Influences of Temperature, Light and Water Stress on Germination of Fringed Sage (Artemisia frigida)

Weed Science ◽  
1995 ◽  
Vol 43 (2) ◽  
pp. 219-225 ◽  
Author(s):  
Yuguang Bai ◽  
James T. Romo ◽  
James A. Young
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Germination Rate ◽  
Early Summer ◽  
Artemisia Frigida ◽  
Wide Range ◽  
Winter Temperatures ◽  
Osmotic Potentials ◽  
Germination Requirements ◽  
Effect Of Light

Experiments were conducted to determine the influences of temperature, light, winter storage, and water stress on seed germination of fringed sage. Seeds collected in 3 yr in central Saskatchewan were placed in sealed vials and buried in the soil after harvest, and germination was tested in spring and early summer. Seeds germinated over a wide range of temperatures with alternating 25/15 C being optimal. The range of optimal temperatures was higher for older seeds than younger seeds. The stimulating effect of light on germination varied among collections and incubating temperatures. Total germination and germination rate was limited by water stress and no seeds germinated at osmotic potentials below −0.9 MPa. Seeds hydrated in the autumn and exposed to low winter temperatures had higher germination the following spring than dry seeds exposed to the same conditions. Results suggest that sufficient soil moisture combined with moderate seedbed temperatures are optimal for fringed sage germination. Periodicity of germination may be influenced by variable germination requirements in different aging seeds.

scholarly journals Water Stress and Osmotic Adjustment during Post-digging Acclimatization of Quercus virginiana Produced in Fabric Containers

1992 ◽  
Vol 10 (4) ◽  
pp. 208-214
Author(s):  
R.C. Beeson ◽  
E.F. Gilman
Keyword(s):  
Water Stress ◽  
Osmotic Adjustment ◽  
Fine Root ◽  
Early Summer ◽  
Root Weight ◽  
Quercus Virginiana ◽  
Water Potentials ◽  
Live Oak ◽  
Oak Trees ◽  
Osmotic Potentials

Abstract Quercus virginiana Mill. (live oak) trees produced in in-ground 61 cm (24 in) diameter fabric containers were overhead misted and given root ball irrigation after harvesting during early summer. Duration and frequency of overhead misting was reduced to zero over a 3 week period. Water potentials (ΨT) were measured diurnally and osmotic potentials measured from leaves at midday. Intermittent overhead misting was as effective as continuous overhead misting in maintenance of ΨT above −1.0 MPa. Water potentials of −1.5 to −2.0 MPa were measured when the period between overhead misting was expanded from 30 min to 45 min. Osmotic adjustment occurred only in trees receiving overhead misting. Trees receiving only root ball irrigation developed ΨT below −2.5 MPa within 5 days after harvesting. After 3 weeks, ΨT and osmotic potentials were the same for all treatments. In a second experiment, trees were root pruned inside the fabric container 11 weeks before harvest. All root pruned trees survived acclimatization, but only 50% of unpruned trees survived. Water relations were similar to trees in Experiment 1. Surviving trees, both pruned and unpruned, had a significantly higher percentage of fine root weight (roots < 2 mm diameter) than trees that did not survive.

Germination and Emergence of Virginia Buttonweed (Diodia virginiana)

Weed Science ◽  
1991 ◽  
Vol 39 (1) ◽  
pp. 37-41 ◽  
Author(s):  
James H. Baird ◽  
Ray Dickens
Keyword(s):  
Water Stress ◽  
Seed Germination ◽  
Germination Rate ◽  
Stress Conditions ◽  
Continuous Darkness ◽  
Virginia Buttonweed ◽  
Osmotic Potentials ◽  
Diodia Virginiana

Virginia buttonweed seeds germinated at temperatures between 15 and 40 C, with optimal germination occurring at 25 or 30 C in 12 h light alternated with 15 to 25 or 20 to 30 C in darkness, respectively. Germination rate was lower in continuous darkness than in light. Germination was reduced under simulated water stress conditions with less than 10% of seeds germinating at osmotic potentials below −0.3 MPa. Overall seed germination was reduced under simulated flooding conditions; greater germination occurred in aerated water than in unaerated water. Maximum germination occurred at pH 6. Seedlings emerged from depths as great as 8 cm, with maximum emergence occurring from 2 cm.

