Factors Affecting Seed Germination of Feather Fingergrass (Chloris virgata)

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 605-612 ◽  
Author(s):  
Nimesha Fernando ◽  
Talia Humphries ◽  
Singarayer K. Florentine ◽  
Bhagirath S. Chauhan
Keyword(s):  
Salt Stress ◽  
Sodium Chloride ◽  
Heat Shock ◽  
Seed Germination ◽  
Environmental Factors ◽  
Laboratory Experiments ◽  
The Other ◽  
Factors Affecting ◽  
The World ◽  
Chloris Virgata

Laboratory experiments were carried out to determine the effect of several environmental factors on seed germination of feather fingergrass, one of the most significant emerging weeds in warm regions of the world. Seed germination occurred over a broad range of temperatures (17/7, 25/10, and 30/20 C), but germination being highest at alternating temperatures of 30/20 C under both 12 h light/12 h dark and 24 h dark conditions. Although seed germination was favored by light, some seeds were capable of germinating in the dark. Increasing salt stress decreased seed germination until complete inhibition was reached at 250-mM sodium chloride. Germination decreased from 64 to 0.7% as osmotic potential decreased from 0 to −0.4 MPa, and was completely inhibited at −0.6 MPa. Higher seed germination (> 73%) was observed in the range of pH 6.4 to 8 than the other tested pH levels. Heat shock had a significant effect on seed germination. Germination of seeds placed at 130 C for 5 min was completely inhibited for both dry and presoaked seeds. The results of this study will help to develop protocols for managing feather fingergrass, and to thus avoid its establishment as a troublesome weed in economically important cropping regions.

scholarly journals ENVIRONMENTAL FACTORS AFFECTING SEED GERMINATION OF COMMON TEASEL (Dipsacus fullonum)

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
J.F.F. DADDARIO ◽  
D.J. BENTIVEGNA ◽  
G. TUCAT ◽  
O.A. FERNÁNDEZ
Keyword(s):  
Salt Stress ◽  
Seed Germination ◽  
Environmental Factors ◽  
Osmotic Stress ◽  
Management Strategies ◽  
Buenos Aires Province ◽  
Factors Affecting ◽  
Dry Storage ◽  
Native Grasslands ◽  
Germination Parameters

ABSTRACT Common teasel is a widespread, invasive species that has been introduced in Buenos Aires province, Argentina, where it alters the species composition of protected areas and native grasslands. A better understanding of seed germination behavior is essential for predicting its invasion potential in new areas and would be useful for developing effective management strategies. This research, conducted under laboratory conditions, evaluated the influence of several environmental factors such as pH, constant temperature, osmotic stress, salt stress and dry storage, on germination and rate of germination of common teasel seed. Between-year variation in germination responses was also examined. Seed germination was not affected by different pH levels. Although common teasel seeds germinated over a range of temperatures from 6 to 36 oC, the optimum temperature was 22 oC. Common teasel seed germination showed moderate tolerance to osmotic stress and a relatively high tolerance to salt stress. No seed germination was observed at - 1 MPa and 640 mM of osmotic potential and salt concentration, respectively. Seed germination remained high (> 90%) after all the dry storage treatments. Besides, the response of seeds to germination parameters showed between-year variation. It was shown that common teasel is able to germinate over a broad range of environmental conditions. This capacity would explain, at least partially, why this species is so widely distributed and its great potential to invade new areas.

GERMINATION OF ALFALFA VARIETIES IN SOLUTIONS OF VARYING OSMOTIC PRESSURE AND RELATIONSHIP TO WINTER HARDINESS

1959 ◽  
Vol 39 (3) ◽  
pp. 384-394 ◽  
Author(s):  
D. H. Heinrichs
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Laboratory Experiments ◽  
Reliable Method ◽  
Winter Hardiness ◽  
The Other ◽  
General Tendency ◽  
Salt Solutions ◽  
Sodium Chloride Solutions ◽  
Alfalfa Varieties

Two laboratory experiments were conducted to evaluate the reliability of amount of germination in solutions of varying osmotic pressure, as a means of separating alfalfa varieties into winter-hardiness classes. In one test 23 varieties or strains were studied, and in the other 36. It was found that significant differences exist between certain alfalfa varieties in their ability to germinate in sucrose or sodium chloride solutions of 3, 6, and 9 atmospheres. There is a general tendency for non-hardy varieties to germinate more rapidly and more completely than hardy ones but there are many exceptions to this trend. Germination in solutions of 6 atmospheres osmotic pressure at 5 days gave the best separation of varieties on the basis of their ability to germinate. Germination was generally better in solutions of sucrose at 6 atmospheres osmotic pressure than in solutions of sodium chloride of the same osmotic pressure but several varieties germinated equally well in either solution. The results indicate that germinating alfalfa in sugar or salt solutions is not a reliable method for differentiating alfalfa varieties into winter hardiness classes.

