scholarly journals Modeling the influence of temperature and water potential on seed germination of Allium tenuissimum L.

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8866
Author(s):  
Hong Xiao ◽  
Helong Yang ◽  
Thomas Monaco ◽  
Qian Song ◽  
Yuping Rong

Allium tenuissimum L. is a widely distributed perennial herbaceous species in temperate and desert steppes. Relative to other wild Allium species, it produces unique sweet flavors, more biomass in arid and cold environments, and has generated greater interest for crop production. Successful crop establishment, however, will depend on rapid and uniform seed germination. Our study aimed to characterize seed germination of A. tenuissimum under various temperature regimes (11, 15, 20, 24 and 28 °C) and water potential levels (0, −0.2, −0.4 and −0.6 MPa), and model germination by hydrotime (HT) and hydrothermal time (HTT) analysis. Final germination percentage (FGP) increased within the range of 11 to 20 °C, yet it declined within the range of 24 to 28 °C and generally decreased as water potential became more negative within each temperature setting. Maximum FGP was observed at 20 °C at all water potential settings and ranged from 55.0 ± 5.3 to 94.8 ± 1.4%. According to HT and HTT models, the base (Tb) and optimum temperatures (To) for seed germination were 7.0 and 20.5 °C, respectively. In addition, base water potential for the fraction of germination within the seed lot (Ψb(g)) shifted to 0 MPa as temperature increased from Tb to ceiling temperature (Tc). For obtaining 50 % seed germination, Ψb(50) and Tc(50) were estimated to be −0.67 MPa and 27.2 °C, respectively. These values for Tb and Ψb(50) suggest seed germination of A. tenuissimum is both cold and drought tolerant and suitable for production in semi-arid regions. Our characterization of the ideal sowing conditions for A. tenuissimum, i.e., 20.5 °C and soil water potential less negative than −0.67 MPa offers information to forecast suitable settings to enhance crop production.

Botany ◽  
2013 ◽  
Vol 91 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Esther Giménez Luque ◽  
Isabel C. Delgado Fernández ◽  
Francisco Gómez Mercado

Limonium cossonianum Kuntze is an interesting endemic plant in the southeastern Iberian Peninsula and the Balearic Islands that can be used in wetland restoration and as an ornamental species in saline areas. Experiments were carried out to investigate seed germination responses in L. cossonianum at different levels of salinity (0, 100, 200, and 400 mmol/L NaCl) and under different temperature regimes (20/10, 25/15, 30/20, and 35/25 °C, day/night), both in a 14 h light – 10 h dark photoperiod. Seed germination in L. cossonianum was significantly affected by salinity levels, temperature, and the interaction of both parameters. Maximum germination was recorded in the lowest saline media (100 mmol/L NaCl) and distilled water (0 mmol/L NaCl) at 20/10 °C. No seeds germinated in concentrations above 200 mmol/L NaCl at the higher temperatures. The increase in salinity delayed the beginning and end of germination, reduced final germination percentage, and increased mean time to germination. The rate of germination decreased with an increase in salinity and temperature.


2005 ◽  
Vol 15 (2) ◽  
pp. 89-97 ◽  
Author(s):  
Roberto Huarte ◽  
Roberto L. Benech-Arnold

Seeds ofCarduus acanthoides,Cynara cardunculus,Cirsium vulgare,Brassica campestris, andSisymbrium altissimumwere incubated at a range of decreasing osmotic potentials (Ψo) under fluctuating temperatures or the median temperature of the fluctuation cycle. Fluctuating temperatures promoted total seed germination in water and at reduced osmotic potential. Total germination was reduced as the Ψodecreased. However, this trend was smallest under fluctuating temperatures, signalling a higher tolerance of seeds to reduced osmotic potential. Effects of osmoticum and temperature were modelled with the hydrotime model. The parameters estimated from the model, the hydrotime constant (θH), the mean base water potential Ψb(50) and its standard deviation (σΨb) gave good descriptions of germination time courses. For all species, incubation under fluctuating temperatures shifted Ψb(50) values downwards without modifying their distribution substantially. This accounted for the greater tolerance of germination to reduced Ψounder fluctuating temperatures. To confirm that these effects were mediated by temperature fluctuationsper se, the behaviour ofC. acanthoidesandC. cardunculusincubated at the minimum, the mean and the maximum temperature of the fluctuation cycle was also analysed. Constant maximum and minimum temperatures of the cycle did not stimulate germination, nor did they shift Ψb(50) towards more negative values. The hydrotime model provides a physiologically based quantitative description for germination promotion due to fluctuating temperature.


