小兴安岭阔叶红松林粗木质残体基础特征

以小兴安岭典型阔叶红松林大面积固定样地(9hm2)为对象,分析粗木质残体(CWD)的物种组成及数量特征、径级结构、存在形式、腐烂等级,揭示小兴安岭阔叶红松林CWD的基础特征。结果表明:9hm2典型阔叶红松林固定样地内共计有胸径≥2cm的CWD3418株(由于高度腐烂鉴别不出种的CWD有864株,占总个体数的25.3%),CWD的密度、胸高断面积和体积分别为380株.hm-2、15.80m2.hm-2和90.1m3.hm-2;花楷槭和枫桦是阔叶CWD的主要组成树种,红松和冷杉是针叶CWD的主要组成树种;针叶树种的胸高断面积(9.12m2.hm-2)和体积(57.68m3.hm-2)分别达到总体CWD的57.7%和64%;在各存在形式下不同种的CWD数量随着径级的增加而减少,均呈反J型;除未知种以外,其他CWD都主要以枯立木、干基折断和干中折断形式存在;针叶树种根桩形式CWD的数量随着径级的增加而增加,这一规律有别于其他种;样地内各树种CWD腐烂等级都大致呈正态分布,主要集中在Ⅱ和Ⅲ腐烂等级上;除针叶树种的Ⅴ腐烂等级外,各树种不同腐烂等级CWD的数量都随着径级的增加呈减少的趋势。     

戊唑醇处理木质材料的防腐性及抗流失性研究

对经过超临界CO2流体携带戊唑醇防腐剂处理后的杉木、马尾松、中密度纤维板和刨花板的防腐性及戊唑醇防腐剂的抗流失性进行测定。结果表明,杉木、马尾松、中密度纤维板和刨花板经戊唑醇处理后,防腐能力都得到了较大提高,在绵腐卧孔菌或彩绒革盖菌的腐蚀下,杉木、马尾松的质量损失率降到10%以下;中密度纤维板、刨花板的质量损失率降到5%以下;戊唑醇防腐剂的抗流失性较好。     

Effect of biocontrol agent Bacillus amyloliquefaciens and 1-methyl cyclopropene on the control of postharvest diseases and maintenance of fruit quality

Efficacy of biocontrol agent Bacillus amyloliquefaciens PPCB004 was evaluated on the control of anthracnose and phomopsis rot in ‘Solo’ papaya pre-treated with 1-methyl cyclopropene (100 μl) (1-MCP) during storage. This treatment was compared to the untreated control, commercial treatment (washing in chlorinated water), stand alone 1-MCP and PPCB004 treatment. Although fruit pre-treated with 1-MCP delayed the ripening (100% yellow) after cold storage by 9-10 d, it showed higher incidence and severity of anthracnose and phomopsis rot than the fruit subjected to commercial treatment. Application of PPCB004 after 1-MCP pre-treatment (1-MCP + PPCB004) reduced the anthracnose and phomopsis incidence and severity after cold storage (10 °C, 85% RH for 14 d) and ripening at 25 °C. The 1-MCP + PPCB004 treatment helped to retain the fruit firmness, overall quality and uniform yellow skin (100%) and flesh colour after ripening. The PPCB004 was effectively recovered from stand alone PPCB004 and 1-MCP + PPCB004 treated fruit after cold storage and ripening. The PPCB004 population showed an increase by 1 log units after ripening in 1-MCP + PPCB004 treated fruit. After ripening the recovery of PPCB004 population was higher (0.7 log units) in 1-MCP + PPCB004. The total recovery of fungal population on the fruit surface after ripening was lower in 1-MCP + PPCB004 and stand alone PPCB004 treated fruit. It can be concluded that application of B. amyloliquefaciens PPCB004 with 1-MCP pre-treated papaya (at 25-30% skin yellow stage) can significantly reduce disease incidence associated with 1-MCP treatment. This treatment has the potential for commercial application in the ‘organic’ papaya industry.     

木塑复合材料耐候性能研究进展

木塑复合材料(WPC)的耐候性能决定了材料的户外使用寿命。文中介绍了国内外在WPC耐热氧老化、耐光氧老化、耐真菌腐朽及耐潮湿与冻融性能方面的研究进展。现有研究表明, 热氧老化与光氧老化均使得WPC发生褪色现象, 力学性能下降, 添加抗氧化剂与光稳定剂可分别改善二者对WPC的破坏作用。WPC中木粉含量较高时更易发生真菌腐朽现象, 添加化学防腐剂或其他助剂、木粉改性及涂饰可有效抑制真菌腐朽。WPC的吸水性是其热氧老化、光氧老化、真菌腐朽及冻融循环过程的催化剂。文中还总结了目前WPC耐候性能研究存在的主要问题, 并对其未来趋势进行了展望。     