scholarly journals Evaluation of the Effective Factors on Social Interactions in the Design of Public Libraries

2020 ◽  
Vol 14 (4) ◽  
pp. 403-410
Author(s):  
Reza Askarizad
Keyword(s):  
Social Interaction ◽  
Social Interactions ◽  
Public Libraries ◽  
Public Library ◽  
The Other ◽  
Factors Affecting ◽  
Effective Factors ◽  
The World ◽  
Controversial Topic ◽  
Inferential Analysis

Nowadays, the interaction of people in the world is deemed a controversial topic and consequently, the creation of an appropriate context for interacting with individuals is one of the issues that is considered by architects in many designs. In this research, it has been endeavored to consider the factors affecting social interactions in the design of public libraries through the descriptive-inferential analysis. The results of this research reveal that in the architectural spaces that have been designed with open-configured plans, spatial integrity and sociability will increase. On the other hand, the factors such as depth and the level of privacy are also reduced. Therefore, in designing a public library with an approach toward social interaction, there should be a variety of open and closed-configured spaces in the plan that allow users to choose the space they optionally want and in which they would enjoy in their own presence by choosing their own activities.

scholarly journals Factors Affecting Seed Dormancy and Germination of Greater Bur-Parsley (Turgenia latifolia)

2018 ◽  
Vol 36 ◽  
Author(s):  
M. REZVANI ◽  
S.A. SADATIAN ◽  
H. NIKKHAHKOUCHAKSARAEI
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seed Dormancy ◽  
Seedling Emergence ◽  
Potassium Nitrate ◽  
Germination Percentage ◽  
Dormancy Breaking ◽  
Planting Depth ◽  
Factors Affecting ◽  
Drought And Salt Stresses

ABSTRACT: Our knowledge about seed dormancy breaking and environmental factors affecting seed germination of greater bur-parsley (Turgenia latifolia) is restricted. This study has addressed some seed dormancy breaking techniques, including different concentrations of gibberellic acid (GA3) and potassium nitrate (KNO3), leaching duration, physical scarification as well as some environmental factors effective on seed germination such as salt and drought stresses, pH and seed planting depth. Seed germination was promoted with lower concentrations of KNO3 (0.01 to 0.02 g L-1), while higher concentrations reduced germination percentage. Seed dormancy was declined by low concentrations of GA3 up to 100 ppm. Seeds of greater bur-parsley germinated in a range of pH from 3 to 7. With enhancement of drought and salt stresses, seed germination decreased. Also, there was no seed germination in a high level of stresses. Seedling emergence reduced as planting depth increased. Use of GA3, KNO3, leaching and physical scarification had a positive effect on seed dormancy breaking of greater bur-parsley. The information from the study increases our knowledge about seed dormancy breaking techniques, response of germination to drought and salt stresses and also determination of distribution regions of greater bur-parsley in the future.

scholarly journals An introduction to the mechanics of the lasso

2014 ◽  
Vol 470 (2171) ◽  
pp. 20140512 ◽  
Author(s):  
Pierre-Thomas Brun ◽  
Neil Ribe ◽  
Basile Audoly
Keyword(s):  
Boundary Layer ◽  
Horizontal Plane ◽  
Laboratory Experiments ◽  
String Model ◽  
Line Tension ◽  
Static Friction ◽  
The Other ◽  
Numerical Continuation ◽  
The World ◽  
Small Loop

Trick roping evolved from humble origins as a cattle-catching tool into a sport that delights audiences all over the world with its complex patterns or ‘tricks’. Its fundamental tool is the lasso, formed by passing one end of a rope through a small loop (the honda) at the other end. Here, we study the mechanics of the simplest rope trick, the Flat Loop , in which the rope is driven by the steady circular motion of the roper's hand in a horizontal plane. We first consider the case of a fixed (non-sliding) honda. Noting that the rope's shape is steady in the reference frame rotating with the hand, we analyse a string model in which line tension is balanced by the centrifugal force and the rope's weight. We use numerical continuation to classify the steadily rotating solutions in a bifurcation diagram and analyse their stability. In addition to Flat Loops , we find planar ‘coat-hanger’ solutions, and whirling modes in which the loop collapses onto itself. Next, we treat the more general case of a honda that can slide due to a finite coefficient of friction of the rope on itself. Using matched asymptotic expansions, we resolve the shape of the rope in the boundary layer near the honda where the rope's bending stiffness cannot be neglected. We use this solution to derive a macroscopic criterion for the sliding of the honda in terms of the microscopic Coulomb static friction criterion. Our predictions agree well with rapid-camera observations of a professional trick roper and with laboratory experiments using a ‘robo-cowboy’.