2018 ◽  
Vol 29 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Malaka M. Wijayasinghe ◽  
K.M.G. Gehan Jayasuriya ◽  
C.V.S. Gunatilleke ◽  
I.A.U.N. Gunatilleke ◽  
Jeffrey L. Walck

AbstractMangroves are highly adapted to extreme environmental conditions that occur at the interface of salt and fresh water. Adaptations to the saline environment during germination are a key to mangrove survival, and thereby, its distribution. The main objective of this research was to study the effect of salinity on seed germination of selected mangrove species and the application of a hydrotime model to explain the relationship between water potential of the medium and rate of seed germination. Germination of seeds was examined at 15, 25 and 35°C in light/dark over a NaCl gradient. Germination time courses were prepared, and germination data were used to investigate whether these species behave according to the principles of the hydrotime model. The model was fitted for the germination of Acanthus ilicifolius seeds at 25°C. Final germination percentage was significantly influenced by species, osmotic potential and their interaction at 25°C. Moreover, temperature had a clear effect on seed germination (Sonneratia caseolaris and Pemphis acidula) which interacted with osmotic potential. Only A. ilicifolius seeds behaved according to the hydrotime principles and thus its threshold water potential was –1.8 MPa. Optimum germination rates for seeds of the other species occurred at osmotic potentials other than 0 MPa. The descending order of salinity tolerance of the tested species was Aegiceras corniculatum > Sonneratia caseolaris > Acanthus ilicifolius > Pemphis acidula > Allophylus cobbe, suggesting that the viviparous species (A. corniculatum) is highly salt tolerant compared with the non-viviparous species. The results revealed that seeds of the study species exhibited facultative halophytic behaviour in which they can germinate over a broad range of saline environments. Use of a hydrotime model for mangroves was limited as germination of their seeds did not meet model criteria.


2014 ◽  
Vol 94 (4) ◽  
pp. 723-726
Author(s):  
D. J. Thompson

Thompson, D. J. 2014. Relating germination requirements of timber milkvetch to seral stage in the Interior Douglas-fir zone. Can. J. Plant Sci. 94: 723–726. Germination of timber milkvetch (Astragalus miser var. serotinus) seeds was studied to determine if it is an early or late seral species. Seeds were collected from a native plant population and those having a dark seed coat were selected. Germination tests were run in the light or dark and under three temperature regimes: low (constant 10°C), high (constant 25°C), and alternating (25°C day and 10°C night). Germination occurred over a protracted period with new germinants up to 90 d at the lowest temperature. Germination was not affected by light. Germination rate was greater at 25°C than 10°C, while fluctuating temperatures (25 and 10°C alternating every 12 h) reduced germination rate to that at the lower temperature. Days to 50% germination was a more sensitive indicator, with the mean for the fluctuating temperatures falling between those continuous to the high and low temperature. Final germination percentage was reduced at 10°C compared with 25°C, but not with fluctuating temperatures. Timber milkvetch seed germination did not respond to light or fluctuating temperatures, adding to a body of evidence that it is a late seral species.


