板条出材率的研究

对原木加工中常出现的三角板条再加工与利用作了初步探索。结果表明,一般原木的板条锯材出材率为3.23—3.42％,带25％钝棱的板条锯材出材率可达4.31—4.56％。     

Do fungi have a role as soil stabilizers and remediators after forest fire?

The functional roles of fungi in recovery of forest ecosystems after fire remain poorly documented. We observed macrofungi soon after fire at two widely separated sites, one in the Pacific Northwest United States and the other in southeastern mainland Australia. The range of species on-site was compared against macrofungi reported after the volcanic eruption at Mount St. Helens, also in the Pacific Northwest. Each of the three sites shared species, particularly representatives of the genus Anthracobia. Soon after disturbance, we noted extensive mycelial mats and masses of fruit-bodies of this genus, particularly at heavily impacted microsites. The mycelial mats appeared to play an important functional role on-site, possibly aggregating soil particles in otherwise highly erodable landscapes. We hypothesise that fungi such as Anthracobia are pivotal species in early system recovery after disturbance, helping minimize the movement of soil in the absence of plant roots. As plant root systems recover, the importance of these fungi in soil stabilization may diminish. Other functional roles of early postfire fungi might include nutrient acquisition, leading to the reestablishment of vegetation. These potential roles need to be experimentally tested and relevant findings incorporated into programs aimed at restoring forest ecosystems after disturbance.     

Spatial patterning and population structure of a common woodland herb, Trillium erectum, in primary and post-logging secondary forests

We investigated the population age structure and spatial patterning of a common understory perennial, Trillium erectum var. album, in primary and post-logging secondary (industrially logged in the early 1900s) cove forests of the southern Appalachian Mountains. Within each of 8 T. erectum populations (4 in primary forest and 4 in secondary forest), we mapped the locations of all T. erectum plants in a 10 m × 10 m plot located within the center of each population. We recorded the height and life stage of each plant and excavated a randomly selected subset for age determination. Trillium erectum populations in primary forests displayed a somewhat stronger and more consistent spatial structure than those found in secondary forests. However, aside from being on-average younger due to a higher concentration of juveniles, age structures of secondary forest populations were similar to those of primary forests and both forest types had similar maximum plant ages. Our results, when considered with the life history of the species, suggest that logging did not eliminate T. erectum from secondary forests. Rather, residual plants and patches of plants that survived logging provided the propagules needed to expand and reestablish populations following logging. This relatively rapid recovery stands in stark contrast to the slow recovery observed by others in post-agricultural secondary forest. When considered in the context of other studies of post-disturbance recovery in secondary forests, our results suggest that the full history of a site must be carefully considered when examining the impacts of disturbance on forest perennial herbs.     

三江源区“黑土滩”型退化草地自然恢复的瓶颈及解决途径

三江源区位于青藏高原腹地,长期在气候变暖和超载放牧的双重压力下,草地大片退化,形成大面积"黑土滩"型退化草地,引起源区生态环境的恶化。本研究以三江源区"黑土滩"型退化草地的土壤、环境和种子库为研究对象,分析了三江源区"黑土滩"型退化草地自然恢复的瓶颈;采用以空间代替时间的群落研究方法,对在"黑土滩"型退化草地上建植多年的人工草地演替过程进行了跟踪研究。结果发现:在"黑土滩"型退化草地上建立多年生人工草地,能够改善土壤微环境,为地带性植被的入侵创造适宜条件,实行人工草地植被演替与地带性植被自然入侵的连接,可以大大缩短"黑土滩"型高寒退化草地地带性植被的恢复进程。本研究为"黑土滩"型退化草地的恢复,改善三江源区生态环境,提供可靠的理论依据与措施。     

Mixing groundnut residues and rice straw to improve rice yield and N use efficiency

Groundnut as a pre-rice crop is usually harvested 1–2 months before rice transplanting. During this lag phase much of N in groundnut residues could be lost due to rapid N mineralization. Mixing of abundantly available rice straw with groundnut residues may be a means for reducing N and improve subsequent crop yields. The objectives of this experiment were to investigate the effect of mixing groundnut residues and rice straw in different proportions on (a) growth and yield of succeeding rice, (b) groundnut residue N use efficiency and (c) N lost (¹⁵N balance) from the plant–soil system and fate of residue N in soil fractions. The experiment consisted of six treatments: (i) control (no residues), (ii) NPK (at recommended rate, 38 kg N ha⁻¹), (iii) groundnut residues 5 Mg ha⁻¹ (120 kg N ha⁻¹), (iv) rice straw 5 Mg ha⁻¹ (25 kg N ha⁻¹), (v) 1:0.5 mixed (groundnut residues 5 Mg: rice straw 2.5 Mg ha⁻¹), and (vi) 1:1 mixed (groundnut residues 5 Mg: rice straw 5 Mg ha⁻¹). After rice transplanting, samples of the lowland rice cultivar KDML 105 were periodically collected to determine growth and nutrient uptake. At final harvest, dry weight, nutrient contents and ¹⁵N recovery of labeled groundnut residues were evaluated.     

