Respiration and temperature patterns in thermogenic flowers of Magnolia ovata under natural conditions in Brazil

2010 ◽  
Vol 37 (9) ◽  
pp. 870 ◽  
Author(s):  
Roger S. Seymour ◽  
Ilse Silberbauer-Gottsberger ◽  
Gerhard Gottsberger
Keyword(s):  
Ambient Temperature ◽  
Respiration Rate ◽  
Energy Savings ◽  
Ambient Air ◽  
Pollination Biology ◽  
Specific Rate ◽  
Maximum Mass ◽  
Natural Conditions ◽  
Female Phase ◽  
Male Phase

The roles of floral thermogenesis in pollination biology include attraction and reward of insects. Magnolia ovata (A.St.-Hil.) Spreng. produces ~56 g, bisexual, protogynous and scented flowers. Two distinct episodes of thermogenesis occur during anthesis: one beginning at about sunset and lasting ~3 h in the female phase and another that occurs synchronously 24 h later and lasting 4 h in the male phase. Female stage flowers produce up to 0.36 W to reach 27.3°C, which is 3.9°C above ambient air. In the male stage, corresponding values are 0.79 W, 29.7°C and 5.4°C, respectively. Most heat is generated in the petals in both phases (74 and 65%). Maximum, mass-specific rate of respiration is 23 nmol s–1 g–1 in the petals and 100 nmol s–1 g–1 in the anthers. The flowers are apparently not thermoregulatory, because respiration rate decreases, rather than increases, with decreasing ambient temperature. Scarab beetles, Cyclocephala literata, enter the floral chamber created by the petals in the female phase, mate, consume floral parts (mainly petals) and then depart in the male phase. Temperatures maintained in the floral chamber are sufficient to provide beetles with significant energy savings during their activities in both phases. Thermogenesis is, therefore, consistent with volatilisation of floral fragrances and energy rewards to beetle visitors.

Thermogenic flowering of taro (Colocasia esculenta, Araceae)

2004 ◽  
Vol 82 (11) ◽  
pp. 1557-1565 ◽  
Author(s):  
Anton Ivancic ◽  
Vincent Lebot ◽  
Olivier Roupsard ◽  
José Quero Garcia ◽  
Tom Okpul
Keyword(s):  
Ambient Air ◽  
Early Morning ◽  
Colocasia Esculenta ◽  
Critical Periods ◽  
Final Phase ◽  
Inflorescence Development ◽  
Air Temperatures ◽  
Female Phase ◽  
Male Phase ◽  
The Mean

Thermogenesis and its association with taro (Colocasia esculenta (L.) Schott) flowering was studied during the warmest period of the year (December 2002 – February 2003) within a large collection of heterogeneous plant material on Espiritu Santo, Vanuatu. On each studied inflorescence, temperatures of the three main parts of the spadix and the ambient air were recorded during a period of 38 h. The investigation indicates that significant thermogenic activity of taro inflorescences takes place during two successive nights: (1) during the night when an inflorescence becomes odorous (the female phase) and (2) a night later, when microsporogenesis approaches its final phase (the male phase). The highest average difference between mean temperatures of the ambient air and inflorescences were documented during the female phase, at 0500 hours (the mean temperature of the sterile appendix was 29.1 ± 0.9 °C (P = 0.05) and this was 6.8 °C above the temperature of the ambient air). Thermogenic activity is synchronized with the protogynous nature of the species and insect pollination in the early morning hours. Its main putative functions are (1) to reduce the deviations of ambient air temperatures during the most critical periods of flowering, and (2) to promote cross-pollination. It stops 1–1.5 h after pollen has been released.Key words: taro, Colocasia esculenta, thermogenesis, inflorescence development, pollination.

Energy savings from vocal regulation of ambient temperature by 3-day-old domestic chicks

1996 ◽  
Vol 74 (4) ◽  
pp. 599-605 ◽  
Author(s):  
Anton Espira ◽  
Roger M. Evans
Keyword(s):  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Thermal Gradient ◽  
Energy Savings ◽  
Net Energy ◽  
Natural Conditions ◽  
Ambient Temperatures ◽  
Domestic Chicks ◽  
Important Means ◽  
Cold Challenge

Precocial domestic chicks (Gallus domesticus) become endothermic at or soon after hatching, but when chilled still vocalize to solicit heat from a parent or surrogate. In this study, we examined the potential energy savings resulting from vocal solicitation of heat by comparing the oxygen consumption of 3-day-old chicks facing a cold challenge of 20 °C with and without the option of regulating ambient temperature by vocally soliciting 2-min periods of rewarming at 35 °C from a surrogate parent in the laboratory. Body temperature was unaffected by vocal regulation, but the thermal gradient between body and ambient temperature was reduced by 5.0 ± 0.4 °C (mean ± SE). Mass-specific oxygen consumption [Formula: see text] increased by 62.5% to a near steady state mean of 3.64 mL∙g−1∙h−1 during constant chilling at 20 °C, but increased by only 48.1%, to 3.08 mL∙g−1∙h−1, during vocal regulation. Relative to chilled controls, vocally regulating chicks had a mean net energy saving of 15.4% during the final, stable 15 min of testing. Vocal solicitation of heat from a brooding parent seems likely to be an important means of saving energy expended in thermoregulation in some precocial species when young chicks are exposed to low ambient temperatures under natural conditions.

