小西葫芦绿斑驳花叶病毒生物学特性及传播方式

小西葫芦绿斑驳花叶病毒(Zucchini green mottle mosaic virus,ZGMMV)是我国新报道的侵染葫芦科作物的烟草花叶病毒属病毒.从感染病毒的葫芦叶片中分离出ZGMMV,摩擦接种西瓜(Citrullus lanatus)、葫芦(Lagenaria siceraria)、西葫芦(Cucurbit...     

制动器耗散功率原理在ABS标定匹配中的应用

为解决ABS逻辑门限值方法匹配成本高、周期长的问题,将制动器耗散功率原理应用于匹配中.结合逻辑门限值与制动器耗散功率的各自优点,将制动器耗散功率原理能自适应识别各种路面状况的特点应用于匹配中;根据制动器耗散功率极大值对应的滑移率略小于临界滑移率且相差不大的原理,采用制动器耗散功率极大值对应的滑移率代替峰值附着系数对应的滑移率对ABS进行控制;滑移率与制动器耗散功率曲线获得较为简单,因此可以大大提高匹配效率.经过实车匹配验证,本方法提高了匹配效率和控制质量,节约了匹配成本.     

Postharvest quality response of strawberries with aloe vera coating during refrigerated storage

Strawberries (Fragaria × ananassa Duch.) were coated either with chitosan (1, 1.5, and 2% solution, w/v) or aloe vera (AV) gel and the coatings were air dried. Coated strawberries were put in a polypropylene box and stored in refrigerator (6 ± 1°C and 50 ± 5% relative humidity. The success of coating in retaining the postharvest quality of the strawberries was evaluated by determining respiration rate, firmness, weight loss, external colour change, ascorbic acid content, total soluble solids, acidity, pH, microbial decay and sensory quality. The incidence of microbial rot started on day-6 in uncoated and 1% chitosan coated strawberries. Strawberries coated with 1.5 and 2% chitosan were affected by microbial decay on day-9 of storage. On the other hand, rot incidence was initiated in AV gel coated strawberries on day-15 of storage. Aloe vera gel or chitosan coating reduced respiration rate, weight loss, and microbial decay and preserved firmness, ascorbic acid content, and other quality parameters, thus delaying ripening and the progress of fruit decay due to senescence or microbial attack. Furthermore, AV gel delayed the changes in external colour and retained all other postharvest quality of strawberries compared to chitosan coated or uncoated ones throughout the storage.     

Role of basidiomycete fungi in the grapevine trunk disease esca

Phaeomoniella chlamydospora and wood-rotting basidiomycete fungi, namely Fomitiporia spp., are known esca pathogens. However, the effect of their mixed infections and the sequence of infection on disease development is unclear. To determine the effects of single and co-inoculations on symptoms, potted Vitis vinifera ‘Crimson Seedless’ was inoculated with P. chlamydospora either alone or in combination with one of four basidiomycetes: Coprinellus radians, Fomitiporia langloisii, F. polymorpha and the novel species Tropicoporus texanus. Basidiomycetes were isolated from vines with foliar symptoms of esca in California and Texas. In sequential co-inoculations, the effects of different sequences of infection (P. chlamydospora first, basidiomycete 6 months later; and vice versa) were tested, compared to simultaneous co-inoculations. Plants inoculated with P. chlamydospora either alone or in combination with a basidiomycete (in any sequence) did not differ significantly in the length of black-streaking lesions. In plants inoculated only with a basidiomycete, the appearance of large brown lesions, coupled with the absence of this wood symptom from control plants, suggests that C. radians, F. langloisii and T. texanus are pathogenic. Foliar symptoms resembling those of esca in the field (marginal and/or interveinal scorching, combined with red and/or yellow discoloration) were statistically more frequent among plants inoculated with F. polymorpha or T. texanus, either simultaneously or following P. chlamydospora, compared to single inoculations. Sequential co-inoculations of a basidiomycete before or after P. chlamydospora were associated with similar lesion lengths, suggesting that basidiomycetes may not require infection by P. chlamydospora in order to extensively colonize the wood.     

