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1.
揭示桉树人工林不同成熟度的叶片器官所需营养元素变化以及土壤肥力对其影响,对于桉树营林和科学施肥具有重要的生产指导意义。选取广西隆安县小林镇和田东县思林镇的桉树2代萌芽林作为研究对象,测定两个人工林嫩叶、成熟叶、黄叶的C、N、P、K、B、Ca、Mg以及土壤C、N、P、K、Ca、Mg元素含量,并进行相关分析。结果表明,植物叶片的N、P、K、Mg营养元素转移规律是黄叶向成熟叶和嫩叶转移,但C、Ca、B营养元素则是随着叶片的生长发育逐渐积累,黄叶中含量最高,说明施肥时应关注Ca、B元素的持续和有效供给。两片人工林都表现出类似的规律,说明土壤肥力的差异不影响桉树人工林叶片营养元素的内循环规律。桉树嫩叶营养元素含量及其生态化学计量比学特征具有与成熟叶和黄叶不同的表征,在营养物质研究中应予以足够重视。 相似文献
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【目的】得到含刚性沉水植物明渠的水流结构。【方法】采用粒子图像测速仪(PIV),用有机玻璃棒模拟刚性植物,在不同来水流量、植物密度条件下对明渠水流结构进行了试验研究。【结果】无植物时平均流速沿垂向呈对数分布规律,有植物时则呈现明显的分区分布特性。无植物时紊动强度值沿垂向变化不大,有植物时在植物顶端位置处紊动最剧烈。流量或植物密度越大,植物顶端位置的流速梯度就越大,植物层上方的流速最大值也越大。植物密度越大,植物顶端位置的紊动强度越大,植物密度对水流紊动强度由最大值减小到最小值的区域影响很大。【结论】刚性沉水植物的存在会改变水流结构,增强紊动掺混,增强流体质点交换和能量传递,且上述影响会随着流量或植物密度的增大而增强。 相似文献
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J L López-Rivero E Agüera J G Monterde J Vivo M V Rodríguez-Barbudo 《American journal of veterinary research》1992,53(5):847-850
The mean area and minimal diameter of 3 histochemically determined myofiber types (1, 2A, and 2B; myosin ATPase in acid buffer) were calculated in middle gluteal muscle biopsy specimens from 62 stallions, 47 Andalusians and 15 Arabians, ranging in age from 6 to 12 years. Fourteen Andalusians and 7 Arabians were untrained, and the remainder were actively endurance-trained. The 6-month training schedules involved walking, slow trotting, and cantering. Fourteen Andalusians were moderately endurance-trained, whereas the other 19 Andalusians and 8 Arabians were strongly endurance-trained. Significant differences were not recorded between untrained and endurance-trained Arabians with respect to the area (type 1, 3,194 +/- 869 microns 2 and 3,150 +/- 370 microns 2; type 2A, 3,819 +/- 890 microns 2 and 3,380 +/- 356 microns 2; and type 2B, 4,872 +/- 962 microns 2 and 4,417 +/- 646 microns 2) or minimal diameter (type 1, 52.2 +/- 7.4 microns and 52.8 +/- 3.1 microns; type 2A, 58.1 +/- 6.7 microns and 55.0 +/- 2.8 microns; and type 2B, 65.3 +/- 6.4 microns and 63.4 +/- 4.3 microns) of the 3 fiber types, nor between untrained and endurance-trained Andalusians with respect to the area (untrained, 3,990 +/- 690 microns 2; moderately endurance-trained, 3,882 +/- 347 microns 2; and strongly endurance-trained, 3,758 +/- 510 microns 2) and minimal diameter (untrained, 58.1 +/- 4.7 microns; moderately endurance-trained, 59.7 +/- 2.7 microns; and strongly endurance-trained, 58.7 +/- 4.5 microns) of 2A fibers.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
6.