Topology of thermogenic tissues of Alocasia macrorrhizos (Araceae) inflorescences

Botany ◽  
2009 ◽  
Vol 87 (12) ◽  
pp. 1232-1241 ◽  
Author(s):  
Anton Ivancic ◽  
Olivier Roupsard ◽  
José Quero-García ◽  
Metka Sisko ◽  
Andreja Urbanek Krajnc ◽  
...  
Keyword(s):  
Ambient Air ◽  
Early Morning ◽  
Main Peak ◽  
Female Part ◽  
Female Phase ◽  
Male Phase ◽  
Male Part ◽  
Fertile Male

Thermogenesis and heat generating tissues in inflorescences of the giant taro ( Alocasia macrorrhizos (L.) G. Don) were studied from December 2005 to February 2006, on the Island of Espiritu Santo, Vanuatu. Temperatures were recorded in the ambient air, in the peduncle tissue, and on 12 positions within spadices during periods of maximum thermogenic activity, in the early morning hours of the female and male phases. The study showed that there were three thermogenic tissues: the sterile appendix, the fertile male part, and the differentiated sterile area below the fertile male part. During the female phase, heat was generated by the sterile appendix and the differentiated sterile area below the fertile male part, the smallest region of the spadix (mean ± SD = 0.86 ± 0.24 cm, 3.17% of the spadix length), and most probably by the fertile male part. Within the spadix, average temperatures gradually increased from the base of the female part and reached the first peak at the midpoint of the differentiated sterile area below the fertile male part (36.11 ± 1.54 °C). After that, they gradually decreased towards the midpoint of the fertile male part and increased again, reaching a second (main) peak at 1/4 of the sterile appendix height (44.83 ± 1.87 °C). From 1/4 to 1/2 of the appendix height they remained at more or less the same level, and then they decreased towards the tip of the spadix. During the male phase, heat was generated only within the fertile male part.

scholarly journals Changes in ambient temperature increase hospital outpatient visits for allergic rhinitis in Xinxiang, China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jianhui Gao ◽  
Mengxue Lu ◽  
Yinzhen Sun ◽  
Jingyao Wang ◽  
Zhen An ◽  
...  
Keyword(s):  
Allergic Rhinitis ◽  
Ambient Temperature ◽  
Positive Association ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Hospital Outpatient ◽  
Distributed Lag ◽  
Outpatient Visits ◽  
Daily Data ◽  
The Relationship

Abstract Background The effect of ambient temperature on allergic rhinitis (AR) remains unclear. Accordingly, this study aimed to explore the relationship between ambient temperature and the risk of AR outpatients in Xinxiang, China. Method Daily data of outpatients for AR, meteorological conditions, and ambient air pollution in Xinxiang, China were collected from 2015 to 2018. The lag-exposure-response relationship between daily mean temperature and the number of hospital outpatient visits for AR was analyzed by distributed lag non-linear model (DLNM). Humidity, long-time trends, day of the week, public holidays, and air pollutants including sulfur dioxide (SO2), and nitrogen dioxide (NO2) were controlled as covariates simultaneously. Results A total of 14,965 AR outpatient records were collected. The relationship between ambient temperature and AR outpatients was generally M-shaped. There was a higher risk of AR outpatient when the temperature was 1.6–9.3 °C, at a lag of 0–7 days. Additionally, the positive association became significant when the temperature rose to 23.5–28.5 °C, at lag 0–3 days. The effects were strongest at the 25th (7 °C) percentile, at lag of 0–7 days (RR: 1.32, 95% confidence intervals (CI): 1.05–1.67), and at the 75th (25 °C) percentile at a lag of 0–3 days (RR: 1.15, 95% CI: 1.02–1.29), respectively. Furthermore, men were more sensitive to temperature changes than women, and the younger groups appeared to be more influenced. Conclusions Both mild cold and mild hot temperatures may significantly increase the risk of AR outpatients in Xinxiang, China. These findings could have important public health implications for the occurrence and prevention of AR.

