Seed Germination Responses Research Articles

Germination responses of seeds of Desmodium triflorum

<p class="abstract"><strong>Background:</strong> Germination of <em>Desmodium triflorum</em> is used for the scarification using the acid is valuable for the different light condition.</p><p class="abstract"><strong>Methods:</strong> The sample was collected as four month of interval of time and the seed is treated with acids with different time. </p><p class="abstract"><strong>Results:</strong> seeds scarified with sulfuric acids for 10 min before sowing had better germination than those scarified for 5 and 15 min. Among them light qualities, red and white light had slightly promoted effect whereas blue light and dark condition had slightly negative effect on seed germination.</p><p><strong>Conclusions:</strong> In comparison to blue light and dark condition, red light and white light were promoted to percentage germination indicating the role of phytochrome in seed germination of <em>Desmodium triflorum</em>. </p>

Seed germination response to high temperature and water stress in three invasive Asteraceae weeds from Xishuangbanna, SW China.

Crassocephalum crepidioides, Conyza canadensis, and Ageratum conyzoides are alien annuals naturalized in China, which produce a large number of viable seeds every year. They widely grow in Xishuangbanna, becoming troublesome weeds that compete with crops for water and nutrients. As seed germination is among the most important life-stages which contribute to plant distribution and invasiveness, its adaptation to temperature and water stress were investigated in these three species. Results showed that: (1) These three species have wide temperature ranges to allow seed germination, i.e., high germination and seedling percentages were achieved between 15°C and 30°C, but germination was seriously inhibited at 35°C; only A. conyzoides demonstrated relative preference for warmer temperatures with approximately 25% germination and seedling percentage at 35°C; (2) light was a vital germination prerequisite for C. crepidioides and A. conyzoides, whereas most C. canadensis seeds germinated in full darkness; (3) Although all three species have good adaptation to bare ground habitat characterized by high temperatures and water stress, including their tolerance to soil surface temperatures of 70°C in air-dried seeds, A. conyzoides seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 40°C, and to water restriction (e.g., ca. 65% seeds germinated to -0.8 MPa created by NaCl), which is consistent with their field behavior in Xishuangbanna. This study suggests that seed high-temperature tolerance contributes to the weed attributes of these three species, and that adaptation to local micro-habitats is a critical determinant for invasiveness of an alien plant.

Germination responses of Ballota hirsuta seeds under conditions of temperature, salinity and water stress

Summary Temperature, salinity and water deficit can be major environmental constraints which reduce distribution of indigenous plants in the Mediterranean region. Laboratory experiments were carried out to assess the effect of temperature, sodium chloride (NaCl) and polyethylene glycol 6000 (PEG) on germination of Ballota hirsuta seeds. The germination responses of seeds were determined over a wide range of temperature (5 to 35°C), salinity (0 to 136 mM NaCl) and water stress (0 to −1 MPa PEG). Germination percentage was optimum at 20°C (78%), and showed a decline at lower (5°C, 25%) or higher (30°C, 18%) temperature values and total inhibition of germination at 35°C. Under salinity and water stress conditions, there was a significant deterioration in most germination parameters such as lower final germination percentage, increased mean germination times and lower germination rates.

Seed-dormancy depth is partitioned more strongly among habitats than among species in tropical ephemerals

Seed biology in the annual herbaceous flora of ecologically stressful, seasonally wet habitats remains largely unexplored. Temporal and spatial species turnover among these habitats is often high, yet little is known about how fine-scale habitat variation drives intraspecific variability in seed dormancy depth and seed germination requirements. The present study characterised seed dormancy and investigated the germination biology of six closely related herbaceous annual species of Byblis from northern Australia. We assessed variation in the response of seeds of all species to temperature cues, as well as light and the naturally occurring germination stimulants karrikinolide (KAR1) and ethylene. We also examined intraspecific variation in germination response and seed-dormancy depth for three widely distributed species with overlapping distribution occurring in habitats with differing soil thermal and hydrological conditions. Seed germination in all six species was significantly increased by exposure to either KAR1 or ethylene, with this effect being amplified in two species (B. filifolia and B. rorida) following a period of warm, dry after-ripening. Seed-dormancy depth and the germination response of seeds to both KAR1 and ethylene were partitioned more strongly among habitats than among species. Populations on shallow (<20-cm soil depth) sandy soils produced less dormant seeds than did populations of the same species on deeper sandy soils (40+ cm) or on heavy cracking clays. The upper soil profile of shallow soil habitats was exposed to higher average temperatures, greater diurnal temperature fluctuation and greatly reduced moisture persistence compared with deeper soils. Fine-scale differences in the thermal and hydrological conditions of seasonally wet habitats appear to be strong drivers of dormancy depth in seeds of tropical Byblis. Widely distributed species exhibit high levels of plasticity in seed-dormancy depth and germination response among different habitats, with similar responses being observed for sympatric species. So as to fully understand species turnover in tropical ephemerals, future studies should examine phenotypic plasticity and the rate of local adaptation of seed traits in greater detail.

