Artificial inoculation and susceptibility of Pinus armandii to Dothistroma septosporum

Dothistroma needle blight (DNB) is a serious needle disease of conifers that primarily affects pine species (Pinus spp.). Dothistroma septosporum is one of the DNB pathogens that has a diverse range of host species excluding Pinus armandii. In 15 inoculated P. armandii seedlings, D. septosporum acervuli were observed in 43 infected needles of ten seedlings with a mean disease severity of 1.11% at 25 weeks after inoculations, demonstrating the potential of D. septosporum to cause symptoms on the needles of P. armandii via artificial inoculation. The disease severity of P. armandii was similar to the positive control, Pinus nigra (median 0.75 for P. armandii to 0.70 for P. nigra), thus, P. armandii acts under artificial conditions as a susceptible host species.     

基于径流分类的日径流量预测神经网络模型

利用聚类分析法将径流序列分解为若干个子径流序列 ,对这些子径流序列分别建立局部神经网络模型 ,而后把这些局部模型合并成一个混合模型。当新的信息进入该模型时 ,首先用分类器判别其类别 ,以确定用混合模型中的何种局部模型加以模拟。通过与不加分类的总体神经网络模型的模拟结果加以对比 ,结果表明这种基于径流分类的降雨 -径流模型表现出了更优良的性能 ,可以较大地提高径流模拟精度。     

铁皮石斛人工繁育技术

以铁皮石斛商品瓶苗和盆栽苗茎段为试材,添加不同浓度6-BA、NAA,诱导茎段腋芽、原球茎和不定根,建立再生体系,快速繁殖铁皮石斛组培苗,以期为秦岭淮河一线以北地区人工繁殖铁皮石斛提供参考依据。结果表明:外植体宜采用70%酒精浸泡20 s,0.1%升汞浸泡8 min消毒;MS+6-BA 3.0~5.0 mg·L^-1+NAA 0.1~1.0 mg·L^-1适合腋芽分化和增殖,分化率92%~100%;1/2MS+6-BA 2.0 mg·L^-1+NAA 0.5 mg·L^-1+土豆泥15%适合原球茎诱导增殖,增殖倍数7.7;1/2MS+NAA 0.3 mg·L^-1生根率为100%;以松针土移栽,成活率83%。     

韩国Ophiostomatoid真菌与棘胫小囊树皮甲虫的互作研究

棘胫小囊树皮甲虫(Coleopterla:Scolytidae)是一种与树木或新鲜木材兰染真菌相关的昆虫。本研究用不同种的松树制备的圆木诱捕、采集棘胫小囊树皮甲虫，并对其种类进行了比较。自4月至7月，从Pinus．rigida和Pinus．korniensis诱捕圆木上收集昆虫，共获得了10种树皮甲虫，其中Hylurgops interstitialis是P．koraiensi上最常见的甲虫，而Tomicus piniperda则在P．rigida上最常见。5月是H．interstitialis出现的高峰期，T.piniperda出现的高峰期是在4月。在6月上旬，新的成虫自蛹中孵化而出。为了研究树皮甲虫的种群与树木兰染真菌分离获得的频率的相关性，采用选择性培养基自成虫、卵／幼虫和树皮甲虫的虫道分离真菌。研究发现在越冬成虫和虫道上兰染真菌出现的频率分别是100％和94％，但在孵化的卵或刚孵出的幼虫上出现的频率相对较低。从兰染真菌分离出现的频率上看，收集的时间与树皮甲虫的种群没有显著的相关性。于4月20日可以首次观察到在虫道的下面出现变色现象，2周内，木材变色迅速增长，100％变色。对这些分离获得真菌进行鉴定，发现Leptographium spp出现频率高于Ophiostoma spp．。     

Neural network prediction of performance parameters of an inclined plate seed metering device and its reverse mapping for the determination of optimum design and operational parameters

