Effect of Low Temperature on Floral Induction of Eucalyptus lansdowneana F. Muell. & J. Brown subsp. lansdowneana

1992 ◽  
Vol 40 (2) ◽  
pp. 157 ◽  
Author(s):  
MW Moncur
Keyword(s):  
Solar Radiation ◽  
Floral Induction ◽  
Day Length ◽  
Vegetative Development ◽  
Breeding Programs ◽  
Stage Of Development ◽  
High Solar Radiation ◽  
Low Levels ◽  
Radiation Conditions ◽  
Short Days

Transferring seedlings of Eucalyptus lansdowneana from a heated glasshouse (24/19°C) to a cold glasshouse (15/10°C) for 5 or 10 weeks and back to the heated glasshouse was sufficient to induce floral buds. Bud production was further enhanced when seedlings were transferred to cold conditions during periods of high solar radiation. Under low levels of solar radiation and short duration of cold, 0-5 weeks, plants reverted to vegetative development, suggesting a low floral induction stimulus. Seedlings that produced a visible floral inflorescence had fewer leaves than seedlings grown under similar conditions that had not produced an inflorescence. This was more noticeable under high-radiation conditions. Plants grown under outside conditions in Canberra and transferred to a heated glasshouse (25/ 18°C) during winter initiated inflorescences 7-9 weeks earlier than plants grown continuously outside. The early initiation enabled buds to develop and flower before the onset of the following winter. More buds were initiated in plants transferred to the glasshouse in September compared with 16 June or 28 July. Plants transferred on 16 June initiated few buds or none at all. These plants may have been in a juvenile or transitional stage of development, experienced insufficient cold for full induction or been limited by the low winter irradiances. Floral response occurred under both long days (phytotron) and short days under outside conditions in Canberra, suggesting that E. lansdowneana may well be relatively insensitive to day length. These results are discussed in relation to controlled breeding programs which aim to manipulate flowering time and duration to decrease the generation interval.

scholarly journals Managing flowering time in Miscanthus and sugarcane to facilitate intra- and intergeneric crosses

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0240390
Author(s):  
Hongxu Dong ◽  
Lindsay V. Clark ◽  
Xiaoli Jin ◽  
Kossonou Anzoua ◽  
Larisa Bagmet ◽  
...  
Keyword(s):  
Flowering Time ◽  
High Latitude ◽  
Floral Induction ◽  
Day Treatment ◽  
Day Length ◽  
Close Relative ◽  
Short Day ◽  
Culm Length ◽  
Low Latitudes ◽  
Short Days

Miscanthus is a close relative of Saccharum and a potentially valuable genetic resource for improving sugarcane. Differences in flowering time within and between Miscanthus and Saccharum hinders intra- and interspecific hybridizations. A series of greenhouse experiments were conducted over three years to determine how to synchronize flowering time of Saccharum and Miscanthus genotypes. We found that day length was an important factor influencing when Miscanthus and Saccharum flowered. Sugarcane could be induced to flower in a central Illinois greenhouse using supplemental lighting to reduce the rate at which days shortened during the autumn and winter to 1 min d-1, which allowed us to synchronize the flowering of some sugarcane genotypes with Miscanthus genotypes primarily from low latitudes. In a complementary growth chamber experiment, we evaluated 33 Miscanthus genotypes, including 28 M. sinensis, 2 M. floridulus, and 3 M. ×giganteus collected from 20.9° S to 44.9° N for response to three day lengths (10 h, 12.5 h, and 15 h). High latitude-adapted M. sinensis flowered mainly under 15 h days, but unexpectedly, short days resulted in short, stocky plants that did not flower; in some cases, flag leaves developed under short days but heading did not occur. In contrast, for M. sinensis and M. floridulus from low latitudes, shorter day lengths typically resulted in earlier flowering, and for some low latitude genotypes, 15 h days resulted in no flowering. However, the highest ratio of reproductive shoots to total number of culms was typically observed for 12.5 h or 15 h days. Latitude of origin was significantly associated with culm length, and the shorter the days, the stronger the relationship. Nearly all entries achieved maximal culm length under the 15 h treatment, but the nearer to the equator an accession originated, the less of a difference in culm length between the short-day treatments and the 15 h day treatment. Under short days, short culms for high-latitude accessions was achieved by different physiological mechanisms for M. sinensis genetic groups from the mainland in comparison to those from Japan; for mainland accessions, the mechanism was reduced internode length, whereas for Japanese accessions the phyllochron under short days was greater than under long days. Thus, for M. sinensis, short days typically hastened floral induction, consistent with the expectations for a facultative short-day plant. However, for high latitude accessions of M. sinensis, days less than 12.5 h also signaled that plants should prepare for winter by producing many short culms with limited elongation and development; moreover, this response was also epistatic to flowering. Thus, to flower M. sinensis that originates from high latitudes synchronously with sugarcane, the former needs day lengths >12.5 h (perhaps as high as 15 h), whereas that the latter needs day lengths <12.5 h.

