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21.
覆盖免耕在休闲期的节水和生育期的调温效应 总被引:10,自引:2,他引:8
对免耕覆盖、秸秆还田和常规耕作在休闲期的节水效果研究表明:在夏季休闲期,免耕覆盖比常规耕作多贮水30.62mm,比秸秆还田多23.91mm;在冬季储水灌溉期间,可将储水定额从2100m3/hm2减少到600和975m3/hm2。对春小麦生育期土壤表层,5、10、15、20和25cm处温度变化观测发现:免耕覆盖土壤温度在气温较低的8:00可以提高土壤表层温度,在气温较高的14:00可以减缓土壤温度的升高,而在19:00气温降低时可以减缓土壤温度的降低,使土壤温度一直保持在一个稳定的状态,这有利于调节农田小气候,创造作物良好的生长环境。 相似文献
22.
哺乳动物附植前胚胎的基因表达调控 总被引:4,自引:0,他引:4
哺乳动物胚胎附植前期包括:合子的形成,胚胎基因组的激活和细胞分化的开始。在这个时期,发育由母源物质控制转为合子基因控制,在此过程,同时形成染色质介导的转录抑制时期,要解除抑制必须经过胚胎基因组的激活。通过对体内、外附植前胚胎的mRNA的表达特点以及它们与成功发育联系的研究,可以筛选出最佳的体外培养条件,设计最佳的核移植方案。 相似文献
23.
灌溉水源是北方地区耕地后备资源能否有效开发的关键。当前,中国正在推动国家水网工程规划建设,为北方地区耕地后备资源开发提供了新的机遇。在以往研究基础上,该研究考虑北方地区已建、在建及规划的供水工程,基于自然适宜、利用高效、发展稳定三方面评价准则,结合三维魔方空间分类方法,开展了雨养情景和供水灌溉情景下耕地后备资源开发潜力分析。结果表明:雨养农业情景下,北方地区勉强适宜(Ⅱ级)、中度(Ⅲ级)和高度(Ⅳ级)适宜的耕地后备资源面积分别为2.9万、1.0万和0.6万km2。灌溉农业情景下,耕地后备资源面积明显增加,勉强适宜(Ⅱ级)、中度(Ⅲ级)和高度(Ⅳ级)适宜的耕地后备资源面积将分别达到5.4万、7.6万和6.5万km2,主要集中于新疆、内蒙古和甘肃3省(自治区)。该研究结果可为中国耕地后备资源开发利用及国家水网工程效益发挥提供参考。 相似文献
24.
试验分别用温汤去雄杂交和两种化学去雄剂化学去雄诱导草地早熟禾雄性不育,结果表明,在两种化学去 雄剂作用下去雄效果比较理想,温汤去雄雄性不育率达100%。 相似文献
25.
改良热硼酸法高效提取苹果果实RNA 总被引:17,自引:1,他引:17
苹果果实、尤其是成熟期的果实中多糖和其他次生物质含量高,难以提取RNA。对此,在原热硼酸法的基础上进行了改进,通过添加提取辅助剂并根据辅助剂特性调整提取步骤,高效、稳定地从苹果果实、尤其是后期果实中提取到了高质量的RNA。所得RNA的A260/A230大于2.0,A260/A280为1.8-2.1,并且RNA产量高,其中前期果实RNA产率在13.40μg/g以上,后期果实RNA产率在7.02μg/g以上,完全可以满足RT-PCR、cDNA-AFLP等分子生物学实验的要求。 相似文献
26.
AIM:To study influence of ischemia-reperfusion(IR) on apoptosis and expression of apoptosis-related genes Fas-L, Bax and Bcl-2 of sinoatrial node(SAN) cells in rabbits in vivo. METHODS:Ninety healthy adult rabbits were divided randomly into control group, ischemia groups (I10 min, I30 min, I60 min and I120 min) and IR groups (I10 minR4h, I30 minR4h, I60 minR4hand I120 minR4h). IR injury model of SAN was established by occluding and loosening the start section of right coronary artery. The apoptosis of SAN cells was detected by TUNEL staining. The expression of Fas-L, Bax and Bcl-2 of SAN cells was detected by immunohistochemistry. RESULTS:①No obvious apoptosis of SAN cells was observed in control group, I10 min and I30 min groups. Apoptosis of different degrees in SAN cells were found in 68.3%(41/60) rabbits in I60 min, I120 min and 4 subgroups of IR. ②The highest expression of Fas-L and Bax was observed in I120 min group and that of Bcl-2 was in I60 min group. ③The highest expression of Fas-L and Bax was observed in I60 minR4h group. The peak level of Bcl-2 was observed in I30 minR4h group. ④The expression of Fas-L and Bax was significant higher in IR group than that in ischemic group at the same time point. CONCLUSION:Ischemia and IR induced apoptosis of SAN cells in rabbit in vivo. Fas-L、Bax、Bcl-2 may participate in the regulation of apoptosis and the injury during IR aggravates the apoptosis of SAN cells. 相似文献
27.
