scholarly journals Application of the thermal time model for different Typha domingensis populations

2020 ◽  
Author(s):  
Fanny Mabel Carhuancho León ◽  
Pedro Luis Aguado Cortijo ◽  
María del Carmen Morató Izquierdo ◽  
María Teresa Castellanos Moncho
Keyword(s):  
Seed Germination ◽  
Mean Value ◽  
Thermal Time ◽  
Plant Responses ◽  
Base Temperature ◽  
Typha Domingensis ◽  
Time Model ◽  
Germination Response ◽  
Thermal Regimes ◽  
Thermal Time Model

Abstract BackgroundCattail (Typha domingensis Pers.) is a perennial emergent plant which is used in Green Floating Filters (GFFs), one of the most innovative systems of wastewater treatment to bioremediate eutrophic waters and produce biomass as biofuel feedstocks. The establishment of cattails in GFFs depends on the seed germination and plant responses under conditions of a new habitat. This study analysed the germination response of four different populations of cattails through a thermal time model to determine which population would have the fastest germination for establishment in GFFs.ResultsSeeds from the Badajoz (Ba), Cuenca (Cu), Madrid (Ma), Seville (Se) and Toledo (To) populations were exposed to different thermal regimes (constant, and alternating temperatures between 15 and 30°C) and differents darkness treatments (between 0 and 20 days with 24h dark photoperiod, then exposed to light with 12h light/dark photoperiod) to determine the parameters of the thermal model from germination levels in each treatment. To population was used to validate the thermal time parameters of other populations. Regardless of the other parameters, no germination occurred in total darkness. The mean value of base temperature (Tb) was 16.4±0.2°C in all treatments. Optimum temperature (To) values in Ma and Ba were 25°C, and those in Cu and Se were 22.5°C. The germination response decreased when the temperature approached Tb and increased when it was close to To. In comparison to alternating temperatures, constant temperatures had the highest germination response and lowest thermal time (θT(50)). Darkness treatments had a direct relationship with θT(50). The population origin also affected seed germination; Cu had the highest values of To and germination response but had a lower θT(50), which coincides with the lowest mean ambient temperatures.Conclusion According to these results, the germination response of cattails was high in all populations under optimal conditions but was affected to a greater or lesser extent depending on thermal regimes, darkness treatments, and populations. The thermal time model allowed us to determine that To was between 22.5-25ºC. In comparison to other populations, Cu is the best population for establishment in GFFs due to its high germination response under the conditions tested.

scholarly journals Application of the thermal time model for different Typha domingensis populations

2020 ◽  
Author(s):  
Fanny Mabel Carhuancho León ◽  
Pedro Luis Aguado Cortijo ◽  
María del Carmen Morató Izquierdo ◽  
María Teresa Castellanos Moncho
Keyword(s):  
Seed Germination ◽  
Mean Value ◽  
Thermal Time ◽  
Plant Responses ◽  
Base Temperature ◽  
Typha Domingensis ◽  
Time Model ◽  
Germination Response ◽  
Thermal Regimes ◽  
Thermal Time Model

Abstract Background: Cattail (Typha domingensis Pers.) is a perennial emergent plant which is used in Green Floating Filters (GFFs), one of the most innovative systems of wastewater treatment to bioremediate eutrophic waters and produce biomass as biofuel feedstocks. The establishment of cattails in GFFs depends on the seed germination and plant responses under conditions of a new habitat. This study analysed the germination responses of four different populations of cattails through a thermal time model to know their basic parameters of germination and which population would be more adapted to the conditions tested.Results: Seeds from the Badajoz (Ba), Cuenca (Cu), Madrid (Ma), Seville (Se) and Toledo (To) populations were exposed to different thermal regimes (constant, and alternating temperatures between 15 and 30°C) and different darkness treatments (between 0 and 20 days with 24h dark photoperiod, then exposed to light with 12h light/dark photoperiod) to determine the parameters of the thermal model from germination levels in each treatment. To population was used to validate the thermal time parameters of other populations. Regardless of the other parameters, no germination occurred in total darkness. The mean value of base temperature (Tb) was 16.4±0.2°C in all treatments. Optimum temperature (To) values in Ma and Ba were 25°C, and those in Cu and Se were 22.5°C. The germination response decreased when the temperature approached Tb and increased when it was close to To. In comparison to alternating temperatures, constant temperatures had the highest germination response and lowest thermal time (θT(50)). Darkness treatments had a direct relationship with θT(50). The population origin also affected seed germination; Cu had the highest values of To and germination response but had a lower θT(50), which coincides with the lowest mean ambient temperatures. Conclusion : According to these results, the germination response of cattails was high in all populations under optimal conditions but was affected to a greater or lesser extent depending on thermal regimes, darkness treatments, and populations. The thermal time model allowed us to determine that To was between 22.5-25ºC and that Cu is the best population regarding the germination response under the conditions tested.