Analysis of The Performance of A PV/PCM System in Variable Solar Radiation Conditions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Carlos Armenta-Deu
Keyword(s):  
Steady State ◽  
Melting Point ◽  
Solar Radiation ◽  
Transient State ◽  
Good Method ◽  
Day Length ◽  
System Response ◽  
Time Interval ◽  
Steady State Temperature ◽  
Radiation Conditions

This paper studies the performance of a PV/PCM system operating at variable solar radiation conditions. The system has been tested for six different solar radiation levels, from 250 W/m2 to 950 W/m2 determining the steady-state temperature for every case. An algorithm has been developed to predict the steady-state temperature. This prediction has produced values within 97% accuracy of experimental data. A reduction of temperature up to 18.9ºC has been achieved. An algorithm has been developed to correlate reduction in temperature with solar radiation levels. This algorithm can be combined with the classical expression for the PV panel efficiency resulting in a good method for determining the increase of the efficiency. Additionally, the system has been tested for continuous solar radiation evolution, analyzing the system response under the transient state. The procedure has been conducted for the former six solar radiation levels considering the solar radiation evolves linearly from one value to another during a time interval. The simulation has been tested against outdoor solar radiation with an accuracy higher than 98%. The predicted value of the PCM Temperature at the end of the day as shown matches the melting point of the PCM used in the experiment (55ºC), which has been verified experimentally. Besides, the transient state analysis has given the temperature evolution of the PCM at every interval, resulting in a very good match with experimental tests. The analysis of the transient state that the system reaches the melting point at 1/3 of the solar day length, maintaining the phase change state for the rest of the day. This is in good agreement with the experimental observation.

scholarly journals 485 PB 125 QUANTIFYING THE EFFECT OF PLUG-FLAT COLOR ON SOIL SURFACETEMPERATURE

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 500g-501
Author(s):  
James E. Faust ◽  
Hiroshi Shimizu ◽  
Royal D. Heins
Keyword(s):  
Solar Radiation ◽  
Surface Temperature ◽  
Soil Temperature ◽  
Soil Surface ◽  
Image Analyzer ◽  
Fine Wire ◽  
High Solar Radiation ◽  
White Sheet ◽  
Soil Surface Temperature ◽  
Radiation Conditions

Surface temperature of a soilless medium in white, gray, and black plug sheets was measured to determine the value of using plug sheets of different colors to control soil temperature during seed germination and young seedling growth. Plugs sheets were placed in a greenhouse set at 25°C. Soil surface temperatures were measured with fine-wire thermocouples inserted into the top 1 mm of the soil. A thermal image analyzer was used to determine the temperature variation across the plug flat. At night, soil temperature in all three colored flats was 3°C below air temperature because of evaporation and net longwave radiative losses to the greenhouse glass. Surface temperature of moist soil increased as solar radiation increased. Soil surface temperature in the white sheet was 6.3 and 10°C warmer than the air under solar radiation conditions of 350 and 700 W ·m-2 (about 700 and 1400 μmol·m-2·s-1), which was 3 and 2°C cooler than soil the black and gray plug sheets, respectively. These data indicate plug sheet color influences soil surface temperature, but not as much as solar radiation does. Preventing high solar radiation during the summer is more critical than plug sheet color.

scholarly journals Managing flowering time in Miscanthus and sugarcane to facilitate intra- and intergeneric crosses

2020 ◽  
Author(s):  
Hongxu Dong ◽  
Lindsay V. Clark ◽  
Xiaoli Jin ◽  
Kossonou Anzoua ◽  
Larisa Bagmet ◽  
...  
Keyword(s):  
Flowering Time ◽  
High Latitude ◽  
Floral Induction ◽  
Day Treatment ◽  
Day Length ◽  
Close Relative ◽  
Short Day ◽  
Culm Length ◽  
Low Latitudes ◽  
Short Days

