scholarly journals Respuesta germinativa y crecimiento de plántulas de Mammillaria magnimamma (Cactaceae) bajo diferentes condiciones ambientales

2017 ◽  
pp. 25
Author(s):  
Marcela Ruedas ◽  
Teresa Valverde ◽  
Silvia Castillo-Argüero
Keyword(s):  
Light Intensity ◽  
Factorial Design ◽  
Seedling Growth ◽  
Nutrient Availability ◽  
Seed Viability ◽  
Germination Percentage ◽  
Light Requirement ◽  
High Viability ◽  
Different Temperatures ◽  
Slow Growing

Germination response and seedling growth of Mammillaria magnimamma were analyzed. Germination percentage and germination velocity of seeds under different conditions were quantified. Treatments included light/ dark conditions, acidity pretreatments and different temperatures. Seeds are photoblastic positive and show a high viability (86%); light requirement decreases as seeds age. Different temperatures during germination resulted in different germination velocities. Pretreatments with chlorhidric acid did not affect seed viability. Seedling growth in greenhouse conditions was studied using a factorial design which included two levels of light intensity, two levels of nutrient availability and two levels of watering frequency. Seedlings are slow growing (between 0.014 and 0.027 g g-1 d-1) and respond positively to an increase in nutrient availability and light intensity.

Effect of temperature and scarification on germination and emergence of wild safflower, Carthamus oxyacantha Bieb.

1975 ◽  
Vol 84 (2) ◽  
pp. 239-243 ◽  
Author(s):  
A. Bassiri ◽  
I. Rouhani ◽  
S. R. Ghorashy
Keyword(s):  
Seedling Growth ◽  
Room Temperature ◽  
Laboratory Experiments ◽  
Germination Percentage ◽  
Effect Of Temperature ◽  
Silty Clay ◽  
Wild Type ◽  
Different Temperatures ◽  
Wild Safflower ◽  
Wild Seed

SUMMARYSeeds of wild safflower, Carthamus oxyacantha Bieb., collected from the Bajgah area, Iran, were subjected to chilling and/or scarification and their germination and emergence characteristics and seedling growth were studied in two laboratory experiments. Seeds of Arak 2811 variety of cultivated safflower, C. tinctorius L., harvested from the same area at the same time was used for comparison.In the first experiment, the untreated, scarified, chilled at 0 °C for 1 month, and chilled and scarified wild seed and seed of the variety Arak 2811 were incubated at six different temperatures (5, 10, 15, 20, 25 and 30 °C) and their germination percentage and seedling lengths were recorded. In the second experiment, the seeds of the above five treatments were planted in a silty clay loam at room temperature (23 ± 2 °C) and their emergence and seedling heights were noted.In all cases, the cultivated variety, Arak 2811, had higher germination and emergence percentages and seedling heights than the wild type. Germination of both strains was greatly reduced at the two extreme temperatures (5 and 30 °C). The optimum temperatures for germination of the wild and the cultivated strains were between 15 and 20 °C.Scarification of the wild seed did not improve the germination or emergence percentages and chilling of the seed for a month at 0 °C reduced the emergence of the wild seed. Temperature of germination, however, seemed to be an important factor affecting germination and seedling growth of wild safflower.

Purple prairie clover seed viability and germinability after passing through the digestive tracts of yearling steers

2019 ◽  
Vol 99 (5) ◽  
pp. 734-739
Author(s):  
Chen Gu ◽  
Alan D. Iwaasa ◽  
Mengli Zhao
Keyword(s):  
Low Cost ◽  
Seed Viability ◽  
Germination Percentage ◽  
Cattle Dung ◽  
Western Canada ◽  
Important Method ◽  
Hard Seed ◽  
Native North American ◽  
High Viability ◽  
Clover Seed

Endozoochory by cattle has been considered an important method for population self-regeneration; however, the effects of cattle digestive tracts on the viability and germinability of purple prairie clover (Dalea purpurea Vent.), a native North American species, remain understudied. The experiment was conducted at the Agriculture and Agri-Food Canada Swift Current Research and Development Centre in the semiarid prairie of western Canada. Purple prairie clover seeds extracted from cattle dung pats were tested for germination and compared with uningested and scarified seeds from the same paddock. The germination percentage (within 200 d) of the ingested seeds was 16.5% ± 0.8%, two times higher after passing through digestive tracts than uningested seeds (8.3% ± 1.2%), while 76.6% ± 1.5% of ingested seeds remained dormant. As many as 92.4% ± 0.9% of purple prairie clover seeds survived digestion due to their high hard seed rate (90.5% ± 1.0%), which was lower than the uningested seeds by 6.9%. Therefore, cattle dispersing purple prairie clover seeds with high viability and germinability is a low-cost method to increase and rejuvenate purple prairie clover for late-season grazing pastures.