scholarly journals Application of the thermal time model for different Typha domingensis populations

2020 ◽  
Author(s):  
Fanny Mabel Carhuancho León ◽  
Pedro Luis Aguado Cortijo ◽  
María del Carmen Morató Izquierdo ◽  
María Teresa Castellanos Moncho
Keyword(s):  
Mean Value ◽  
Thermal Time ◽  
Plant Responses ◽  
Base Temperature ◽  
Typha Domingensis ◽  
Time Model ◽  
Ambient Temperatures ◽  
Germination Response ◽  
Thermal Regimes ◽  
Thermal Time Model

Abstract BackgroundTypha domingensis Pers. is a perennial emergent plant that in comparison to other Typha species, produces more biomass. This species is used in Green Floating Filters (GFFs), one of the most innovative systems of wastewater treatment to bioremediate eutrophic waters and produce biomass as biofuel feedstocks. The establishment of a GFF depends on the seed germination and plant responses under conditions of a new habitat. This study analysed the germination response of four different populations of T. domingensis through a thermal time model to determine which population would have the fastest germination for establishment in a GFF.ResultsSeeds from the Badajoz (Ba), Cuenca (Cu), Madrid (Ma) and Seville (Se) populations were exposed to different thermal regimes (constant and alternating temperatures between 15 and 30°C) and photoperiods (0, 3, 5, 7,10 and 20 days in darkness) to determine the parameters of the thermal model. Regardless of other parameters, no germination occurred in total darkness (20 days). The mean value of the base temperature (Tb) was 16.4±0.2°C in all treatments. The optimum temperature (To) values in Ma and Ba were 25°C, and those in Cu and Se were 22.5°C. The germination response decreased when the temperature approached Tb and increased when it was close to To. In comparison to temperatures with a ΔT= 5°C or 10°C, those with a ΔT= 15°C or ΔT= 0°C had the highest germination response and lowest thermal time (θT(50)). The photoperiod had a relationship with θT(50), but it was not proportional. The populations also affected germination; Cu had the highest values of To and germination response but had a lower θT(50). which coincides with the lowest mean ambient temperatures.Conclusion According to these results, the germination response of T. domingensis under optimal conditions was high in all populations but was affected to a greater or lesser extent depending on thermal regimes, photoperiods, and population. The thermal time model allowed us to determine that in comparison to other populations, Cu is the best population for establishment in a GFF due to its high germination response under the conditions tested.

Germination response of black nightshade (Solanum nigrum) to temperature and the establishment of a thermal time model

Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Ziqing Ma ◽  
Hongjuan Huang ◽  
Zhaofeng Huang ◽  
Dongjing Guo ◽  
Muhammad Saeed ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Northern China ◽  
Solanum Nigrum ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Black Nightshade ◽  
Germination Response ◽  
Thermal Time Model

Abstract Black nightshade (Solanum nigrum L.) is one of the worst weeds in crop fields, and it spreads mainly by the dispersal of seeds. Temperature is one of the key environmental factors affecting seed germination. We investigated the seed germination response to temperature in six populations of S. nigrum from mid to northern China and derived mathematical models from germination data. The results showed that S. nigrum seeds exhibit distinct germination responses to temperature within the range of 15 to 35 °C. The optimum temperatures for the populations XJ1600, JL1697 and HLJ2134 were 30 °C, and those for the populations NMG1704, HN2160 and LN2209 were 25 °C, 20 °C and 15 °C, respectively. Based on the nonlinear fitting and thermal time models, the predicted base temperatures of the six populations ranged from 2.3 to 6.4 °C, and the required accumulated growing degree days (GDD) ranged from 50.3 to 106.0 °C·d. The base temperatures and the accumulated GDD for germination differed among populations, and there was a significant negative correlation. HLJ2134 population required a high base temperature and accumulated GDD for germination, indicating that it might highly adapted to a warmer and moister environment. Based on the different germination responses of S. nigrum populations to temperature, the thermal time model reflects an innate relationship between base temperature and accumulated GDD required for initiation of seed germination, which provides a better basis for predicting seedling emergence and the timing for optimal control of S. nigrum under field conditions.

