Short‐term heat stress during flowering results in a decline in Canola seed productivity

2021 ◽  
Author(s):  
Neeta Lohani ◽  
Mohan B. Singh ◽  
Prem L. Bhalla
Keyword(s):  
Heat Stress ◽  
Canola Seed ◽  
Seed Productivity ◽  
Short Term

scholarly journals Characterization of Short-Term Heat Stress in Holstein Dairy Cows Using Altered Indicators of Metabolomics, Blood Parameters, Milk MicroRNA-216 and Characteristics

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 722
Author(s):  
Jang-Hoon Jo ◽  
Jalil Ghassemi Nejad ◽  
Dong-Qiao Peng ◽  
Hye-Ran Kim ◽  
Sang-Ho Kim ◽  
...  
Keyword(s):  
Heat Stress ◽  
Dairy Cows ◽  
Milk Yield ◽  
Milk Fat ◽  
Blood Parameters ◽  
Negative Effects ◽  
Short Term ◽  
Lactating Cows ◽  
Humidity Index ◽  
Holstein Dairy Cows

This study aims to characterize the influence of short-term heat stress (HS; 4 day) in early lactating Holstein dairy cows, in terms of triggering blood metabolomics and parameters, milk yield and composition, and milk microRNA expression. Eight cows (milk yield = 30 ± 1.5 kg/day, parity = 1.09 ± 0.05) were homogeneously housed in environmentally controlled chambers, assigned into two groups with respect to the temperature humidity index (THI) at two distinct levels: approximately ~71 (low-temperature, low-humidity; LTLH) and ~86 (high-temperature, high-humidity; HTHH). Average feed intake (FI) dropped about 10 kg in the HTHH group, compared with the LTLH group (p = 0.001), whereas water intake was only numerically higher (p = 0.183) in the HTHH group than in the LTLH group. Physiological parameters, including rectal temperature (p = 0.001) and heart rate (p = 0.038), were significantly higher in the HTHH group than in the LTLH group. Plasma cortisol and haptoglobin were higher (p < 0.05) in the HTHH group, compared to the LTLH group. Milk yield, milk fat yield, 3.5% fat-corrected milk (FCM), and energy-corrected milk (ECM) were lower (p < 0.05) in the HTHH group than in the LTLH group. Higher relative expression of milk miRNA-216 was observed in the HTHH group (p < 0.05). Valine, isoleucine, methionine, phenylalanine, tyrosine, tryptophan, lactic acid, 3-phenylpropionic acid, 1,5-anhydro-D-sorbitol, myo-inositol, and urea were decreased (p < 0.05). These results suggest that early lactating cows are more vulnerable to short-term (4 day) high THI levels—that is, HTHH conditions—compared with LTLH, considering the enormous negative effects observed in measured blood metabolomics and parameters, milk yield and compositions, and milk miRNA-216 expression.

scholarly journals Analytical dataset of short-term heat stress induced reshuffling of metabolism and transcriptomes in maize grown under elevated CO2

Data in Brief ◽  
2020 ◽  
Vol 28 ◽  
pp. 105004
Author(s):  
Jemaa Essemine ◽  
Jikai Li ◽  
Genyun Chen ◽  
Mingnan Qu
Keyword(s):  
Heat Stress ◽  
Elevated Co2 ◽  
Short Term

Effect of short-term exposure to high ambient temperatures on gas exchange and heat production in boars of different breeds

1998 ◽  
Vol 66 (2) ◽  
pp. 431-440 ◽  
Author(s):  
A.-H. Tauson ◽  
A. Chwalibog ◽  
J. Ludvigsen ◽  
K. Jakobsen ◽  
G. Thorbek
Keyword(s):  
Heat Stress ◽  
Gas Exchange ◽  
Heat Production ◽  
Live Weight ◽  
Mean Value ◽  
Short Term ◽  
Ambient Temperatures ◽  
Cooling Period ◽  
Basal Period ◽  
Short Term Exposure