scholarly journals Effect of light Intensity and photoperiod on growth of Chlorella pyrenoidosa and CO2 Biofixation

2018 ◽  
Vol 31 ◽  
pp. 03003
Author(s):  
Teuku Johar Gunawan ◽  
Yusni Ikhwan ◽  
Fajar Restuhadi ◽  
Usman Pato
Keyword(s):  
Light Intensity ◽  
Factorial Design ◽  
Environmental Factor ◽  
Chlorella Pyrenoidosa ◽  
Potential Solution ◽  
Light Requirement ◽  
Two Factors ◽  
Average Biomass ◽  
D 12 ◽  
Effect Of Light

Microalgae have been viewed as one of potential solution for CO2 biofixation or CO2 sequestration. However, many factors need to be evaluated to support development of CO2 biofixation. One important environmental factor for the growth of micro algae is related with light requirement. The aim of this study was to evaluate the effect of light intensity and photoperiod on growth of Chlorellapyrenoidosa (C.pyrenoidosa) and CO2 biofixation. Experiments were carried out in 1000 mL semi batch photo bioreactors, purged continuously with air (0.034% CO2). An Experiment of Factorial Design was employed in which the light intensity was evaluated 4 level at 2000, 4000, 6000 and 8000 lux with 3 level of photo period at L/D (light /dark) 8 hours/16 hours; L/D 12 hours/12 hours and L/D 16 hours/8 hours. The result indicated that both light intensity and photo period had significant effect (p< 0.05) on growth of C. pyrenoidosa. However, the photo period showed stronger effect relative to light intensity on growth of C.pyrenoidosa within the range reviewed. The interaction between the two factors was indicative but statistically not significant. Best growth profile sustained at combination of L/D 16 hours/8 hours of photoperiod and light intensity of 8000 lux with the highest average biomass observed at 0.516 ± 0.069gr/L. An increase in CO2biofixation rate of around 2 times was also observed between highest setting (8000 lux; L/D 16/12 hours) relative to that of lowest setting (2000 lux; L/D 8/12 hours).

Salinity Tolerance of Black Gram Cultivars During Germination and Early Seedling Growth

2018 ◽  
Vol 51 (3) ◽  
pp. 51-68 ◽  
Author(s):  
M.K. Hasan ◽  
M.S. Islam ◽  
M.R. Islam ◽  
H.N. Ismaan ◽  
A. El Sabagh
Keyword(s):  
Salt Stress ◽  
Salinity Tolerance ◽  
Seedling Growth ◽  
Negative Impact ◽  
Germination Rate ◽  
Dry Weight ◽  
Germination Percentage ◽  
Shoot Length ◽  
Sand Culture ◽  
Black Gram

Abstract A laboratory experiment regarding germination and seedling growth test was conducted with three black gram genotypes tested under three salinity levels (0, 75 and 150 mM), for 10 days, in sand culture within small plastic pot, to investigate the germination and seedling growth characteristics. Different germination traits of all black gram genotypes, like germination percentage (GP), germination rate (GR), coefficient of velocity of germination (CVG) greatly reduced, as well as mean germination time (MGT) increased with increasing salt stress. At high salt stress, BARI Mash-3 provided the highest GP reduction (28.58%), while the lowest was recorded (15.79% to control) in BARI Mash-1. Salinity have the negative impact on shoot and root lengths, fresh and dry weights. The highest (50.32% to control) and lowest reduction (36.39%) of shoot length were recorded in BARI Mash-2 and BARI Mash-1, respectively, under 150 mM NaCl saline conditions. There were significant reduction of root lengths, root fresh and dry weight, shoot length, shoot fresh and dry weight in all genotypes under saline condition. The genotypes were arranged as BARI Mash-1 > BARI Mash-3 > BARI Mash-2, with respect to salinity tolerance.

scholarly journals GERMINATION AND VIGOUR IN SEEDS OF THE COWPEA IN RESPONSE TO SALT AND HEAT STRESS

2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra
Keyword(s):  
Salt Stress ◽  
Heat Stress ◽  
High Temperature ◽  
Low Temperature ◽  
Vigna Unguiculata ◽  
Salt Concentration ◽  
Dry Weight ◽  
Germination Percentage ◽  
Different Types ◽  
Different Temperatures

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.

scholarly journals Seed germination requirements of Hypericum scruglii, an endangered medicinal plant species of Sardinia (Italy)

