植物提取液对黄瓜白粉病的抑菌活性筛选研究

首先通过叶圆盘法用29种植物提取液对黄瓜白粉病菌的抑菌效果进行了生物活性测定,初步筛选出槐、黄檀、南瓜和石楠等4种植物的提取液对黄瓜白粉病有较好的预防效果。然后对这4种植物提取液进行预防性和治疗性的室内盆栽药效试验,结果表明黄檀提取液对黄瓜白粉病的预防效果达到72.97%,治疗效果达到91.28%,并且在处理12 d后仍保持42.60%以上的防效。而槐提取液的预防效果和治疗效果分别为79.73%和79.19%,处理12 d后也保持在50%以上的防效。这两种植物提取液均极显著优于对照药剂三唑酮。     

Cu2+对中华倒刺鲃超氧化物歧化酶活性的影响

Cu2+是养殖水体的常见污染物,为了评估Cu2+对鱼类超氧化物歧化酶(SOD)的影响,将中华倒刺鲃暴露于含0.01～0.32 mg/L Cu2+的水体中饲养8 d,测定肌肉、血浆及肝脏中SOD活性的变化.实验结果显示,低浓度Cu2+(0.01 mg/L)对肌肉、血浆及肝脏的SOD有诱导作用,随着处理时间的延长而升高.但当浓度较高(0.04mg/L以上)时,SOD活性均呈现先诱导后抑制的趋势.Cu2+浓度越高,SOD活性上升越急剧,出现活性抑制的时间就越提前.此外,SOD在3种组织中的分布亦存在明显差异,肝脏的SOD活性最大.这些结果表明,肝脏SOD活性更宜作为Cu2+污染的生物标记.     

Energy balance for ethyl alcohol production from crops

Energy requirements to produce ethyl alcohol from three different crops in Brazil (sugarcane, cassava, and sweet sorghum) were calculated. Figures are presented for the agricultural and industrial phases. The industrial phase is always more energy-intensive, consuming from 60 to 75 percent of the total energy. Sugarcane is the more efficient crop for ethyl alcohol production, followed by sweet sorghum and cassava from a net energy viewpoint. The utilization of sweet sorghum stems might increase the total energy gain from this crop to almost the same level as sugarcane. Cassava has a lower energy gain at the present state of agriculture in Brazil.     

植物生长素在大果沙棘嫩枝扦插中的应用研究

在温室内对5个大果沙棘品种嫩枝用4种植物生长激素处理进行扦插育苗试验,结果表明,吲哚丁酸和生根粉处理效果显著,浑金和向阳两品种更容易扦插成活。     

Coelioscopic-assisted prefemoral ovariosalpingectomy in a d`Orbigny slider (Trachemys dorbigni) using a digital otoscope

The purpose of this study was to assess the unilateral prefemoral coelioscopic-assisted approach for ovariosalpingectomy in a d`Orbigny slider (Trachemys dorbigni) using a digital otoscope. Twenty healthy turtles were randomly assigned to one of two groups, for right (GR; n=10) or left (GL; n=10) prefemoral access, for coelioscopic-assisted ovariosalpingectomy. Anesthesia and surgery times, body weight, and ovary/oviduct weight data were recorded. Anesthesia and surgery times did not differ significantly between the groups. Wound closure was the most time-consuming surgical step. Ovary and body weights significantly affected the exposure time of the ipsilateral and contralateral ovaries, respectively. Two intraoperative complications were reported. All the animals recovered uneventfully. The digital otoscope can be safely and effectively used for coelioscopic-assisted single-access, unilateral prefemoral ovariosalpingectomy in d`Orbigny slider.     