The influence of ethanol as a solvent on the gibberellic acid-induced germination of Brachyscome and Allittia (Asteraceae) seeds

Gibberellic acid (GA3) is routinely used as a germination stimulant for seeds. However, the methods used to dissolve GA3 powder – particularly if using organic solvents – have the potential to affect germination outcomes. In this study we examined the influence of the solvent ethanol, used to dissolve GA3, on the seed germination of 14 species of Brachyscome and two species of Allittia. These species are important Australian native composites with potential for use in habitat restoration. Seeds of 11 of these species were found to be particularly responsive to GA3. However, the use of a low concentration of ethanol (0.5%) to dissolve GA3 affected subsequent germination outcomes, with four species responding positively and eight negatively to this solvent. The pure effect of GA3 was therefore masked by the presence of small concentrations of ethanol, whose effects varied between the species examined. Because of these potentially confounding effects of ethanol, we recommend the use of pure water for dissolution of GA3 when testing seed germination responses in these genera.

Seed germination response of a noxious agricultural weed Echium plantagineum to temperature, light, pH, drought stress, salinity, heat and smoke

Echium plantagineum is a significant pasture weed in the Mediterranean climatic zone of several countries, including Australia. This invasive weed, introduced as an ornamental into Australia (where it is known as Paterson’s curse), quickly became established and is now a significant weed of agriculture. Although E. plantagineum is a well-established, highly competitive weed that thrives under disturbance and is tolerant of a wide variety of conditions, including varying soil moisture and drought, and some aspects of its ecology remain unknown. This study investigated germination response to temperature and light, pH, soil moisture, salinity, and pre-germination exposure of seed to heat and smoke. Temperature was found to be more influential on germination than light and the species is tolerant to a wide range of pH. However, available moisture may limit germination, as may elevated salinity. Management of this weed requires approaches that minimise soil seedbank input or prevent germination of soil seedbanks.

The fitness benefits of germinating later than neighbors.

Phenology, the seasonal timing of development, can alter biotic interactions. Emergence from dormant or quiescent stages often occurs earlier when neighbors are present, which may reduce the neighbors' competitive effects. Delayed emergence in response to neighbors also has been observed, but the potential benefits of such delays are unclear. Further, emergence time may respond to neighbors experienced by parents, which may predict future competition in offspring. In the annual plant Arabidopsis thaliana (Brassicaceae), we quantified seed germination responses to neighbors in parental and offspring (seed) environments. To examine how observed changes in germination affect interactions with neighbors, we performed an outdoor experiment using neighbors of different sizes to represent different germination times. Seeds were more likely to germinate if their parent had neighbors, but they were less likely to germinate if they themselves experienced a neighbor cue (canopy). As seeds lost dormancy over time, they gained the ability to germinate under a canopy, which suggests that they germinate later in the presence of neighbors. Neighbors of both sizes reduced growth, survival to reproduction, fecundity, and total fitness, but large neighbors increased seedling survival. Smaller neighbors provided no such benefit and had stronger negative effects. Delayed germination in response to neighbors can reduce negative interactions and promote positive ones if it occurs late enough to expose seedlings to larger neighbors. By altering relative phenologies and, in turn, the outcomes of biotic interactions, phenological responses to environmental change may influence species interactions and community dynamics.