Botany ◽  
2020 ◽  
Vol 98 (10) ◽  
pp. 615-621 ◽  
Author(s):  
Marco Porceddu ◽  
Martina Sanna ◽  
Sara Serra ◽  
Maria Manconi ◽  
Gianluigi Bacchetta
Keyword(s):  
Medicinal Plant ◽  
Seed Bank ◽  
Seed Viability ◽  
Base Temperature ◽  
Endemic Plant ◽  
Endangered Medicinal Plant ◽  
High Viability ◽  
Wide Range ◽  
Baseline Information ◽  
Germination Requirements

Hypericum scruglii Bacch., Brullo & Salmeri is an endangered endemic plant of Sardinia, and the phloroglucinol compounds identified in this species have been reported to inhibit the activity of the Human Immunodeficiency Virus. Seed banks are a genetic repository that effectively preserve taxa of conservation interest, and they hold knowledge about the biology and germination ecophysiology of the taxa they preserve. The main goals of this study were to investigate the germination requirements for H. scruglii, to evaluate the seed viability after eight years of long-term conservation and to suggest an efficient protocol for germination. Seeds stored at –25 °C in the seed bank were tested at temperatures from 5 to 30 °C and 25/10 °C. Base temperature (Tb) and thermal time (θ50) for germination were estimated. Seeds of H. scruglii germinated over a wide range of temperatures, responding positively to high temperatures and 25/10 °C. Tb was estimated at 4.92 °C, and θ50 was estimated at 198.27 degree days. The high viability detected in seeds of H. scruglii allows us to suggest the use of seeds stored in a seed bank when fresh material for plant propagation is scarce. Our results provide new and useful baseline information for implementing conservation and multiplication strategies for this endangered medicinal plant.

scholarly journals Response of Photosynthesis and Chlorophyll Fluorescence Parameters of Castanopsis kawakamii Seedlings to Forest Gaps

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Zhong-sheng He ◽  
Rong Tang ◽  
Meng-jia Li ◽  
Meng-ran Jin ◽  
Cong Xin ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Light Intensity ◽  
Seedling Growth ◽  
Group Treatment ◽  
Control Group ◽  
Low Light ◽  
Chlorophyll Fluorescence Parameters ◽  
Forest Gaps ◽  
Low Light Intensity ◽  
Weak Light

Light is a major environmental factor limiting the growth and survival of plants. The heterogeneity of the light environment after gap formation in forest influences the leaf chlorophyll contents, net photosynthetic rate (Pn), and chlorophyll fluorescence, thus influencing the growth and regeneration of Castanopsis kawakamii seedlings. The aim of this study was to explore the effects of weak light on the photosynthetic physiology of C. kawakamii seedlings in forest gaps and non-gaps. The results showed that (1) the contents of chlorophyll a (Chl-a), chlorophyll b (Chl-b), and total chlorophyll (Chl-T) in forest gaps were lower than in non-gaps. Seedlings tended to increase chlorophyll content to absorb light energy to adapt to low light intensity in non-gap environments. (2) The Pn values of C. kawakamii seedlings in forest gaps were significantly higher than in non-gaps, and forest gaps could improve the seedlings’ photosynthetic capacity. (3) The C. kawakamii seedlings in forest gaps were more sensitive to weak light and control group treatment, especially the tall seedlings, indicating that seedlings require more light to satisfy their growth needs in the winter. The seedlings in non-gaps demonstrated better adaptability to low light intensity. The light intensity was not adequate in weak light conditions and limited seedling growth. We suggest that partial forest selection cutting could improve light intensity in non-gaps, thus promoting seedling growth and regeneration of C. kawakamii more effectively in this forest.

scholarly journals A Comparative Study on Dye Degradation by Leaf and Root Extracts of Parthenium hysterophorus L

2018 ◽  
Vol 6 (4) ◽  
pp. 327-331
Author(s):  
Dipesh Shahi ◽  
Rajiv Sapkota
Keyword(s):  
Malachite Green ◽  
Seedling Growth ◽  
Congo Red ◽  
Dye Degradation ◽  
Cost Effective ◽  
Germination Percentage ◽  
Parthenium Hysterophorus ◽  
Treated Wastewater ◽  
Root Extracts ◽  
Phytotoxicity Test

