor a 150 mm. Finalmente, debido a la variabilidad observada al menos en P. ligularis, se sugiere que para futuros programas de mejoramiento con estas especies nativas sería necesario analizar un mayor número de poblaciones para seleccionar los potenciales bancos de semilla.

Seed Germination Behavior of Withania spp. under Different Temperature Regimes

ABSTRACTThe genus Withania comprises 23 species, among which only two [W. somnifera (Ashwagandha) and W. coagulans (Ashutoshbooti)] have been reported from India. Withania spp. dried roots are widely used in traditional system of medicine. Optimal germination potential is essential for commercial growers to justify buying premium-priced seed and ensure acceptable performance of their crop. An experiment was initiated to determine seed germination potential and vigor index of W. somnifera and W. coagulans at three constant (15°C, 20°C, and 25°C) and one alternating (15/35°C) temperature (10/14 h) regimes in Petri dishes, with daily 16 h light (180 lx)/8 h dark photoperiod. Highest germination percentage (92%) and seedling vigor index II (0.2583) were observed at 15/35°C, followed by 15°C (90.7% and 0.1207, respectively) in W. somnifera. Vigor index I was highest (344.5) at 15°C, followed by 15/35°C (319.7) in W. somnifera. In the case of W. coagulans, highest germination percentage (65%), seedling vigor index I (499.9), and vigor index II (0.0609) were recorded at 15°C, followed by 20°C (germination = 55%, vigor index I = 450.01, and vigor index II = 0.0516). This information should help growers in raising a healthy nursery of W. somnifera at 15/35°C or 15°C and 15 or 20°C for W. coagulans.

Dormancy breaking and germination of Adenocarpus desertorum, Astragalus gines-lopezii and Hippocrepis grosii (Fabaceae) seeds, three threatened endemic Spanish species

The effectiveness of different presowing treatments for removing hardseededness in Adenocarpus desertorum, Astragalus gines-lopezii and Hippocrepis grossi, three endemic and threatened perennial leguminous species of Spain, was evaluated. Untreated seeds of all three species were germinated over a range of constant (15, 20 and 25°C) and alternating temperatures (15/25 and 20/30°C) under a 16-hour light photoperiod. A considerable fraction of these seeds had physical dormancy caused by a water-impermeable seed coat. Germination was studied for seeds subjected to different presowing treatments: dry heat, hot water, ultra-low freezing, liquid nitrogen, freeze-thaw and mechanical scarification. The most effective method for promoting germination of Adenocarpus desertorum (two populations) and Astragalus gines-lopezii (two populations) was mechanical scarification with pliers. The highest germination percentages of H. grosii were reached by seeds mechanically scarified and also by seeds stored in an ultra-low freezer for 24 hours. Our data provided useful information in germination protocols for ex situ propagation of these three endemic and threatened species, being the first report on seed germination behaviour of Adenocarpus desertorum and Hippocrepis grosii.

SEED MORPHOMETRY AND GERMINATION OF Aechmea costantinii (Mez) L. B. Sm. (BROMELIACEAE)

ABSTRACT: The potential economic and environmental benefits brought by bromeliads production are significant. It is noteworthy that the high degree of degradation of some ecosystems as the Atlantic forest involve reduction of these species. This factor has been worsened by the elevated degree of endemism of these plants, e.g. Aechmea costantinii (Mez) L. B. Sm., which is a high ornamental potential bromeliad but understudied. Thus, the present research aimed to characterize physical and morphological features of A. costantinii fruit and seeds, describing the different stages of post-seminal development, as well as evaluating seed germination behavior with respect to temperature and light. For this purpose, we used fruit and seeds freshly harvested from an Atlantic Forest fragment, located in the city of Maceió, Alagoas State, Brazil. Tests were carried out under a completely randomized design, in a 6x4 factorial scheme (temperature x light) with four replications of 25 seeds. The polyspermic fruit are of tricarpellate/triloculate type and originated from inferior ovary, containing an average of 73 elliptical and mucilaginous seeds with basal embryo. The germination is epigeal-type and occurs in a great intensity and high speed at 35 °C, regardless light presence or quality.