AbstractThe effects of short-term exposure to high ambient temperatures on gas exchange, heat production (HE), respiration rate (RR) and rectal temperature were evaluated individually with boars of approximately 100 kg live weight. The boars were of different breeds with four of Yorkshire (YS), eight of Danish Landrace (DL), out of which three were found stress susceptible by the halothane test (DLH+), eight of Duroc (DR) and eight of Hampshire (HS) breeds. After 1 h rest in the respiration chamber at 17·0°C the gas exchange measurements started with al-h basal period at 17 °C, followed by 2h of heating during which temperature increased to 35·0 °C (period I) and then further to 39·7X1 (period II). Then cooling of the chamber started, and after 1 h (period III) temperature had decreased to 21·8°C, and after the 2nd h of cooling (period IV) temperature was 18·2 °C. The gas exchange was measured for each hour from 09.00 h (basal period) until 14.00 h (period IV). RR was recorded every 15 min. Rectal temperatures were measured when the animals were removed from the chamber. The gas exchange and HE increased slowly during period I but rapidly in period II, followed by decreasing values in the cooling periods. HS and DLH+ had considerably higher gas exchange and HE than other breeds in these two periods and the values remained high during period III. In period IV all breeds had gas exchange rates and HE below those of the basal period. RR increased slightly in period I and then a sharp increase followed during period II. Maximum RR was recorded in period III with an average of 183 breaths per min for all breeds. RR increased earlier and more steeply in HS and reached the highest mean value of 236 breaths per min. Four HS boars salivated heavily during heat stress and rectal temperatures of these animals were 39·7 °C when removed from the chamber compared with close to 39·0 °C for all other breeds. It was concluded that there were considerable breed differences in response to heat stress and that DLH+ and HS were more severely stressed than boars ofYS, DL and DR.

Effects of short-term heat stress on the development and reproduction of predatory mite Neoseiulus barkeri (Acari, Phytoseiidae)

2021 ◽  
Vol 26 (4) ◽  
pp. 713-723
Author(s):  
Wei Zhen Li ◽  
Hao Long Li ◽  
Zi Kun Guo ◽  
Su Qin Shang
Keyword(s):  
Heat Stress ◽  
Life Span ◽  
Treatment Time ◽  
Predatory Mite ◽  
Immature Stage ◽  
Oviposition Period ◽  
Hatching Rate ◽  
Short Term ◽  
Developmental Duration ◽  
Adult Females

The predatory mite Neoseiulus barkeri (Acari: Phytoseiidae), which is one of the best natural enemies, has been used as a biological control agent against multiple insect pests, such as spider mite, Tetranychus urticae and thrips. Its growth and development were affected by the environmental temperature changes. This study was conducted to evaluate the hatching rate of the eggs and the immature developmental times of N. barkeri after incubation of the eggs under heat stress at 38, 40 and 42℃, 85% ± 5% RH and a 16h:8h light: dark (L:D) photoperiod for 2, 4 and 6h. After adult females emerged, they were treated under the same conditions again, and the parameters such as oviposition period, fecundity and female longevity were observed. The results showed that with the increase of the temperature and the extension of the duration of the heat stress, the hatching rate was lower. The eggs treated at 42℃ for 2h or more could not hatch, and the developmental duration of each immature stage showed a trend of decreasing at first and then increasing. The fastest development was observed after incubation of eggs at 40℃ for 2h, and the shortest developmental duration was 4.60d. Under the condition of 38℃, the oviposition period and life span of adult females were shortened with the extension of treatment time, and the fecundity decreased at first and then increased. At 40℃, the fecundity, oviposition period and longevity of adult females showed a trend of gradual increase with the extension of treatment time. The shortest oviposition period, the lowest fecundity and the shortest life span of adult females were 12.14d, 18.92 eggs and 16.65d, respectively after incubation of eggs at 40℃, for 2h. Therefore, the short-term heat stress had a significant effect on the hatching rate and the duration of the immature stage, and also had a negative effect on the fecundity, oviposition period and longevity of adult females. In rearing and field release, heat stress should be avoided as much as possible to achieve the best predation and control effect of N. barkeri.

Heat acclimation, aerobic fitness, and hydration effects on tolerance during uncompensable heat stress

1998 ◽  
Vol 84 (5) ◽  
pp. 1731-1739 ◽  
Author(s):  
Stephen S. Cheung ◽  
Tom M. McLellan
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Aerobic Fitness ◽  
Protective Clothing ◽  
Sweat Rate ◽  
Heat Acclimation ◽  
Short Term ◽  
Chemical Protective Clothing ◽  
Uncompensable Heat Stress ◽  
C 30

