棉花冠层设计超高产栽培技术研究与应用

棉花产量的高低与棉花栽培技术措施密切相关。棉花冠层设计超高产栽培技术是以长江下游地区9、10月丰富的热量资源条件为基础,以提高棉花顶部经济性能为目标的栽培技术措施的集成与优化,通过推迟打顶时间,推迟治虫结束时间,增加盖顶肥用量,增加化控量,即“两推迟,两增加”四项技术的创新应用,实现单产较大幅度的提高。试验田测产及生产示范推广结果均表明,棉花冠层设计栽培技术能够明显提高棉花顶部成铃和单铃重,平均增产幅度在两成以上。这项技术的推广与应用,对于利用好本地区秋季优越的热量资源和棉花顶部优势结铃部位,实现棉花生产高产高效将起到积极的的推动作用。     

Morphological plasticity and phosphorus uptake mechanisms of hybrid <Emphasis Type="Italic">Eucalyptus</Emphasis> roots under spatially heterogeneous phosphorus stress

In this study, we subjected the root systems of eight Eucalyptus hybrids currently cultivated in southern China to heterogeneous phosphorus stress to provide a scientific basis for the selection of a highly phosphorus-efficient Eucalyptus variety. When the ability of these hybrids to locate phosphorus under different experimental conditions (phosphorus supply in a homogeneous or heterogeneous manner vs. no phosphorus supply) was compared, the main growth characteristics of Eucalyptus, such as plant height, diameter, dry mass, and phosphorus content, significantly improved when the phosphorus supply was increased from no phosphorus or heterogeneous phosphorus (half of the phosphorus amount) to homogeneous phosphorus. Across these three conditions, the growth traits of different Eucalyptus hybrids differed significantly, indicating different adaptabilities of the hybrids to various phosphorus conditions. The growth traits of the aboveground tissues of Eucalyptus under different phosphorus conditions were largely influenced by the morphology of the underground root system. In addition, the root morphology of Eucalyptus under heterogeneous phosphorus treatment suggested that there were two mechanisms for locating nutrients. Eucalyptus hybrids such as Urophylla 3229, Grandis 9, Guanglin 3, 201-2, and Dunn produced more roots proximal to the phosphorus supply; the other hybrids, Urophylla 3216, Grandis 5, and Guanglin 9, relied mainly on the growth of roots opposite the phosphorus supply to obtain adequate nutrients for growth. With these two strategies, a wide range of nutrients was obtained, root distribution was greater, more soil volume was covered, the contact area of the roots with soil phosphorus was increased, and the uptake of phosphorus by the root system was increased. These results demonstrate that Eucalyptus relies on changes to morphological characteristics of the root system to increase accessibility to phosphorus resources.     

基于低空无人机遥感技术的油菜机械直播苗期株数识别

植株数量识别是油菜机械直播效果和质量评估的关键.该文针对油菜机械直播田间植株数量检测中人工统计耗时、费工、效率低下的现实,通过自主搭建的低空无人机遥感平台采集油菜机械直播区域的遥感影像,基于超高分辨率(0.18 cm/pixel)遥感影像计算的颜色植被指数进行油菜目标识别及其形态特征信息提取.结合田间调查数据,采用逐步回归分析方法,建立了机械直播油菜在苗期的株数与遥感特征信息之间的关系.结果显示,油菜目标的株数与其外接矩形的长宽比、像素分布密度和周长栅格数具有较好的线性关系,回归模型的决定系数R2为0.803,并通过显著性检验,其标准估计误差为0.699.模型检验结果显示,观测值与预测值之间的R2为0.809,均方根误差RMSE为0.728.研究结果表明,利用集成超高分辨率传感器的低空无人机遥感平台,通过计算颜色植被指数并分析油菜目标数量与形态特征的相关性,能有效识别油菜机械直播的出苗株数,可为后续油菜机械直播效果的快速、准确评估提供技术支持.     

