不同地下水位植物蒸腾耗水特性研究   总被引：20，自引：6，他引：20  

赵明  郭志中  王耀琳  李爱德  张德魁  贾宝全 《干旱区研究》2003,20(4):286-291

在甘肃省民勤治沙站利用非称量测渗仪研究了梭梭、柠条等 10种沙区植物的蒸腾耗水特征。结果表明 ,各种植物 5a的总蒸腾量由大到小排列为 :沙枣、花棒、沙木蓼、柠条、梭梭、白皮沙拐枣 ;随植物年龄增长 ,蒸腾系数有上升的趋势 ,而蒸散系数有下降的趋势 ;在民勤沙区 6～ 9月是主要蒸腾季节 ,该时段的蒸腾量占全年蒸腾量的80 %～ 90 % ;植物的蒸腾量随年龄的增长而迅速增加 ,但增长幅度随物种不同而异。一般生长快的植物增长快 ,生长慢的植物增长慢。  相似文献   

沙漠化过程土壤种子库特征的研究   总被引：13，自引：5，他引：13  

赵丽娅  李锋瑞 《干旱区研究》2003,20(4):317-321

采用野外定点取样与室内萌发实验相结合的方法 ,研究了 4种不同类型退化沙地土壤种子库特征 ,主要结论是 :(1)土壤种子库密度随沙漠化程度的增加而下降 ,不同沙漠化发展阶段下降速率不同 ,从固定到半固定沙地是种子库密度衰减最快的时期 ;(2 )土壤种子库植物种数从固定到半流动沙地变化很小 ,半流动到流动沙地衰减速度明显加快 ,是种子库植物种数衰减最快的时期 ;(3) 4种类型退化沙地土壤种子库的种类组成以 1、2年生草本植物为主 ,所占比例 79%～ 88% ,多年生草本和灌木所占比例很小 ;(4 )土壤种子库物种多样性指数并非随着沙漠化程度的增加而下降 ,其中半流动沙地的物种多样性指数最小 ;(5 ) 4种类型退化沙地土壤种子库组成上的相似性系数变化范围为 0 .82 9～ 1.0 0 0 ,表现出较小的空间异质性。  相似文献   

Inhibitory effects of LDL-ACM complex on subcutaneous implanted tumors in nude mice()     

JIANG An-li  KANG Lu-dong  ZHAO Chun-hua  BI Wen-xiang  HU Xiao-yan  KONG Feng  XU Song-de 《园艺学报》2003,19(1):55-58

AIM: In order to evaluate the applicable value of LDL as a targeted vehicle for chemotherapeutic agents, we investigated and compared the inhibitory effects of LDL-ACM complex and free ACM on nude mice's subcutaneous implanted tumors derived from gastric cancer cell lines, SGC-7901 and NKM-45. METHODS: LDL-ACM complex was prepared and the tumor model of nude mice was established by subcutaneous implantation of SGC-7901 and NKM-45. Then, the groups of nude mice developed subcutaneous implanted tumors were received either LDL-ACM complex or free ACM. Subsequently, the tumor size, weight and leukemia cell counts were measured and the rates of tumor-inhibition and the survival were compared among the groups. RESULTS: The inhibitory effects of LDL-ACM complex on the tumors, especially on SGC-7901 implanted tumors were much more obvious than that of free ACM. It was also indicated that the action of LDL-ACM complex was mediated by LDL receptor. CONCLUSION: These results showed that LDL-ACM complex had significant inhibitory effects on the implanted tumors and the effect might be mediated by LDL receptor.  相似文献   

Effect of adenosine on myocardial expression of TNF-α, IL-6 mRNA in rats with pneumonia     

TAN Jian-xin  HUANG Yu-ge  HUANG Xiu-lan  HE Hui-juan  ZHAO Jia-ming 《园艺学报》2003,19(10):1403-1406

  相似文献   

Gene Flow Analysis of Phytophthora porri Reveals a New Species: Phytophthora brassicae Sp. Nov.     

Willem A. Man in 't Veld  Arthur W.A.M. de Cock  Elena Ilieva  C. André Lévesque 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(1):51-62

Isozyme analysis and sequence analysis of the internal transcribed spacer regions (ITS-1 and ITS-2) and the 5.8S subunit of the ribosomal DNA gene repeat were used to examine whether isolates of Phytophthora porri from Allium and Brassica represent a single homogeneous species. Twenty-six strains of P. porri, 16 strains isolated from the genus Allium, and 10 strains isolated from the genus Brassica, were analyzed using malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH) and lactate dehydrogenase (LDH), represented altogether by four putative loci (Mdh-2, Idh-1, Idh-2, and Ldh-2). Isozyme analysis revealed that strains isolated from Allium contained five private alleles at three isozyme loci (Ldh-2 ⁸³, Ldh-2 ¹⁰⁴, Idh-1 ¹⁰⁸, Idh-1 ¹¹², and Idh-2 ⁹⁸), whereas six different alleles were observed at four isozyme loci (Ldh-2 ⁸⁵, Ldh-2 ¹⁰⁰, Ldh-2 ¹¹⁴, Idh-1 ¹⁰⁰, Idh-2 ¹⁰⁰, and Mdh-2 ¹¹¹) in strains obtained from Brassica. The heterozygosity at the Ldh-2 locus, differing in allele composition, however, between strains from Allium and Brassica, was present in all strains, indicating that it is probably fixed. Sequence analysis of the ITS regions and the 5.8S subunit showed consistent differences between isolates from Allium and isolates from Brassica. Based on isozyme data, ITS sequence analysis and formerly published differences in restriction enzyme patterns of mitochondrial DNA, morphology and pathogenicity, it was concluded that the isolates of P. porri Foister did not represent a homogeneous species. Isolates from Brassica constitute a distinct species which is described here as P. brassicae sp. nov. It was inferred from isozyme patterns, which were in no case intermediate between the two species, that P. porri and P. brassicae do not hybridize and are reproductively isolated by barriers to gene flow.  相似文献   

