scholarly journals Thermal stress and physiological changes in watermelon seeds

2018 ◽  
Vol 48 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Rita de Cássia Barbosa da Silva ◽  
Marcelo do Nascimento Araujo ◽  
Fábio Luiz Santos Ornellas ◽  
Bárbara França Dantas
Keyword(s):  
Enzyme Activity ◽  
Thermal Stress ◽  
Germination Rate ◽  
Germination Percentage ◽  
Initial Growth ◽  
Physiological Changes ◽  
Percentage Germination ◽  
Stress Protection ◽  
Evaluation Parameters ◽  
The Ideal

ABSTRACT Given that watermelon is a crop widespread around the world, there is considerable interest in verifying how its seeds physiologically behave under unfavorable temperature conditions. This study aimed to evaluate the biochemical changes mobilization and reserves degradation, as well as the enzyme activity, during seed germination and initial growth of watermelon seedlings subjected to thermal stress, using temperature, germination percentage, germination rate and relative germination frequency over the incubation time as evaluation parameters. The experimental design was completely randomized, in a 5 x 3 factorial scheme, with five temperatures (17 ºC, 20 ºC, 25 ºC, 30 ºC and 35 ºC) and three cultivars (Charleston Gray, Fairfax and Crimson Sweet), with 4 replicates of 50 seeds. Germination, seedling growth, reserve degradation and stress protection system were evaluated. Thermal stress caused deleterious effects on watermelon seeds with germination capacity at well defined temperature limits, being 25 ºC the ideal temperature, with the highest percentage of normal seedlings. Sub- (17 ºC) and supra-optimal (30 ºC) temperatures presented more than 80 % of abnormal seedlings. The α-amylase enzyme activity is intense only at the beginning of germination. Under thermal stress, the proline contents increase mainly in the cotyledons.

Physical and physiological changes of Crambe abyssinica Hochst seed during maturation

2020 ◽  
Vol 42 ◽  
pp. e49895
Author(s):  
Ana Paula de Oliveira Silva ◽  
Isabella Sousa Ribeiro ◽  
Tathiana Elisa Masetto ◽  
Luiz Carlos Ferreira Souza
Keyword(s):  
Water Content ◽  
Seed Development ◽  
Germination Rate ◽  
Germination Percentage ◽  
Seed Maturation ◽  
Physiological Changes ◽  
Crambe Abyssinica ◽  
Mato Grosso ◽  
Physiological Quality ◽  
Physical Attributes

Determination of seed-maturation indicators enables the identification of the ideal moment for harvest to achieve the best production and conservation potential. Our objective here was to evaluate some physical and physiological changes of crambe (Crambe abyssinica Hochst) seeds as possible indicators of seed maturation. Crambe flowering was monitored in Dourados, Mato Grosso do Sul, Brazil. Plants were tagged, and 13, 22, 26, and 28 days after the initiation of flowering, the seeds were collected and following physical attributes evaluated: length, diameter, total mass, dry matter and water content. Physiological quality of the seeds was assessed using the germination test, by registering the percentage of normal seedlings and dormant seeds, immediately after each harvest, and again after six months of storage. The water-absorption curves were characterized as a function the seed-development stages. All physical attributes were observed to increase because of the accumulation of reserve substances during seed development, except for water content, which gradually decreased from 72.2% at the start of development to 29.5% at maturity. At 28 days after anthesis the germination percentage of crambe seeds at physiological maturity was only 17%, indicating that they became dormant while maturing. However, seed germination rate was 89% after six months of storage, indicating that dormancy was almost fully overcome after this period.