The use of different dyes and pigments is increasing with the increase in industrialization leading to the high production of effluent. The effluent contaminated with dyes and dye-stuff has harmful effects on public health and the environment. Thus, the treatment of effluent is essential. Biological approaches are gaining much interest due to their cost-effective and eco-friendly nature over various physicochemical methods for the treatment of dye-contaminated wastewater. This study highlights on the biodegradation of congo red and malachite green by using leaf and root extracts of Parthenium hysterophorus. The extract and the dye were mixed in the ratio of 1:2 and incubated at 40ºC for 90 minutes. Decolorization assay was performed using UV visible spectrophotometer which indicated that decolorization was due to degradation of dyes into non-colored metabolites. The leaves extract exhibited higher decolorizing activity than roots extract. The maximum decolorization for leaves extract was 55.8% (congo red) and 51.6% (malachite green). Furthermore, phytotoxicity test was carried out to determine the effect of dyes and their degradation metabolites on seed germination and seedling growth of chickpea (Cicer arietinum L). The germination percentage and seedling growth were more in degradation metabolites than untreated dyes, indicating less toxic nature of degradation metabolites. Hence, it can be inferred that P. hysterophorus extracts can be used to treat dye wastewater and treated wastewater can be used for irrigation. Int. J. Appl. Sci. Biotechnol. Vol 6(4): 327-331

scholarly journals Seed longevity of maize conserved under germplasm bank conditions for up to 60 years

2021 ◽  
Author(s):  
Filippo Guzzon ◽  
Maraeva Gianella ◽  
Jose Alejandro Velazquez Juarez ◽  
Cesar Sanchez Cano ◽  
Denise E Costich
Keyword(s):  
Seed Germination ◽  
Plant Genetic Resources ◽  
Seed Viability ◽  
Storage Conditions ◽  
Seed Longevity ◽  
Germplasm Bank ◽  
Significant Difference ◽  
Different Temperatures ◽  
Germination Experiments

Abstract Background and Aims The long-term conservation of seeds of plant genetic resources is of key importance for food security and preservation of agrobiodiversity. Nevertheless, there is scarce information available about seed longevity of many crops under germplasm bank conditions. Methods Through germination experiments as well as the analysis of historical monitoring data, we studied the decline in viability manifested by 1000 maize (Zea mays subsp. mays) seed accessions conserved for an average of 48 years at the CIMMYT germplasm bank, the largest maize seedbank in the world, under two cold storage conditions: an active (–3 °C; intended for seed distribution) and a base conservation chamber (–15 °C; for long-term conservation). Key Results Seed lots stored in the active chamber had a significantly lower and more variable seed germination, averaging 81.4 %, as compared with the seed lots conserved in the base chamber, averaging 92.1 %. The average seed viability detected in this study was higher in comparison with that found in other seed longevity studies on maize conserved under similar conditions. A significant difference was detected in seed germination and longevity estimates (e.g. p85 and p50) among accessions. Correlating seed longevity with seed traits and passport data, grain type showed the strongest correlation, with flint varieties being longer lived than floury and dent types. Conclusions The more rapid loss of seed viability detected in the active chamber suggests that the seed conservation approach, based on the storage of the same seed accessions in two chambers with different temperatures, might be counterproductive for overall long-term conservation and that base conditions should be applied in both. The significant differences detected in seed longevity among accessions underscores that different viability monitoring and regeneration intervals should be applied to groups of accessions showing different longevity profiles.

Exposure of Polymeric Glazing Materials Using NREL’s Ultra-Accelerated Weathering System (UAWs)

2010 ◽  
Author(s):  
Carl Bingham ◽  
Gary Jorgensen ◽  
Amy Wylie
Keyword(s):  
Light Intensity ◽  
Thermal Effects ◽  
Outdoor Exposure ◽  
Exposure Chamber ◽  
Accelerated Weathering ◽  
Intensity Level ◽  
Design And Implementation ◽  
Different Temperatures ◽  
Exposure Testing ◽  
Ultraviolet Irradiance

NREL’s Ultra-Accelerated Weathering System (UAWS) selectively reflects and concentrates natural sunlight ultraviolet irradiance below 475 nm onto exposed samples to provide accelerated weathering of materials while keeping samples within realistic temperature limits. This paper will explain the design and implementation of the UAWS which allow it to simulate the effect of years of weathering in weeks of exposure. Exposure chamber design and instrumentation will be discussed for both a prototype UAWS used to test glazing samples as well as a commercial version of UAWS. Candidate polymeric glazing materials have been subjected to accelerated exposure testing at a light intensity level of up to 50 UV suns for an equivalent outdoor exposure in Miami, FL exceeding 15 years. Samples include an impact modified acrylic, fiberglass, and polycarbonate having several thin UV-screening coatings. Concurrent exposure is carried out for identical sample sets at two different temperatures to allow thermal effects to be quantified along with resistance to UV.

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