—The purpose of the present study was to determine the separate and combined effects of aerobic fitness, short-term heat acclimation, and hypohydration on tolerance during light exercise while wearing nuclear, biological, and chemical protective clothing in the heat (40°C, 30% relative humidity). Men who were moderately fit [(MF); <50 ml ⋅ kg−1 ⋅ min−1maximal O2 consumption; n = 7] and highly fit [(HF); >55 ml ⋅ kg−1 ⋅ min−1maximal O2 consumption; n = 8] were tested while they were euhydrated or hypohydrated by ∼2.5% of body mass through exercise and fluid restriction the day preceding the trials. Tests were conducted before and after 2 wk of daily heat acclimation (1-h treadmill exercise at 40°C, 30% relative humidity, while wearing the nuclear, biological, and chemical protective clothing). Heat acclimation increased sweat rate and decreased skin temperature and rectal temperature (Tre) in HF subjects but had no effect on tolerance time (TT). MF subjects increased sweat rate but did not alter heart rate, Tre, or TT. In both MF and HF groups, hypohydration significantly increased Tre and heart rate and decreased the respiratory exchange ratio and the TT regardless of acclimation state. Overall, the rate of rise of skin temperature was less, while ΔTre, the rate of rise of Tre, and the TT were greater in HF than in MF subjects. It was concluded that exercise-heat tolerance in this uncompensable heat-stress environment is not influenced by short-term heat acclimation but is significantly improved by long-term aerobic fitness.

Short-term exercise improves myocardial tolerance to in vivo ischemia-reperfusion in the rat

2001 ◽  
Vol 91 (5) ◽  
pp. 2205-2212 ◽  
Author(s):  
Haydar A. Demirel ◽  
Scott K. Powers ◽  
Murat A. Zergeroglu ◽  
R. Andrew Shanely ◽  
Karyn Hamilton ◽  
...  
Keyword(s):  
Heat Stress ◽  
Maximum Rate ◽  
Treadmill Exercise ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Antioxidant Defenses ◽  
Whole Body ◽  
Sprague Dawley ◽  
Short Term

These experiments examined the independent effects of short-term exercise and heat stress on myocardial responses during in vivo ischemia-reperfusion (I/R). Female Sprague-Dawley rats (4 mo old) were randomly assigned to one of four experimental groups: 1) control, 2) 3 consecutive days of treadmill exercise [60 min/day at 60–70% maximal O2 uptake (V˙o 2 max)], 3) 5 consecutive days of treadmill exercise (60 min/day at 60–70%V˙o 2 max), and 4) whole body heat stress (15 min at 42°C). Twenty-four hours after heat stress or exercise, animals were anesthetized and mechanically ventilated, and the chest was opened by thoracotomy. Coronary occlusion was maintained for 30-min followed by a 30-min period of reperfusion. Compared with control, both heat-stressed animals and exercised animals (3 and 5 days) maintained higher ( P < 0.05) left ventricular developed pressure (LVDP), maximum rate of left venticular pressure development (+dP/d t), and maximum rate of left ventricular pressure decline (−dP/d t) at all measurement periods during both ischemia and reperfusion. No differences existed between heat-stressed and exercise groups in LVDP, +dP/d t, and −dP/d t at any time during ischemia or reperfusion. Both heat stress and exercise resulted in an increase ( P < 0.05) in the relative levels of left ventricular heat shock protein 72 (HSP72). Furthermore, exercise (3 and 5 days) increased ( P < 0.05) myocardial glutathione levels and manganese superoxide dismutase activity. These data indicate that 3–5 consecutive days of exercise improves myocardial contractile performance during in vivo I/R and that this exercise-induced myocardial protection is associated with an increase in both myocardial HSP72 and cardiac antioxidant defenses.

Short-term heat stress induces mitochondrial degradation and biogenesis and enhances mitochondrial quality in porcine oocytes

2018 ◽  
Vol 74 ◽  
pp. 256-263 ◽  
Author(s):  
Nobuhiko Itami ◽  
Koumei Shirasuna ◽  
Takehito Kuwayama ◽  
Hisataka Iwata
Keyword(s):  
Heat Stress ◽  
Short Term

Stage-dependent temperature sensitivity function predicts seed-setting rates under short-term extreme heat stress in rice

2018 ◽  
Vol 256-257 ◽  
pp. 196-206 ◽  
Author(s):  
Ting Sun ◽  
Toshihiro Hasegawa ◽  
Liang Tang ◽  
Wei Wang ◽  
Junjie Zhou ◽  
...  
Keyword(s):  
Heat Stress ◽  
Temperature Sensitivity ◽  
Sensitivity Function ◽  
Extreme Heat ◽  
Seed Setting ◽  
Short Term ◽  
Extreme Heat Stress
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