The germination of Potamogeton pectinatus tubers: environmental control by temperature and light

1988 ◽  
Vol 66 (12) ◽  
pp. 2523-2526 ◽  
Author(s):  
John D. Madsen ◽  
Michael S. Adams
Keyword(s):  
Low Temperature ◽  
Light Intensity ◽  
Temperature Regulation ◽  
Laboratory Experiments ◽  
Environmental Control ◽  
Early Growth ◽  
Potamogeton Pectinatus ◽  
Experimental Range ◽  
Effects Of Temperature ◽  
Germination And Growth

The effects of temperature and light intensity on Potamogeton pectinatus L. tuber germination were investigated in two laboratory experiments. The hypothesis tested was that the initiation of biomass development in the stream is dependent on the temperature regulation of tuber germination. Overwintering tubers were used to eliminate the effects of preconditioning. Low temperature significantly inhibited germination and growth. In addition, germination and growth were significantly higher in the light than in the dark. However, light intensity in the experimental range had no significant effect on tuber germination or early growth.

ENVIRONMENTAL CONTROL OF BUD AND RHIZOME DEVELOPMENT IN THE SEEDLING OF AGROPYRON REPENS L. BEAUV.

1967 ◽  
Vol 45 (8) ◽  
pp. 1315-1326 ◽  
Author(s):  
G. I. McIntyre
Keyword(s):  
Low Temperature ◽  
Light Intensity ◽  
Environmental Control ◽  
Nitrogen Supply ◽  
High Nitrogen ◽  
Bud Development ◽  
High Nitrogen Level ◽  
Terminal Shoot ◽  
Rhizome Development ◽  
Agropyron Repens

The effects of various environmental conditions on bud development in seedlings of Agropyron repens L. Beauv. were investigated. The bud in the axil of leaf 1 was the most responsive. At a high nitrogen level (315 p.p.m.) most of the buds at this position developed as tillers, and at a low level (2.1 p.p.m.) as rhizomes. A transition from rhizome to shoot development was induced by increasing the nitrogen supply after the rhizomes were initiated. Temperature had a similar effect, tillers being produced at a high (day) temperature (27 °C) and rhizomes at a low temperature (10 °C). Reducing the daylength from 18 to 9 h strongly promoted tillering and almost completely prevented rhizome development. A reduction of light intensity from 4000 to 2000 ft-c did not affect bud development but appeared to increase the tendency for rhizomes to form a terminal shoot. Similar effects were shown by the buds at the coleoptile and leaf 2 positions but the inherent tendency for the former to develop as rhizomes and the latter as tillers limited their response.There was some evidence from these results that bud and rhizome development is controlled by a similar mechanism and that the carbohydrate level may be an important factor in determining the inherent pattern of bud development.

Behaviour of Coli Phages in Oxidation Ponds

1985 ◽  
Vol 17 (10) ◽  
pp. 219-227 ◽  
Author(s):  
T. Omura ◽  
H. K. Shin ◽  
A. Ketratanakul
Keyword(s):  
Laboratory Experiments ◽  
Field Investigation ◽  
Host Cells ◽  
Coliform Bacteria ◽  
Alkaline Ph ◽  
Viral Inactivation ◽  
Effects Of Temperature ◽  
Oxidation Ponds ◽  
Incubation Temperatures ◽  
Inactivation Efficiency

Coliphages are among the most promising indicators of viral inactivation efficiency of wastewater treatment. Therefore, it is important to investigate the behaviour of coliphages in oxidation ponds from the viewpoint of predicting the inactivation of infectious viruses. In this study, numbers of coliphages were measured in oxidation ponds consisting of a series of facultative and maturation ponds. In parallel with this investigation, the effects of temperature and pH on the behaviour of coliphages were examined in the laboratory, employing three species of coliform bacteria as host cells. The field investigation showed that there was positive correlation between counts of coliphages and those of coliform bacteria, and that more than 99% of coliphages were inactivated. The inactivation efficiency of coliphages in the facultative pond was much higher than in the maturation pond. The results of the laboratory experiments indicated that at 30°C more than 99% of the coliform group were destroyed in 7 days of incubation and that coliphages counts increased from 105/100 ml to 107/100 ml with a lag time of 3 days. Greater reduction of the coliform count was obtained at higher incubation temperatures. It was observed that the coliphages possessed greater ability to attack coliform bacteria at acidic rather than alkaline pH.

scholarly journals Effect Factors of Benzene Adsorption and Degradation by Nano-TiO2Immobilized on Diatomite

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Lijun Cheng ◽  
Yong Kang ◽  
Guishui Li
Keyword(s):  
Relative Humidity ◽  
Light Intensity ◽  
Experimental Results ◽  
Benzene Adsorption ◽  
Effect Factors ◽  
Benzene Concentration ◽  
Effects Of Temperature ◽  
Safe Concentration

Difference between adsorption of benzene by diatomite and nano-TiO2immobilized on diatomite was investigated. And effects of temperature, light intensity, relative humidity, and initial benzene concentration on adsorption and degradation of benzene by nano-TiO2immobilized on diatomite were also studied. The experimental results showed that when initial benzene concentration was2.2×10−3 mg L−1, it could be degraded to below safe concentration (1.1×10−4 mg L−1) after 50 h when temperature was 20°C, but it just needed 30 h at 35°C. When light intensity was 6750 Lx, it needed 30 h for benzene to be degraded to below safe concentration, but benzene could barely be degraded without light. When relative humidity was 50%, benzene could be degraded to1.0×10−4 mg L−1after 30 h, while its concentration could be reduced to7.0×10−5 mg L−1at the relative humidity of 80%.

