作 者 ：许雪峰,吴义莲,欧永跃,吴霖生
期 刊 ：生态学报 2008年 28卷 10期 页码：4782~4786
Keywords:Takydromus wolteri, egg, incubation, embryonic growth, mobilization of material and energy,
摘 要 ：研究白条草蜥卵在温、湿度分别为30℃、-12kPa的条件下，孵化过程中胚胎生长以及对物质和能量的动用。孵化过程中，每隔5d测定卵重。孵化第10、15、20天，分别解剖来自不同窝的卵15、15、12枚，分离为胚胎、卵黄和卵壳。初生幼体测量、称重后冰冻处死，随后解剖分离为躯干、剩余卵黄和腹脂肪体。所有材料65℃恒温干燥，用索氏脂肪提取仪测定脂肪含量，氧弹式热量计测定能量含量，马福炉测定无机物含量。白条草蜥卵的平均孵化期为24.7d。卵孵化时从基质中吸水导致重量增加。卵孵化0~15d、15~20d、20~24.7d，胚胎分别利用新生卵能量的11%、14%和75%。0~20d，胚胎生长缓慢；20d后生长迅速。卵孵化过程中，干重、非极性脂肪和能量的转化率分别为50.3%、24.9%和51.9%。初生幼体的能量组分为：躯干952%，脂肪2.2%，剩余卵黄2.6%。胚胎发育所需要的无机物来自卵黄和卵壳。结果显示，白条草蜥从卵到孵出幼体物质和能量较低的转化率主要与较高胚胎发育投资和较小的剩余卵黄有关。
Abstract:We incubated Takydromus wolteri eggs at 30℃ using wet vermiculite as the incubation substrate of which the moisture was kept at -12kPa, we paid particular attention to the embryonic growth and embryonic use of material and energy during incubation. Eggs were weighed at 5-day intervals to test for temporal changes in egg mass. From the tenth, fifteenth, twentieth day of incubation, we randomly selected 15,15,12 eggs from different clutches respectively, opened and separated them into shell, embryo and yolk. The three egg components were oven dried to constant mass at 65℃, weighed and preserved frozen for later determination of composition. Upon emergence, size and mass were measured on each hatchling. Hatchlings (n= 29) were then killed by freezing to -15℃ for later study. Upon thawing, we separated each hatchling into weighed and preserved frozen for later determination of composition. We extracted non-polar lipids from dried carcass, residual yolk and fat bodies. The three hatchling components were oven dried to constant mass at 65℃,samples in a Soxhlet apparatus for a minimum of 5.5 h using absolute ether as solvent. The amount of lipids in a sample was determined by subtracting the lipid-free dry mass from the total sample dry mass. The total lipid in each hatchling was calculated as the sum of the lipids in its carcass, residual yolk and fat bodies. We determined energy content of dried samples using an adiabatic bomb calorimeter and ash content in each sample using a muffle furnace at 700℃ for a minimum of 8 h and then weighing the remaining ash. The duration of incubation averaged 24.7 days in this study. Eggs increased in wet mass during incubation due to the absorption of water from the substrate. At the stage of 0-15, 15-20, 20-24.7 days of incubation, the developing embryos mobilized approximately 11%, 14% and 75% of the total egg energy in the yolk of the freshly laid egg, respectively. Embryos grew slowly during the first 20 days, the maximal embryonic growth occurred at the stage of 20-24.7 days of incubation. During incubation, approximately 50.3%dry material, 24.9%non-polar lipids and 51.9%energy in egg contents of the freshly laid egg were transferred to the hatchling. Of all energy in the newly emerged hatchling, 95.2%was in the carcass, 2.2%in fat bodies and 2.6 %in the residual yolk. Embryos used both yolk and eggshell as the sources of inorganic material for development. Our data show that the lower conversion efficiencies of energy and material from egg to hatchling in T. wolteri can be mainly attributed to their greater energetic costs of embryonic development and lower residual yolk sizes.
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