Germination in Stylosanthes humilis Populations in the Presence of NaCl

1994 ◽  
Vol 42 (6) ◽  
pp. 717 ◽  
Author(s):  
MB Lovato ◽  
PS Martins ◽  
Filho JPD Lemos
Keyword(s):  
Salt Tolerance ◽  
Significant Variation ◽  
Germination Rate ◽  
Natural Populations ◽  
Germination Percentage ◽  
Percentage Germination ◽  
North East ◽  
Germination Response ◽  
Stylosanthes Humilis

The germination response to NaCl treatments (0, 67, 134, 201 and 268 mol m-3) was investigated in 6 natural populations of Stylosanthes humilis from 3 ecogeographic regions of Pernambuco State, north-east Brazil. In general, salt tolerance was high, with percentage germination unaltered up to 67 mol m-3 NaCl in 2 populations and unaltered up to 134 mol m-3 NaCl in the remaining 4. The estimated concentration which reduced percentage germination to 50% varied between populations from 200 to 295 mol m-3 NaCl. Salt affected germination rate even more than it did the germination percentage, being altered at 67 mol m-3 NaCl in all populations. The germination rate was reduced to 50% in the range of 131-176 mol m-3 NaCl. There was a significant variation in salt tolerance between these natural populations, and no relation was found between salt tolerance of the populations and the aridity of their provenance.

scholarly journals Effects of cycocel priming on growth and early development of rapeseed under drought stress

2013 ◽  
Vol 5 (1) ◽  
pp. 5-18
Author(s):  
Alireza Pourmohammad ◽  
Fariborz Shekari ◽  
Veeda Soltaniband
Keyword(s):  
Germination Rate ◽  
Dry Weight ◽  
Germination Percentage ◽  
Percentage Germination ◽  
Stress Control ◽  
Positive Effects ◽  
The Third ◽  
Germination Characteristics ◽  
Three Stages ◽  
Total Dry Weight

Abstract An experiment was concluded to evaluate the effects of priming on germination characteristics and establishment of rapeseed seedlings during three stages. In the first and second stages of experiment, the effects at three factors vis: cultivars (RVS, Hayola), waterdeficit stress (Control,-6 and -12 bar) and cycocel treatment (dry seeds, 300, 600, 900, 1200 and 1500 μM) on germination and seedling growth of plant were assayed. The results showed that priming had positive effects on germination percentage, germination rate index, germination index, and radicle length under water-deficit conditions. RVS had greater efficiency than other cultivars. The third section of experiment revealed that the priming of RVS seeds improved the stem, root and dry weight, total dry weight as well as leaf number and area of seedlings.

scholarly journals The Alleviation Effect of Silicon on Seed Germination and Seedling Growth of Tomato Under Salinity Stress

2012 ◽  
Vol 76 (1) ◽  
pp. 119-126 ◽  
Author(s):  
Maryam Haghighi ◽  
Zahra Afifipour ◽  
Maryam Mozafarian
Keyword(s):  
Seed Germination ◽  
Salinity Stress ◽  
Seedling Growth ◽  
Germination Rate ◽  
Germination Percentage ◽  
Percentage Germination ◽  
Tomato Seeds ◽  
Germination Characteristics ◽  
Salinity Levels ◽  
Mean Germination Time

The Alleviation Effect of Silicon on Seed Germination and Seedling Growth of Tomato Under Salinity StressThis study was conducted to evaluate the effectiveness of silicon (Si) application under salinity levels on seed germination and growth characteristics of tomato seeds. A laboratory experiment was performed on completely randomized design with two levels of salinity (25 and 50 mM NaCl) and 2 concentration of Si (1 and 2 mM) with 4 replications. Germination percentage, germination rate, seedling shoot and root length, fresh and dry weight of seedling and mean germination time was measured. Seed germination ofLycopersicon esculentumL. was significantly affected by salinity levels, Si and their interaction. Germination characteristics of tomato seeds decreased drastically by increasing NaCl concentrations. However, 1 mM Si had positive effects on seed germination characteristics and improved germination percentage, germination rate and mean germination time. Si alleviated the harmful effect of salinity stress on tomato seed germination at almost all germination characteristics.

scholarly journals Morphometry and Germination of Passovia pyrifolia, Struthanthus marginatus and Phoradendron mucronatum Diaspores