植物残体的化学组成及土壤水分条件对新形成腐殖质组成和性质的影响

1.在相同的腐解条件下,不同物料腐解产物的 C/有机 N 比值和 HA/FA 因物料种类而异。2.与旱地条件下的相比,田菁、草木樨、紫云英在水田条件下腐解产物的 C/有机N 比值较宽,而稻草和绿萍的则相反。3.土壤水分条件和植物残体的化学组成对腐解产物的氮素形态分布没有明显影响。4.在其它条件相同时,与旱地条件下的相比,渍水条件下腐解产物的 HA/FA 大多较宽,而胡敏酸的光密度(E_4)值则较小。     

不同腐烂程度毛竹蔸微生物变化规律

研究不同腐烂程度毛竹蔸中的微生物菌群,结果发现细菌对数值最低为5.477,最高为7.380;真菌对数值最低为5.301,最高为6.903;放线菌对数值最低为5.740,最高为7.000;纤维素降解菌对数值最低为4.301,最高为6.477;木质素降解菌最低为4.415,最高为6.799。毛竹蔸腐烂过程中,前期各菌增长较快;中期细菌、真菌、放线菌对数值不断变化;后期菌对数值都较高;各菌之间存在着一定的协助和竞争。了解竹林砍伐前期的竹蔸腐烂规律,可为砍伐后的竹蔸降解提供参考,同时为竹蔸微生物在种级单位上的分离提供依据。     

不同药剂处理毛竹的室内耐腐性

选择ACQ、铜唑、CCA、有机酸四类13种防腐剂对毛竹材进行处理,研究竹材的室内耐腐性能.结果表明:随着吸药量的增加,药剂对腐朽菌的抑制效力明显增加.ACQ防腐剂中,综合抗菌性能依次为ACQ-B、ACQ-D,ACQ-C对白腐菌的毒性最差,失重率约6%;铜唑类防腐剂对白腐菌的抗菌性最好的是CuAz-1,最差的是CuAz-2;对褐腐菌的抗菌性相差不大.通过对比,ACQ和铜唑类防腐剂的抗菌性与CCA相当,明显优于有机酸类防腐剂.     

Nursery soil cover influences germination of Thujopsis dolabrata var. hondai seeds

We examined the influence of nursery soil cover on germination of Thujopsis dolabrata var. hondai. Seeds were sown under seeding bed conditions: (1) nursery soil (andosol) without soil cover, (2) Kanuma pumice without soil cover, (3) nursery soil with nursery soil cover, and (4) nursery soil with sterilized sand cover. Germination percentages were compared between these conditions. The germination percentage (8.8%) at 10 weeks after sowing under condition 3 was significantly lower than under conditions 1, 2, and 4 (56.8%, 52.0%, and 47.2%, respectively). Of the nongerminated seeds under condition 3, 75.0% were decayed and several fungi were isolated from decayed seeds. An inoculation test of isolated fungi Cylindrocarpon tenue, Cylindrocarpon sp., Fusarium oxysporum, and Botrytis sp. to seeds showed that these fungi caused seed decay. Our results indicated that nursery soil cover may not be suitable for T. dolabrata var. hondai seeds sown in nursery soil because of seed decay by pathogens.     

Decay Detection of Ancient Wood Rafters in Tibet by Stress Wave Testing Method

Visual classification and stress wave non-destructive testing technology were adopted to evaluate the decay status of ancient Populus wood members （rafters） replaced from the Potala Palace. The decay status of wood members was evaluated by stress wave testing and visual observation. For most of the ancient wood members, the evaluation results by two methods were consistent with each other. Also stress wave testing techniques can find the internal wood member decay to eliminate the hidden hazard for ancient wood members, and offer relatively accurate quantitative information for the safety status of ancient wood members. Thus during the maintaining for ancient architectures, visual observation combined with stress wave testing techniques is a good way to evaluate the degradation of ancient wood members.     

湘中丘陵区马尾松林粗木质残体研究

以湘中丘陵区马尾松林为研究对象,分析粗木质残体(CWD)的储量特征、物种组成、径级结构以及腐烂等级,研究湘中丘陵区马尾松林CWD的基本特征。结果表明:湘中丘陵区马尾松林CWD的平均储量为1.72 t/hm2,马尾松和杉木是针叶CWD的主要组成树种,樟树、南酸枣、枫香是阔叶CWD的主要组成树种。马尾松-阔叶树种混交林的CWD总储量显著大于马尾松-杉木混交林的,两者的CWD总储量与其对应森林总生物量的比例差异明显,且均表现为随森林生物量增长而增加的趋势。CWD的个体数量随着径级的增加而减少,呈反J型下降趋势,且不同存在形式CWD的数量比例大致表现为倒木枯立木大枝根桩。CWD具备完整的腐烂等级(Ⅰ~Ⅴ级),主要集中在Ⅰ、Ⅱ腐烂等级,且随着径级的增加,各腐烂等级CWD的数量比例呈现逐渐减少的趋势。