AbstractMiscanthus is a close relative of Saccharum and a potentially valuable genetic resource for improving sugarcane. Differences in flowering time within and between Miscanthus and Saccharum hinders intra- and interspecific hybridizations. A series of greenhouse experiments were conducted over three years to determine how to synchronize flowering time of Saccharum and Miscanthus genotypes. We found that day length was an important factor influencing when Miscanthus and Saccharum flowered. Sugarcane could be induced to flower in a central Illinois greenhouse using supplemental lighting to reduce the rate at which days shortened during the autumn and winter to 1 min d-1, which allowed us to synchronize the flowering of some sugarcane genotypes with Miscanthus genotypes primarily from low latitudes. In a complementary growth chamber experiment, we evaluated 33 Miscanthus genotypes, including 28 M. sinensis, 2 M. floridulus, and 3 M. ×giganteus collected from 20.9° S to 44.9° N for response to three day lengths (10 h, 12.5 h, and 15 h). High latitude-adapted M. sinensis flowered mainly under 15 h days, but unexpectedly, short days resulted in short, stocky plants that did not flower; in some cases, flag leaves developed under short days but heading did not occur. In contrast, for M. sinensis and M. floridulus from low latitudes, shorter day lengths typically resulted in earlier flowering, and for some low latitude genotypes, 15 h days resulted in no flowering. However, the highest ratio of reproductive shoots to total number of culms was typically observed for 12.5 h or 15 h days. Latitude of origin was significantly associated with culm length, and the shorter the days, the stronger the relationship. Nearly all entries achieved maximal culm length under the 15 h treatment, but the nearer to the equator an accession originated, the less of a difference in culm length between the short-day treatments and the 15 h day treatment. Under short days, short culms for high-latitude accessions was achieved by different physiological mechanisms for M. sinensis genetic groups from the mainland in comparison to those from Japan; for mainland accessions, the mechanism was reduced internode length, whereas for Japanese accessions the phyllochron under short days was greater than under long days. Thus, for M. sinensis, short days typically hastened floral induction, consistent with the expectations for a facultative short-day plant. However, for high latitude accessions of M. sinensis, days less than 12.5 h also signaled that plants should prepare for winter by producing many short culms with limited elongation and development; moreover, this response was also epistatic to flowering. Thus, to flower M. sinensis that originates from high latitudes synchronously with sugarcane, the former needs day lengths >12.5 h (perhaps as high as 15 h), whereas that the latter needs day lengths <12.5 h.

scholarly journals A Simplified Simulation Model for Predicting Radiative Transfer in Long Street Canyons under High Solar Radiation Conditions

Energies ◽  
2015 ◽  
Vol 8 (12) ◽  
pp. 13540-13558 ◽  
Author(s):  
Carlos Rubio-Bellido ◽  
Jesús Pulido-Arcas ◽  
Benito Sánchez-Montañés
Keyword(s):  
Solar Radiation ◽  
Radiative Transfer ◽  
Simulation Model ◽  
Street Canyons ◽  
High Solar Radiation ◽  
Radiation Conditions

Implementation of a modified P&O-MPPT algorithm adapted for varying solar radiation conditions

2016 ◽  
Vol 99 (3) ◽  
pp. 839-846 ◽  
Author(s):  
Abdelhakim Belkaid ◽  
Ilhami Colak ◽  
Korhan Kayisli
Keyword(s):  
Solar Radiation ◽  
Radiation Conditions

INFLUENCE OF PHOTOPERIOD ON THYROTROPIN RELEASING HORMONE-INDUCED PROLACTIN RELEASE IN EWES

1983 ◽  
Vol 63 (1) ◽  
pp. 67-73 ◽  
Author(s):  
B. E. HOWLAND ◽  
D. SONYA ◽  
L. M. SANFORD ◽  
W. M. PALMER
Keyword(s):  
Thyrotropin Releasing Hormone ◽  
Day Length ◽  
Constant Light ◽  
Serum Prolactin ◽  
Prolactin Release ◽  
Blood Samples ◽  
Releasing Hormone ◽  
Before And After ◽  
Release Curve ◽  
Short Days

The influence of photoperiod on serum prolactin levels and prolactin release induced by thyrotropin releasing hormone (TRH) was determined in ewes maintained under the following lighting regimes: Room 1, lighting mimicked natural changes in photoperiod; Room 2, annual photoperiod changes condensed into 6 mo with short days in June; Room 3, same as Room 2 except photoperiod changed abruptly from 16.5 to 8.0 h on 21 Mar. and back to 16.5 h on 21 June; Room 4, constant light. Weekly blood samples were obtained from February to August. Additionally, blood samples were collected before and after treatment with 10 μg TRH on 19 May, 13 June, 27 June and 19 July. Prolactin levels were elevated in ewes exposed to long days or constant light. The mean of all pre-TRH samples was significantly correlated with stress-induced elevations in prolactin (highest pre-TRH value) (r = 0.72) and area under the TRH-induced release curve (r = 0.56). The prolactin release in response to TRH was greatest in ewes exposed to long days or constant light. Abrupt increase of day length elevated pretreatment prolactin levels (P < 0.01) and increased area under the response curve (P < 0.05). Key words: Photoperiod, TRH, prolactin, ewes

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