AIM:To explore the expressive profile of nestin protein in the focal ischemic brain and to study the recovery mechanism of brain focal infarct.METHODS:Cellular morphology,time-course and distribution pattern of nestin positive response were immunohistochemically examined in different brain regions of 36 adult male SD rats. RESULTS:Nestin positive response of different brain regions in sham operated rats was present in small- and micro-vasculartures and the third ventricle bottom and ependyma. A large number of nestin positive cells were detected in ischemic brain, and were more remarkable in the cortical areas of parietal lobe and preoptic area as well as ischemic caudoputamen. Stellate nestin positive cells were located in the deep layer of ischemic cortex, but fibrillary cells were located in the shallow layer. Nestin positive cells in the ischemic caudoputamen showed the same changes of morphology as those cells in the deep layer of ischemic cortex. Morphological and number alterations of nestin positive cells were the most remarkable at 1 weeks post-ischemia, which showed more hypertrophy and proliferation in morphology, and a marked increase in number was present in the ischemic cerebral cortex and the ischemic caudoputamen. These alterations of nestin positive cells persisted up to 6 weeks post-ischemia, and then, the nestin positive response in the ischemic brain decreased gradually.CONCLUSION:Focal cerebral ischemia induces nestin re-expression on reactive astrocytes, which may be very important to the self-recovery of cerebral infarct. 相似文献
28.
CHEN Ya-hong ZHAO Ming-wu FU Min-gui YAO Wan-zhen WANG Xiao-hong WANG Jian-li TANG Chao-shu 《园艺学报》2002,18(2):157-160
AIM:To investigate the role of calcineurin (CaN) in airway remodeling in guinea pig model of asthma.METHODS:Male guinea pigs were randomly divided into three groups: control, asthma group and CsA group. The following parameters were measured: 1. The protein content, cell count and differential count of BALF; 2. The amount of [3H]-TdR incorporation into central airway smooth muscle; 3. The mean thickness of airway wall and airway smooth muscle of small airwaysl; 4.CaN activity of trachea and lung tissue.RESULTS:1. The protein content, cell count and eosinophil of BALF in CsA group were 46%, 51% and 60% lower than those in asthma group, respectively (P<0.01); 2. [3H]-TdR incorporation in CsA group was 22% lower than that in asthma group (P<0.05);3. The mean thickness of airway wall and airway smooth muscle were 34% and 37% less in CsA group than those in asthma group, respectively (P<0.01); 4. CaN activity of lung tissue and trachea were 52% and 44% lower in CsA group than those in asthma group, respectively (P<0.01).CONCLUSION:CsA reduced airway remodeling in guinea pig model of asthma, indicating the role of CaN in the airway remodeling. 相似文献
29.
ZHENG Hui LI Hong-yi WANG Zi-neng ZHAO Ying-she YU Li HE Si-cun BAI Zhi-quan ZHOU Zuo-yan YAO Ping WANG Yue-chun 《园艺学报》2002,18(5):553-555
AIM: The purpose of the present study was to explore the relationship between interleukin-6 mRNA expression and endometriosis. METHODS: Using the rat model, IL-6 mRNA expression in the endometrium was examined by RT-PCR. RESULTS: The expression of IL-6 mRNA in control rats did not change at 2, 4, 6 and 8 weeks after sham operation (P>0.05), but in model rats it gradually increased at 2, 4, 6 and 8 weeks after endometriosis (P<0.01). The expression of IL-6 mRNA in uterine endometrium with endometriosis was lower than in endometriotic tissue, but higher than in endometrium from healthy controls. CONCLUSION: The IL-6 mRNA expression may contribute to the development of endometriosis . The increase in IL-6 mRNA expression may promote the implantation and growth of endometriotic tissue. 相似文献
30.
AIM: To observe the expression of undulin (Un) in liver tissue and to clarify the diagnostic significance of serum Un in experimental rat liver fibrosis. METHODS: Rat liver fibrosis was induced by carbon tetrachloride. The expression of Un in liver tissue was detected by immunohistochemical method. Serum Un levels was measured by enzyme immunoassay. RESULTS: Expression of Un increased in fibrotic liver than normal liver, and it was mainly distributed in portal tract stroma, central veins and fibrotic septa in fibrotic liver. Also, the level of serum Un was significantly higher in fibrotic liver than normal liver. CONCLUSION: These data suggest that Un should be a component of the hepatic extracellar matrix, and its expression could be increased greatly in fibrotic rat liver. Serum Un levels may be used as an indicator in liver fibrosis diagnosis. 相似文献