摘要
研究红耳滑龟 ( Trachemys scripta elegans)当年孵出幼体的热耐受性和运动表现热依赖性 ;设计具有和缺乏温度梯度两种热环境 ,研究幼龟体温昼夜变化和体温调节。高、低温耐受性分别用临界高温和临界低温表示 ,体温为泄殖腔温度 ,水温和气温分别是幼龟所处位置的水温和 1 cm高气温。临界高温和临界低温分别为 41 .9℃和 1 .6℃。在有温度梯度的热环境中 ,体温、水温和气温平均值有显著的昼夜差异 ,水温和体温的日平均值无显著差异 ,两者均大于气温的日平均值。在缺乏温度梯度的热环境中 ,体温、气温和水温平均值亦有显著的昼夜差异 ,但气温、水温和体温的日平均温度无显著差异。温度梯度是幼龟进行体温调节的必要条件 ,体温调定点 (选择体温 )有显著的昼夜变化 ,最大和最小值分别为 30 .4℃和 2 6.6℃。在0 0 :0 0～ 1 0 :0 0时间段内 ,幼龟选择体温明显较低 ,其它测定时刻的选择体温无显著差异。幼龟各测定时刻的平均体温与平均气温和水温均呈正相关。去除气温差异的影响后发现 ,处于温度梯度中幼龟的体温比处于缺乏温度梯度中的幼龟高 2 .0℃ ,这种差异是前者利用温度梯度进行体温调节的结果。去除水温差异的影响后发现 ,处于温度梯度中幼龟的体温比处于缺乏温度梯度中的幼龟高 1 .0℃。体温显著影响?
We studied thermal tolerance, body temperature, and thermal dependence of locomotor performance of hatchling red eared slider turtles ( Trachemys scripta elegans ). Two thermal environments, one with and the other without thermal gradients, were designed to study diel variation in body temperature (Tb) . Turtles were obtained from a pet shop in Hangzhou, with body mass, carapace length and carapace width being 9 5 ± 0 2 (7 7~11 1) g, 35 6 ± 0 2 (32 7~37 4) mm and 35 3 ± 0 2 (33 6~36 9) mm, respectively. Turtles were marked individually by toe clipping for future identification, and then were housed, 7~8 of them, in individual 50×30×30 cm 3 (length × width × height) glass cages, of which the bottom was filled with an oblique layer of sand (the maximum depth = 5 cm), water (the average depth = 2 5 cm) and debris to mimic natural conditions to some extent. The thermal gradients ranging from 18 °C to 60 °C were established by suspending two 250 W light bulbs at one end and approximately 20 cm above the bottom of the cage. Turtles in the environments either with or without thermal gradients were exposed to a natural light cycle, but those in the thermal gradients could regulate body temperatures within their voluntary range when the light bulbs were turned on. Body (cloacal temperature), water ( Tw, where turtles were measured for Tb ) and air ( Ta , 1 cm above the turtle measured for Tb ) temperatures were taken to nearest 0 1 °C, using a RC(95 electronic thermometer (Shanghai Jinghua Instruments, China), at intervals of 4 h in two consecutive days. The mean body temperature of active turtles in the thermal gradients was considered as the selected (or preferred) body temperature ( T sel) at the time. The upper ( CT Max, critical thermal maximum) and lower ( CT Min, critical thermal minimum) limits of thermal tolerance were determined in a LRH 250G incubator (Guangdong Medical Instruments, China), where turtles were cooled or heated from 28 °C at the rate 0 1 °C per min. During the experiments, we observed the behavior of the experimental turtles through a window on the door of the incubator. Body temperatures associated with a transient loss of righting response (the animals did not respond to intense mechanical stimulation and could not turn back when being turned over) at lower and upper thermal limits were used as endpoints for CT Min and CT Max. Locomotor performance was tested at 8 constant body temperatures (18, 22, 25, 30, 33, 36, 39 and 41 ℃), the sequence being randomized. Prior to each trial, turtles were placed in an incubator for a minimum of 4 h, thereby controlling their body temperatures at the expected level. Locomotor performance was assessed by chasing the turtles down a 200×10×15 cm 3 racetrack with one side transparent, which allow lateral filmation with a digital video camera (Panasonic NV DS77). It was always the same person (the second author) who chased the turtles, thereby standardizing the stimulus. The video tapes were later examined using the MGI VideoWave III software for sprint speed in the fastest 25 cm interval, number of stops in the racetrack and the maximum length of continuous locomotion. CT Max and CT Min were 41 9℃ and 1 8℃, respectively. Diel variation in body, water and air temperatures were found in the environments both with and without thermal gradients. In the environment with thermal gradients, the daily means of body and water temperatures were nearly the same, both being greater than the daily mean air temperature. In the environment without thermal gradients, body, water and air temperatures did not differ from each other in the daily mean value. The existence of thermal gradients is a necessary for turtles to regulate body temperatures within their voluntary range. T sel varied from 26 6 ℃ to 30 4 ℃, and it was lower during the period of 00:00 ～ 10:00 and higher at the other time phase in a 24 h cycle. Body temperatures were positively correlated with both water and air temperatures. An ANCO
出处
《生态学报》
CAS
CSCD
北大核心
2003年第6期1048-1056,共9页
Acta Ecologica Sinica
基金
浙江省 1 5 1人才基金
杭州市跨世纪人才基金资助项目~~
关键词
红耳滑龟
初生幼体
体温
选择体温
热耐受性
体温调节
运动表现
red eared slider turtle ( Trachemys scripta elegans )
hatchling
body temperature
selected body temperature
thermal tolerance
thermoregulation
locomotor performance
