Germination of seeds as influenced by matric potential and by area of contact between seed and soil water

Soil Research ◽  
1966 ◽  
Vol 4 (2) ◽  
pp. 145 ◽  
Author(s):  
N Collis-George ◽  
JB Hector
Keyword(s):  
Seed Germination ◽  
Soil Water ◽  
Lactuca Sativa ◽  
Contact Area ◽  
Germination Rate ◽  
Free Water ◽  
Matric Potential ◽  
Germination Behaviour ◽  
Wetted Area ◽  
Design Experiments

Experiments with Medicago tribuloides and Lactuca sativa confirm Sedgley's conclusion that the wetted area of contact is a factor controlling germination of the seed. The evidence suggests that this is of consequence at matric potentials near that of free water and is most important for germination of the last seeds in each population. Matric potential is shown to be an important factor in seed germination over and above its effect in controlling the wetted contact area of seed and medium. Prewetting the seed at matric potentials near that of free water for a few minutes increases the germination rate markedly and minimizes the normal effect of matric potential. The results and experimental conclusions are discussed and are shown to indicate the need for further investigation. They show that it is practicable to design experiments to distinguish the effects of the various facets of soil water energy on seed germination behaviour.

scholarly journals Effect of Osmotic and Matric Potentials on the Availability of Water for Seed Germination

1971 ◽  
Vol 24 (3) ◽  
pp. 423 ◽  
Author(s):  
JR Mcwilliam ◽  
PJ Phlllips
Keyword(s):  
Soil Moisture ◽  
Seed Germination ◽  
Osmotic Stress ◽  
Soil Water ◽  
Seed Coat ◽  
Moisture Diffusivity ◽  
Matric Potential ◽  
Water Potentials ◽  
Germination Behaviour ◽  
Dry Soil

Under special conditions where soil-moisture diffusivity and seed-soil contact are non-limiting, the osmotic and matric potentials of the substrate were found to be equivalent in their effect on the germination of seeds of ryegrass and dehulled phalaris over a range of water potentials from 0 to -15 bars. However, with intact phalaris seeds it appears that the seed coat constitutes a large resistance to the absorption of soil water, and under these conditions the equivalence between osmotic and matric potential no longer holds, and results of germination under osmotic stress must be used with caution in predicting the germination behaviour of seeds in dry soil.

Comparison of the effects of soil matric potential and isotropic effective stress on the germination of Lactuca sativa

Soil Research ◽  
1968 ◽  
Vol 6 (2) ◽  
pp. 179 ◽  
Author(s):  
N Collis-George ◽  
J Williams
Keyword(s):  
Free Energy ◽  
Seed Germination ◽  
Soil Water ◽  
Effective Stress ◽  
Lactuca Sativa ◽  
Soil Matric Potential ◽  
Matric Potential ◽  
Soil System

The matric potential contributes positively to the isotropic effective stress operating in the solid framework of a soil system. Collis-George and Hector (1966) suggested that the matric potential may influence seed germination through its contribution to the effective stress in the solid framework surrounding the seed. Experiments are described which separate the effects of matric potential on seed germination into those that can be attributed to the free energy of the soil water and those that can be attributed to the effective stress in the soil system. The results clearly indicate that (1) seed germination is influenced by the isotropic effective stress in the solid framework of the soil system, and (2) the influence of matric potential on seed germination in the range 0 to - 400cm of water can be wholly attributed to the isotropic effective stress in the solid framework and not to the free energy of the soil water as defined by the matric potential. These conclusions are discussed in terms of the behaviour of other organisms in response to an applied matric potential.

scholarly journals A new framework for modelling seed germination and seedling tillering of winter wheat in the field

2021 ◽  
Author(s):  
Jinping Chen ◽  
Peter Whalley ◽  
Yang Gao ◽  
xiaoxian zhang ◽  
Malcolm J. Hawkesford ◽  
...  
Keyword(s):  
Seed Germination ◽  
Winter Wheat ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Genetic Heterogeneity ◽  
Germination Rate ◽  
Environmental Cues ◽  
Metabolic Reactions ◽  
New Framework

Seed germination is regulated by multiple environmental cues and understanding their relationships is critical to planning seed drilling and subsequent seedling management. We develop a new framework by viewing the metabolic reactions associated with seed germination as a moving event in a physiological dimension to simulate seed germination. Fluctuations in environmental cues and genetic heterogeneity of seed lot make the metabolic reactions in each seed uncertain, and we use an average germination rate to describe the average metabolic reactions and a dispersion coefficient to describe the genetic heterogeneity. We apply the model to winter wheat seeds drilled at different dates in plots under different soil water contents and prove that the model accurately reproduces the time course of germination in all treatments. We found the average germination rate increases nonlinearly with temperature in the base-suboptimal temperature range, and there is an optimal soil water content where the germination rate peaks due to soil anaerobicity. Our model can be fitted to field data using temperature and soil water content to describe the trade-off impact of soil water on soil anaerobicity and imbibition, whereas the difficulty of obtaining accurate water potential and oxygen measurements makes this difficult with the hydrothermal time models.

