陕西省退耕还林工程区植被覆盖度的变化分析

利用MODIS NDVI数据和像元二分模型计算的植被覆盖度,比较分析退耕还林工程区与周边区域、主要土地利用类型、不同坡度耕地植被覆盖度变化程度和趋势。结果表明：（1） 陕西省退耕还林区植被覆盖度从2000年到2011年呈现显著的增长趋势,增长速率高于周边区域;（2） 退耕还林区植被覆盖变化百分率≥10%的面积占79.8%,≤-10%所占面积不及1%;（3） 退耕还林区植被覆盖度显著增加的面积占其总面积的70.6%,显著减少的面积仅占0.1%,植被覆盖度显著增加的情况主要出现在未利用地、草地、林地和耕地,显著和极显著降低的发生在城乡、工矿、居民用地和极少部分耕地;（4） 坡耕地植被覆盖改善比例大,坡耕地植被覆盖改善对于耕地植被改善贡献较大。在陕西省气候呈现暖干化发展趋势背景下,退耕还林区植被覆盖度呈现显著增长趋势,增长速率高于周边区域,坡耕地、林地、草地均比其他类型有明显的增加,退耕还林政策实施区域取得了良好的植被恢复效果。     

Lentivirus-mediated calcitonin gene-related peptide transfection enhances endothelial differentiation of rat bone marrow mesenchymal stem cells

AIM：To study the effect of calcitonin gene-related peptide (CGRP) gene transfection mediated by lentivirus on the differentiation of rat bone marrow mesenchymal stem cells (MSCs) to endothelial cells. METHODS：Rat bone marrow MSCs were isolated by density gradient centrifugation combined with adherence method. Recombinant lentivirus vector carrying CGRP gene (Lenti-CGRP) was transfected into the MSCs. The secretion of CGRP in culture supernatants of the transfected MSCs was detected using ELISA method. The cells at passage 3 were divided into three groups: CGRP group (MSCs transfected with Lenti-CGRP), CGRP+CGRP8-37 (an antagonist of CGRP receptor) group and control group (MSCs transfected with PBS). The differentiation of the MSCs was detected by immunocytochemical staining for CD31 and factor Ⅷ-related antigen. The proliferation of the cells was measured by cell counting, and the angiogenic ability of the cells was analyzed using Matrigel assay. RESULTS：The proportion of CD31-and factor Ⅷ-related antigen-positive cells in CGRP and CGRP+CGRP8-37 groups was larger than that in control group (P<0.05). The numbers of the cells in CGRP and CGRP+CGRP8-37 groups were significantly increased compared with control group (P<0.05). Lumen-like structures were observed in CGRP and CGRP+CGRP8-37 groups. The above indexes in CGRP+CGRP8-37 group were reduced compared with CGRP group. CONCLUSION: Transfection with CGRP gene induces rat bone marrow MSCs to differentiate into endothelial cells and enhances their proliferation, suggesting that CGRP may play a role in the regulation of angiogenesis.     

Effects of up-regulation of c-myc expression on U937 cell line

AIM:To establish a human monocytic　leukemia cell line U937 stably expressing c-myc gene and to investigate the biological characteristics of this cell line. METHODS:The recombinant plasmid MSCV-c-myc-IRES-GFP (MMIG) was constructed. MMIG and MSCV-IRES-GFP (MIG) were used to package the viruses for infecting U937 cells. Fluorescence-activated cell sorter (FACS) was used for sorting U937/GFP and U937/MYC cells. The GFP-positive cells were detected by fluorescence microscopy and FACS. The protein expression of c-Myc, survivin, X-linked inhibitor of apoptosis protein (XIAP) and Bcl-2 was detected by Western blotting. Cell proliferation was evaluated by MTT assay. Propidium iodide (PI) staining was used to determine the cell cycle distribution. Self-renewal ability was observed by colony- forming assay. RESULTS:The GFP expression in the cells infected with MIG or MMIG virus was observed under fluorescence microscope. The green fluorescent rate of the cells infected with MIG was 26.0%, while that of the cells infected with MMIG was 27.7%. The protein expression of c-Myc in MMIG-infected U937 cells was higher than that in MIG-infected cells. After sorting, the green fluorescent rates of U937/GFP and U937/MYC cells reached 98.7% and 93.7%, respectively. The protein expression of c-Myc in U937/MYC cells was higher than that in U937/GFP cells. In addition, survivin, a downstream protein of c-Myc, was up-regulated, while the protein expression of XIAP and Bcl-2 remained unchanged. Cell cycle analysis showed that the percentage of the cells in S phase increased in U937/MYC cells. Moreover, the proliferation and colony-forming ability of U937/MYC cells were also enhanced. CONCLUSION: U937/MYC cell line stably expressing c-myc gene was successfully established. c-Myc may increase cell viability via enhancing the expression of anti-apoptotic protein survivin, the cell cycle transition and the self-renewal ability.     

