将体质量（125．60±19．84） g的红耳龟饲养在盐度为5、15、25、35和自来水的水泥池中，进行了90 d的盐度对其胁迫试验。试验结果表明，除胃组织中的Na＋/K＋-ATP酶活性随盐度的升高而显著下降（P＜0．05）外，红耳龟的肠、肝脏及肌肉组织中的Na＋/K＋-ATP酶活性均随时间的延长先升后降，在盐度为5时达到最大值；胃蛋白酶活性随盐度的升高呈先升后降的趋势，在盐度5时活性最高，盐度25时酶活性不及对照组的1/2；肝脏脂肪酶活性随盐度的升高呈现下降-升高-下降的趋势，且在盐度15时活性最高，肠脂肪酶和肠淀粉酶活性随着盐度的升高而下降。高盐（＞15）显著抑制红耳龟消化酶和Na＋/K＋-ATP酶的活性，影响其生长存活，但低盐（5以下）环境在一定程度上激活红耳龟消化酶和Na＋/K＋-A T P酶的活性，可正常存活3个月以上。红耳龟有可能入侵到更多水域包括半咸水水域。
Effects of Salinity on Na+/K+-ATPase and Digestive Enzyme Activities of Turtle Trachemys scripta elegans
Turtle Trachemys scripta elegans with initial body weight of (125 .60 ± 19 .84) g were reared in a concrete tank at a salinity of 5 ,15 ,25 ,and 35 and freshwater for 90 days .The Na+ /K+-ATPase activi-ties in intestine ,liver and muscle were found to be increased firstly and then decreased with elapse of salin-ity stress ,the maximum at a salinity of 5 .In the stomach ,however ,Na+ /K+-ATPase activity was weak-ened with increase in salinity significantly (P<0 .05) .The pepsin activities were consistent with the chan-ges of ambient salinity and all increased firstly then decreased ,the maximum at a salinity of 5 ,and the he-patic lipase activity was decreased firstly and increased secondly ,and then decreased ,the maximum at a salinity of 15 .Intestinal lipase and amylase activities were weakened with increase in salinity .It is conclu-ded that high salinity (over 15) led to inhabit Na+ /K+-ATPase activity ,thus mortality of the turtle . However ,since low salinity (below 5)promoted Na+ /K+-ATPase activity ,and hence the turtle can sur-vive in low salinity (a salinity of below 5) waters more than 3 months .It is speculated that the turtle could invade in a wide range of waters ,even brackish water .
Trachemys scripta eleganssalinity stressdigestive enzymeNa+/K+-ATPase
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