Using hydrothermal time concept to describe sesame (Sesamum indicum L.) seed germination response to temperature and water potential

To quantify both temperature (T) and water potential (ψ) effects on sesame (Sesamum indicum L.) seed germination (SG) and also to determine the cardinal T s for this plant, a laboratory experiment was carried out using hydrothermal time model (HTT). For this purpose, four sesame cultivars (‘Asbomahalleh’, ‘Darab’, ‘Dashtestan’ and ‘Yellowhite’) were germinated at seven constant T s (20, 25, 30, 35, 37, 39 and 43 °C) at each of the following ψ s (0, − 0.12, − 0.24 and − 0.36 MPa; provided by PEG 8000). Germination rate (GR) and germination percentage (GP) significantly influenced by ψ, T and their interactions in all cultivars (P ≤ 0.01). There was no significant difference, based on the confidence intervals of the model coefficients, between cultivars, so an average of cardinal T s was 14.7, 35.4 and 47.2 °C for the minimum (T b), optimum (T o) and maximum (T c) T s, respectively, in the control condition (0 MPa). Hydrotime values in all cultivars decreased when T was increased to T o and then remained constant at T s > T o (15 MPa h−1). An average value of ψ b(50) was estimated to be − 1.23 MPa at T s ≤ T o and then increased linearly (0.1041 MPa°Ch−1, the slope of the relationship between ψ b(50) and supra-optimal T s) with T when T s increased above T o and finally reached to zero at T c. The T b and T o values were not influenced by ψ, but T c value decreased (from 47.2 for zero to 43.5 °C for − 0.36 MPa) at supra-optimal T s as a result of the effect of ψ on GR. Based on our findings, this model (as a predictive tool) and or the estimated parameter values in this study can easily be used in sesame SG simulation models to quantitatively characterize the physiological status of sesame seed populations at different T s and ψ s.

Resposta fisiológica de sementes de chia e linhaça ao estresse hídrico

Studies on water resources are important to understand seed germination. The objective of this study was to evaluate the physiological (germination) response of chia seeds and linseed to water stress. The seeds were placed on paper soaked in solutions of polyethylene glycol in diff erent osmotic potentials. Percentage of germination, fi rst germination count, and germination speed index were evaluated. The reduction of the osmotic potential of the substrate promoted a signifi cant decrease in the germination and vigor of the chia seeds and linseed. In conclusion, seeds of these species are not able to tolerate osmotic potentials equal to or lower than -0.15MPa, being making possible its cultivation areas with concentrations above osmotic potentials.

Hyperspectral Technologies for Assessing Seed Germination and Trifloxysulfuron-methyl Response in Amaranthus palmeri (Palmer Amaranth)

Weed infestations in agricultural systems constitute a serious challenge to agricultural sustainability and food security worldwide. Amaranthus palmeri S. Watson (Palmer amaranth) is one of the most noxious weeds causing significant yield reductions in various crops. The ability to estimate seed viability and herbicide susceptibility is a key factor in the development of a long-term management strategy, particularly since the misuse of herbicides is driving the evolution of herbicide response in various weed species. The limitations of most herbicide response studies are that they are conducted retrospectively and that they use in vitro destructive methods. Development of a non-destructive method for the prediction of herbicide response could vastly improve the efficacy of herbicide applications and potentially delay the evolution of herbicide resistance. Here, we propose a toolbox based on hyperspectral technologies and data analyses aimed to predict A. palmeri seed germination and response to the herbicide trifloxysulfuron-methyl. Complementary measurement of leaf physiological parameters, namely, photosynthetic rate, stomatal conductence and photosystem II efficiency, was performed to support the spectral analysis. Plant response to the herbicide was compared to image analysis estimates using mean gray value and area fraction variables. Hyperspectral reflectance profiles were used to determine seed germination and to classify herbicide response through examination of plant leaves. Using hyperspectral data, we have successfully distinguished between germinating and non-germinating seeds, hyperspectral classification of seeds showed accuracy of 81.9 and 76.4%, respectively. Sensitive and resistant plants were identified with high degrees of accuracy (88.5 and 90.9%, respectively) from leaf hyperspectral reflectance profiles acquired prior to herbicide application. A correlation between leaf physiological parameters and herbicide response (sensitivity/resistance) was also demonstrated. We demonstrated that hyperspectral reflectance analyses can provide reliable information about seed germination and levels of susceptibility in A. palmeri. The use of reflectance-based analyses can help to better understand the invasiveness of A. palmeri, and thus facilitate the development of targeted control methods. It also has enormous potential for impacting environmental management in that it can be used to prevent ineffective herbicide applications. It also has potential for use in mapping tempo-spatial population dynamics in agro-ecological landscapes.

