干旱胁迫对小叶杨幼苗生长的影响

[目的]了解小叶杨的抗旱机理,为山西省北部半干旱风沙区小叶杨防护林建设提供科学依据。[方法]通过在山西省苗圃基地盆栽模拟干旱试验,以小叶杨生长过程中的苗木株高和地径,根、茎、叶生物量,叶片相对含水量和水势,净光合速率、蒸腾速率等为生长和生理指标,研究干旱胁迫对小叶杨幼苗生长的影响。[结果]干旱胁迫抑制了小叶杨幼苗的生长,包括地上部分和根系的生长;叶片相对含水量和水势随土壤相对含水量降低而下降;各干旱梯度下CK,T1,T2,T3,T4,T5的净光合速率、蒸腾速率也随干旱梯度加深而降低,但从CK(田间持水量,土壤含水量20.3%)到T3(田间持水量的40%,土壤含水量8.12%)净光合速率和蒸腾速率随干旱梯度加深降幅逐渐较小,并且干旱时也能保持较大的光合速率和蒸腾速率,表明小叶杨具有明显抗旱特性;当土壤水分进一步减少,T4(田间持水量的30%,土壤含水量为6.09%)时小叶杨开始出现干枯现象,T5(田间持水量量的20%,土壤含水量为4.06%)时小叶杨全部死亡。[结论]山西省西南部及其周边地区进行小叶杨造林时,土壤水分应尽量要保持在6.09%(T4)以上。     

Different approaches to evaluating soil quality using biochemical properties

Soil biochemical properties are indicators of soil quality, but there is still no consensus as to how they should be used. We review the trends in their use over the last decade. Generally, biochemical properties related to the biocycles of the elements (C, N, P and S) are used to diagnose soil quality. These properties include both general biochemical parameters (i.e. microbial biomass C, dehydrogenase activity and N mineralization potential) and specific biochemical parameters (i.e. the activity of hydrolytic enzymes, such as phosphatase, urease and β-glucosidase). Biochemical properties can be used both individually, as simple indices, or in combination using complex equations derived from mathematical combinations or the application of statistical programs. The results described in the literature for both are contradictory and question the validity of the use of biochemical properties as quality indicators. Complex expressions, in which different properties are combined, are thought to be highly suitable for estimating soil quality, although their use is limited to the area and situation in which they have been described. Generally, the greatest problems posed by the use of biochemical properties as soil quality indicators include the lack of reference values, the contradictory behaviour shown by these properties when a soil is degraded, and the regional variations in expression levels. Most of these problems are derived from the scarce information available on the biochemical properties of soil. For this reason, obtaining soil quality indicators of general use will require a coordinated effort from the international scientific community to standardise the analytical methods and to compile databases of biochemical properties from soils under diverse geographic conditions and with different uses and management.     

葛叶粉对肉鸡生长性能及血清生化、抗氧化和免疫指标的影响

选择同一条件下饲养的21日龄体重相近的新广麻鸡母鸡384只,随机分为4组,每组6个重复,每个重复16只,分别饲喂含0(对照组)、1%、2%和3%野葛(Pueraria lobata)叶粉的试验饲粮,试验期共49 d,旨在研究肉鸡饲粮中添加葛叶粉对其生长性能、血清生化、抗氧化和免疫指标的影响。结果表明:1)肉鸡饲粮中添加1%~3%葛叶粉对肉鸡平均日增重、平均日采食量和料肉比均无显著影响(P>0.05);2)添加2%、3%葛叶粉均能显著提高肉鸡血清白蛋白和低密度脂蛋白含量、降低甘油三酯含量和谷草转氨酶活性(P<0.05);添加3%葛叶粉还可提高肉鸡血清总蛋白含量,显著降低尿素氮、总胆固醇、高密度脂蛋白含量和谷丙转氨酶活性(P<0.05);3)添加1%~3%葛叶粉可显著提高肉鸡血清总抗氧化能力和谷胱甘肽过氧化物酶活性(P<0.05)、添加3%葛叶粉可显著降低血清丙二醛含量(P<0.05);4)添加1%葛叶粉能显著提高肉鸡血清免疫球蛋白M含量;添加2%葛叶粉显著提高肉鸡血清免疫球蛋白M含量、降低白细胞介素1β含量;添加3%葛叶粉显著提高肉鸡血清免疫球蛋白G和免疫球蛋白M含量、降低白细胞介素1β和白细胞介素2含量(P<0.05)。综上所述,饲粮中添加1%~3%葛叶粉对肉鸡生长性能无负面影响,能在一定程度上提高肉鸡抗氧化性能和免疫功能,有利于机体健康。葛叶粉可应用到肉鸡饲料中,添加3%效果更好。     

高等植物亚硫酸盐氧化酶研究进展

亚硫酸盐氧化酶(sulfite oxidase,SO)作为钼酶家族的第4个成员,参与生物体内硫代谢等重要的生理和生化过程。笔者对高等植物亚硫酸盐氧化酶的结构特征、生化特性及生物学功能等方面的最新研究进展作一综述,并展望了SO在提高植物抗环境污染(SO2、酸雨等)方面的应用潜力。     

小麦株高构成指数的研究

对 1 0个小麦品种 (系 )的株高构成指数进行了研究。结果表明 ,株高构成指数在品种间存在着极显著差异 ,该值的提高可通过杂交选择来实现。各I值与克草粒数、经济系数和籽粒产量均呈正相关 ,I1值与产量的相关达到了极显著水平 ,可作为高产育种的重要筛选指标。     

两种山羊及杂交代血液生化遗传标记研究(Ⅰ)