Seed planting equipment with inclined plate seed metering devices is the most commonly used equipment for planting of peanut crop in India. For obtaining the high yield, it is very essential to drop the peanut seeds in rows maintaining accurate seed rate and seed spacing with minimum damage to seeds during metering. This mainly depends on forward speed of the planting equipment, rotary speed of the metering plate and area of cells on the plate. The relationship between these factors and the performance parameters viz., seed rate, seed spacing and percent seed damage can be established using regression analysis. But they may not be very accurate and may pose difficulty in the determination of inputs for a set of desired outputs (reverse mapping). Hence, an attempt has been made in this paper to develop the feed forward artificial neural network (ANN) models for the prediction of the performance parameters of an inclined plate seed metering device. The data were generated in the laboratory by conducting experiments on a sticky belt test stand provided with a seed metering device and an opto-electronic seed counter. The generated data was used to develop both statistical and neural network models. The performance of the developed models was compared among themselves for 4 randomly generated test cases. The results show that the ANN model predicted the performance parameters of the seed metering device better than the statistical models. In order to determine the optimum forward speed of the planting equipment, peripheral speed of the metering plate and the area of cells on the plate to obtain the recommended seed rate of 33.33 seeds/m², seed spacing of 100 mm and percent seed damage of 0.2% with 100% fill of the cells, a novel technique of reverse mapping using ANN model was followed. It was observed that the optimum forward speed of the planting equipment and optimum area of cells on the metering plate had good correlation with size of seed. Linear regression equations were developed to predict the optimum forward speed of the planting equipment and optimum area of cells on the metering plate using the size of seeds as independent parameter. The peripheral speed of the metering plate of 0.237 m/s was found to be optimum for the size of seeds in the range of 95.42-123.01 mm². However, the results need to be verified by conducting planting operation under actual field conditions.     

不同产地红松苗期生长的初步研究

为探讨不同种源在辽东山区的生长表现,对17个产地红松子代在辽宁省草河口镇的苗期生长性状进行调查分析,结果表明,红松苗高和地径的生长在产地间的差异达到极显著水平,辽宁地区种源普遍优于吉林、黑龙江地区种源;红松苗期生长性状的基本变异模式是海拔垂直梯度为主,纬向渐变为辅的连续型变异。     

双壳贝类营养需求及人工饵料的研究进展

工厂化养殖是未来贝类产业可持续发展的必然趋势。由于微藻的培养容易受到气温、光照等自然环境条件的影响,而且占用大量水体,因此研发双壳贝类人工饵料已成为贝类工厂化养殖的关键因素。本文简述了蛋白质、脂类和碳水化合物对双壳贝类生长、繁殖及免疫的影响,详细叙述了微藻干粉、大型海藻处理物、酵母、微粒饲料、液态微胶囊饲料和固态微胶囊饲料6种人工饵料的研究进展,以期为研发新型的双壳贝类人工饵料及开展工厂化养殖提供依据。     

马尾松不同抚育方式对林地生产的影响

对马尾松幼林采用全面劈草、全面劈草局部松土、全面除草松土3种抚育方式对林地植被生长、表层土壤变化及幼林生长的影响进行研究,结果表明:植被覆盖率、植被枯落物随抚育强度提高而降低,而土壤侵蚀则随抚育强度提高而增强,马尾松幼林生长与抚育强度提高成正比.在南方马尾松集约经营的山区,宜提倡带状抚育,既可促进幼林生长,又能维护地力.     

重庆市石宝镇马尾松单木生长模型研究

为了更加科学地保护和利用马尾松森林资源并为其可持续经营提供参考依据,利用多模型选优法对重庆市忠县石宝镇马尾松的单木胸径生长模型进行了探讨与分析,结果表明：对竞争优势木和竞争劣势木的拟合效果最好的均是Richards函数,其次是Schumacher函数,而Gauss函数和Logistic函数的拟合效果较差.考虑到模型运算的简便性和结构的清晰性,结合研究区马尾松胸径生长量的预测情况,选取了模型参数相对较少的Schumacher 函数作为描述重庆市忠县石宝镇马尾松生长过程的最佳模型.