Modeling germination of smallflower umbrella sedge (Cyperus difformis L.) seeds from rice fields in California across suboptimal temperatures

2019 ◽  
Vol 33 (5) ◽  
pp. 733-738 ◽  
Author(s):  
Rafael M. Pedroso ◽  
Durval Dourado Neto ◽  
Ricardo Victoria Filho ◽  
Albert J. Fischer ◽  
Kassim Al-Khatib
Keyword(s):  
Growth Models ◽  
Rice Fields ◽  
Control Measures ◽  
Thermal Time ◽  
Model Parameters ◽  
Base Temperature ◽  
Probit Regression ◽  
Time Model ◽  
Thermal Requirements ◽  
Thermal Time Model

AbstractSmallflower umbrella sedge is a prolific C3 weed commonly found in rice fields in 47 countries. The increasing infestation of herbicide-resistant smallflower umbrella sedge populations threatens rice production. Our objectives for this study were to characterize thermal requirements for germination of smallflower umbrella sedge seeds from rice fields in California and to parameterize a population thermal-time model for smallflower umbrella sedge germination. Because the use of modeling techniques is hampered by the lack of thermal-time model parameters for smallflower umbrella sedge seed germination, trials were carried out by placing field-collected seeds in a thermogradient table set at constant temperatures of 11.7 to 41.7 C. Germination was assessed daily for 30 d, and the whole experiment was repeated a month later. Using probit regression analysis, thermal time to median germination [θT(50)], base temperature for germination (Tb), and SD of thermal times for germination [σθT(50)] were estimated from germination data, and model parameters were derived using the Solver tool in Microsoft Excel®. Germination rates increased linearly below the estimated optimum temperatures of 33.5 to 36 C. Estimated Tb averaged 16.7 C, whereas θT(50) equaled 17.1 degree-days and σθT(50) was only 0.1 degree-day. The estimated Tb for smallflower umbrella sedge is remarkably higher than that of japonica and indica types of rice, as well as Tb of important weeds in the Echinochloa complex. Relative to the latter, smallflower umbrella sedge has lower thermal-time requirements to germination and greater germination synchronicity. However, it would also initiate germination much later because of its higher Tb, given low soil temperatures early in the rice growing season in California. When integrated into weed growth models, these results might help optimize the timing and efficacy of smallflower umbrella sedge control measures.

Seed and Germination Biology ofDittrichia graveolens(Stinkwort)

2013 ◽  
Vol 6 (3) ◽  
pp. 371-380 ◽  
Author(s):  
Rachel N. Brownsey ◽  
Guy B. Kyser ◽  
Joseph M. DiTomaso
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Seed Viability ◽  
Base Temperature ◽  
Time Model ◽  
Wide Range ◽  
Total Seed ◽  
Thermal Time Model ◽  
Seed Characteristics

AbstractUnderstanding seed characteristics and seedling establishment patterns is essential for the development of effective management strategies for invasive annual species.Dittrichia graveolens(stinkwort) has increased its range rapidly within California since 1995, yet its biology is not well understood, which has led to poorly timed management. In this study, seed viability, germination, longevity, and dormancy, as well as seedling emergence characteristics ofD. graveolenswere evaluated in field, greenhouse, and laboratory experiments in Davis, CA, over a 2-yr period (fall 2010 to summer 2012). In the laboratory, seed germination ofD. graveolensoccurred at a wide range of constant temperatures (12 to 34 C). Cumulative germination was comparable to total seed viability (80 to 95%) at optimal germination temperatures, indicating that primary (innate) dormancy is likely absent. The base temperature for germination was identified using a thermal time model: 6.5 C and 4 C for 2010 and 2011 seed populations, respectively. In the field, seedlings emerged from fall through spring following precipitation events. A very low percentage of seedlings (2.5%) emerged in the second year after planting. Equivalent seedling emergence was observed over a wide range of light conditions (100, 50, 27, and 9% of available sunlight) in a greenhouse experiment, indicating that seed germination is not limited by high or low light. Results from these seed experiments improve our understanding of the reproductive biology of this rapidly expanding exotic annual and provide valuable information for developing effective timing and longevity of management programs.

