The adaptation of Medicago polymorpha to a range of edaphic and environmental conditions: effect of temperature on growth, and acidity stress on nodulation and nod gene induction

1993 ◽  
Vol 33 (1) ◽  
pp. 25 ◽  
Author(s):  
A Loi ◽  
JG Howieson ◽  
PS Cocks ◽  
S Caredda
Keyword(s):  
High Altitude ◽  
Environmental Conditions ◽  
Rhizobium Meliloti ◽  
Solution Culture ◽  
Effect Of Temperature ◽  
Medicago Polymorpha ◽  
Diverse Range ◽  
Temperature Regimes ◽  
Effects Of Ph ◽  
Nod Gene Induction

Three experiments were conducted with Medicago polymorpha collected from a diverse range of sites in Sardinia, to investigate the relationship between edaphic and environmental conditions at collection sites, and the growth and nodulation of the genotype. Growth response to 2 temperature regimes (20/15�C, 11/9�C) was greater for genotypes collected from high altitude than for those from 1350 m. Shoot yield was more depressed by low temperature and more stimulated by high temperature in high altitude than low altitude genotypes. All genotypes nodulated when exposed to considerable acidity stress (pH 5.4) and 1 mmol Ca/L in solution culture. However, there were differences between genotypes in nodulation reduction caused by exposure to acidity. These differences were not well related to the soil pH at the site of collection, or to the effects of pH on the ability of root exudates from the genotypes to stimulate nod gene expression in Rhizobium meliloti.

Strategies and adaptations to aquatic life at high altitude

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Environmental Conditions ◽  
Low Temperatures ◽  
Cold Adaptation ◽  
Inorganic Carbon ◽  
Direct Result ◽  
Aquatic Life ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Regulatory Capacity

Chapter 5 is focused on how organisms cope with the environmental conditions that are a direct result of high altitude. Organisms reveal a number of fascinating ways of dealing with a life at high altitude; for example, avoidance and pigmentation as protection against damaging high levels of ultraviolet radiation, accumulation of antifreeze proteins, and metabolic cold adaptation among species encountering low temperatures with the risk of freezing, oxy-regulatory capacity in animals due to low availability of oxygen, and root uptake from the sediment of inorganic carbon by plants living in waters poor in dissolved carbon dioxide. These and more adaptations are carefully described through a number of examples from famous flagship species in addition to the less well-known ones. Harsh environmental conditions work as an environmental filter that only allows the well-adapted species to slip through to colonize high altitude waters.

scholarly journals Morphological variation in Leptorhynchos squamatus (Gnaphalieae: Asteraceae)

2002 ◽  
Vol 15 (2) ◽  
pp. 205 ◽  
Author(s):  
Christina Flann ◽  
Pauline Y. Ladiges ◽  
Neville G. Walsh
Keyword(s):  
High Altitude ◽  
Morphological Variation ◽  
Environmental Conditions ◽  
Leaf Size ◽  
Alpine Plants ◽  
The Other ◽  
Herbarium Specimens ◽  
South Eastern ◽  
Eastern Australia ◽  
Low Altitude

A study of morphological variation in Leptorhynchos squamatus (Labill.) Less. across its range in south-eastern Australia was undertaken to test the hypothesis that L. squamatus includes two taxa. Phenetic pattern analyses of both field-collected and herbarium specimens on the basis of morphology confirmed two major groups. Bract, cypsela, pappus bristle and leaf characters were particularly important in separating the two groups. The taxa are separated by altitude differences with one being a low-altitude plant found in many habitats and the other being a high-altitude taxon that is a major component of alpine meadows. Lowland plants have dark bract tips, fewer and wider pappus bristles than alpine plants, papillae on the cypselas and more linear leaves. A somewhat intermediate population from the Major Mitchell Plateau in the Grampians shows some alpine and some lowland characters but is included in the lowland taxon. Seeds from five populations (two alpine, two lowland and Major Mitchell) were germinated and plants grown for 18 weeks under four controlled sets of environmental conditions. The experiment showed that leaf size and some other characters are affected by environmental conditions, but that there are underlying genetic differences between the lowland and alpine forms. Leptorhynchos squamatus subsp. alpinus Flann is described here to accommodate the highland taxon.