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
J.M.L. AZEVEDO ◽  
C.G.G. SANTOS ◽  
C.S. CAIRES ◽  
J.C. ARAÚJO NETO ◽  
R.C. SOUZA
Keyword(s):  
Moisture Content ◽  
Germination Rate ◽  
Germination Percentage ◽  
Percentage Germination ◽  
Essential Characteristic ◽  
Germination Time ◽  
Randomized Design ◽  
Different Temperatures ◽  
Mean Germination Time ◽  
Completely Randomized Design

ABSTRACT: The goal of this work was to characterize morphometrically diaspores from three species of mistletoes (Passovia pyrifolia, Struthanthus marginatus e Phoradendron mucronatum), as well as to study its germination behavior according to temperature and luminosity. In germination tests, the completely randomized design was used, in factor scheme 4 x 2, with 4 replications of 15 diaspores. The factors for the first test were different temperatures and two diaspore conditions (intact and without epicarp). In the second test, factors were different light qualities and two diaspore conditions. The analyzed variables were: germination percentage, germination rate index (GRI) and mean germination time (MGT). Mistletoe’s diaspores present an elliptic shape with viscin layer, an essential characteristic for the dispersion of the species. In addition to this, they present a distinction as for the moisture content when compared to the Loranthaceae and Viscaceae, where the latter presents the highest content. Germination is greater at the alternated temperature of 20-30 oC for P. pyrifolia and P. mucronatum diaspores and 20 oC for S. marginatus. Luminosity interfered in the germination of P. mucronatum and S. marginatus but did not influence P. pyrifolia. The diaspore condition influenced the germination of the three studied species, observing a significant increase in their germination when the epicarp was removed. Temperature and luminosity interfere directly in the GRI and MGT of the three mistletoes species.

scholarly journals Improving Germination Rate of Coastal Glehnia by Cold Stratification and Pericarp Removal

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 944
Author(s):  
Moon-Sun Yeom ◽  
Thi Kim Loan Nguyen ◽  
Ju-Sung Cho ◽  
Myung-Min Oh
Keyword(s):  
Mass Production ◽  
Germination Rate ◽  
Germination Percentage ◽  
Cold Stratification ◽  
Percentage Germination ◽  
Breaking Dormancy ◽  
Glehnia Littoralis ◽  
Germination Speed ◽  
Germinating Seeds ◽  
Inhibited Water

The medicinal plant, coastal glehnia (Glehnia littoralis F. Schmidt ex Miq.), belongs to the Apiaceae, which is known to exhibit morpho-physiological seed dormancy (MPD). In this study, we aimed to determine the dormancy type of this plant, along with the conditions for breaking dormancy, and how to increase its germination rate for mass production. Initially, the seeds of coastal glehnia had undeveloped embryos, which gradually developed following cold (5 °C) stratification over eight weeks. The embryo to seed (E:S) ratio increased to 66.7%, confirming that the seeds had the MPD type. Coastal glehnia seeds with pericarp did not show inhibited water uptake, and the germination inhibitory chemicals were not detected. However, removal of the pericarp improved the final germination percentage, germination speed, and T50 of coastal glehnia seeds compared with those of seeds with pericarp at 20 °C, which showed the highest value compared with other temperature treatments. Thus, cold stratification at 5 °C for eight weeks and removing the pericarp of germinating seeds maintained at 20 °C is efficient ways to break dormancy and improve the germination rate for the mass production of coastal glehnia.

scholarly journals Effect of Aqueous Extracts from Weed Species on Germination and Initial Growth in Raphanus sativus L.

2015 ◽  
Vol 7 (4) ◽  
pp. 464-470
Author(s):  
Anisoara STRATU ◽  
Zenovia OLTEANU ◽  
Andrei LOBIUC
Keyword(s):  
Raphanus Sativus ◽  
Germination Rate ◽  
Germination Percentage ◽  
Amaranthus Retroflexus ◽  
Spectrophotometric Analysis ◽  
Initial Growth ◽  
Aqueous Extracts ◽  
Weed Species ◽  
Convolvulus Arvensis ◽  
Test Species

