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93.
牛早期胚胎体外发育条件的研究 总被引:5,自引:0,他引:5
本试验研究了精卵共育时间和培养液等因素对牛早期胚胎体外发育的影响。精卵共育6~12h能显著提高受精卵的囊胚发育率,受精卵的囊胚发育率为23.2%~25.3%,共育时间为24h时,囊胚发育率降低,但精卵共育6h时卵裂率较低;TCM199、mBECMaa、mSOFaa均能支持体外受精卵的发育,其囊胚发育率分别为18%、30.7%和29.2%。试验结果表明:精卵于BM受精液中共育9h后,将其置于添加5%OCS的mBECMaa或mSOFaa中培养,能得到较高的体外生产胚胎的囊胚发育率。 相似文献
94.
Soil CH4 production potentials were investigated by incubating air-dried soils under anaerobic conditions in the laboratory. Twenty-eight
soils from different fields and locations were collected for this study. Soil CH4 production during a 100-day incubation differed greatly and were significantly correlated with soil organic content (r=0.61, P<0.01). The statistical significance increased when soils were grouped according to soil reduction rates. A significant correlation
was also found between CH4 production and total N content (r=0.64, P<0.01) and between CH4 production and soil particle sizes of 0.25–0.05 mm (r=0.48, P<0.05). A negative exponential correlation was found between CH4 production and aerobic soil pH (r=–0.74, P<0.01). The 28 soils were stratified into four groups on the basis of variation in CH4 production rates which were associated with the soil reduction rate and soil organic content. The faster the Eh of soil fell,
the more CH4 was formed. Adding rice straw to Hangzhou and Beijing soils increased CH4 production. The increase in CH4 production was more pronounced in the soil with the lowest organic matter content and slowest reduction rate than in the
soil with highest organic matter and fastest reduction rate. Inorganic fertilizer had no significant influence on CH4 production potentials of either type of soil.
Received: 26 November 1997 相似文献
95.
2018年4~6月,在武汉市黄陂区境内对青头潜鸭的繁殖行为进行了初步观察,以了解青头潜鸭在该区域的繁殖生境、繁殖行为及繁殖受胁情况等。采用定点观察法观察繁殖前期行为,对2巢青头潜鸭采用录像监控法记录孵化行为及出雏情况。测量了2巢及卵特征参数。发现青头潜鸭4月中旬开始分群,求偶交配,5月初基本完成配对,6月下旬出雏。巢为圆形碗状水面浮巢,巢材主要为草叶及草茎,巢内径(13. 5±7. 78) cm,巢外径(35. 5±6. 36) cm,巢高(21. 5±4. 95) cm,巢深(9. 5±0. 71) cm,窝卵数8~9枚,平均(8. 5±0. 71)枚(n=2);平均卵重(37. 32±4. 82) g,卵长径(50. 94±1. 75) mm,卵短径(37. 32±1. 41) mm(n=17)。孵卵期23~27 d,孵化率为17. 6%。青头潜鸭繁殖受人类活动干扰威胁较为严重,应当加大保护力度。 相似文献
96.
不同孵化温度对雏番鸭第二性比及孵化率的影响研究 总被引:2,自引:0,他引:2
试验研究孵化前期(1~10d)7个不同温度(36.3~39.3℃)对雏鸭出壳时第二性比(♂∶♀)和受精蛋孵化率的影响结果表明,不同孵化温度出壳的雏番鸭公母性别存在明显差异(P<0.01),且公雏率随温度升高而升高,母雏率随温度升高而下降;孵化前期温度为36.3~37.3℃时出壳雏番鸭公少于母,第二性比介于0.24~0.95;而孵化前期温度为37.8~39.3℃时出壳雏番鸭公多于母,第二性比为1.39~5.38;且只有在温度37.3℃和37.8℃时第二性比与遗传性比(1∶1)无差异(P>0.05),而其他温度时第二性比均表现明显差异(P<0.05或P<0.01)。雏番鸭第二性比与孵化前期温度间相关指数R2为0.99,预测误差率为-34.88%~ 14.58%间,说明调控孵化温度可在一定程度上控制雏番鸭第二性比,孵化温度对受精蛋孵化率有明显影响,36.3~37.8℃内孵化率随温度的升高而升高,在37.8~39.3℃内则随温度的升高而降低。 相似文献
97.
《Communications in Soil Science and Plant Analysis》2012,43(12):1417-1424
ABSTRACTSoil salinity and sodicity are two important factors in land degradation, especially in arid and semi-arid regions of the world. Application of soil amendments, such as organic matter, can be a suitable method for improving the fertility of saline-sodic soils. In this research, a saline-sodic soil was chosen, mixed with three levels of 1%, 3%, and 5% (weight) of Cow manure, Vermicompost, and Azolla, and incubated for 5 months at field capacity and a temperature of 20°C. Then, safflower seeds were planted and treatments were placed in a greenhouse for two months. After this period, plant indices were measured. The results showed that the addition of treatments caused differences in safflower growth in comparison to the control treatment. The noted differences were mostly negative for the treatment of cow manure, they were negligible for Azolla, and were positive for Vermicompost. Vermicompost applied at 5% level provided the most suitable substrate for safflower growth in saline-sodic soil. 相似文献
98.
[目的]研究No051内生真菌次生代谢产物量与培养时间的关系。[方法]以从辽宁省西北地区根系土壤中分离得到的No051内生真菌为材料,对其进行液体培养,分别在培养5、9、13、17、21和25 d后进行次生代谢产物干物质量的测定,同时进行高效液相色谱分析。[结果]液体培养9 d为次生代谢产物产生的高峰期;高效液相色谱分析表明该时期产生的次生代谢产物中包含的活性物质较多。[结论]该研究为No051内生真菌次生代谢产物的进一步研究提供了理论依据。 相似文献
99.
100.
Controversial conclusions from different studies suggest that the decomposition of old soil organic matter (SOM) is either more, less, or equally temperature sensitive compared to the younger SOM. Based on chemical kinetic theory, the decomposition of more recalcitrant materials should be more temperature sensitive, unless environmental factors limit decomposition. Here, we show results for boreal upland forest soils supporting this hypothesis. We detected differences in the temperature sensitivity 1) between soil layers varying in their decomposition stage and SOM quality, and 2) inside the layers during a 495 day laboratory incubation. Temperature sensitivity increased with increasing soil depth and decreasing SOM quality. In the organic layers, temperature sensitivity of decomposition increased during the early part of a 495 day laboratory incubation, after respiration rate and SOM quality had notably decreased. This indicates that decomposition of recalcitrant compounds was more temperature sensitive than that of the labile ones. Our results imply that Q10 values for total heterotrophic soil respiration determined from short-term laboratory incubations can either underestimate or overestimate the temperature sensitivity of SOM decomposition, depending on soil layer, initial labile carbon content and temperature range used for the measurements. Using Q10 values that ignore these factors in global climate models provides erroneous estimates on the effects of climate change on soil carbon storage. 相似文献