森林和景观—联系生态学和美学

森林作为陆地的最大生态系统,是游憩娱乐场所、宜人生态环境的提供者及可持续发展的重要保障,对缓解城市环境危机,实现资源的最大化利用具有重要影响。笔者从森林的生态、视觉等研究出发,阐述了森林和景观的密切联系,使森林的生态价值、美学价值以及可持续价值得到最大发挥并形成统一整体。     

灭多威对离体培养MDEC-07114细胞的抑制作用

[目的]利用自建家蝇胚胎细胞系进行灭多威毒性测定,为灭多威毒性机理研究提供依据。[方法]采用MTT法,检测灭多威对家蝇胚胎细胞的增殖抑制作用。[结果]2 mg/ml灭多威对家蝇胚胎细胞有抑制作用,抑制率随药物浓度增加而升高。[结论]以家蝇胚胎细胞系为工具细胞进行灭多威的毒性作用研究,具有可行性。     

1981-2003年黑龙江省植被变化及其对气候的响应

基于遥感方法监测植被变化以及分析植被对气候变化的响应与反馈机制已经成为全球变化研究的一个重要领域(马国明等,2006;Mark et al．,2001).尽管归一化植被指数(NDVI)在高植被区的饱和性使其与一些植被生理参数之间的关系往往是非线性的(Carlson et al．,1990;Gillies et al．,1997),并且容易受到土壤背景的影响(Huete,1997),但由于NDVI与叶面积指数、光合有效辐射吸收率、生物量、初级生产力和植被盖度等植被生物物理特征的高度相关性(马国明等,2006;Veroustraete et al．,2002),使其成为研究大尺度植被变化的重要指标.     

龙血树DCDPK2基因的克隆及表达分析

通过RACE技术克隆龙血树CDPK基因的全长cDNA,并对基因序列进行相关分析与基因表达分析。结果表明:该基因全长为1 810 bp,编码区长度为1 587 bp,编码528个氨基酸,其氨基酸序列具有CDPK基因编码氨基酸的所有典型结构特征;经序列比对发现其核酸序列与玉米CDPK基因的同源性高达81%,氨基酸序列与其它植物中的CDPK氨基酸序列同源性很高。该基因命名为DCDPK2基因。对未经血竭诱导和诱导的龙血树组培苗进行半定量RT-PCR表达分析,发现在添加了诱导物的组培苗中DCDPK2基因的表达显著增强。     

Adverse effect of the chitinolytic enzyme PjCHI‐1 in transgenic tomato on egg mass production and embryonic development of Meloidogyne incognita

A novel chitinase gene (PjCHI‐1) isolated from Paecilomyces javanicus, a non‐nematophagous fungus, and driven by a CaMV35S promoter, was delivered into CLN2468D, a heat‐tolerant cultivar of tomato (Solanum lycopersicum). T₁ tomato plants exhibited high endochitinase activity and reduced numbers of eggs and egg masses when infected with the root‐knot nematode (RKN) Meloidogyne incognita. The eggs found in transgenic tomato had lower shell chitin contents than eggs collected from control plants. Egg masses from transgenic plants exhibited higher chitinase activity than those from control plants. Moreover, only 30% of eggs from transgenic plants were able to develop to the multi‐cell/J1 stage, compared with more than 96% from control plants. The present study demonstrated that the expression of the PjCHI‐1 chitinase gene can effectively reduce the production of egg masses and repress the embryonic development of M. incognita, presenting the possibility of a novel agro‐biotechnological strategy for preventing crop damage by RKN.     

1831与稻瘟灵混配对稻瘟病菌的毒力测定

室内毒力测定结果表明,1831与稻瘟灵不同配比的混合物对稻瘟病菌均有一定的增效作用,其中2∶8混配物的增效作用最明显。     

浅谈改进计算机实验教学的两项技术

实验教学在计算机课程中具有举足轻重的作用,它的效果直接反映学生学习情况的好坏。利用现代化的网络和多媒体技术可给实验教学带来便利,提高教学质量。