Germination Response of Seeds of Aconitum grossedentatum (Ranunculaceae) to Temperature and its Significance to the Expansion of the Distribution

Germination Response of Seeds of Aconitum grossedentatum (Ranunculaceae) to Temperature and its Significance to the Expansion of the Distribution

Water availability shifts the optimal temperatures for seed germination: A modelling approach

Hydrothermal time (HTT) models have been widely applied to describe the germination responses of seeds to temperature and water. Some HTT models assume that the thermoinhibition of germination is caused by an upward shift in base water potential Ψb(g) that only happens above the optimum temperature To, and that To is a parameter independent of the water stress level. However, the available data suggest that these assumptions may be invalid in practice. We introduce a new HTT model that uses a log-logistic distribution for Ψb(g) and assumes a linear increase in Ψb(g) across both sub- and supra-optimal temperature ranges. We also provide explicit mathematical solutions for estimating To and other cardinal temperatures within a HTT modelling framework. Germination data were obtained for two winter annual plant species (Hordeum spontaneum and Phalaris minor) and used to build and test the model. For both species, the linear upward shift in Ψb(g) was confirmed across both sub-and supra-optimal ranges, while the hydrotime constant θH decreased nonlinearly with temperature. This interplay between θH and Ψb(g) resulted in a curvilinear germination rate response to temperature that accounts for thermoinhibition of germination at high temperatures. The optimal temperature decreased proportionally with decreasing water potential and became cooler for higher (slower) germination fractions than for the lower (faster) ones. The new modelling approach not only gave good fits to germination data (with root mean square errors <10%), but also provided useful insights about the adaptive strategies evolved by plant species to optimize their germination timing under the various temperature and moisture environments.

Evaluation of Nonlinear Regression Models to Describe Seed Germination Response of Mountain Rye (Secale mountanum) to Temperature

Evaluation of Nonlinear Regression Models to Describe Seed Germination Response of Mountain Rye (Secale mountanum) to Temperature

Germination and Vigour Responses of Seeds of Three Cassava Varieties to Pre-germination Treatments and Storage Durations

Germination and Vigour Responses of Seeds of Three Cassava Varieties to Pre-germination Treatments and Storage Durations

Seed-germination response of Leymus chinensis to cold stratification in a range of temperatures, light and low water potentials under salt and drought stresses

Leymus chinensis has important forage value and is considered a useful grass species for grassland restoration in Northeast China. However, little information exists concerning the germination responses of this species to interactions of cold stratification, light, temperature and low water potential caused by salinity and drought. Experiments were conducted in growth chambers, and the results showed that in all conditions of light, temperature and water stresses, the germination percentages of cold-stratified seeds were higher than of non-stratified seeds. Light had an inhibitory effect on germination percentage under both non-saline and salt stress conditions; darkness is beneficial for germination of this species. In addition, seeds germinated much better under alternating temperature regimes than under constant temperatures. Both salt and drought stresses decreased the germination percentage of Leymus chinensis, but the reductions under drought stress were much greater. Moreover, after being transferred to distilled water, most non-germinated seeds under drought stress germinated well, and the total percentage reached that of the non-saline condition level. Therefore, cold stratification is an effective measure to increase seed germination and salt or drought tolerance, especially in darkness. We conclude that Leymus chinensis has definite salt and drought tolerance during the germination stage and it is a promising species for the restoration of deteriorated grassland in Northeast China.