scholarly journals Temperature and Pseudobulb Size Influence Flowering of Odontioda Orchids

HortScience ◽  
2008 ◽  
Vol 43 (5) ◽  
pp. 1404-1409 ◽  
Author(s):  
Matthew G. Blanchard ◽  
Erik S. Runkle
Keyword(s):  
Constant Temperature ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Open Flower ◽  
Inflorescence Development ◽  
The Andes ◽  
Stress Symptoms ◽  
Leaf Necrosis ◽  
Thermal Time Model

Odontioda is a cool-growing, sympodial epiphytic genus of orchids originating from the Andes Mountains of South America. Several hybrids are commercially grown as potted flowering plants for their brightly colored flowers and compact growth habit. We quantified how constant and fluctuating day/night temperatures influenced inflorescence initiation, time from visible inflorescence (VI) to flower, and pseudobulb development. Odontioda George McMahon ‘Fortuna’ and Lovely Penguin ‘Emperor’ were grown at constant temperature set points of 14, 17, 20, 23, 26, or 29 °C and day/night (12 h/12 h) temperatures of 20/14, 23/17, 26/14, 26/20, 29/23, or 29/17 °C. Plants were grown in glass greenhouses under a 12-h photoperiod and a maximum irradiance of 500 μmol·m−2·s−1. Within 6 weeks, heat stress symptoms such as leaf necrosis were observed on plants grown at a day temperature of 26 °C or greater regardless of the night temperature. After 20 weeks, 90% or greater of both clones had a VI when grown at a constant temperature of 14 or 17 °C. Plants grown at a constant temperature of 17 °C had the greatest pseudobulb diameter with a mean increase of 3.5 to 4.0 cm. In all treatments, a minimum pseudobulb diameter was required for uniform inflorescence initiation; pseudobulbs with a diameter of 5.5 cm or greater developed a VI in 93% of plants. Data for time from VI to open flower were converted to a rate, and a thermal-time model relating temperature with inflorescence development was developed. The base temperature and thermal time for VI to flower in George McMahon ‘Fortuna’ and Lovely Penguin ‘Emperor’ were estimated at −0.1 °C and 1429 °C·d−1 and 0.8 °C and 1250 °C·d−1, respectively. This information could be used by commercial orchid growers to assist in producing potted flowering Odontioda orchids for specific market dates.

scholarly journals Base temperature and simulation model for nodes appearance in cape gooseberry (Physalis peruviana L.)

2008 ◽  
Vol 30 (4) ◽  
pp. 862-867 ◽  
Author(s):  
Melba Ruth Salazar ◽  
James W. Jones ◽  
Bernardo Chaves ◽  
Alexander Cooman ◽  
Gerhard Fischer
Keyword(s):  
Statistical Analysis ◽  
Thermal Time ◽  
Base Temperature ◽  
Linear Segment ◽  
Greenhouse Condition ◽  
Time Model ◽  
Segmented Model ◽  
Physalis Peruviana ◽  
Thermal Time Model ◽  
Cape Gooseberry

Data was analyzed on development of the solanaceen fruit crop Cape gooseberry to evaluate how well a classical thermal time model could describe node appearance in different environments. The data used in the analysis were obtained from experiments conducted in Colombia in open fields and greenhouse condition at two locations with different climate. An empirical, non linear segmented model was used to estimate the base temperature and to parameterize the model for simulation of node appearance vs. time. The base temperature (Tb) used to calculate the thermal time (TT, ºCd) for node appearance was estimated to be 6.29 ºC. The slope of the first linear segment was 0.023 nodes per TT and 0.008 for the second linear segment. The time at which the slope of node apperance changed was 1039.5 ºCd after transplanting, determined from a statistical analysis of model for the first segment. When these coefficients were used to predict node appearance at all locations, the model successfully fit the observed data (RSME=2.1), especially for the first segment where node appearance was more homogeneous than the second segment. More nodes were produced by plants grown under greenhouse conditions and minimum and maximum rates of node appearance rates were also higher.