scholarly journals Osmotic and Turgor Adjustment in Rosa Foliage Drought-stressed under Varying Irradiance

1990 ◽  
Vol 115 (4) ◽  
pp. 661-667 ◽  
Author(s):  
Robert M. Augé ◽  
Ann J.W. Stodola ◽  
Brian D. Pennell
Keyword(s):  
Soil Moisture ◽  
Elastic Modulus ◽  
Water Stress ◽  
Relative Water Content ◽  
The Other ◽  
Ambient Light ◽  
Moisture Treatment ◽  
Relative Water ◽  
Osmotic Potentials ◽  
Water Contents

The influence of irradiance and drought on osmotic and turgor adjustment was examined in leaves of rose (Rosa hybrida L. `Samantha'). Plants cultured under full ambient light in the greenhouse were placed in shade chambers and, after 2 weeks of acclimation, exposed to drought for 21 days. Treatments consisted of a water stress factor (well-watered and drought-stressed) and an irradiance factor (100%, 70%, and 30% of ambient irradiance). Pressure-volume analyses of leaves indicated that osmotic potentials at full turgor were decreased 0.42, 0.36, and 0.23 MPa by drought in the 100%, 70%, and 30% irradiance treatments, respectively. Plants stressed under 100% and 70% irradiance exhibited similar osmotic adjustments. Plants under 30% irradiance had higher osmotic potentials at full turgor under well-watered conditions than plants in the other two irradiance treatments and showed only 55% as much adjustment to drought. In each irradiance treatment, drought induced an increase in elastic modulus and a decrease in relative water content at zero turgor. Turgor pressures were higher across a range of relative water contents in plants in the two higher irradiance treatments under both soil moisture treatments. Turgor also was higher at any particular water potential at 100% and 70% irradiance than 30% irradiance, within each soil moisture treatment. Heavy, but not mild, shading inhibited osmotic and turgor adjustments in leaves during drought.

scholarly journals Germination of Jacaranda mimosifolia (D. Don - Bignoniaceae) seeds: effects of light, temperature and water stress

2004 ◽  
Vol 47 (5) ◽  
pp. 785-792 ◽  
Author(s):  
Fábio Socolowski ◽  
Massanori Takaki
Keyword(s):  
Water Stress ◽  
White Light ◽  
Germination Rate ◽  
Stress Conditions ◽  
Optimum Temperature ◽  
Promotive Effect ◽  
Germination Temperature ◽  
Jacaranda Mimosifolia ◽  
Effect Of Light

Investigations were carried out to study the effect of light, temperature and water stress on the germination of seeds of Jacaranda mimosifolia which showed the minimum and maximum germination temperature at 15 and 40º C, respectively. The optimum temperature was 25º C with high percentage and germination rate. Slight promotive effect of white light was observed. Under water stress conditions the effect of light was high but at optimum temperature no effect of light was observed. At -0.9MPa few seeds germinated.

Soil factors affecting the yield of winter wheat: analysis of results from I.C.I. surveys 1979–80

1984 ◽  
Vol 103 (3) ◽  
pp. 639-649 ◽  
Author(s):  
A. H. Weir ◽  
J. H. Rayner ◽  
J. A. Catt ◽  
D. G. Shipley ◽  
J. D. Hollies
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Sowing Date ◽  
Early Summer ◽  
Soil Survey ◽  
Soil Types ◽  
Soil Series ◽  
Factors Affecting ◽  
Wide Range ◽  
Almost All

