大豆食心虫非典型气味受体基因克隆及发育期表达分析

非典型气味受体是昆虫嗅觉识别过程中重要的蛋白之一。本研究利用RT-PCR和巢式PCR的方法克隆了大豆食心虫非典型气味受体Olfactory co-receptor基因,命名为Lgly Orco,其编码区为1 419 bp,编码473个氨基酸,氨基酸序列中存在3个N位糖基化位点,分子量为53.5 k D,等电点为7.12,含7个跨膜结构以及4个位于细胞膜外的亲水区,符合气味受体的典型结构特征。与鳞翅目已知昆虫的Orco同源性达到89%以上。不同发育期Lgly Orco表达量分析表明,Lgly Orco在二龄和三龄幼虫中的表达量是一龄幼虫的4~5倍,在四龄和五龄幼虫中的表达量是一龄幼虫的70%和50%,而在雌性成虫中的表达量是雄性成虫中的11倍。本研究将为大豆食心虫的嗅觉识别系统和大豆食心虫防治技术研究提供理论依据。     

阿赛管道稳定运行的进站温度预测与评价

长距离热油管道输送介质的组成一般比较复杂,为维持其经济输送温度,常出现蜡等重有机物固相沉积问题。当固相沉积超过一定程度时,不仅显著增加管道系统的动力消耗,而且严重威胁其运行安全。因此,合理预测热油管道稳定运行的进站温度对保障其安全经济运行尤为重要。依据阿尔善-赛汉塔拉输油管道2008-2010年的历史运行参数,结合苏霍夫温降理论,反算全线7个管段稳定运行期间的总传热系数K,提出不同管段的月推荐K值,以此预测各管段2011年上半年的进站温度,探讨偏差产生的主要原因与预测结果的可靠性。研究结果表明:由热油管道历史运行参数反算得出的推荐K值,可以较好地预测该管道今后的温降趋势,误差在-4～4℃内的可信度高于90%,但进站温度预测值可能因固相沉积而略低于实际值。     

Comparison between rice grain yield predictions using artificial neural networks and a very simple model under different levels of water and nitrogen application

It is important to model water and nitrogen requirements for rice yield in order to improve production. In this study, an artificial neural network (ANN) was used to predict rice grain yield under different water and nitrogen application. Grain yield was predicted based on five variables: nitrogen application rate, seasonal amount of applied irrigation water, plant population, and mean daily solar input before and after flowering. Furthermore, the ANN method was compared with a very simple model (VSM) for prediction of rice grain yield. Two approaches were considered for ANNs. In the first (local partitioning), rice grain yield and variable data from the south of Iran were used for training, and the network was then tested using independent data from the north of Iran. In another approach, the data for both experiments were mixed and randomized dividing was applied (stochastic partitioning). The results showed that stochastic partitioning networks are more accurate than local partitioning networks. Comparison between ANN and VSM results showed that using ANNs gives a more accurate prediction of grain yield. Therefore, ANNs with stochastic partitioning of data is an accurate method to predict rice grain yield using readily available inputs.     

Dynamic prediction of forest fuel loads by Grey Verhulst model

The variation of fuel loads after a fire for three forest types,phododendron--Larix gmelinii forest,herb--Larix gmelinii forest andherb--Betula platyphlla forest, in the northern forest area of Daxing’anling region was discussed. The dynamic models were developed by gray theory for estimating the fuels loads of arbor, shrub, herbs, grass, litter, and semi-decomposed litter, inflammable fuel and the total fuels in each forest type. After a fire, the inflammable fuel loads inphododendron-Lxirix gmelinii forest and in the herb- -Betula platyphlla fores was estimated at 10.958 t/hm² and 10.473 t/hm² respectively, by 13 years later, and that was 12.297 t/hm² inherb--Larix gmelinii forest by 7 years later. It was predicated that a big fire may occur after 10 years based on inflammable fuel biomass accumulated.     

Estimation of the Gentan probability using the price of logs in private plantation forests

The Gentan probability is defined as the probability that a newly planted forest stand will be harvested at a certain age. In this study, the Gentan probability was estimated using the price of logs, in accordance with the notion that the probability is influenced by economic factors. In order to estimate the Gentan probability, we adopted a probability density function based on the forest owners’ decision-making process, which consisted of a decision criterion, a decision criterion function and a criterion threshold. The price of logs was employed for the criterion, and the decision criterion function was defined as the value of the forest stand based on the price of logs. Moreover, the mechanism of changes in the threshold was formulated based on the random walk concept. The parameters of the suggested Gentan probability were calibrated to fit the harvesting tendencies observed in the past. Finally, the Gentan probability distributions estimated using the prices of logs over the past 20 years were compared with those estimated using felling age means and variances. The two distributions were closely correlated during most years. The proposed Gentan probability model takes advantage of short-term yield predictions such as an analysis of forest owners’ reactions to the current price changes.     

0-1时间序列分析及其在害虫预测中的应用

害虫种群由非暴发状态发展为暴发,不仅是量的变化,而且也是质变。这是一种两类状态的问题。在我国,因各种原因,至今很少地方用数值表示森林害虫种群动态的时间序列x_1,x_2,…,x_N。很多地方只有暴发和非暴发的记载。这可看成由两种状态构成的0-1时间序列,0-1时间序列分析方法为这种历史信息提供了简便的分析与预测的手段。     

植物叶片弹性模量的测量

现代农业要求对植物叶片进行高精度测量,为了确定最佳的测量力就要对植物的弹性模量进行精确测量。本文针对这一问题提出了两种测量方法,即胡克定律法和悬臂梁法。针对这两种方法分别设计了测量装置,并用这两种测量装置对同种植物进行测量,对实验数据进行误差分析。通过对这两种方法进行研究比较,筛选出一种比较准确的测量方法,本研究对植物叶片测量仪器的设计参数选择具有重要价值。     

我国花卉产业发展中若干问题的探讨

简要论述了花卉产业在我国国民经济和社会发展中的地位和作用 ,分析了我国花卉产业的现状及存在问题 ,并对我国花卉市场发展前景进行了预测     

林分直径结构模拟与预测研究概述

从林分直径结构模拟预测模型的选择以及模型参数的求解方法2个方面,对林分直径结构模拟与预测模型的国内外研究现状进行了较为详细的论述,总结指出林分直径结构模型的研究正围绕参数法和非参数法2种方法展开,重点归纳总结了理论方程法、最相似回归法等几种主要模拟预测方法以及百分位法、回归法等常用的模型参数求解和预测方法,分别指出了各种模型及参数求解方法的优劣,并对当前研究工作存在的问题及今后研究的重点进行了讨论。本项研究着眼于实际应用的层面,旨在为今后的研究提供阶梯,以有助于该项研究工作的展开。     

卷荚相思良种采穗圃营建及管理技术研究

通过正交试验设计研究卷荚相思采穗圃母株不同定植密度、不同截干高度及施用不同种类的基肥对母株产穗量的影响;研究了不同种源家系对母株产穗量的影响。结果表明:卷荚相思母株定植株行距25 cm×25 cm,距母株根茎部位20 cm处截干,结合施用1 050 kg.hm-2硫酸钾复合肥作基肥(A3B3C2)的组合产穗量最高;卷荚相思7个最优家系最优单株中,以At15、At8家系产穗量最高。