The thermoregulatory behavior of sea hare Aplysia californica was determined in a horizontal thermal gradient;with a preferred temperature (PT) of 18.3°C for the day cycle and 20.8°C for the night cycle. The...The thermoregulatory behavior of sea hare Aplysia californica was determined in a horizontal thermal gradient;with a preferred temperature (PT) of 18.3°C for the day cycle and 20.8°C for the night cycle. The displacement velocity demonstrated an initial rate of 30 cm·hˉ1 and gradually the velocity diminished to 18 cm·hˉ1 with several fluctuations mainly at 02:00 am. Critical Temperature Maxima (CTMax refers to the temperature point where at least 50% of the experimental group have a loss of attachment) was measured at three acclimation temperatures (16°C, 19°C and 22°C). At the lowest acclimation temperature (16°C), 50% of the experimental group had an attachment loss at CTMax 32.7°C, and in a higher acclimation temperature (22°C) CTMax was 36.2°C. The Oxygen Consumption Rate (OCR) was closely correlated to acclimation temperature, and at 16°C and 19°C sea hare had a relatively stable metabolic rate, with OCR increasing to 9 mg O2 hˉ1·kgˉ1 w.w. in a higher acclimation temperature.展开更多
Objective:To determine the effect of prior heat shock on the CTMax of differently acclimated Portunus pelagicus(P.pelagicus)as well as the time course of the changes in CTMax post heat shock.Methods:Crabs P.pelagicus ...Objective:To determine the effect of prior heat shock on the CTMax of differently acclimated Portunus pelagicus(P.pelagicus)as well as the time course of the changes in CTMax post heat shock.Methods:Crabs P.pelagicus were held in laboratory aquaria in tanks,which were supplied with filtered and aerated seawater.Crabs were acclimated at 20℃,25℃,30℃and 35℃for 3 weeks before their CTMax was determined.The CTMax was recorded for each crab as the median temperature during the 5 min period when a crab was not able to right itself,the average CTMax was calculated.The effect of heat shock on subsequent CTMax was measured.Crabs were heat shocked at temperature 1℃lower than the CTMax for 20 min,followed by either 0.5 h,1 h or 1.5 h recovery at 20℃.The same procedure was repeated at other acclimation temperatures(25℃,30℃and 35℃).Results:Temperature acclimation of P.pelargicus from 20-35℃progressively increased the CTMax.Acclimation at 35℃the CTMax was 42.66℃,whereas acclimation at 20℃the CTMax was 39.8℃.In P.pelagicus acclimated,at 20℃the CTMax values after heat shock were significantly higher than crabs in control for 30 min,1 h and 1.5 h after heat shock.In the 25℃and 30℃acclimated crabs,the CTMax values after heat shock were significantly higher than control only in 30 min and 1 h after heat shock.No significant differences in 35℃acclimated crabs between control and heat shocked crabs were found after recovery for 30 min,1 h,or 1.5 h.Conclusions:Heat shock caused significant rises in the CTMax,however,this increase was progressively reduced with longer recovery times at the acclimation temperature.For 20℃acclimated crabs,the increased CTMax was still evident after 90 min,but for 25℃and 30℃crabs,the response was over after 90 min.Heat shock of 35℃crabs was problematical,the CTMax gave no increased thermotolerance.It must be concluded that the combination of a high heat shock temperature and CTMax determinations were too damaging.展开更多
文摘The thermoregulatory behavior of sea hare Aplysia californica was determined in a horizontal thermal gradient;with a preferred temperature (PT) of 18.3°C for the day cycle and 20.8°C for the night cycle. The displacement velocity demonstrated an initial rate of 30 cm·hˉ1 and gradually the velocity diminished to 18 cm·hˉ1 with several fluctuations mainly at 02:00 am. Critical Temperature Maxima (CTMax refers to the temperature point where at least 50% of the experimental group have a loss of attachment) was measured at three acclimation temperatures (16°C, 19°C and 22°C). At the lowest acclimation temperature (16°C), 50% of the experimental group had an attachment loss at CTMax 32.7°C, and in a higher acclimation temperature (22°C) CTMax was 36.2°C. The Oxygen Consumption Rate (OCR) was closely correlated to acclimation temperature, and at 16°C and 19°C sea hare had a relatively stable metabolic rate, with OCR increasing to 9 mg O2 hˉ1·kgˉ1 w.w. in a higher acclimation temperature.
基金Supported by the Deanship of Scientific Research(DSR),King Abdulaziz University,Jeddah[Grant No.(14/247/1433)].
文摘Objective:To determine the effect of prior heat shock on the CTMax of differently acclimated Portunus pelagicus(P.pelagicus)as well as the time course of the changes in CTMax post heat shock.Methods:Crabs P.pelagicus were held in laboratory aquaria in tanks,which were supplied with filtered and aerated seawater.Crabs were acclimated at 20℃,25℃,30℃and 35℃for 3 weeks before their CTMax was determined.The CTMax was recorded for each crab as the median temperature during the 5 min period when a crab was not able to right itself,the average CTMax was calculated.The effect of heat shock on subsequent CTMax was measured.Crabs were heat shocked at temperature 1℃lower than the CTMax for 20 min,followed by either 0.5 h,1 h or 1.5 h recovery at 20℃.The same procedure was repeated at other acclimation temperatures(25℃,30℃and 35℃).Results:Temperature acclimation of P.pelargicus from 20-35℃progressively increased the CTMax.Acclimation at 35℃the CTMax was 42.66℃,whereas acclimation at 20℃the CTMax was 39.8℃.In P.pelagicus acclimated,at 20℃the CTMax values after heat shock were significantly higher than crabs in control for 30 min,1 h and 1.5 h after heat shock.In the 25℃and 30℃acclimated crabs,the CTMax values after heat shock were significantly higher than control only in 30 min and 1 h after heat shock.No significant differences in 35℃acclimated crabs between control and heat shocked crabs were found after recovery for 30 min,1 h,or 1.5 h.Conclusions:Heat shock caused significant rises in the CTMax,however,this increase was progressively reduced with longer recovery times at the acclimation temperature.For 20℃acclimated crabs,the increased CTMax was still evident after 90 min,but for 25℃and 30℃crabs,the response was over after 90 min.Heat shock of 35℃crabs was problematical,the CTMax gave no increased thermotolerance.It must be concluded that the combination of a high heat shock temperature and CTMax determinations were too damaging.