Morpho-Physiological Dynamics of Weedy Rice Seeds Collected from Two Contrasting Agro-Ecological Zones in Sri Lanka

Weedy rice (Oryza sativa L. f. spontanea), seeds remain a longer period in soils at different depths enriching soil seed bank and that contribute to the success of weedy rice as a “weed.” Hence basic information on the level of longevity, dormancy and germination behaviour of weedy rice seeds with relation to its morphology is very important to implement efficient control measures. In this study, weedy rice seeds were collected from six infested locations in Ampara and Matara districts representing two different agro-ecological zones in Sri Lanka. Two widely grown improved varieties (At 362 and Bg 379-2) were assembled as check lines. Thirty panicles per population were randomly collected from each location to determine their morphological characteristics including awn lengths, seed shape, hull colour, pericarp colour along with physiological phenologies such as degree of dormancy, viability, longevity and rate of survival.Significant variability of seed shape, awn length, hull colour and pericarp colour was observed. Germination rate and survival rates were highly variable and closely associated with awn characteristics. Our study clearly indicated that prolong longevity (more than 24 weeks) and viability of weedy rice seeds in field conditions implying their key role as a weed by enriching soil seed bank. Awned populations are dormant and influence weedy rice population dynamics leading to the competitiveness of this weed. Therefore, management practices have essentially to take them into account and be adapted accordingly. Further, this study inferred that the morpho-physiological variation of the weedy rice seed populations was not associated with the agro-ecological conditions; for example, the dry and the wet zone suggesting rapid seed mediated gene flow throughout the country.

Sonication of seeds increase germination performance of sesame under low temperature stress

A laboratory experiment was conducted to determine the effect of ultrasound (US) exposure time on germination behavior of sesame seeds. All tests were carried out at 20 kHz in a water bath ultrasonic device varying two factors, treatment duration (10, 20 and 30 min) and germination temperature (15, 20 and 25 ºC). Parallel tests were run in which seeds were soaked in water without sonication in order to eliminate the effect of water from US test results. US treatments enhanced seeds water uptake. At mild exposure time it improved sesame seed germination performance and seedling growth at suboptimal temperatures as indicated by higher germination percentage and germination rate. US applying for 20 min had relatively high superoxide dismutase activity; however, had not significant differences with control and US duration for 10 min. The catalase activity was strongly increased by applying the US for a 10 and 20 min. Among the treatments, application of US vibration for 10 and 20 min reduced both of malondialdehyde and H2O2 contents, however high US duration (30 min) increased both of the traits. In general, ultrasonic priming technique can be useful for early planting the sesame seeds, and lead to higher yields.

Effects of pre-chilling, incubation temperature and light on seed germination of Saponaria officinalis

Saponaria officinalis L. has been used as a soft cleaning agent and medicinal plant. Understanding germination patterns of seeds of S. officinalis is required for domestication. We examined seed germination behaviors in S. officinalis by pre-treatment with chilling (4 °C), incubation at two constant (20 °C and 25 °C) and an alternating (20 °C/30 °C) temperatures, and incubation in dark and light/dark (8h/16h) conditions. Although the seeds had a seed viability of 96% determined by tetrazolium test, it showed 0.5˜3% of the germination rate at 20 °C and 25 °C in 28 days after incubation. When incubated at 20 °C/30 °C, seeds showed that 75% of the germination rate and 10.2 of the number of days to germination. Pre-chilling promoted seed germination to 85% and 97% in 20 °C- and 20 °C/30 °C-incubation, respectively. The number of days to germination intensively decreased to 7.7 at 20 °C/30 °C. Any positive effect of pre-chilling on seed germination was not found at 25 °C-incubation. Light seemed to have negative effect on seed germination of S. officinalis as the germination rate strikingly decreased to 2.5% in 20 °C- and 75% in 20 °C/30 °C-incubation under light/dark condition despite pre-chilling. These results indicate that pre-chilling and alternating temperature accelerate seed germination of S. officinalis and keeping dark during incubation is more effective.