Environmental Influence on the Tolerance of Corn to Atrazine

Weed Science ◽  
1970 ◽  
Vol 18 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Lafayette Thompson ◽  
F. W. Slife ◽  
H. S. Butler
Keyword(s):  
Zea Mays ◽  
High Temperature ◽  
Low Temperature ◽  
Light Intensity ◽  
Environmental Influence ◽  
High Light Intensity ◽  
High Light ◽  
Growth Chamber ◽  
Peptide Conjugates ◽  
Before And After

Corn(Zea maysL.) in the two to three-leaf stage grown 18 to 21 days in a growth chamber under cold, wet conditions was injured by postemergence application of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) plus emulsifiable phytobland oil. Injury was most severe when these plants were kept under cold, wet conditions for 48 hr after the herbicidal spray was applied, followed by exposure to high light intensity and high temperature. Under these growth chamber conditions, approximately 50% of the atrazine-treated plants died. Since wet foliage before and after application increased foliar penetration and low temperature decreased the rate of detoxication to peptide conjugates, atrazine accumulated under cold, wet conditions. This accumulation of foliarly-absorbed atrazine and the “weakened” conditions of the plants grown under the stress conditions is believed to be responsible for the injury to corn. Hydroxylation and the dihydroxybenzoxazin-3-one content in the roots were reduced at low temperature, but it is unlikely that this contributed to the death of the corn.

scholarly journals Analysis of heat and mass transfer mechanism during thermal energy storage and temperature regulation

2020 ◽  
Vol 24 (5 Part B) ◽  
pp. 3185-3193
Author(s):  
Sina Dang ◽  
Hongjun Xue ◽  
Xiaoyan Zhang ◽  
Chengwen Zhong
Keyword(s):  
Mass Transfer ◽  
Energy Storage ◽  
Low Temperature ◽  
Phase Change ◽  
Heat And Mass Transfer ◽  
Latent Heat ◽  
Temperature Regulation ◽  
Phase Change Materials ◽  
Heat Energy ◽  
Temperature Environment

To strengthen the heat and mass transfer capacity and improve the temperature regulation rate, potential storage is taken as the research object in this research to study the heat energy storage of the battery in the low temperature environment. Lattice Boltzmann method is adopted to study the heat energy storage influence mechanism of the temperature regulation system of the low temperature phase-change materials. In addition, the influence of different physical parameters (thermal conductivity and latent heat of phase change) on the thermal insulation of the system in the process of temperature control is revealed. The results show that the mechanism of heat and mass transfer in the process of heat storage and temperature control is related to the different physical properties of phase change materials. The decrease of thermal conductivity and the increase of latent heat of phase change materials will greatly increase the effect of heat energy storage. Therefore, under the action of phase change latent heat, phase change material can effectively extend the holding time of the battery in the low temperature environment.

INTERACTION OF TEMPERATURE AND CO2 ENRICHMENT ON SOYBEAN: GROWTH AND DRY MATTER PARTITIONING

1987 ◽  
Vol 67 (1) ◽  
pp. 59-67 ◽  
Author(s):  
NASSER SIONIT ◽  
B. R. STRAIN ◽  
E. P. FLINT
Keyword(s):  
Low Temperature ◽  
Environmental Control ◽  
Weight Ratio ◽  
Controlled Environment ◽  
Plant Responses ◽  
Growth Responses ◽  
Dry Matter Partitioning ◽  
Leaf Weight ◽  
Temperature Regimes ◽  
Increasing Temperature

Projected increases in atmospheric CO2 concentration will affect growth and productivity of many plant species under various environmental conditions. Since these increases in CO2 may also increase mean annual temperatures, it is important to determine how the soybean (Glycine max (L.) Merr.) will respond to changes in temperature regimes associated with atmospheric CO2 enrichment. Morphology and growth responses of the Ransom cultivar, which is adapted to a southern U.S.A. climate, to day/night temperature regimes of 18/12, 22/16, and 26/20 °C and atmospheric CO2 concentrations of 350, 675 and 1000 μL L−1 were studied in controlled environment chambers. Plant responses were determined at 20, 40, 67 and 115 (late senescence to maturity) days after planting. Plant height and number of branches increased slightly with CO2 enrichment and more significantly with increasing temperature. Root to shoot ratio remained unchanged at different CO2 concentrations but decreased as temperature increased. Leaf weight ratio and specific leaf weight decreased with increasing temperature. Low temperature reduced dry weight of all plant parts, but the reduction was ameliorated by increasing atmospheric CO2 concentration. The results show that increasing the atmospheric CO2 level causes soybean to grow more vigorously at low temperatures. Although controlled environment experiments have their drawbacks in regard to natural field conditions, the present data indicate that soybean will have enhanced growth even at moderately cool temperatures in the future global CO2 concentrations.Key words: Soybean growth, low temperature, CO2 × temperature interaction, environmental control

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