用聚丙烯酰胺垂直平板电泳法，研究安哥拉山羊、山谷型藏山羊及杂种Ｆ１、Ｆ２血液中Ｈｂ、Ａｌｂ、Ｔｆ、ＡＫＰ、ＥＳ、ＬＤＨ、Ａｍ等基因座表明，血液Ｈｂ、Ａｌｂ、ＬＤＨ、Ａｍ呈单态；血液Ｔｆ、ＡＫＰ、ＥＳ等基因座呈多态。Ｔｆ基因座有三种基因型（ＡＡ、ＡＢ、ＢＢ）由Ａ基因和Ｂ基因控制。ＡＫＰ有两种基因型（ＡＫＰＦ、ＡＫＰＯ）。ＥＳ酶带类型复杂，可分为三区：ＥＳⅠ呈红色、ＥＳⅡ呈褐色、ＥＳⅢ呈紫褐色。运用血液Ｈｂ、Ｔｆ、ＡＫＰ、Ａｌｂ、Ａｍ的基因频率计算基因杂合度表明，安哥拉山羊的杂合度最小，Ｆ１代的杂合度最大。分析群体间遗传相似系数与级进杂交的变化一致；分析基因型分布差异表明亲本品种差异最大，安哥拉山羊与Ｆ１、Ｆ２间，Ｆ１和Ｆ２间差异较小。     

起垄高度对黑果枸杞生长及生理特性的影响

为了探究低洼盐碱地的合理利用方式，以黑果枸杞为试验材料，设置不起垄（对照，H1）、起垄20 cm(H2)、起垄40 cm(H3)共3个栽培处理，研究不同起垄高度对黑果枸杞生长和抗逆生理指标的影响。结果表明：起垄处理的土壤全盐含量显著高于不起垄处理。起垄处理的植株枝长和叶面积显著高于不起垄处理；叶绿素含量除8月份外，其他时期均显著高于对照。可溶性糖含量不同时期的变化幅度较小。脯氨酸含量仅在后期大幅上升，其中H2处理显著高于对照。在8月份时起垄处理的叶片K+含量显著高于H1处理，10月份时则呈相反趋势；Na+含量则一直呈现出起垄处理显著低于对照的趋势。总的来看，起垄种植黑果枸杞更有优势，起垄处理虽增加了土壤盐分含量，但对黑果枸杞生长的影响较小，而相对降低的地下水位埋深对黑果枸杞的生长影响更大，研究结果对低洼盐碱地黑果枸杞的规范化栽培具有一定的理论指导意义。     

V_A,V_D和V_E添加水平对蛋鸡血清生化指标的影响

比较了按比例组成的 5个VA、VD、VE 添加水平组合 (VA1 50 0 ,3 0 0 0 ,6 0 0 0 ,90 0 0 ,1 2 0 0 0U /kg;VD3 4 5 ,690 ,1 380 ,2 0 70 ,2 760U/kg ;VE4 5 ,7 5 ,9 6 ,1 4 4,1 9 2U/kg) ,对 0～ 1 2周龄蛋用型育成鸡的免疫功能和某些血清生化指标的影响。结果表明 :血清VA 含量在一定范围内可反映饲粮VA 供应状况 ,VA6 0 0 0或 90 0 0U/kg组血清VA 含量最高 ;仅 8周末血清VE 受添加水平影响 ;VD 添加水平只与 1 2周末血清钙、磷含量及碱性磷酸酶活性呈强负相关 ;试验鸡的新城疫抗体效价未受维生素添加水平的影响     

Simultaneous estimates of the diversity and the degradative capability of heavy-metal-affected soil bacterial communities

Summary A method for simultaneous estimation of the impact of heavy metal stress on the diversity and the degradative capability of soil bacteria was developed and tested. It is based on the ability of soil bacteria to use aromatic substances as C sources. Though these characters were selected to indicate specific biochemical potential, they were sufficiently capable of differentiating the isolated strains into biochemical types. Using these characters implied that only organisms capable of growing at the expense of aromatics were tested. However, this made it possible to restrict the number of assays to 20 and to test up to 200 isolates per soil sample. In three out of five experiments, we found that heavy metal stress definitely decreased the diversity of bacteria in a flora. In two other experiments, an unchanged or even higher diversity in the metal-contaminated soils was observed. These unexpected results may have been caused by a high soil pH rendering metals unavailable or by selection of fast-growing strains in the control soil (decrease in evenness). The relative scoring of all characters in a community (also the average number of substrates used per isolate) was not a reliable indicator of changes in the degradative capability of bacterial communities. However, the ratio of the 10 lowest-scoring to the 10 highest-scoring out of the 20 characters tested was capable of indicating these changes. In all heavy-metal-affected bacterial communities so far tested, this ratio was lower than in the corresponding unaffected communities. These data suggest that some of the rare biochemical capabilities of bacterial flora were lost following contamination of soils by heavy metals.     

山茶属8种野生资源的生化特性研究

对贵州省山茶属的皱叶瘤果茶、威宁短柱茶、四球茶、小黄花茶、狭叶瘤果茶、美丽红山茶、长柱红山茶和油茶等8种植物叶片的研究表明:过氧化物酶同工酶(POD)谱带型相似,且均有3条明显的谱带,各种间谱带的强弱差异因生态环境而聚类;POD是由单基因编码的单肽酶。酯酶同工酶(EST)谱带型和强弱在各种间具有明显差异,但都有1条相同的谱带;EST谱带型及强弱差异因种类而异,同样依生态环境而聚类。超氧化物歧化酶(SOD)活力和茶多酚(TP)含量的种间差异系数(c.v.)分别为26.19和79.60,SOD活力与其叶绿素含量和TP含量皆无显著相关。TP含量与其叶绿素含量呈极显著正相关。