Effect of Priming on Seed Germination Response in Woody Plants

Effect of Priming on Seed Germination Response in Woody Plants

Effect of Flood Stress on Soybean Seed Germination in the Field

Flooding is an abiotic stress that impacts soybean [Glycine max (L.) Merr.] growth and reduces seed germination. Effect of flooding on soybean plant grown at different growth stage has been previously conducted and reported. However, soybean seed germination responses to flood stress are largely unknown. The objective of this study was to elucidate flooding influence on soybean seed germination after planting in the field. The research showed that seed germination rate (SGR) of each genotype, without flood stress, was significantly different and ranged between 64.7% to 84.0% and 69.0% to 90.7% while using untreated and fungicide-treated seed (P < 0.0001), respectively. Results indicated that fungicide treatment improved soybean seed survival and germination in the field. The average of SGR of high-yielding soybean group was significantly higher than those of non-high-yielding soybean (P < 0.0001). The results indicated that high-yielding trait of each genotype was correlated with seed germination and survival. Under flood stress in the field, SGR means of untreated and fungicide-treated seed significantly decreased over eight flooding treatment times (P < 0.0001). Flooding effect on germination between untreated and fungicide-treated seed was not significantly different (P = 0.1559). Furthermore, comparing the high-yielding and flood-tolerant soybean groups showed no difference in their SGR means over eight flooding treatment times (P = 0.7687 and P = 0.8490), indicating that soybean seed germination did not depend on genotype, yield, and flood tolerance trait, and seed treated by fungicide did not increase its germination in the field under the flood stress. Hence, it is necessary to develop new soybean seed pelleting to improve seed germination in the field under flooding conditions.

Seed germination responses to salt stress in wild and cultivated Sicilian cardoon genotypes

Seed germination responses to salt stress in wild and cultivated Sicilian cardoon genotypes

Comparative Salt Tolerance Study of Some Acacia Species at Seed Germination Stage

Objective: The purpose of this study was to assess and compare the seed germination response of six Acacia species under different NaCl concentrations in order to explore opportunities for selection and breeding salt tolerant genotypes. Methodology: Germination of seeds was evaluated under salt stresses using 5 treatment levels: 0, 100, 200, 300 and 400 mM of NaCl. Corrected germination rate (GC), germination rate index (GRI) and mean germination time (MGT) were recorded during 10 days. Results: The results indicated that germination was significantly reduced in all species with the increase in NaCl concentrations. However, significant interspecific variation for salt tolerance was observed. The greatest variability in tolerance was observed at moderate salt stress (200 mM of NaCl) and the decrease in germination appeared to be more accentuated in A. cyanophylla and A. cyclops. Although, A. raddiana, remains the most interesting, it preserved the highest percentage (GC = 80%) and velocity of germination in all species studied in this study, even in the high salt levels. This species exhibited a particular adaptability to salt environment, at least at this stage in the life cycle and could be recommended for plantation establishment in salt affected areas. On the other hand, when ungerminated seeds were transferred from NaCl treatments to distilled water, they recovered largely their germination without a lag period and with high speed. This indicated that the germination inhibition was related to a reversible osmotic stress that induced dormancy rather than specific ion toxicity. Conclusion: This ability to germinate after exposure to higher concentrations of NaCl suggests that studied species, especially the most tolerant could be able to germinate under the salt affected soils and could be utilized for the rehabilitation of damaged arid zones.

Effects of nutrient addition and soil drainage on germination of N-fixing and non-N-fixing tropical dry forest tree species

To develop generalised predictions regarding the effects of atmospheric nitrogen (N) and phosphorus (P) deposition on vegetation communities, it is necessary to account for the impacts of increased nutrient availability on the early life history stages of plants. Additionally, it is important to determine if these responses (a) differ between plant functional groups and (b) are modulated by soil drainage, which may affect the persistence of added nutrients. We experimentally assessed seed germination responses (germination proportion and germination energy, i.e. time to germination) of commonly occurring N-fixing and non-N-fixing tropical dry forest tree species found in India to simulated N and P deposition in well-drained soils, as well as soils with impeded drainage. When soils were not allowed to drain, germination proportion declined with nutrient addition, while germination energy remained unchanged. Stronger declines in germination proportion were observed for N-fixing species. In free-draining soils, nutrient addition did not affect germination proportion in either functional group. However, we detected a trend of delayed germination with nutrient addition, especially in N-fixers. Our results suggest that nutrient deposition can lead to potential shifts in functional dominance and tree community composition of tropical dry forests in the long term through its effects on early life stages of trees, although the mechanisms underlying the observed germination responses remain unclear. Further, such effects are likely to be spatially variable across the geographic range in which tropical dry forests occur depending on soil drainage properties.