Enhancement by Low Temperatures of the Anaerobic Induction of Cocklebur Seed Germination

1977 ◽  
Vol 4 (6) ◽  
pp. 849 ◽  
Author(s):  
Y Esashi ◽  
Y Ohhara
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Gibberellic Acid ◽  
Low Temperatures ◽  
Anaerobic Treatment ◽  
Maximal Response ◽  
Benzyl Adenine ◽  
Anaerobic Induction ◽  
Time Period ◽  
Proportional Increase

Non-dormant, upper cocklebur (Xanthium pensylvanicum Wallr.) seeds, incapable of germinating under ordinary conditions, can germinate when previously subjected to anaerobiosis; this has been termed the anaerobic induction of seed germination. Aerobic presoaking of the seeds was also required for successful anaerobic induction, and exerted two counter-acting effects on seed germination. When the time period of aerobic presoaking was sufficiently prolonged, the increasing duration of an anaerobic treatment resulted in proportional increase of germination potential but, when it was short, the effect of the anaerobiosis was saturated in a few days. Prolonging the aerobic presoaking period caused less response of the seed to the anaerobic induction, suggesting the development of some germination-inhibiting system during the aerobic presoaking period. This system could not develop in the absence of O2 or at low temperature. Thus, low temperature during prolonged presoaking produced a maximal response to anaerobic induction. Various germination stimulants, CO2, ethylene, gibberellic acid and benzyl adenine, did not significantly alter the effects of the presoaking.

GERMINATION RESPONSE OF DORMOAT SEEDS TO LOW TEMPERATURE AND GIBBERELLIN

1972 ◽  
Vol 52 (3) ◽  
pp. 295-303 ◽  
Author(s):  
C. J. ANDREWS ◽  
V. D. BURROWS
Keyword(s):  
Abscisic Acid ◽  
Low Temperature ◽  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Avena Sativa ◽  
Low Temperatures ◽  
Dry Storage ◽  
Secondary Dormancy ◽  
Derivatives Of ◽  
Different Levels

Dormoats are derivatives of crosses between Avena sativa L. and A. fatua L., designed to be sown in the fall to germinate the following spring. Strains vary in levels of seed dormancy at harvest and in their rates of after-ripening in dry storage. Germination of the seeds is stimulated by gibberellic acid. Embryos isolated from dormant seeds exhibit no dormancy but their germination is prevented by abscisic acid. Low temperatures (ca. 7 C) stimulate germination to different levels in various strains. Seeds enter a secondary dormancy when they fail to germinate in the imbibed state due to primary domancy. Seeds with secondary dormancy are not stimulated to germinate by low temperatures until partial after-ripening of the seeds in the dry state has occurred, but germination is stimulated by gibberellic acid without after-ripening. Secondary dormancy is proposed as a factor in the maintenance of undergerminated seed in the soil from fall planting into winter.

LOW-TEMPERATURE GROWTH RESPONSES OF THE TOMATO

1968 ◽  
Vol 48 (3) ◽  
pp. 281-286 ◽  
Author(s):  
G. A. Kemp
Keyword(s):  
Growth Rate ◽  
Seed Germination ◽  
Low Temperature ◽  
Seedling Growth ◽  
Low Temperatures ◽  
Fruit Set ◽  
Growth Responses ◽  
Growth Phases ◽  
Night Temperature ◽  
Temperature Growth

The effects of low temperatures on several growth phases of the tomato were studied. The tests, each conducted over a 2-week period, included seed germination at 8.5 °C, rate of seedling growth at a night temperature of 10 °C, root and top growth of plants in soil at 15 °C, and fruit set at a night temperature of 4.5 °C.Varietal response to growth rate at low temperatures differed in all phases studied, and varieties that performed well in some phases did not always perform well in others. Of the varieties studied, six grew well under most of the low-temperature conditions. These were: Earlinorth, Bonita, Azerbidzivisky, P.I. 205040, P.I. 280597, and Cold Set.

Seed afterripening and germination photoinhibition in the genusCrocus(Iridaceae)

2015 ◽  
Vol 25 (3) ◽  
pp. 306-320 ◽  
Author(s):  
Evangelia Skourti ◽  
Costas A. Thanos
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Low Temperatures ◽  
Temperate Climate ◽  
Optimal Temperature ◽  
Continuous Darkness ◽  
Dry Storage ◽  
The Mediterranean ◽  
Germination Experiments ◽  
First Time

AbstractMediterranean characteristics are attributed to the genusCrocus, which is inadequately studied in terms of seed germination. An afterripening requirement is very common in environments with warm and dry periods, and photoinhibition has been detected in many angiosperms inhabiting dry and open areas. The effects of afterripening and light on seed germination were investigated for the first time in 23 native GreekCrocustaxa, collected from various localities with either a Mediterranean or a temperate climate. Germination experiments were conducted in continuous darkness and in light at the optimal temperature for each taxon, with both freshly collected and afterripened seeds; warm stratification (20°C, darkness) was also examined in 22 taxa. A number of selected taxa were additionally investigated with respect to afterripening outdoors, afterripening and warm stratification at higher temperatures (35 and 25°C, respectively), stratification at 20/10°C, dry storage at low temperatures, response to gibberellic acid and phenology of embryo growth. It was postulated that an afterripening requirement is a characteristic of the genusCrocus, and we found that it can be fulfilled in nature during the Mediterranean dry summer. Also, for the vast majority of the taxa, warm stratification and stratification at 20/10°C can both meet the afterripening requirement. Embryos of the taxa studied are underdeveloped and have to grow prior to germination. Intrageneric differences of seed germination were observed only towards light, with photoinhibition being predominant in taxa from drier environments.

