排序方式: 共有34条查询结果,搜索用时 15 毫秒
31.
Temperature-dependent sex determination (TSD) occurs in all major reptile lineages, but the selective forces and physiological mechanisms that link sex to incubation temperature may differ among and within those groups. Different models for TSD evolution make different predictions about when offspring sex will respond to environmental cues. Although TSD has evolved in several lizard lineages, there is less detailed information on these taxa than in turtles and crocodilians with TSD. We incubated eggs of an agamid lizard (Amphibolurus muricatus) and a scincid lizard (Bassiana duperreyi), two species with TSD. Rather than manipulate incubation temperature to identify periods of sexual lability (as in most previous studies of this topic), we topically applied the aromatase inhibitor fadrozole to eggs at a variety of times through the incubation period. Fadrozole application sex-reversed the resultant hatchlings if applied from the time of oviposition until at least 60% of the way through incubation. In all of the TSD lizard species studied so far, offspring sex is determined either while the eggs are held inside the mother's body or soon after oviposition, providing substantial maternal control over incubation temperatures at this critical period. Hence, the hypothesis that TSD evolves because it enables offspring sex to be matched to conditions that are unpredictable at the time of laying is less likely to apply to squamates than to turtles, sphenodontians, and (especially) crocodiles, in which the period of sexual lability is delayed until long after oviposition. 相似文献
32.
Seasonal variations in physico-chemical parameters and heavy metals in water and sediments of Uppanar estuary, Nagapattinam, India 总被引:2,自引:0,他引:2
Sankar R Ramkumar L Rajkumar M Sun J Ananthan G 《Journal of environmental biology / Academy of Environmental Biology, India》2010,31(5):681-686
The present study was carried out to determine the physico-chemical characteristics and heavy metals in water and sediments in Uppanar Estuary, Nagapattinam, Southeast coast of India during January to December 2007. The minimum and maximum values of atmospheric and surface water temperatures (degrees C), salinity (per thousand), pH and dissolved oxygen (ml l(-1)) were: 26.0-35.0; 25.0-33.5; 8.0-35.0; 7.2-8.2 and 2.8-5.5 respectively. The ranges of nitrate, nitrite, phosphate and silicate were: 7.05-24.23; 0.82-3.15; 0.31-2.18 and 40.0-198.0 (microM) respectively. The ranges of heavy metals in water (microg 1(-1)) and sediment (microg g(-1)) copper zinc, cadmium and mercury were: 2.45-18.25; 26.43-101.24; 1.23-24.35 and 0.01-0.22 and 5.02-81.27; 22.47-75.42; 2.25-10.06 and 0.01-0.16 respectively. 相似文献
33.
Pradeep Govind Shaijumon C. S. Rajkumar R. Pradeep Jayadev 《Environment, Development and Sustainability》2022,24(8):9929-9962
Environment, Development and Sustainability - India has the largest dairy industry in the world and accounts for a significant share of the global emission of livestock methane ( $$\hbox... 相似文献
34.
Sarella Chakravarthi Galipelli Rajkumar Sabavath Shankar 《Environmental science and pollution research international》2022,29(31):46570-46586
Environmental Science and Pollution Research - Cold recycling techniques emerged in road construction to recycle deteriorated pavements as bases and surfaces. A detailed review is carried out in... 相似文献