林木生长和收获模型研究进展与发展趋势

论述林木生长与收获模型的概念、分类及各类模型的优缺点,林木生长和收获模型的国内外发展历程与研究状况,提出了林木生长和收获模型研究的关键领域和发展趋势,即:提高精度和智能化,与实际生产相结合,加强空间结合,向三维可视化方向发展,由纯林向混交林深入,向广义化和更好的生物学意义与可解释性方向发展,向系统化和整体化(耦合)方向发展,与社会经济及生态环境等因子相结合.     

湖泊水-沉积物界面SiO3-Si交换通量研究

以乌梁素海(WLSH)和岱海(DH)为研究对象,采用柱状芯样模拟法,开展了湖泊水-沉积物界面溶解性硅酸盐(SiO₃-Si)扩散通量研究。结果表明,在夏季90 d的时间内,浅水草型湖泊乌梁素海明水区沉积物-水界面交换速率约为1.28 mmol·m^-2·d^-1,沉积物约向上覆水体释放了963.07 t SiO₃-Si;而深水藻型湖泊岱海深、浅湖区沉积物-水界面交换速率分别为1.10、1.95 mmol·m^-2·d^-1,沉积物约向上覆水体释放了893.41 t SiO₃-Si.SiO₃-Si在水-沉积物界面的交换速率与两湖沉积物中粘土矿物含量、生物硅(BSi)含量及沉积物的粒度有较好的相关性。沉积物释放的SiO₃-Si对维持湖泊初级生产力有重要作用,乌梁素海沉积物释放的硅可提供浮游植物所需硅的11.96%,岱海沉积物释放的硅可提供浮游植物所需硅的41.3%.从元素化学计量学角度考虑,结合两个湖泊上覆水营养盐浓度变化,随湖泊富营养化水平的逐渐提高,磷有可能成为乌梁素海初级生产力的潜在限制因子,而Si是岱海初级生产力可能的限制因子。     

犬细小病毒核酸疫苗制备及免疫试验

以犬细小病毒基因组DNA为模板,应用PCR方法扩增了全长VP1基因,PCR产物经纯化和NotⅠ/BamHⅠ双酶切后与同样处理的真核表达载体pIRES进行连接,转化到感受态细胞JM109中,筛选了真核重组表达质粒pIRESVP1,并进行了序列测定。对6只9月龄犬分别接种不同剂量的pIRESVP1或空载体质粒及生理盐水,8周接种1次,每次接种前采血,测定血清的血凝抑制抗体效价,第2次免疫后即可检测到较高的血清效价。在第3次接种4周后,对全部实验犬进行攻毒,攻毒后第7天及第14天时采血,测定血清的血凝抑制抗体效价。所有接种pIRESVP1疫苗的犬均能抵抗CPV强毒的攻击,而接种空载体质粒和生理盐水的对照犬则全部发病。证明所构建的核酸疫苗(pIRESVP1)能使犬免受犬细小病毒强毒的感染。     

The selective sequestration of glucosinolates by the cabbage aphid severely impacts a predatory lacewing

The cabbage aphid Brevicoryne brassicae is a notorious agricultural pest that specializes on plants of the Brassicaceae family, which are chemically defended by glucosinolates. By sequestering glucosinolates from its host plants and producing its own activating enzyme (myrosinase), this aphid employs a self-defense system against enemies paralleling that in plants. However, we know little about the metabolic fate of individual glucosinolates during aphid sequestration and activation and about the biochemical effects of this defense on aphid enemies. Here, we probed these questions focusing on B. brassicae and a predatory lacewing, Chrysoperla carnea. We found that distinct glucosinolates were accumulated by B. brassicae at different rates, with aliphatic glucosinolates being taken up more quickly than indolic ones. B. brassicae myrosinase enzymatic activities toward different glucosinolates were strongly correlated to their rates of accumulation in vivo. Surprisingly, after simulated predation, the production of toxic isothiocyanate products (ITCs) was quantitatively outweighed by less toxic products such as nitriles and ITC-conjugates. Nevertheless, the defensive cocktails significantly impaired C. carnea development. Tissue-specific quantification of glucosinolate metabolites revealed that the lacewings employ both conjugation and mobilization to reduce the toxicity of aliphatic ITCs, but these strategies were only partially effective. These results clarify the metabolic fates of glucosinolates after sequestration by an aphid herbivore and further in a higher trophic level, as well as the consequences for predator survival and development, and might be instructive for integrative pest management approaches targeting the cabbage aphid.