The current paper presents the results of a study on the effects of aqueous extracts from five weed species (Amaranthus retroflexus, Cirsium arvense, Convolvulus arvensis, Echinochloa crus-galii, Setaria verticillata) on germination and initial growth in Raphanus sativus L. The following indicators have been analyzed: indices of germination (the germination percentage; the speed of germination; the speed of accumulated germination and the coefficient of germination rate), the length of the root and hypocotyls, the pH of aqueous extracts, the UV-Vis absorption spectra of aqueous extracts. The results of the investigations showed the following aspects: the aqueous extracts reduced the values of calculated germination indices and root growth in the first ontogenetic stages of the test species; the pH of the extracts was slightly acid to neutral. Qualitative spectrophotometric analysis indicated the possible presence of phenolic and organic compounds in the extracts. C. arvense, S. verticillata and E. crus-galii presented the most pronounced effect on germination and growth processes.

scholarly journals Antioxidant enzyme activity in germination of Dalbergia spruceana seeds under different temperatures

2021 ◽  
Vol 43 ◽  
Author(s):  
Clenes Cunha Lima ◽  
Ely Simone Cajueiro Gurgel ◽  
Eduardo Euclydes de Lima e Borges
Keyword(s):  
Enzyme Activity ◽  
Heat Stress ◽  
Antioxidant Enzyme ◽  
Germination Percentage ◽  
Antioxidant Enzyme Activity ◽  
Percentage Germination ◽  
Germination Process ◽  
Germination Speed ◽  
Different Temperatures ◽  
Effects Of Temperature

Abstract: Antioxidant enzyme activity can be used to measure heat stress and predict the tolerance of a species to heat stress. This study investigated the effects of temperature on germination and antioxidant enzyme activity in Dalbergia spruceana Benth. seeds. Seeds were incubated at constant temperatures of 20, 25, 30, 35, and 40 °C for ten days; and germination percentage, germination speed index, antioxidant enzyme activity, and electrical conductivity were evaluated. Temperature affected the seed germination process but not antioxidant enzyme activity. Germination percentage and germination speed index were higher at 25 and 35 °C and lower at 20 and 40 °C. Superoxide dismutase activity was not affected by temperature. Catalase and peroxidase activities were too low to be used as indicators of temperature stress. The pattern of increasing electrolyte leakage manifested a trend toward loss of cell membrane semipermeability at higher temperatures.

scholarly journals Effect of Nitrogen Addition on Selection of Germination Trait in an Alpine Meadow on the Tibet Plateau

2021 ◽  
Vol 12 ◽  
Author(s):  
Kun Liu ◽  
Yang Liu ◽  
Zhilong Zhang ◽  
Shiting Zhang ◽  
Carol C. Baskin ◽  
...  
Keyword(s):  
Seed Germination ◽  
Alpine Meadow ◽  
Germination Rate ◽  
Nitrogen Addition ◽  
Germination Percentage ◽  
N Addition ◽  
Percentage Germination ◽  
Alpine Meadows ◽  
Environmental Filter ◽  
Germination Traits

Seed germination requirements may determine the kinds of habitat in which plants can survive. We tested the hypothesis that nitrogen (N) addition can change seed germination trait-environmental filter interactions and ultimately redistribute seed germination traits in alpine meadows. We determined the role of N addition on germination trait selection in an alpine meadow after N addition by combining a 3-year N addition experiment in an alpine meadow and laboratory germination experiments. At the species level, germination percentage, germination rate (speed) and breadth of temperature niche for germination (BTN) were positively related to survival of a species in the fertilized community. In addition, community-weighted means of germination percentage, germination rate, germination response to alternating temperature and BTN increased. However, germination response to wet-cold storage (cold stratification) and functional richness of germination traits was lower in alpine meadows with high-nitrogen addition than in those with no, low and medium N addition. Thus, N addition had a significant influence on environmental filter-germination trait interactions and generated a different set of germination traits in the alpine meadow. Further, the effect of N addition on germination trait selection by environmental filters was amount-dependent. Low and medium levels of N addition had less effect on redistribution of germination traits than the high level.

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