Real-time PCR identification and detection of Fuscoporia torulosa in Quercus ilex

Fuscoporia torulosa is the causal agent of white alveolar wood decay on several species including a large number of forest trees. Early detection of the fungus is essential to identify diseased trees before spread occurs to healthy plants. However, current detection methods based on isolation from infected tissues on semi-selective media are laborious, time consuming and require expertise in identifying the pathogen after isolation. In the present study, a rapid and reliable Scorpion-PCR based molecular method to identify and detect F. torulosa in planta was developed in a highly polymorphic portion of the internal transcribed spacer (ITS) regions. Specificity of primers and probe was assessed by means of both BLAST analyses and by using genomic DNA from 131 F. torulosa isolates and 43 other fungi and oomycetes from different hosts and geographic areas. In Scorpion-PCR the limit of detection was 1 pg of total DNA and a high correlation ( r ² = 0·996) was achieved between target DNA quantity and cycle threshold (Ct). Real-time PCR combined with effective procedures for DNA extraction enabled the detection of F. torulosa from naturally infected tissues of oaks with and without fruit bodies in approximately 6 h. Comparative testing showed that detection of F. torulosa in wood samples is more sensitive and reliable with real-time PCR than with conventional isolation.     

Causes of incipient rot and rot in regrowth Eucalyptus diversicolor (karri) trees

Eucalyptus diversicolor (karri) is the second most important commercial timber tree in Western Australia. Sawlogs from regrowth trees often have a discoloration in the heartwood that is more abundant than in sawlogs from mature trees. Other symptoms in regrowth logs include white rot, white pocket rot and brown rot. Fungal isolations and pathogenicity tests were conducted to determine whether this discoloration was incipient rot, and if so, what caused it and which rot(s) would eventually develop. A combined sample of 329 discs from recently felled trees and freshly cut scantling had discoloration in 48%, white rot in 14%, white pocket rot in 12% and brown rot in 4% of pieces of wood. Hymenochaete semistupposa was isolated from 22% of discoloured wood and 39% of white pocket rot samples. Stereum hirsutum was isolated from 4% of discoloured wood and 13% of white rot samples. Koch's postulates in regrowth karri trees showed that H. semistupposa caused extensive discoloration, with white pocket rot developing in the heartwood within 4 years, while S. hirsutum caused extensive discoloration, with white rot developing in both the heartwood and sapwood within 2 years. It was concluded that the discoloration was incipient rot, which would eventually develop into either white rot or white pocket rot.     

基于相似系数和距离的农机选型评价模型

为了科学、合理地评价农机设备,针对单一数量指标有时不能确定决策方案优劣的缺陷,综合考虑相似系数和距离,给出一种农机选型的综合评价方法。通过对农用运输车选型的综合评价以及与其他评价方法相比较,验证了该方法是可行和有效的。     

影响杂交大豆制种的几个因素分析

为了探索不同因素对大豆杂交制种产量影响,设计了播期、行距、父母本行数比例三因素裂区试验和播期、母本与油葵距离二因素试验,结果表明,播期对制种产量影响显著,行距、父母本行数比例,三因素之间两两互作、三者互作均对制种产量影响不显著。播期5 月10 日、行距50 cm、父本:母本=1:2 处理时制种产量最高。母本与油葵距离对大豆制种产量影响极显著。母本距油葵90 cm 处理下产量最高。结论表明,在一定范围内,较早播期、较短母本与油葵距离,可以显著或极显著地提高杂交大豆制种产量。     

翠冠梨主要贮藏病害及其冰温贮藏技术的研究

以砂梨系统的翠冠梨为试验材料,用30μm厚的PE打孔袋包装,分别于（0±0.5）℃（CK）和（-1.5±0.5）℃（冰温）两个低温下贮藏120 d,研究贮藏过程中果实腐烂率、褐变率、品质和生理指标的变化。结果表明,翠冠梨在低温贮藏过程中的褐变程度较轻,可能与贮藏环境中较低的CO2浓度（〈0.2%）有关;但果实的腐烂问题较为严重,以侵染性病害黑斑病和褐腐病造成的腐烂为主;冰温贮藏可以显著降低果实的呼吸强度、相对电导率、PPO活性和MDA含量,延缓果实衰老,降低腐烂率和褐变率,保持果实较高的TSS、TA含量和硬度与脆度,贮藏期可以达到120d,而对照果实的贮藏期仅为90d。     

采收期和贮藏温度对上饶早梨保鲜效果的影响

以"天桂梨"为试材,研究不同采收期和采后贮藏温度对上饶早梨保鲜效果的影响。结果表明,上饶早梨适宜的采收期为盛花期后102 d,采后适宜的贮藏温度为2℃,该条件可有效延缓上饶早梨果实贮藏期间硬度的下降,降低果实的呼吸强度和VC损失,延缓货架期果实的褐变和腐烂,提高食用品质。