     

用毛细吸渗原理快速测量土壤田间持水量的研究

田间持水量是衡量田间土壤保持水分能力的重要指标,视为对作物有效的土壤水分的上限,对农田灌溉和作物水分管理具有十分重要意义。该研究提出了能快速测量土壤田间持水量的新型毛细吸渗法。该方法以田间持水量为无地下水影响下土壤基质所能吸持的最大含水量为物理基础,设计了一套满足田间持水量要求的实验方法、装置和程序,采用5种不同土壤测量了其田间持水量,并与用威尔科克斯法测量得到的田间持水量进行了对比。结果表明：所提出的新型测量方法,无论是基本原理还是室内试验均可行。与威尔科克斯法相比,其测量值略微偏小;两种测量值相关性很好,相差约为9％,产生这种现象的原因主要是土壤的吸湿过程与脱湿过程中土壤含水率的滞后所致。与传统的测量方法相比,该方法可大大缩短测量时间,具有利用前景。     

Effect of dietary supplementation of chitosan and galacto-mannan-oligosaccharide on serum parameters and the insulin-like growth factor-I mRNA expression in early-weaned piglets

The study was to determine effects of dietary supplementation of chitosan (COS) and galacto-mannan-oligosaccharids (GMOS) on some serum biochemical indices, serum growth hormone (GH) and insulin-like growth factor-I (IGF-I) levels, and hepatic and long gissimus muscle IGF-I mRNA expression in early-weaned piglets. Twenty six Duroc × Landrace × Yorkshire piglets at the age of 15 days were used. The piglets had access to creep feed during the suckling. Six piglets were sacrificed for sampling at the beginning of the study. The other 20 piglets were individually housed in metabolic cages and randomly allotted to four corn and soybean meal-based diets including the control group, the antibiotic group with 110 mg lincomycin/kg diet, the COS group containing 0.025% COS, and the GMOS group with 0.20% GMOS, respectively, in a 2-week feeding experiment. Blood urea nitrogen (BUN) level was reduced whereas serum total protein concentration was increased (P < 0.05) in responses to the COS and GMOS supplementation. Dietary supplementation of COS and GMOS also increased (P < 0.05) the serum GH and IGF-I levels along with enhanced hepatic and the muscle IGF-I mRNA abundance. Dietary supplementation of oligosaccharides such as COS and GMOS may improve growth and feed conversion efficiency by increasing plasma GH and IGF-I levels, in the early-weaned piglets.     

基于拉曼光谱的稻叶瘟病害程度划分研究

随着植保变量喷施作业机械的研究和应用,急需一种高效的病害程度识别技术。为此,针对水稻稻叶病运用拉曼光谱仪采集正常及受病害叶片的光谱特性,通过绘制折线图及受试者工作特征曲线进行水稻受病害程度分析,并运用动量因子BP神经网络优化算法,建立了寒地水稻稻叶瘟的病害程度检测模型。结果表明:优化的BP神经网络算法网络预测集的均方误差为0. 002 409 6、相关系数为0. 998 2。该方法可以较好地区分水稻正常叶片、稻叶瘟重度和轻度叶片,是一种高效的病害程度识别技术。     

小麦灌浆期间营养器官对籽粒氮积累的影响

小麦灌浆期间叶片、颖壳、茎秆、叶鞘分解输出的氮素约占籽粒积累氮素量的60%～73%;各器官对籽粒含氮量的贡献依次为叶片>茎节>颖壳>叶鞘.施N量0～10.5kg/亩,各营养器官在灌浆初期含氮量均提高,最终输出率也相应提高;施N量超过10.5 kg/亩,最终输出率反而下降.     

大肠杆菌BL21(DE3)中表达重组蛋白的研究

为了研究在大肠杆菌BL2 1(DE3)中重组蛋白的表达特点 ,探讨重组蛋白在大肠杆菌中表达时可溶性蛋白与包涵体出现的特点 ,从表达载体中表达了植物ACC合成酶 .经SDS PAGE电泳与双波长扫描分析 ,确定目的蛋白随表达时间、菌液密度的增加而增加 .但是其最佳表达时间为 2 5h ,菌液密度OD6 0 0 为 0 6 ,IPTG的最佳浓度为 0 6mmol L ,此时目的蛋白含量占全菌蛋白含量之比最高 .植物ACC合成酶在大肠杆菌中表达时以包涵体的形式存在 ,未能检测到可溶性蛋白的表达     

几种胡敏酸还原容量的表征与比较

还原容量(RC)是衡量胡敏酸(HA)还原特性的重要指标。采用饱和H2振荡法和土壤溶液法对HA分别进行化学和微生物预处理,分别以硝酸铁(Fe(NO3)3)、柠檬酸铁(FeCit)作电子受体,测定了三种HA(上海巨枫SH,天津光复TJ,缙云山JY)的本底还原容量(NRC),化学还原容量(CRC),微生物还原容量(MRC)。对不同电子受体条件下、不同初始状态和不同种类的胡敏酸的RC进行比较。结果表明：三种HA中,以缙云山土壤提取的胡敏酸RC值最高,还原容量最大,分别为20.21?0.26mmolc mol-1C (NRC)、26.02?1.12mmolc mol-1C (CRC)和29.29?1.56mmolc mol-1C (MRC)。两种电子受体中,采用Fe(NO3)3得到的RC明显高于在FeCit条件下。另外,溶液态HA的RC明显高于固态。由此证明胡敏酸还原容量是一个相对量;其容量大小不仅和自身结构、性质有关,也受到HA初始形态和不同电子受体的影响。对比三个还原容量指标发现CRC和MRC显著大于NRC,而CRC和MRC之间无明确大小关系,因此用CRC来表征HA被微生物还原后的还原容量(MRC)还需作进一步验证。