scholarly journals Whole-body imaging of neural and muscle activity during behavior in Hydra: bidirectional effects of osmolarity on contraction bursts

2019 ◽  
Author(s):  
Wataru Yamamoto ◽  
Rafael Yuste
Keyword(s):  
Nervous System ◽  
Body Size ◽  
Neuronal Activity ◽  
Environmental Conditions ◽  
Muscle Activity ◽  
Muscle Cells ◽  
Major Effect ◽  
Whole Body ◽  
Effect Of Temperature ◽  
Whole Body Imaging

AbstractThe neural code relates the activity of the nervous system to the activity of the muscles to the generation of behavior. To decipher it, it would be ideal to comprehensively measure the activity of the entire nervous system and musculature in a behaving animal. As a step in this direction, we used the cnidarian Hydra vulgaris to explore how physiological and environmental conditions alter the activity of the entire neural and muscle tissue and affect behavior. We used whole-body calcium imaging of neurons and muscle cells and studied the effect of temperature, media osmolarity, nutritional state and body size on body contractions.In mounted Hydra, changes in temperature, nutrition or body size did not have a major effect on neural or muscle activity, or on behavior. But changes in media osmolarity altered body contractions, increasing them in hipo-osmolar media solutions and decreasing them in hyperosmolar media. Similar effects were seen in ectodermal, but not in endodermal muscle. Osmolarity also bidirectionally changed the activity of contraction bursts neurons, but not of rhythmic potential neurons.These findings show osmolarity-dependent changes in neuronal activity, muscle activity, and contractions, consistent with the hypothesis that contraction burst neurons respond to media osmolarity, activating ectodermal muscle to generate contraction bursts. This dedicated circuit could serve as an excretory system to prevent osmotic injury. This work demonstrates the feasibility of studying the entire neuronal and muscle activity of behaving animals.Significance StatementWe imaged whole-body muscle and neuronal activity in Hydra in response to different physiological and environmental conditions. Osmolarity bidirectionally altered Hydra contractile behavior. These changes were accompanied by corresponding changes in the activity of one neuronal circuit and one set of muscles. This work is a step toward comprehensive deciphering of the mechanisms of animal behavior by measuring the activity of all neurons and muscle cells.

The effect of temperature stress on grain development in wheat

1965 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
RD Asana ◽  
RF Williams
Keyword(s):  
Growth Analysis ◽  
Important Determinant ◽  
Effect Of Temperature ◽  
Synthetic Activity ◽  
Grain Development ◽  
Night Temperature ◽  
Complex Interactions ◽  
Temperature Regimes ◽  
Controlled Environments ◽  
Stable Characteristic

Experiments were conducted in controlled environments to determine the effects of high temperatures on grain development and yield in wheat. Two Australian and three Indian cultivars of wheat were exposed, from a week after anthesis until maturity, to "day" temperatures of 25, 28, and 3l°C, and "night" temperatures of 9 and 12°C. There was a mean reduction in yield of 16%' for the 6° rise in day temperature, but the cultivars did not differ significantly in their response to these temperatures. There were no significant effects of night temperature on grain weight, but stem weight was less at 12°C. Senescence was hastened only slightly by high day temperature, and there were no differential effects between cultivars in this respect.In a subsidiary experiment one Indian and five Australian cultivars were subjected to three day-night temperature regimes (24/19°, 27/22°, and 30/25°C). Highly significant but complex interactions were established between temperature regime and cultivar. A growth analysis for the Australian cultivars Ridley and Diadem indicated that the developing grain of Ridley had a greater capacity for growth than that of Diadem from the earliest stage. This, together with the confirmation of grain size as a very stable characteristic for all the varieties, points to the developmental and synthetic activity of the grain as an important determinant of grain yield. The relevance of this study to the production of wheat in India is briefly discussed.