Antibodies to bovine serum albumin in swine sera: implications for false-positive reactions in the serodiagnosis of African swine fever 总被引:2,自引:0,他引:2
J M Escribano M J Pastor J M Sánchez-Vizcaíno 《American journal of veterinary research》1989,50(7):1118-1122
Antibodies to bovine serum albumin were detected in swine sera by use of an immunoblotting technique. Such sera had false-positive reactions, as determined by results of African swine fever virus serodiagnostic techniques when bovine serum albumin was a contaminant in the soluble cytoplasmic antigen obtained from infected cells cultured in the presence of bovine serum. The soluble cytoplasmic antigen obtained from cell cultures infected with African swine fever virus in the presence of porcine serum did not react with the false-positive sera and, therefore, was used for African swine fever virus serodiagnostic methods, with 0% false-positive results. 相似文献
7.
甘草为豆科多年生草本植物,以根和根茎入药,含甘草酸、甘草素、甘草次酸等,其味甘、性平、无毒,有补脾益气、止咳祛痰、清热解毒、调和诸药的功效,还可做为食品添加剂和化妆品的配料,用途广泛,市场需求量大.以前甘草主要依靠野生资源,但因乱采滥挖而使野生资源面临枯竭.近年来国家实施生态保护,限制采挖和应用野生甘草,各地人工种植甘草已蓬勃兴起.环县2003年种植甘草4 000 hm2,直播种植两年后,条草产量可达4 500~5 000 kg/hm2,按2005年6元/kg计,产值可达27 000~30 000 元/hm2,再加上毛草4 500元/hm2,总产值可达31 500~34 500 元/hm2.实践证明,人工种植甘草可满足市场需求,增加农民收入,其发展前景十分广阔.环县目前人工种植甘草主要采用种子繁殖,现根据笔者种植甘草的实践,将甘草人工种植的技术总结如下. 相似文献
8.
苦皮藤素微粉剂对玉米中玉米象种群的控制 总被引:2,自引:1,他引:1
苦皮藤素微粉剂1和微粉剂2以不同的浓度混入玉米中,当使用剂量为1000mg/kg时,对玉米象成虫的种群繁殖抑制率分别为96.66%和96.02%,能有效控制玉米象成虫的危害,但对幼虫和卵的控制效果不明显。 相似文献
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ZHANG Jing-fang ZHANG Yuan-ping HAO Feng-yun ZHANG Cai-xin LI Yu-jun JI Xiang-rui 《园艺学报》2006,22(7):1353-1358
AIM:To investigate DNA ploidy and the expression of TIMP-2 and E-cadherin in gastric carcinoma in order to understand its molecular basis and probable mechanism of invasion and metastasis. METHODS:Immunohistochemical methods were used to detect the expression for TIMP-2 and E-cadherin in 99 cases of gastric carcinoma, 16 cases of adjacent noncancerous mucosa, 16 cases of distant metastases and 25 cases of metastatic lymph nodes. Flow cytometry DNA ploidy and S-phase fraction (SPF) analysis was performed on 47 cases of gastric cancer, 6 cases of adjacent noncancerous mucosa and 4 cases of distant metastasis cancer with the use of formalin-fixed paraffin embedded specimens. RESULTS:The expression of TIMP-2 was significantly correlated with Borrmann’s classification, LN metastasis and the depth of invasion. The expression of E-cadherin was significantly correlated with tumor cell differentiation, Lauren’s classification, Borrmann’s classification, LN metastasis and the depth of invasion. There was a positive relationship between DNA aneuploid rate and differentiation and LN metastasis. There was a positive relationship between SPF that is higher than 15% and tumor size, differentiation and LN metastasis. And there was a significantly difference between carcinoma and noncarcinoma when the expression of E-cadherin, DNA aneuploid rate and SPF were analyzed. There was no correlation between TIMP-2 and E-cadherin. There was a positive relationship between DNA ploidy or SPF and the expression of E-cadherin. CONCLUSION:As the development of tumor progression and heterogeneity, the abnormal expression of TIMP-2 or E-cadherin or the rate of DNA aneupoid or higher SPF gradually correspondingly increases, suggesting that they play a crucial role in gastric carcinoma progression. Furthermore, each factor influences one another and further accelerates the process of tumor progression. 相似文献
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