Pollination of Amorphophallus johnsonii (Araceae) by carrion beetles (Phaeochrous amplus) in a Ghanaian rain forest

1996 ◽  
Vol 12 (3) ◽  
pp. 409-418 ◽  
Author(s):  
Daniel D. N. Beath
Keyword(s):  
Rain Forest ◽  
Rainy Season ◽  
Male Inflorescence ◽  
Large Numbers ◽  
Female Phase ◽  
Male Phase ◽  
Carrion Beetles ◽  
Main Rainy Season

ABSTRACTAmorphophallus johnsonii (N. E. Brown) flowers during April in the main rainy season in Ghana. Anthesis starts at dusk with fluid oozing from the upper spadix accompanied by a strong aminoid odour. Just after dark large numbers of carrion beetles (Phaeochrous amplus) and occasional dung fly species (Hemigymnochaeta unicolor and Paryphodes tigrinus) visit the inflorescences. The beetles become trapped in the lower spathe overnight and remain in the spadix until the following evening. Between 1630 and 1645 h the following day, the anthers produce long threads of sticky pollen. The trapped beetles escape just after dark by crawling up the spadix, past the dehisced anthers and fly away from the spadix tip. Marked beetles were seen to transfer pollen from male phase to female phase inflorescences. Successful fertilisation was only effected if pollen was transferred on the same night from a male inflorescence 30 m or less away. Pollen is psilate and typical of beetle pollinated Araceae. Berries ripen approximately 70 d after fertilization and ripen basisetally in the infructescence.

Performance Improvement of Gas Turbine Power Plant by Intake Air Passive Cooling Using Phase Change Material Based Heat Exchanger

2017 ◽  
Author(s):  
Devendra Dandotiya ◽  
Nitin D. Banker
Keyword(s):  
Heat Exchanger ◽  
Ambient Temperature ◽  
Phase Change ◽  
Gas Turbine ◽  
Air Temperature ◽  
Power Output ◽  
Ambient Air ◽  
Passive Cooling ◽  
Air Intake ◽  
Change Material

The power output of a gas turbine plant decreases with the increase in ambient temperature. Moreover, the ambient temperature fluctuates about 15–20°C in a day. Hence, cooling of intake air makes a noticeable improvement to the gas turbine performance. In this regard, various active cooling techniques such as vapor compression refrigeration, vapor absorption refrigeration, vapor adsorption refrigeration and evaporative cooling are applied for the cooling of intake air. This paper presents a new passive cooling technique where the intake air temperature is reduced by incorporating phase change material (PCM) based heat exchanger parallel to conventional air intake line. During the daytime, the air is passed through the PCM which has melting temperature lower than the peak ambient temperature. This will reduce the ambient air temperature before taking to the compressor. Once the PCM melts completely, the required ambient air would be drawn from the ambient through conventional air intake arrangement. During the night, when there is lower ambient temperature, PCM converts from liquid to solid. The selected PCM has a melting temperature less than the peak ambient temperature and higher than the minimum ambient temperature. It is observed from the numerical modeling of the PCM that about four hours are required for the melting of PCM and within this time, the intake air can also be cooled by 5°C. The thermodynamic analysis of the results showed about 5.2% and 5.2% improvement in net power output and thermal efficiency, respectively for four hours at an ambient temperature of 45°C.

scholarly journals Male flowers of Aconitum compensate for toxic pollen with increased floral signals and rewards for pollinators

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A.-L. Jacquemart ◽  
C. Buyens ◽  
M.-F. Hérent ◽  
J. Quetin-Leclercq ◽  
G. Lognay ◽  
...  
Keyword(s):  
Larval Food ◽  
Chemical Defences ◽  
Toxic Nectar ◽  
Pollen Transfer Efficiency ◽  
Aconitum Napellus ◽  
Female Phase ◽  
Male Phase ◽  
Male Flowers ◽  
Nectar Rewards ◽  
Toxic Pollen

Abstract Many plants require animal pollinators for successful reproduction; these plants provide pollinator resources in pollen and nectar (rewards) and attract pollinators by specific cues (signals). In a seeming contradiction, some plants produce toxins such as alkaloids in their pollen and nectar, protecting their resources from ineffective pollinators. We investigated signals and rewards in the toxic, protandrous bee-pollinated plant Aconitum napellus, hypothesizing that male-phase flower reproductive success is pollinator-limited, which should favour higher levels of signals (odours) and rewards (nectar and pollen) compared with female-phase flowers. Furthermore, we expected insect visitors to forage only for nectar, due to the toxicity of pollen. We demonstrated that male-phase flowers emitted more volatile molecules and produced higher volumes of nectar than female-phase flowers. Alkaloids in pollen functioned as chemical defences, and were more diverse and more concentrated compared to the alkaloids in nectar. Visitors actively collected little pollen for larval food but consumed more of the less-toxic nectar. Toxic pollen remaining on the bee bodies promoted pollen transfer efficiency, facilitating pollination.