Toxins and Environmental Neurologic Injury

2021 ◽  
pp. 1170-1176
Author(s):  
Sara E. Hocker ◽  
Ali Daneshmand
Keyword(s):  
Occupational Exposure ◽  
Peripheral Nerve ◽  
High Altitude ◽  
Environmental Conditions ◽  
Substance Misuse ◽  
Environmental Exposures ◽  
Neurologic Injury ◽  
Clinical Syndromes ◽  
Nerve Dysfunction ◽  
Physical Effects

Toxins and environmental exposures may result in central or peripheral nerve dysfunction. Toxins may be purposely ingested (eg, substance misuse), or exposure may be accidental (eg, occupational exposure or terrorism). Certain environmental exposures (eg, lightning or high altitude) may also result in neurologic injury. This chapter reviews neurologic clinical syndromes associated with toxins and the physical effects of certain environmental conditions.

Effect of temperature regimes on the stability of the process of drawing optical fibers

1986 ◽  
Vol 27 (3) ◽  
pp. 417-423
Author(s):  
V. L. Kolpashchikov ◽  
Yu. I. Lanin ◽  
O. G. Martynenko ◽  
A. I. Shnip
Keyword(s):  
Optical Fibers ◽  
Effect Of Temperature ◽  
Temperature Regimes ◽  
The Stability

Effect of Temperature, Vapour-Pressure Deficit and Irradiance on Transpiration Rates of Maize, Paspalum, Westerwolds and Perennial Ryegrasses, Peas, White Clover and Lucerne

1977 ◽  
Vol 4 (6) ◽  
pp. 889 ◽  
Author(s):  
BJ Forde ◽  
KJ Mitchell ◽  
EA Edge
Keyword(s):  
Water Use ◽  
Transpiration Rate ◽  
White Clover ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Effect Of Temperature ◽  
Climate Conditions ◽  
Growth Environment ◽  
Temperature Regimes ◽  
C3 Species

Rates of water use [g H2O (g dry wt leaf)-1 h-1] of young plants of maize, paspalum, perennial ryegrass, Westerwolds ryegrass, peas, white clover and lucerne were measured during the day under controlled climate conditions with ample water available to the plant. Plants were grown and observations made with day/night temperatures of 32.5/27.5°C, 27.5/22.5°, 22.5/17.5°, and 17.5/12.5°C with a day/night vapour pressure deficit (VPD) of the air of 10/2mbar. Water use measurements were also made at 27.5/22.5° and 17.5/12.5°C under day/night VPD regimes of 5/2 and 15/2 mbar. Irradiance during the 12-h day was 170 W m-2 (400-700 nm). Further water use determinations were made at the four temperature regimes under 10/2 mbar VPD and an irradiance of 60 W m-2 (400-700 nm). For a given species, transpiration rates increased with temperature at constant VPD under both irradiance environments, by factors ranging from 1.4 to 2.3. Transpiration rates of maize and paspalum (C4) were lower at a given temperature than were the rates of the C3 species, while lucerne and clover had the highest rates. Water use by lucerne was 2.5 to 3.5 times that of maize. Transpiration rates of maize and paspalum were lower under 60 W m-2 than under 170 W m-2 but irradiance had little effect on transpiration rate of the C3 species. Though transpiration rate generally increased with increasing VPD, the difference in rates between plants at 5 mbar and 10 mbar VPD was much greater than between 10 mbar and 15 mbar. The physiological adaption of different species to their growth environment is discussed, and the implications of the results with reference to water loss by young, single-spaced plants in the field is outlined.

scholarly journals Effect of temperature and carpel size during pre-anthesis on potential grain weight in wheat

1999 ◽  
Vol 132 (4) ◽  
pp. 453-459 ◽  
Author(s):  
D. F. CALDERINI ◽  
L. G. ABELEDO ◽  
R. SAVIN ◽  
G. A. SLAFER
Keyword(s):  
Heat Treatment ◽  
Environmental Conditions ◽  
Buenos Aires ◽  
Grain Weight ◽  
Effect Of Temperature ◽  
Sowing Dates ◽  
Short Period ◽  
Background Temperature ◽  
Higher Temperature ◽  
Maximum Temperatures