Thermal time model analysis for seed germination of four Vicia species

2013 ◽  
Vol 36 (8) ◽  
pp. 841-848 ◽  
Author(s):  
Xiao-Wen HU ◽  
Juan WANG ◽  
Yan-Rong WANG
Keyword(s):  
Seed Germination ◽  
Model Analysis ◽  
Thermal Time ◽  
Time Model ◽  
Thermal Time Model

scholarly journals Screening for Cold Tolerance during Germination within Sweet and Fiber Sorghums [Sorghum bicolor (L.) Moench] for Energy Biomass

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 620
Author(s):  
Cristina Patanè ◽  
Salvatore L. Cosentino ◽  
Valeria Cavallaro ◽  
Alessandro Saita
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Cold Tolerance ◽  
Fiber Type ◽  
Warm Season ◽  
Early Spring ◽  
Thermal Time ◽  
Base Temperature ◽  
Biomass Sorghum ◽  
Germination Response

Within the project “BIOSEA” funded by the Italian Ministry of Agriculture and Forestry, a preliminary laboratory test was conducted to assess the variability for cold tolerance during germination in 30 cultivars of biomass sorghum, among fiber and sweet types. Seed germination (%) and mean germination time (MGT) were examined at seven constant temperatures (from 8 °C to 35 °C) and base temperature (Tb) and thermal time (θT) for 50% germination were calculated. A wide genetic diversity in the germination response of sorghum was ascertained at 8 °C (CV 45%) and 10 °C (CV 25.4%). At 8 °C, in cultivars of ‘Padana 4’, ‘PR811F’, ‘PSE24213’, ‘PR849’ and ‘Zerberus’, seed germination exceeded 80%. Seeds of ‘Zerberus’ were also the fastest, requiring less than 13 days for final germination at this low temperature. Great differences were found in Tb and θT among cultivars. Tb varied between 7.44 °C (‘PR811F’) and 13.48 °C (‘Nectar’). Thermal time (θT) was, on average, 24.09 °Cd−1, and ranged between 16.62 (‘Nectar’) and 33.42 °Cd−1 (‘PSE24213’). The best combination of the two germination parameters (i.e., low Tb and θT) corresponded to ‘Zerberus’, ‘Sucrosorgo 506’, ‘Jumbo’ and ‘PR811F’. Accordingly, these cultivars are more tolerant to cold stress during germination and, thus, more adapt to early spring sowings in Mediterranean areas (March-April). Cultivars ‘PR811F’ (fiber type) and ‘Sucrosorgo 506’ (sweet type) also combine high cold tolerance with good productivity in terms of final dry biomass, as assessed in open-field conditions (late spring sowing). The genetic variation in the germination response to a low temperature is useful for the identification of genotypes of sorghum suitable to early sowings in semi-arid areas. Selection within existing cultivars for cold tolerance during germination may also contribute to the expansion of biomass sorghum into cooler cultivation areas, such as those of Northern Europe, which are less suitable to this warm season crop.

scholarly journals Predicting Rooting Stages in Poinsettia Cuttings Using Root Zone Temperature-based Models

2005 ◽  
Vol 130 (3) ◽  
pp. 302-307 ◽  
Author(s):  
Erin G. Wilkerson ◽  
Richard S. Gates ◽  
Sérgio Zolnier ◽  
Sharon T. Kester ◽  
Robert L. Geneve
Keyword(s):  
Root Elongation ◽  
Root Zone ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Root Zone Temperature ◽  
Nonlinear Growth ◽  
Threshold Temperatures ◽  
Thermal Time Model ◽  
Zone Temperature

Root zone temperature optima for root initiation and root elongation stages for rooting in poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch `Freedom Dark Red') cuttings was determined to be 28 and 26 °C, respectively. Threshold temperatures where rooting development was slow (>24 days) or did not occur were ≤20 and ≥32 °C. Time to visible rooting and postemergent root elongation was modeled based on cumulative daily mean root zone temperatures in growth chamber studies using a thermogradient table to provide simultaneous temperatures between 19 to 34 °C. Time to root emergence at different root zone temperatures was best described using a nonlinear growth rate derived mathematical model, while postemergent root elongation up to 100 cm could be described using either a linear thermal time model or a nonlinear equation based on elongation rate. These temperature-based mathematical models were used to predict rooting in six greenhouse experiments. Using a root zone base temperature of 21 °C, observed vs. predicted time to visible root emergence was highly correlated (r2 = 0.98) with a mean prediction error (MPE) of 1.6 d. Observed vs. predicted root length using the linear thermal time model had a r2 = 0.69 and an MPE of 14.6 cm, which was comparable to the nonlinear model with an r2 = 0.82 and an MPE of 14.8 cm.

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