Heat and Mass Transfer Analysis of a Pot-in-Pot Refrigerator Using Reynolds Flow Model

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Ramendra Pandey ◽  
Bala Pesala
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Ambient Temperature ◽  
Heat And Mass Transfer ◽  
Heat Load ◽  
Radiation Heat Transfer ◽  
Ambient Air ◽  
Total Heat ◽  
Maximum Efficiency ◽  
Radiation Heat

Heat and mass transfer analysis of evaporative cooling process in a pot-in-pot cooling system is done based on Reynolds flow hypotheses. The model proposed herein assumes that the heat transfer due to natural convection is coupled with an imaginary ambient air mass flow rate (gAo) which is an essential assumption in order to arrive at the solution for the rate of water evaporation. Effect of several parameters on the pot-in-pot system performance has been studied. The equations are iteratively solved and detailed results are presented to evaluate the cooling performance with respect to various parameters: ambient temperature, relative humidity (RH), pot height, pot radius, total heat load, thermal and hydraulic conductivity, and radiation heat transfer. It was found that pot height, pot radius, total heat load, and radiation heat transfer play a critical role in the performance of the system. The model predicts that at an ambient temperature of 50 °C and RH of 40%, the system achieves a maximum efficiency of 73.44% resulting in a temperature difference of nearly 20 °C. Similarly, for a temperature of 30 °C and RH of 80%, the system efficiency was minimum at 14.79%, thereby verifying the usual concept that the pot-in-pot system is best suited for hot and dry ambient conditions.

Impact of ambient air temperature on human health in India

2018 ◽  
Vol 33 (4) ◽  
pp. 433-439 ◽  
Author(s):  
Harshal R. Salve ◽  
Raghavan Parthasarathy ◽  
Anand Krishnan ◽  
D.R. Pattanaik
Keyword(s):  
Ambient Temperature ◽  
Air Temperature ◽  
Ambient Air ◽  
Current Evidence ◽  
Standard Data ◽  
Ambient Air Temperature ◽  
All Cause Mortality ◽  
Integrated Response ◽  
Public Health Practitioners ◽  
Relationship Of

Abstract A systematic search was carried out in the databases of Pubmed, Indmed and Mausam for articles on the effect of ambient temperature on health. Relevant data were extracted using a standard data abstraction form by two authors independently. The overall effects of ambient air temperature are reported as odds ratio (OR) and 95% confidence intervals (CIs) on mortality. Of 812 records identified, only seven were included in the final review as per pre-defined criteria. An increase in the all-cause mortality rate of 41% are reported during a heat wave in India. Risk ratios for all-cause mortality was in the range of 1.7–2.1. The dose-response relationship of ambient temperature and all-cause mortality and cardiovascular diseases are been reported. Current evidence on the effect of ambient temperature and health is sufficient to initiate an integrated response from policy makers, climate scientists and public health practitioners in India. Continued advocacy and generation of more robust evidence is needed.

scholarly journals Linking pollinator efficiency to patterns of pollen limitation: small bees exploit the plant–pollinator mutualism

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180635 ◽  
Author(s):  
Matthew H. Koski ◽  
Jennifer L. Ison ◽  
Ashley Padilla ◽  
Angela Q. Pham ◽  
Laura F. Galloway
Keyword(s):  
Pollen Limitation ◽  
Pollen Deposition ◽  
Pollinator Efficiency ◽  
Flower Visitation ◽  
Female Phase ◽  
Male Phase ◽  
Single Flower ◽  
Floral Visitation ◽  
Low Efficiency ◽  
Plant Pollinator

Seemingly mutualistic relationships can be exploited, in some cases reducing fitness of the exploited species. In plants, the insufficient receipt of pollen limits reproduction. While infrequent pollination commonly underlies pollen limitation (PL), frequent interactions with low-efficiency, exploitative pollinators may also cause PL. In the widespread protandrous herb Campanula americana , visitation by three pollinators explained 63% of the variation in PL among populations spanning the range. Bumblebees and the medium-sized Megachile campanulae enhanced reproductive success, but small solitary bees exacerbated PL. To dissect mechanisms behind these relationships, we scored sex-specific floral visitation, and the contributions of each pollinator to plant fitness using single flower visits. Small bees and M. campanulae overvisited male-phase flowers, but bumblebees frequently visited female-phase flowers. Fewer bumblebee visits were required to saturate seed set compared to other bees. Scaling pollinator efficiency metrics to populations, small bees deplete large amounts of pollen due to highly male-biased flower visitation and infrequent pollen deposition. Thus, small bees reduce plant reproduction by limiting pollen available for transfer by efficient pollinators, and appear to exploit the plant–pollinator mutualism, acting as functional parasites to C. americana . It is therefore unlikely that small bees will compensate for reproductive failure in C. americana when bumblebees are scarce.

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