农田沙漠化演变中土壤质量的生物学特性变化   总被引：9，自引：5，他引：9  

苏永中  赵哈林  张铜会  文海燕 《干旱区研究》2002,19(4):64-68

通过研究处于沙漠化过程中的科尔沁沙地旱作农田土壤酶活性与基础土壤呼吸活性，分析了土壤质量生物学特性的沙漠化演变。结果表明，土壤酶活性与基础土壤呼吸对沙漠过程中环境的变化反应敏感，随着沙漠化程度增加，与土壤物理化学肥力因素有关的过氧化氢酶、脲酶和碱性磷酸酶的活性和土壤呼吸活性随之下降。土壤酶活性和呼吸活性与土壤有机质和养分有极显著的相关，在一定程度上可以用酶活性和呼吸强度表征有机质和养分的状况及其数量的变异，因此，可以作为农田沙漠化演变中土壤质量特征变化的重要辅助指标。  相似文献   

苏云金芽孢杆菌cry基因在大肠杆菌中表达产物和生物活性   总被引：4，自引：0，他引：4  

韩岚岚  宋福平  李长友  张杰  赵奎军  黄大昉 《植物保护》2002,28(5):5-9

研究了几种Bt cry基因于大肠杆菌(Escherichia coli)中表达产物在pH 10.0的50mmol/L碳酸钠和20mmol/L乙醇胺溶解液中的溶解性 ,发现同样的Cry蛋白在碳酸钠中的溶解度大于乙醇胺。通过胰蛋白酶消化 ,明确Cry1Ca7、Cry1Ia8酶解产物为 38kD多肽 ;Cry1Ie1、Cry1Cb2、Cry2Ab4酶解产物为 41kD多肽 ;Cry1Ac酶解产物为60kD多肽。采用FPLC层析方法对 6种原毒素及其酶解后得到的毒素多肽进行了分离纯化 ,比较了原毒素和毒素的杀虫活性的差异。其结果表明 ,Cry1Ac的原毒素和毒素对棉铃虫初孵幼虫的校正死亡率均为 100% ,Cry2Ab4的原毒素的毒力高于其酶解毒素。  相似文献   

2%氨基寡糖防治苹果花叶病   总被引：19，自引：0，他引：19  

赵小明  ;李东鸿;杜昱光;白雪芳 《植物保护》2002,28(5):15-17

2001年8月应用2%氨基寡糖对苹果花叶病进行了田间防治试验 ,结果表明:2%氨基寡糖水剂稀释300、500倍液,对苹果花叶病防效达93.85%、89.42%。其防效比对照药剂20%病毒A 81.11%的防效高 ,比对照区增产21%、23% ,是防治苹果花叶病较理想的药剂  相似文献   

植物杀虫剂苦皮藤素对柑橘潜叶蛾控制效果的研究   总被引：1，自引：0，他引：1  

丁伟  赵志模  李小珍 《中国植保导刊》2002,22(1):5-7

用植物性杀虫剂苦皮藤素Ⅳ(KPT乳油)有效成分30、15mg/kg防治柑橘潜叶蛾,采用离体叶片浸叶法处理5s,3d后,幼虫校正虫口减退率分别为89.63%、63.02%;枝梢浸液法处理5s,5d后,潜道伸长度校正抑制率分别为76.12%和41.51%;10d后,对秋梢的相对保叶效果分别为69.34%和52.29%。结果表明,采用KPT乳油有效成分30mg/kg对柑橘潜叶蛾有较好的控制作用,对柑橘秋梢有良好的保护效果。  相似文献   

滑菇优良品种筛选试验初报   总被引：1，自引：0，他引：1  

曹玉谦  张善才  迟峰  张印  赵玉良 《中国食用菌》2002,21(5):8-10

本试验对 6个不同滑菇品种进行了菌丝体生长和制种观察 ;在栽培试验过程中进行了多点小试和中试 ,初选出Ph0 8号和Ph0 6号两个品种。Ph0 8的单盘产量比CK1高出 2 5 8% ,比CK2 高出 35 3% ;Ph0 6的单盘产量比CK1高出 2 1 5 % ,比CK2 高出 30 6 %。它们均属早生品种 ,适合辽宁地区的气候特点 ,在幼菇期菌盖呈半球形、桔红色、附着的粘液多 ,菌柄比对照短 ,菇体健壮 ,符合商品收购和产品加工的要求  相似文献