Breed and environmental factors affecting the reconception of indigenous beef cows in Botswana

1982 ◽  
Vol 35 (3) ◽  
pp. 413-420
Author(s):  
N. G. Buck ◽  
D. Light
Keyword(s):  
Environmental Factors ◽  
Environmental Effects ◽  
Reproductive Performance ◽  
Beef Cows ◽  
The Other ◽  
Factors Affecting ◽  
Lactating Cows ◽  
Management Interventions ◽  
Lower Fertility ◽  
Main Effects

ABSTRACTThe breeding records of 2710 lactating cows, of the Africander (1208), Tswana (542) and Tuli (960) breeds, were analysed to examine the effects of breed and environment on reconception. The reconception rate of Africander cows (0·56) was significantly lower than that of Tswana and Tuli cows (0·80 and 0·81 respectively) (P<0·01). The environmental effects of ranch, calving year, calving period and age/parity all had significant effects on reconception (P<0·01). Interactions between breed and the other main effects were all significant.The Africander is considered to be a breed of lower fertility than the other two Sanga breeds, the Tswana and Tuli, in Botswana. The results are discussed with respect to determining management interventions to improve cow reproductive performance.

scholarly journals Alterations in the root proteomes of Brassica napus cultivars under salt stress

2021 ◽  
Vol 45 (1) ◽  
pp. 87-96
Author(s):  
Hakan Terzi ◽  
Mustafa Yıldız
Keyword(s):  
Salt Stress ◽  
Brassica Napus ◽  
Heat Shock ◽  
Seed Germination ◽  
Nacl Stress ◽  
Soil Salinization ◽  
Comparative Proteomics ◽  
Nacl Concentration ◽  
Protein Alterations ◽  
Root Proteins

Soil salinization is an important environmental problem affecting agricultural production worldwide. Seed germination is a critical process, and seedling establishment under saline conditions can be achieved by successful germination. In the present study, comparative proteomics combined with physiological analyses were used to investigate the protein alterations in germinating Brassica napus cultivars (Caravel and Sary) under NaCl stress. Seed germination declined with the increasing NaCl concentration. However, Caravel exhibited better performance in terms of seed germination and seedling growth under salinity stress. Therefore, Caravel was found to be more tolerant to salinity than Sary. The root proteins were extracted from B. napus cultivars germinating on a plant growth medium with or without 100 mM NaCl for seven days. After the root proteins had been separated by two-dimensional (2-D) gel electrophoresis, the differentially accumulated proteins were identified using MALDI-TOF/TOF MS. The comparative proteomics analysis revealed 12 and 27 statistically significant proteins accumulated in the NaCl-treated roots of Caravel and Sary, respectively. The identified proteins were mostly involved in protein metabolism, stress defense, cytoskeleton and cell wall metabolism, and energy metabolism. The salt-sensitive cultivar Sary displayed an elevated accumulation of proteins involved in antioxidant defense and the protein catabolic process such as superoxide dismutase [Fe], L-ascorbate peroxidase 1, and different components of the proteasome system. On the other hand, the levels of molecular chaperones including 20 kDa chaperonin, chaperonin CPN60, heat shock cognate protein HSC70, and heat shock 70 kDa protein 1 were higher in Caravel than Sary under salt stress. These findings will provide the possible mechanisms which contribute to salt tolerance and may serve as the basis for improving salinity tolerance in rapeseed.

scholarly journals First record of Octopus vulgaris (Cuvier, 1797) (Octopodidae) in the Iraqi coastal waters, NW Arabian Gulf

2021 ◽  
Vol 13 (3) ◽  
pp. 1048-1051
Author(s):  
Anwar M.J. Al-Maliky ◽  
Khaled Kh. Al-Khafaji ◽  
Tariq H. Al-Maliky
Keyword(s):  
Environmental Factors ◽  
Coastal Waters ◽  
Persian Gulf ◽  
Arabian Gulf ◽  
First Record ◽  
Morphological Features ◽  
The Other ◽  
Octopus Vulgaris ◽  
The World ◽  
First Time

The present study identifies one species of the genus Octopus in the order: Octopoda (Cephalopoda: Mollusca), recorded forthe first time in the Iraqi coastal waters and Arabian-Persian Gulf. The study extended from January 2019 to December of thesame year. The Octopus specimens were seasonally obtained from the fishing trawlers operating in the Iraqi coastal waters inthe South of Al- Fao District, Basrah- Iraq, NW Arabian Gulf. The Octopus was identified as O. vulgaris in Iraqi coastal watersdepending on morphological features. The habitats of living specimens are briefly described. Some observations were reported on the occurrence of this species and the measurement of some environmental factors. The species was identified up to spe-cies level using standard literature. This species looks similar morphologically to the species which is already identified from the other areas around the world. The present study records significant expansion in the distribution range of this species.

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