一株海洋石油烃降解菌的分离鉴定及特性研究

在福建省厦门市集美嘉庚公园旁的码头,从受污染的海水中筛选出一株能以0#柴油为唯一碳源的石油降解菌JMUXMS-100,通过生理生化鉴定和16SrDNA同源性序列分析,鉴定该菌为不动杆菌属（Acinetobacter sp．）．实验研究了时间、底物浓度、pH值和温度对该菌生长和降解率的影响,结果表明,降解率随时间的延长而增大,随着底物浓度的上升而降低．最佳初始pH值为7．0,最适生长温度为28℃．经3d培养,对质量浓度为100—500mg／L的柴油降解率为38．7％～57．2％．     

烟焦油及被动吸烟对小鼠肺芳香烃羟化酶活性的影响

为研究烟焦油和被动吸烟对小鼠肺芳香烃羟化酶(AHH)活性的影响,同时观察烟焦油对AHH活性影响的剂量反应关系和时间反应关系,以1%LD50(5.29 mg/kg),2%LD50(10.58 mg/kg)和3%LD50(15.87mg/kg)的烟焦油分别使小鼠染毒24,48 h和72 h,每日1次,然后测定肺AHH的活性。被动吸烟组置于体积50 L自制染毒柜中,烟雾浓度为69.41 g/m3,每日2次。对照组不吸烟,但处于相同条件。2周后测定肺AHH的活性。结果表明,2%LD50烟焦油组在72h后和3%LD50烟焦油组在48 h和72 h后均可以提高小鼠肺AHH的活性。2%LD50和3%LD50烟焦油作用小鼠72 h和48 h比较,对AHH活性的影响差异显著(P<0.05)。被动吸烟也可提高小鼠肺AHH的活性。表明烟焦油在一定的浓度和时间内可使AHH的活性上调,这种上调作用表现为剂量依赖性和时间依赖性,被动吸烟也可提高小鼠肺AHH的活性。     

Recovery of Proteins from Rohu Processing Waste Using pH Shift Method: Characterization of Isolates

Yield and physicochemical characteristics of protein isolates recovered from rohu processing waste by acid- and alkali-aided protein solubilization methods were studied. pH 2.0 from acidic side and pH 13.0 from alkaline side resulted in maximum protein solubility, whereas minimum solubility was observed at pH 5.5. Except for pH 13.0, theoretical protein recovery was more than the actual recovery after centrifugation. Maximum protein recovery after the first centrifugation cycle was observed for pH 2.0 and pH 13.0, and the maximum protein recovery during the second centrifugation cycle was observed at precipitation pH 5.5 in both acidic and alkaline methods. Acidic and alkaline methods resulted in a total process recovery of 31.81% ± 0.001% and 31.11% ± 0.01%, respectively. Isolates prepared by acidic method had more whiteness and high foaming capacity, whereas isolates prepared using alkaline methods had less whiteness, tough texture, and high foaming stability. No microbial counts were detected in any of the isolates. Acid and alkaline methods described in this study can be used for the recovery of proteins from rohu processing waste with good yields and functionality.     

Eradication of the invasive Pseudorasbora parva results in increased growth and production of native fishes

Abstract –  The topmouth gudgeon, Pseudorasbora parva , has been described as Europe's most invasive fish. To control their UK invasion, some lentic populations at risk of causing fluvial dispersal have been eradicated. The first of these operations was from a lake in north-west UK in March 2005 using rotenone application; prior to eradication, their mean density was estimated as 6.1 m⁻² whereas since eradication, no P . parva have been recorded. Prior to rotenone application, the majority of native fishes were removed, held off-site and reintroduced following degradation of rotenone to safe levels. In the three growth seasons since their reintroduction and P . parva eradication, the abundance, somatic growth rate and production of roach Rutilus rutilus and common bream Abramis brama have increased significantly; production is now driven by a lower number of comparatively larger, faster growing individuals. These data suggest that the eradication of this P . parva population has been highly beneficial for the growth, recruitment and production of these native species.     

延迟采收对豫中烤烟上部叶生理指标和代谢组学的影响

为探究延迟采收对豫中烤烟上部叶生理指标和代谢组学的影响,本研究以中烟100为试验材料,研究延迟采收对上部叶抗氧化性指标、氮代谢关键酶活性、还原糖含量以及代谢组学的影响。结果显示,随着延迟采收时间的延长,烟叶中抗氧化系统中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性逐渐降低,丙二醛(MDA)和脯氨酸(Pro)含量较常规采收时上升。与常规采收相比,延迟采收8 d时烟叶中还原糖含量达到最高,增加了97.10%。氮代谢中的关键酶硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性随着采收期延长逐渐降低,延迟16 d时活性达到最低。不同处理的上部叶代谢物经过时间序列分析(STEM)发现变化趋势相似的代谢物聚为一类,经过代谢途径分析(KEGG)发现,随着采收期的延长,主要富集在萜类化合物和类固醇的生物合成,D-谷氨酰胺和D-谷氨酸代谢、不饱和脂肪酸的生物合成,托品烷、哌啶和吡啶生物碱的生物合成等代谢途径中的代谢物表达持续下调,富集在淀粉和蔗糖代谢途径、酪氨酸代谢、植物激素的生物合成等途径中的代谢物在延迟采收8 d时表达下调。综上表明,豫中烟区烤烟上部叶延迟采收8 d为最佳采收期。本研究为确定豫中上部烟叶的适宜采收时间,科学指导田间采收提供了重要的理论依据。