动物胚胎冷冻保存技术研究进展

胚胎冷冻保存一般指0~-80℃的温度下保存胚胎,而超低温冷冻保存则是在极低的温度(液氮-196℃、液氦-269℃)下保存动物胚胎。处于超低温下的胚胎,其新陈代谢几乎完全暂时停止,因而可以达到长期保存的目的。朱等(1998)对小鼠扩张囊胚在液氮中冷冻保存1h、1年和2年,解冻后的囊胚恢     

外源氮添加对湿地土壤N_2O排放量的影响

为搞清湿地土壤驱动N2O排放的关键氮源类型,有效减少湿地N2O的排放,本文通过室内控制温湿度,用气相色谱法分析不同外源氮素对湿地N2O排放的影响。结果表明:外加氮源组总是高于对照组N2O排放量(4.4 mg·m-3)。在设定的剂量范围内,单独添加尿素或尿素与硝酸铵1∶1配合时N2O排放量呈现先增后减的单峰分布趋势,峰值分别为10.6 mg·m-3和229.0 mg·m-3;单独添加硝酸铵时N2O排放量(32.6~111.0 mg·m-3)随着氮素添加量增加呈现持续上升趋势。单独添加尿素或硝酸铵、尿素与硝酸铵1∶1配合均促进N2O的排放,但硝酸铵尿素混合添加对N2O排放量的贡献单独添加硝酸铵单独添加尿素。这为预测内蒙古高原区农牧交错带湿地氮素输入可能带来的温室效应和有效减排提供科学依据。     

强改造区龙马溪组页岩气保存条件指数评价

研究区内龙马溪组页岩有机质类型以Ⅰ型和Ⅱ型干酪根为主,富有机质页岩厚度一般大于30m,总有机碳质量分数普遍大于2%,有机质总体仍处于过成熟阶段,岩石脆性矿物含量相对高、黏土矿物含量相对低,具低孔、渗特性,为页岩气成藏提供良好的物质基础;自中生代以来,研究区经历了5期构造运动,为强隆升、强剥蚀、强变形的强改造区;野外采集了海拔、地层出露特征、地层剥蚀情况、褶皱形态、节理及断裂特征、泉水及热液矿床的分布等资料,以海拔、剥蚀、倾角、变形、破裂5个指数定性半定量评价页岩气保存条件。结果表明:研究区西北部海拔较低,剥蚀量相对小,地层倾角相对较缓,变形强度、破裂强度相对小,页岩气保存条件好;东南部海拔虽低,但剥蚀量相对大,多为高角度地层,变形强度、破裂强度相对大,页岩气保存条件差。     

Effect of L-lysine Added in Diluent on the Fresh Semen Quality of Dorper Sheep

In order to explore the effect of different L-lysine levels added in semen dilution on the fresh Dorper sheep quality stored at liquid state,3 health Dorper ram were used to collect semen which were equal-packaged and added to solution containing different levels (0,0.1,0.2,0.3,0.4 and 0.5 g) L-lysine in 120 mL diluent and at 0,6,24,30,48,54,72 and 78 h,the sperm motility,membrane integrity and acrosome integrity were detected.The results showed that the sperm motility in groups added 0,0.1 and 0.2 g L-lysine were higher than other groups,and that in 0.4 and 0.5 g L-lysine groups decreased faster than other groups;The sperm motility in 0.5 g L-lysine group reduced to 0 at 30 h,and it reduced to 0 at 48 h in the group added 0.4 g L-lysine;The effective survival time and survival index in the group added 0.1 g L-lysine was higher than other groups (P< 0.05);The membrane integrity of 0.1 g group was the highest,that had no significant difference with control group from 0 to 54 h (P >0.05),while after 72 h the two groups had significant differences (P< 0.05).The membrane integrity in 0.4 and 0.5 g groups were the worst,and that was significant different with other groups (P< 0.05);The acrosome integrity of 0.1 g group was the highest which had no significant difference with control group (P >0.05),0.4 and 0.5 g groups were the worst,the difference between them was not significant (P >0.05),while was extremely significant difference with other groups except for 0 and 6 h (P< 0.01).The results suggested that dilution added a high concentration of L-lysine could inhibit sperm quality,when the count of L-lysine was more than 0.2 g,sperm quality was significantly decreased,adding 0.1 g L-lysine could improve Dorper sheep fresh sperm quality stored at liquid state.     

日光温室氮素减量对作物生长及土壤性质的影响

通过布置日光温室氮素追肥减量试验发现,减量追肥氮素施用降低大椒产量0.2%~11.32%,而追肥氮素减少10%~20%的施用量,大椒可基本维持高产,对畸裂果率、商品果率等指标影响较小;减少追肥氮素的施用,显著降低土壤硝态氮含量6.5%~48.5%,但对其他养分指标影响不明显。     

新疆兵团棉花种植的适度规模及其调控对策——基于第一师的实证分析

以新疆生产建设兵团棉产量最大的产棉区第一师的棉花种植现状为研究对象,对2000年之后的第一师植棉区的数据进行统计分析,探究其产量和面积的时序演变规律;运用柯布-道格拉斯生产函数,构建了第一师棉花收入的影响因素及其种植规模的相关模型,利用Stata 12软件进行回归分析,揭示第一师植棉户的适度种植规模.结果表明:土地面积的变化对植棉收入的影响较大,资本投入次之,劳动力投入最小;兵团第一师的棉花种植适度规模的下限为2.667 hm2;目前第一师已有75％左右的农户达到了此下限.大于2.667 hm2也可以作为兵团确定农户棉花适度种植规模和优化农业产业结构的依据.     

优化施肥对春小麦产量、氮素利用及氮平衡的影响

2009 ～ 2010年,在宁夏引黄灌区分别以宁春11号和宁春16号小麦为供试作物,利用田间试验研究了优化施肥(OPT)和习惯施肥(CON)对春小麦产量、氮素吸收利用和土壤硝态氮累积的影响,表观评估了土壤—小麦体系氮素平衡.结果表明,相对于CK处理,OPT和CON都显著提高春小麦籽粒产量地上部生物量,并促进籽粒N和地上...     

果树如何施用生物肥料

正果树品种很多,一生可分幼树期,结果初期,结果盛期、结果后期、衰老期等五个时期各期对营养元素的需求是不同的,在幼树期,由于根系和地上部生长旺盛,需要大量的氮磷补给:结果期,由于大量结果之需要,亦需要大量的氮钾供应,尤以盛果期为多,衰老期则养分需要趋势,但为促进更新复壮,保持树势,氮素供应不应过少。果树施肥最重要的环节是施用基肥。基肥的作     

水稻氮同化相关基因及氮高效利用水稻株型研究进展

提高水稻氮素利用率、减少氮肥投入一直是水稻种植者不懈追求的目标，充分发挥氮高效基因的作用可以提高氮素利用率。文章综述了水稻氮素同化相关基因的研究进展，总结了氮高效利用植株的形态及未来展望。     

几种肉牛能量饲料的介绍

1谷实类饲料 主要来源于禾本科植物的籽实,我国常用的有玉米、大麦、燕麦、黑麦、小麦、稻谷和高粱等。 玉米中所含的可利用物质高于任何谷实类饲料,在肉牛中使用的比例最大,因而被称为饲料之王。由于玉米的不饱和脂肪酸含量高,粉碎后的玉米粉易于酸败变质,不宜长期保存。