SummaryThe soils of fields where winter wheat yields were measured for the I.C.I. Ten Tonne Club Survey in 1979 and 1980 were identified according to the soil series recognized by the Soil Survey of England and Wales. The yield distributions were almost normal, with means 1·49 and 1·60 t/ha greater than the national average. Soil series accounted for 18–19% of the yield variance in both years, which was much more than any other single factor measured. If introduced in best order, soil series, crop variety, previous crop and sowing date accounted for 31% of the variance in both years. However, classes based on soil particle size and drainage, as derived from series identifications, accounted for very little of the variance. Only thick brickearth (loess) soils gave greater mean yields in both years than the overall means of all sites where series were identified. The same soil types provided 35% of the sites where > 10 t/ha was achieved in either year, though a wide range of soil types gave such large yields.Yields were greater in 1980 than in 1979 in almost all parts of the country. Although rainfall was only slightly less in the spring and early summer of 1980 than in the same period in 1979, many parts of the country suffered large potential soil moisture deficits in 1980, but these decreased yields slightly on a few series only. Factors other than rainfall used to calculate soil moisture deficits (radiation or wind) probably affected yields much more than rainfall itself.

Factors Affecting Germination of Citronmelon (Citrullus lanatusvar.citroides)

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Analiza Henedina M. Ramirez ◽  
Amit J. Jhala ◽  
Megh Singh
Keyword(s):  
Water Stress ◽  
Environmental Factors ◽  
Climatic Conditions ◽  
Dark Condition ◽  
Light Conditions ◽  
Factors Affecting ◽  
Wide Range ◽  
Citrus Orchards ◽  
Favorable Weather ◽  
Effect Of Light

Citron melon is a monoecious, hairy annual vine commonly found in citrus orchards, and cotton and peanut fields. Information is not available on the effect of various environmental factors on the germination of citron melon. Laboratory and greenhouse experiments were carried out in 2011 and 2012 to determine the effect of light, temperature, salinity, pH, simulated water stress, and depth of sowing on the germination of citron melon. Citron melon germination was affected by various environmental factors. Highest germination was observed at day/night temperatures of 25/20 to 30/25 C regardless of light conditions. At temperatures below 25 C and beyond 35 C, germination declined and was higher under dark condition than light. Germination decreased as osmotic potential became more negative (−0.3 MPa to −1.5 MPa) and salt concentration increased (50 to 350 mM). No germination was observed at > −0.9 MPa and ≥ 300 mM salt concentrations. However, germination was observed over a broad range of pH (3 to 9) and up to 10-cm sowing depths. Seeds sown at the surface did not germinate but maximum germination (88 to 96%) occurred at 2- to 4-cm depth. The results of this study suggest that citron melon can grow in a wide range of climatic conditions and therefore can persist in Florida because of favorable weather and environmental conditions.

Factors Affecting Seed Germination of Cadillo (Urena lobata)

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Jingjing Wang ◽  
Jason Ferrell ◽  
Gregory MacDonald ◽  
Brent Sellers
Keyword(s):  
Water Stress ◽  
Seed Germination ◽  
Soil Surface ◽  
Invasive Weed ◽  
Factors Affecting ◽  
Hard Seed ◽  
Disturbed Areas ◽  
Wide Range ◽  
Hard Seed Coat ◽  
Effect Of Light

Cadillo is an invasive species commonly found in pastures, rangelands, and disturbed areas. It is becoming a significant problem weed in Florida pastures and natural areas. The objectives of this research were to determine effective techniques to break seed dormancy and the effect of light, temperature, pH, water stress, and depth of seed burial on Cadillo germination. Cadillo seeds had significant levels of innate dormancy imposed by a hard seed coat; chemical scarification was the most effective technique for removing dormancy. Seeds germinated from 15 to 40 C, with an optimal temperature of 28 C. Germination was unaffected by pH levels. Water stress below −0.2 MPa reduced seed germination. Cadillo germination was not light-dependent and seeds emerged from depths up to 9 cm, with the greatest occurring emergence near the soil surface. Considering that Cadillo seed can germinate under a wide range of environmental conditions, it is not surprising that it has become a serious invasive weed in Florida.