1993 ◽  
Vol 41 (1) ◽  
pp. 79 ◽  
Author(s):  
KM Maze ◽  
TB Koen ◽  
LA Watt

The effect of light, storage time, temperature regimes and water potential were examined on the germination of five native grasses of central New South Wales (Enteropogon ramosus, Bothriochloa macra, Elymus scabrus, Chloris truncata and Danthonia caespitosa), and one introduced grass (Eragrostis curvula). Caryopses of E. ramosus, B. macra and E. curvula reached maximum germination soon after harvest. The remaining species reached maximum germination after 6-10 months storage. For all species, except E. scabrus, the effect of light on germination changed with duration of storage and with the presence of the lemma and palea. The viability of naked caryopses was reduced more rapidly than the viability of caryopses stored with the lemma and palea intact, for all tested species; E. scabrus and E. curvula were not tested. E. scabrus, C. truncata, D. caespitosa and E. curvula had greater than 50% germination over a range of alternating temperatures. E. ramosus had the narrowest temperature range for good germination, exceeding 50% germination only at temperatures above 30/20*#176 (day/night). E. ramosus and E. curvula germinated over a wider range of water potential than the other species. The germination of D. caespitosa, B. macra and C. truncata fell significantly at a water potential of -0.1 MPa. It is concluded that temperature is likely to impede the germination of most of these grasses only in mid winter, and that soil water potential will probably have an overriding influence on the season of germination.


HortScience ◽  
1994 ◽  
Vol 29 (12) ◽  
pp. 1443-1444 ◽  
Author(s):  
N. Wartidiningsih ◽  
R.L. Geneve

Six seed lots of purple coneflower were purchased from four commercial seed sources and evaluated for germination in either light or darkness in combination with two temperature regimes (constant 27C vs. alternating 30C for 8 hours and 20C for 16 hours). Seed lot differences accounted for the majority of variation, with two seed lots exhibiting high (81% to 91%) germination and the remaining seed lots having 39% to 66% germination. There was no effect of light on germination, regardless of the seed lot. However, alternating temperatures improved germination in one of the low-germination seed lots. Seed size and inflorescence position did not affect seed germination. Seed harvested at physiological maturity (maximum seed dry weight), but before drying had occurred, had a higher germination percentage than seeds harvested after desiccation, and they maintained a higher germination percentage even after 1 year in storage.


2018 ◽  
Vol 46 (1) ◽  
pp. 286-291 ◽  
Author(s):  
Mariola MONLLOR ◽  
Pilar SORIANO ◽  
Josep V. LLINARES ◽  
Monica BOSCAIU ◽  
Elena ESTRELLES

Evaluation of tolerance to temperatures in the germination stage is an important tool to foresee the possible effect of global warming. Moreover, establishing germination protocols for endemic and threatened species is most interesting for restoration and management plans that focus on habitat conservation. Seed germination was analysed in four species of the genus Limonium (L. virgatum, L. narbonense, L. girardianum and L. santapolense) growing in two saline habitats on the eastern coast of the Iberian Peninsula. The study aim was to compare responses of seed germination to different temperature regimes. Seeds were collected in two protected areas, ‘L´ Albufera de Valencia’ (province of Valencia) and ‘Clot de Galvany’ (province of Alicante). Responses to temperature were checked within a constant range, 10-30 °C at 5 °C intervals, by considering the environmental conditions at both sampling sites. The final germination percentage and mean germination time (MGT) were calculated after 30 days. In order to compare thermal responses, base temperature (Tb) and thermal time (S) were determined for each species. The possible correlations of soil parameters with the species´ germination pattern were also analysed. To identify distinct behavioural groups, a non-linear principal component analysis was performed. Significant differences between species were found in the velocity of germination. A fast response as opportunistic germination was observed in all the species. The base temperature and thermal time showed significant differences in competitiveness between species.


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
W. John Bullied ◽  
Paul R. Bullock ◽  
Rene C. Van Acker

Soil water retention is important for the study of water availability to germinating weed seeds. Six soil water retention models (Campbell, Brooks-Corey, four- and five-parameter van Genuchten, Tani, and Russo) with residual soil water parameter derivations were evaluated to describe water retention for weed seed germination at minimum threshold soil water potential for three hillslope positions. The Campbell, Brooks-Corey, and four-parameter van Genuchten model with modified or estimated forms of the residual parameter had superior but similar data fit. The Campbell model underestimated water retention at a potential less than −0.5 MPa for the upper hillslope that could result in underestimating seed germination. The Tani and Russo models overestimated water retention at a potential less than −0.1 MPa for all hillslope positions. Model selection and residual parameter specification are important for weed seed germination by representing water retention at the level of minimum threshold water potential for germination. Weed seed germination models driven by the hydrothermal soil environment rely on the best-fitting soil water retention model to produce dynamic predictions of seed germination.


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