The impact of low temperatures in controlling the geographical distribution of plants

1990 ◽  
Vol 326 (1237) ◽  
pp. 585-593 ◽  
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Low Temperatures ◽  
Marked Change ◽  
Tilia Cordata ◽  
Natural Range ◽  
Distribution Limits ◽  
The Impact ◽  
Temperature Responses

The distribution limits of three species, in the British Isles are discussed. For Verbena officinalis and Tilia cordata low temperatures are shown to influence distribution, by limiting the capacity either to flower or to fertilize ovules, respectively. In the case of Umbilicus rupestris , a long-term transplant population beyond the natural geographical limit of the species has evolved new low-temperature responses of seed germination and winter survival. The effect is a marked change of phenology, compared with populations of the species within its natural range, which enhances the capacity of the population to survive in a colder environment.

scholarly journals Effects of Gibberellic Acid and Low Temperature on Germination of Some Prunus Species Embryos (Without Cotyledons) Under Laboratory Conditions

2018 ◽  
Vol 21 (2) ◽  
pp. 42-47 ◽  
Author(s):  
Mahmoud. A. Ghayyad
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Gibberellic Acid ◽  
Filter Paper ◽  
Sweet Cherry ◽  
Cold Treatment ◽  
Germination Percentage ◽  
Strong Positive Correlation ◽  
Prunus Species ◽  
Laboratory Conditions

Abstract Seeds of Prunus species do not germinate as a result of different mechanisms of dormancy such as physiological, physical and/or chemical ones. This study was carried out in order to determine the effects of three concentrations of Gibberellic acid (GA3) 1, 3, and 5 mg.L−1 and low temperature at 5 °C on germination and on the length of isolated embryos from cotyledons of almond, apricot, plum, peach, mahaleb and sweet cherry on top of filter paper under laboratory conditions. The highest germination percentage (96.67%) was at 1 mg.L−1 GA3 without cold treatment or 3 mg.L−1 GA3 + cold treatment in almond, the highest length of embryos (15.47 mm) was also in almond at 1 mg.L−1 GA3 without cold treatment. Embryos of mahaleb and sweet cherry germinated at low germination percentages of 31.16%, 33.33% respectively at 3 mg.L−1 GA3 + cold treatment. It was concluded that embryos of almond, apricot, plum and peach were germinated successfully on top of filter paper under laboratory conditions and GA3 increased significantly the germination percentages of the isolated embryos either after cold treatment or without compared with controls. A strong positive correlation was found between seed germination without testa, embryos germination and final embryos length simultaneously.

Interrelation Between Low Temperature and Anaerobiosis in the Induction of Germination of Cocklebur Seed

1978 ◽  
Vol 5 (3) ◽  
pp. 337 ◽  
Author(s):  
Y Esashi ◽  
Y Tsukada ◽  
Y Ohhara
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Low Temperature ◽  
Seed Coat ◽  
Germination Potential ◽  
Anaerobic Induction ◽  
Preceding Period ◽  
Exogenous Ethylene

Non-dormant upper cocklebur (Xanthium pensylvanicum Wallr.) seeds germinated bimodally, in response to low temperature as well as to high temperature. At low temperature, the process was aerobic. Increase in germination potential by pre-exposure to low temperature was termed 'chilling induction'. Similarly to anaerobic induction of cocklebur seed germination, chilling induction required a certain time of presoaking to be effective. The germination pattern was identical in both cases, the seed coat being broken at the axial end. In contrast to anaerobic induction, however, chilling induction was not affected by exogenous ethylene and the effect of chilling was cumulative within 3-4 days, but decreased with increasing duration of chilling beyond these times. The effect of anaerobic induction was enhanced by a pre- ceding chilling, as described in a previous paper and, similarly, the effect of chilling induction for fully presoaked seeds was additively increased by a preceding period of anaerobiosis. However, the effect of the chilling was decreased by a subsequent anaerobiosis.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

INVAR M93

Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Low Temperatures ◽  
Bend Strength ◽  
Temperature Performance ◽  
Ni Content ◽  
Precision Alloys ◽  
Ni Alloy

Abstract Invar is an Fe-Ni alloy with 36% Ni content that exhibits the lowest expansion of known metals from very low temperatures up to approximately 230 deg C (445 deg F). Invar M93 is a cryogenic Invar with improved weldability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear and bend strength as well as fracture toughness and fatigue. It also includes information on low temperature performance as well as forming and joining. Filing Code: FE-143. Producer or source: Metalimphy Precision Alloys.

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