Biscogniauxia (Hypoxylon) Canker or Dieback in Trees

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
Claudia Paez ◽  
Jason A. Smith
Keyword(s):  
Water Stress ◽  
Tree Species ◽  
Soil Compaction ◽  
Urban Areas ◽  
Root Disease ◽  
Poor Health ◽  
Green Spaces ◽  
Opportunistic Pathogens ◽  
Wide Range ◽  
Quercus Spp

Biscogniauxia canker or dieback (formerly called Hypoxylon canker or dieback) is a common contributor to poor health and decay in a wide range of tree species (Balbalian & Henn 2014). This disease is caused by several species of fungi in the genus Biscogniauxia (formerly Hypoxylon). B. atropunctata or B. mediterranea are usually the species found on Quercus spp. and other hosts in Florida, affecting trees growing in many different habitats, such as forests, parks, green spaces and urban areas (McBride & Appel, 2009).  Typically, species of Biscogniauxia are opportunistic pathogens that do not affect healthy and vigorous trees; some species are more virulent than others. However, once they infect trees under stress (water stress, root disease, soil compaction, construction damage etc.) they can quickly colonize the host. Once a tree is infected and fruiting structures of the fungus are evident, the tree is not likely to survive especially if the infection is in the tree's trunk (Anderson et al., 1995).

scholarly journals Global soil moisture data derived through machine learning trained with in-situ measurements

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sungmin O. ◽  
Rene Orth
Keyword(s):  
Machine Learning ◽  
Soil Moisture ◽  
Large Scale ◽  
Short Term Memory ◽  
Temporal Dynamics ◽  
Soil Moisture Data ◽  
Wide Range ◽  
Global Soil

AbstractWhile soil moisture information is essential for a wide range of hydrologic and climate applications, spatially-continuous soil moisture data is only available from satellite observations or model simulations. Here we present a global, long-term dataset of soil moisture derived through machine learning trained with in-situ measurements, SoMo.ml. We train a Long Short-Term Memory (LSTM) model to extrapolate daily soil moisture dynamics in space and in time, based on in-situ data collected from more than 1,000 stations across the globe. SoMo.ml provides multi-layer soil moisture data (0–10 cm, 10–30 cm, and 30–50 cm) at 0.25° spatial and daily temporal resolution over the period 2000–2019. The performance of the resulting dataset is evaluated through cross validation and inter-comparison with existing soil moisture datasets. SoMo.ml performs especially well in terms of temporal dynamics, making it particularly useful for applications requiring time-varying soil moisture, such as anomaly detection and memory analyses. SoMo.ml complements the existing suite of modelled and satellite-based datasets given its distinct derivation, to support large-scale hydrological, meteorological, and ecological analyses.

scholarly journals TEMPERATURE - GERMINATION RESPONSES OF SUNFLOWER (Helianthus annuus L.) GENOTYPES / GERMINACION COMO REACCION A LA TEMPERATURA EN LOS GENOTIPOS DEL GIRASOL (Helianthus annuus L.) / GERMINATION - RÉACTION À LA TEMPÉRATURE DANS LES GÉNOTYPES DE TOURNESOL (Helianthus annuus L.)

Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 97-104
Author(s):  
F.M. Khalifa ◽  
A.A. Schneiter ◽  
E.I. El Tayeb
Keyword(s):  
Seed Germination ◽  
Helianthus Annuus ◽  
Maximum Rate ◽  
Germination Rate ◽  
Thermal Time ◽  
Large Temperature ◽  
Climatic Zones ◽  
Helianthus Annuus L ◽  
Wide Range ◽  
Cardinal Temperature

SUMMARY Seed germination of six sunflower (Helianthus annuus L.) hybrids was investigated across a range of eleven constant temperatures between 5°C and 45°C. Large temperature differences in germination rate 1/t (d-1), cardinal temperature (°C) and thermal time θ (°cd) were observed among hybrids. Base temperatures (Tb) varied between 3.3°C and 6.7°C whereas maximum germination temperatures (Tm) varied between 41.7°C and 48.9°C. Final germination fraction was attained at 15°C - 25°C whereas the maximum rate of germination was attained at 30.4°C - 35.6°C. The maximum germination rate of hybrid USDA 894, the cultivar with the slowest germination rate, was only 50% of that of hybrid EX 47. The low Tb and high Tm of sunflower appear to be one of the factors which explain the successful adaptation of sunflower to a wide range of temperature. These findings are discussed in relation to the origin of the crop and its wide adaptations in diverse habitats and climatic zones.

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