The effect of environmental conditions immediately before anthesis on potential grain weight was investigated in wheat at the experimental field of the Faculty of Agronomy (University of Buenos Aires, Argentina) during 1995 and 1996. Plants of two cultivars of wheat were grown in two environments (two contrasting sowing dates) to provide different background temperature conditions. In these environments, transparent boxes were installed covering the spikes in order to increase spike temperature for a short period (c. 6 days) immediately before anthesis, i.e. between ear emergence and anthesis. In both environments, transparent boxes increased mean temperatures by at least 3·8 °C. These increases were almost entirely due to the changes in maximum temperatures because minimum temperatures were little affected. Final grain weight was significantly reduced by higher temperature during the ear emergence–anthesis period. It is possible that this reduction could be mediated by the effect of the heat treatment on carpel weight at anthesis because a curvilinear association between final grain weight and carpel weight at anthesis was found. This curvilinear association may also indicate a threshold carpel weight for maximizing grain weight.

scholarly journals Long-term Effect of Temperature and Triadimefon on Proliferation of Uncinula necator: Implications for Fungicide Resistance and Disease Risk Assessment

Plant Disease ◽  
1997 ◽  
Vol 81 (10) ◽  
pp. 1187-1192 ◽  
Author(s):  
H. L. Ypema ◽  
W. D. Gubler
Keyword(s):  
Risk Assessment ◽  
Disease Risk ◽  
Resistant Isolate ◽  
Effect Of Temperature ◽  
Daily Maximum ◽  
Uncinula Necator ◽  
Risk Assessment Models ◽  
Temperature Regimes ◽  
Entire Duration ◽  
Maximum Temperatures

Triadimefon has been used in California to control Uncinula necator, causal agent of grape powdery mildew, since 1982. Instances of unsatisfactory control have occurred mainly in the cooler coastal areas of California. The effect of temperature and application of triadimefon was investigated over a 53-day-period on two U. necator isolates, sensitive and resistant to triadimefon. At 15°C, 25°C, or temperatures fluctuating between 15 and 25°C, in absence of triadimefon, the isolates continued to produce high numbers of conidia for the entire duration of the experiment. Sporulation declined at daily maximum temperatures of 32°C for 6 h, 36°C for 3 h, and 40°C for 1 h, but was detectable when the experiment was terminated. At these temperature regimes, sporulation of the triadimefon-treated sensitive isolate ceased after 23 days. When treated with triadimefon, sporulation of the resistant isolate was comparable to that of the water-treated control. At daily maximum temperatures of 32°C for 11 h, 36°C for 6 h, and 40°C for 3 h, sporulation of both isolates generally ceased after 23 days, regardless of triadimefon application. Triadimefon resistance is most likely to manifest itself under high disease pressure, which is in part a function of temperature. The duration of daily maximum temperatures may be a valuable addition to disease risk assessment models.

A method for quantifying the effect of temperature treatments on plant quality

2000 ◽  
Vol 134 (2) ◽  
pp. 221-226 ◽  
Author(s):  
MARINA I. SYSOYEVA ◽  
TATJANA G. KHARKINA
Keyword(s):  
Growth And Development ◽  
Quality Characteristics ◽  
Plant Quality ◽  
Effect Of Temperature ◽  
Plant Growth And Development ◽  
Night Temperature ◽  
Temperature Regimes ◽  
Acceptable Quality ◽  
Precise Analysis ◽  
Plant Characteristics

A method that allows the effect of temperature treatments on plant quality to be quantified is described. The proposed method is based on the analysis of temperature regions for plant quality characteristics and enables an easier and more precise analysis of the influence of day and night temperature on plant growth and development. Plant quality may be evaluated by the combination of any number of plant characteristics. The proposed method can assist growers in determining what temperature regimes are necessary to produce acceptable-quality crops on specified days.

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