基于SCoT 标记的芥菜种质遗传多样性与指纹图谱

利用SCoT 标记对46 份芥菜种质资源进行遗传多样性分析。从70 条引物中筛选出21 条用于PCR 扩增,共扩增出200 条条带,其中多态性条带140 条,多态性比率为70%。供试材料相似系数介于0.77～0.95 之间,平均Nei’s 基因多样性为0.198,平均Shannon 信息指数为0.301,平均多态信息含量为0.822 7。利用UPGMA 构建46 份芥菜种质资源的聚类树状图,在相似系数D1=0.780 处,可以将46 份芥菜种质分为两大类;而在D2=0.807 处,第Ⅱ类可进一步细分为5 个亚类。选出清晰的16 个多态性位点,构建46 份芥菜种质的SCoT 指纹图谱,结果由引物SP4、SP19、SP20、SP23、SP30 所构建的DNA 指纹图谱可将供试材料完全区分开。     

管道输液对龙眼的产量及果实品质的影响

以"桂香"、"早熟一号"龙眼品种为试材,比较了管道输液施肥和常规土施对龙眼果实生长、产量和果实品质的影响。结果表明:管道输液显著提高了果实品质,果实纵横径、单果重、单株产量、可食率、可溶性固形物和可溶性糖含量均优于土施处理。"桂香"和"早熟一号"龙眼的输液处理比土施处理的纵径分别提高了3.24、2.40mm,横径分别提高了0.72、2.45mm;"桂香"和"早熟一号"龙眼的输液处理比土施处理的单果重分别提高了19.57%、20.28%;单株产量分别提高了23.23%、5.73%;可食率分别提高了4.45%、5.27%;可溶性固形物含量分别提高了10.83%、17.24%;可溶性糖含量分别提高了18.89%、10.48%。管道输液还有效地提高了龙眼果实矿质营养元素N、K、Ca的含量,但对果实矿质营养元素P和Mg的含量影响不明显。"桂香"和"早熟一号"龙眼的输液处理比土施处理的果实N含量分别提高了17.37%、23.27%;果实K含量分别提高了12.93%、17.30%;果实Ca含量分别提高了32.33%、16.96%。     

采收期对“徐香”猕猴桃果实品质的影响

以"徐香"猕猴桃为试材,研究了盛花期后97、104、111、118、125、132、139和146d(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ、Ⅶ、Ⅷ)不同采收期的"徐香"猕猴桃果实在常温(20～22℃)下的后熟品质,探讨"徐香"猕猴桃最适采收期。结果表明:早期采收(Ⅰ、Ⅱ、Ⅲ、Ⅳ)时,果个小、果实可溶性固形物和干物质含量较低,可滴定酸含量偏高,糖酸比偏低,后熟软化过程中的失重率、腐烂率也较高。晚期采收(Ⅶ、Ⅷ)的果实个大,可溶性固形物、干物质、总糖、糖酸比高,但果实后熟软化期明显缩短,失重率和腐烂率增加。盛花后125～132d(Ⅴ、Ⅵ期)采收的果实,果实可溶性固形物达6.67%以上,维生素C含量、糖酸比、果实硬度较高,失重率、腐烂率低,表明其为"徐香"猕猴桃的适宜采收期。     

DTOPSIS法在综合评价水稻新品种中的初步应用

以广东省2002年早季杂交水稻(中熟组)区试资料为例,探讨了DTOPSIS法在水稻新品种综合评价中的应用.结果表明,该法分析结果与区试常规分析结果基本一致,但该法比单用产量分析更为合理.对DTOPSIS法在水稻新品种综合评价中的有关问题进行了讨论.     

邵东县有机肥料资源利用现状及对策

在目前化肥投入增大的情况下,增加使用有机肥料,可提高土壤肥力,保护农业生态环境,促进无公害农产品生产,推进农业可持续发展.通过对邵东县有机肥料资源情况和利用现状的调查和分析,总结了当前有机肥料利用的经验和存在的主要问题,指出了有机肥料发展的方向和对策.     

基于机械零件腐蚀寿命的模糊可靠性计算

论述了腐蚀的分类、机理及影响因素,提出机械零件腐蚀深度的测量值呈正态分布,并依据机械零件腐蚀的基本规律及其模糊性,建立了数学模型,推导了机械零件耐腐蚀性的模糊可靠性计算公式,结合实例,编写了机械零件耐腐蚀模糊可靠度计算的Matlab程序,为预测机械零件剩余寿命提供参考。     

水解羽毛粉替代豆粕饲喂生长猪的效果研究

选用20kg左右的DLY生长猪64头,随机分为4个处理,每个处理4个重复,每个重复4头,分别饲喂基础日粮、添加2%、4%、6%水解羽毛粉（等蛋白替代豆粕）的日粮。结果表明,随着试验日粮中水解羽毛粉添加量的提高,试验猪的日采食量和日增重降低,而料肉比上升,并且6%处理组差异达到显著（P〈0.05）;各处理组的干物质表观消化率、蛋白质表观消化率和有机物表观消化率均差异不显著（P〉0.05）,而氮的表观生物学价值和净蛋白利用率随着水解羽毛粉添加量的提高明显降低,并且6%处理组的净蛋白利用率显著低于对照组（P〈0.05）和2%处理组（P〈0.05）;2%处理组的单位增重饲料成本较对照组降低0.20元/kg。