Seed stratification and germination strategy in the Mediterranean pines Pinus brutia and P. halepensis

1995 ◽  
Vol 5 (3) ◽  
pp. 151-160 ◽  
Author(s):  
Antonis Skordilis ◽  
Costas A. Thanos
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Red Light ◽  
Pinus Brutia ◽  
Temperature Range ◽  
Promotive Effect ◽  
Germination Behaviour ◽  
Mediterranean Pine ◽  
Of Greece

AbstractThe ecophysiology of germination in Pinus brutia and P. halepensis was studied in seeds collected from different areas of Greece. In regard to the temperature range of germination, both P. halepensis and the southern provenance (Lasithi, Crete) of the East Mediterranean pine, P. brutia, follow a typical Mediterranean pattern. In the latter species, dramatic differences in the degree of dormancy were noted among the three provenances investigated; in all seed lots however, 20°C was clearly the optimal temperature for germination. Stratification resulted in a considerable promotion of P. brutia seed germination. Nevertheless, the inductive effect of stratification was shown to differ among the three provenances used, escalating from a simple increase of germination rate (in the southern seed lot from Lasithi, Crete) through a broadening of the temperature range of germination (in the intermediate lot from Thasos Island) to, finally, a dramatic release from a particularly deep dormancy (in the northern lot from Soufli). These deeply dormant seeds of the latter provenance displayed an absolute stratification requirement; prolonged illumination or seed coat scarification could not substitute for the promotive effect of prechilling. A considerable interaction between far-red light and stratification was revealed in the dormant seeds of P. brutia (Soufli provenance); far-red pulses during stratification could either cancel or diminish the germination promotion induced by low temperatures. The differences observed in the germination behaviour among the various P. brutia provenances may be attributed to a variable ecophysiological strategy in regard to the temporal pattern of seedling emergence and establishment. According to the variants of this strategy, seed germination is timed to occur during either spring (in regions with relatively cold and moist climates), or autumn and early winter (in southern, mild and dry areas) or both (in intermediate conditions).

Comparison of the effects of the physical and chemical components of soil water energy on seed germination

1962 ◽  
Vol 13 (4) ◽  
pp. 575 ◽  
Author(s):  
N Collis-George ◽  
JE Sands
Keyword(s):  
Free Energy ◽  
Soil Moisture ◽  
Seed Germination ◽  
Osmotic Potential ◽  
Chemical Components ◽  
Matric Potential ◽  
Experimental Procedure ◽  
Germination Behaviour ◽  
Physical And Chemical ◽  
Osmotic Potentials

The components of total soil moisture energy of consequence to a biological system are matric potential and osmotic potential. An experimental procedure, which allows the effects of the potentials to be considered independently, is described and discussed. Germination behaviour does not support the hypothesis that matric and osmotic potentials should have similar biological consequences because their free energy measurements are identical. The results support a diffusion phenomenon hypothesis with movement of solute from the soil solution through the cell membranes, so that any biological consequence is that of an internal "toxicity" rather than an osmotic "drought". For some osmotic systems, 100 cm of matric potential is as effective as 10 000 cm of osmotic potential in retarding seed germination rates.

Seed Germination Physiology of Eucalyptus delegatensis R. T. Baker in Tasmania

1993 ◽  
Vol 41 (1) ◽  
pp. 119 ◽  
Author(s):  
M Battaglia
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Geographic Origin ◽  
Moisture Stress ◽  
Germination Capacity ◽  
Soil Matric Potential ◽  
Matric Potential ◽  
Inhibition Of Growth ◽  
Germination Response ◽  
Eucalyptus Delegatensis

The seed germination response of seedlots from five geographically disparate provenances of Eucalyptus delegatensis to temperature, stratification, soil matric potential, relative humidity and interrupted imbibition was examined. The species was found to have a distinct temperature optimum of between 15 and 20°C, and a minimum temperature for germination of approximately 2°C. Short periods of exposure to high temperatures did not substantially affect germination performance. Stratification greatly increased the range of temperatures over which a high proportion of the seed germinated. Increases in the rate of germination with stratification are related to accrued thermal time during stratification. Pre-imbibing seeds at water potentials down to -2 MPa increased the rate of germination; however, no advantage was found after pre-imibibing at -3 MPa. This increased germination rate was associated with a shortening of the time to commencement of germination and more synchronous germination. Germination rate and germination capacity were impeded by soil matric potentials below -0.01 MPa, and germination was totally inhibited by soil matric potentials below -0.5 MPa. Soil matric potential and temperature interacted in their effects on germination capacity, and seeds germinating at near optimum temperatures were less sensitive to soil moisture stress. Seeds survived dehydration within 60 h of the commencement of imbibition, but were increasingly affected by dehydration thereafter. The rate of imbibition was influenced by the ambient temperature and solution water potential. At modest levels of water stress, imbibition was not impeded and the reduction in germination capacity was probably due to the inhibition of growth related processes. Differences in germination response were detected between the seedlots and these could be related to the geographic origin of the seedlots.

GERMINATION OF WHEAT AS AFFECTED BY SOIL WATER STRESS

1972 ◽  
Vol 52 (4) ◽  
pp. 619-623 ◽  
Author(s):  
M. C. PAWLOSKI ◽  
C. F. SHAYKEWICH
Keyword(s):  
Water Stress ◽  
Hydraulic Conductivity ◽  
Water Potential ◽  
Soil Water ◽  
Germination Rate ◽  
Membrane System ◽  
Semipermeable Membrane ◽  
Matric Potential ◽  
Soil Water Stress ◽  
Water Potentials

Germination rate of wheat was determined at several water potentials (−0.8, −5.3, −7.8, and −15.3 bars) on two soils and a semipermeable membrane. Germination rate decreased as matric potential decreased. At a given water potential, germination rates were the same for both soils but germination on the membrane system was faster than on soils. Hydraulic conductivity was different on the two media, indicating that the hydraulic conductivity is an important component of soil water stress. Germination rate was not affected by decreasing water potential to −7.8 bars on each medium. At the −15.3-bar potential germination rate was considerably slower.

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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