黍族植物的叶片扩张和蒸腾作用对土壤水分亏缺的响应特征

Plant processes, such as leaf expansion, stomatal conductance and transpiration, are affected by soil water, particularly in water-stressed environments. Quantifying the effects of soil water on plant processes, especially leaf expansion and transpiration, could be useful for crop modeling. In order to quantify the leaf expansion and transpiration in response to soil water deficit in three millet species, common (Panicum miliaceum L.), pearl (Pennisetum glaucum L.) and foxtail (Setaria italica L.) millets, a pot experiment was performed at the Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. The soil water status was characterized by the fraction of transpirable soil water (FTSW). Leaf area and transpiration were measured daily. Relative leaf area expansion (RL) and relative transpiration (RT) data were plotted against FTSW. Finally the FTSW thresholds for RL and RT were calculated using linear-plateau and logistic models. The results showed that the thresholds for RL and RT were 0.68 and 0.62, respectively, based on all measured data of the three millet species using the linear-plateau model, indicating that RL and RT were constant when FTSW decreased from 1 to the threshold point. Thereafter, until FTSW = 0, RL and RT declined linearly with a slope of 1.48 and 1.43, respectively. Although millet is cultivated as a resistant crop in arid, semiarid and marginal lands, it showed an early response to soil water deficit at high FTSW thresholds. As leaf expansion and transpiration can be considered morphological and physiological variables, respectively, the results in this study indicate that millet has strong morphological flexibility when faced with soil water deficit.     

西藏核桃休眠及萌芽特性研究

利用浓硫酸浸泡处理西藏核桃种子,通过种子吸水率、不同层积方法和内源抑制物对小白菜萌发影响试验等方面来研究西藏核桃的休眠及萌芽特性.结果表明:用浓硫酸处理种吸水率大于对照,种壳并不是引起休眠的主要原因,外壳、内种皮、种仁可能均含有抑制种子发芽物质.用浓硫酸浸泡90 min,变温层积萌动时间早,且萌动率高;低温层积160 d,再在22℃恒温条件下发芽率高,为68%.     

森林公园道路景观林的改造配置模式——以老山森林公园为例

道路景观林是山林景观的窗口和向导,道路景观林的建设是森林林相改造的重要内容。以南京市老山森林公园为例,探讨道路景观林建设的指导思想、原则与方法,并结合案例提出道路景观林改造模式,以实现森林公园由经济林转变为景观生态林的改造目标。     

Alkaline hydrolyzable nitrogen and properties that dictate its distribution in paddy soil profiles

Nitrogen (N) is a key nutrient for rice production, and its bioavailability in paddy soils is strongly coupled to soil organic matter (SOM) cycling. A better understanding of potentially available N forms in soil, such as alkaline hydrolyzable N (AH-N), and their depth distribution will support the development of best management practices to improve the N use efficiency of rice while minimizing adverse environmental effects. Fifteen rice (Oryza sativa L.) fields from Southern Brazil were selected, and stratified soil samples were taken to a depth of 60 cm before crop establishment. Selected soil physical and chemical properties were analyzed to evaluate their relationships with AH-N contents in the soil profile. The AH-N contents below 20 cm varied extensively (increased, reduced, or constant) compared with that above 20 cm. Although clay and clay + silt contents were highly correlated to AH-N for some soils, the major property dictating AH-N distribution by depth was total N (TN), as the correlation between TN and AH-N was mainly by direct effect. The proportion of TN recovered as AH-N across sites and depths presented high amplitude, and thus AH-N was not a constant N pool across depths, indicating that AH-N can be affected by soil management practices even when TN showed no major changes. The distinct distribution of AH-N across soil sampling sites and depths indicates that depths greater than 20 cm should be considered when calibrating the AH-N index for N fertilizer recommendations for flooded rice in Southern Brazil.     

日本大耳白兔、新西兰兔血液蛋白多态性的研究

采用垂直板聚丙烯酰胺凝胶电泳法对日本大耳白兔、新西兰兔血液中的血清转铁蛋白 (Tf)、前转铁蛋白 (Prt)、后白蛋白 (Po)、血液结合素 (Hp)、红细胞酯酶 (ES - 1、ES - 2和ES - 3)等 7个蛋白座位进行测定。结果表明 :这 7个座位均呈多态。在多态座位中 ,Tf、Prt、Po、Hp、ES - 1、ES - 2、ES - 3分别出现 3、3、6、3、3和 3种表型 ,受 2、2、3、2、2和 2个共显性等位基因控制。X2 检验表明 ,新西兰兔在这 7个座位上均处于平衡状态 (P >0 .0 5 ) ,日本大耳白兔在Tf、Po、ES -1、ES - 34个座位处于平衡 (P >0 .0 5 ) ,而在Prt、Hp、ES - 2出现不平衡状态 (P <0 .0 5 )。