Comparative aggressiveness of standard and variant hybrid alder phytophthoras, Phytophthora cambivora and other Phytophthora species on bark of Alnus, Quercus and other woody hosts

Pathogenicity tests were carried out on the bark of Alnus glutinosa with 19 isolates of the standard (near-tetraploid) hybrid alder phytophthora, nine isolates representing its known heteroploid variants and 11 isolates of P. cambivora , a probable parent species of the hybrid. Over a 4-year period, 12 experiments were conducted on living alder logs incubated at 20°C. Most isolates of the standard hybrid and those of the 'Dutch variant' were highly aggressive to alder bark. Isolates of the 'Swedish', 'UK' and 'German variants', and of P. cambivora , were only weakly pathogenic. Also, isolates of P. fragariae , P. cinnamomi , P . sp. 'O-group', P. cryptogea , P. megasperma , P. gonapodyides and P. citricola were either weakly or nonpathogenic. Rates of lesion development were greatest on logs cut during July–October, slower on logs cut between November and March and zero on logs cut during April, indicating a strong seasonal effect. Other evidence indicated that lesion development was subject to critical thresholds of host resistance. The standard hybrid was nonpathogenic to the bark of four other hardwood and two conifer species, indicating that it is relatively host specific. In contrast, P. cambivora was an aggressive pathogen on live bark of Quercus and Castanea . The significance of these results is discussed.     

Root infection by Phytophthora cinnamomi in seedlings of three oak species

The combination of soil infestation with Phytophthora cinnamomi and repetitive flooding was studied on 1-year-old plants of Quercus ilex (holm oak) and Q. suber (cork oak). In a second experiment, using 2-year-old plants of the same species and of red oak ( Q. rubra ), the soil infestation was followed by two drought-rewatering cycles. Oak predawn leaf water potential (PLWP) and stomatal conductance (gs) were monitored during both experiments. Root infection, root loss, wilting and mortality were assessed at the end of the experiments. Q. ilex exhibited the highest susceptibility to P. cinnamomi , and Q. rubra the lowest. Root infections caused by P. cinnamomi were more severe in the flooding than in the drought experiment. The most noticeable effect of the infection on plant water relations was a decrease in stomatal conductance. This occurred at different times after inoculation, varying with species susceptibility and experiment. Inoculation with P. cinnamomi induced a decrease of PLWP in Q. ilex plants, and in some Q. suber plants exhibiting a severe root loss. The results further showed that the relationship between PLWP and gs was modified by infection with P. cinnamomi . The combination of flooding and infection with P. cinnamomi acted synergistically on the water relations of Q. ilex . By contrast, there was no significant increase in disease severity due to the postinoculation water stress imposed on the oaks.     

关于柞树在植物分类阶元“科”、“种”、“属”的几个问题考证

关于栎属(Quercus)植物柞树在植物分类阶元"科"的中文名称,有的文献称之为山毛榉科(Fagaceae),有的称之为壳斗科(Fagaceae);"科"所辖"属"的种类以及栎属的分组、柞树树种的中文名称也不尽相同。对上述分类阶元名称及栎属分组的考证结果认为:柞树在植物分类阶元"科"上的中文名称宜统称为壳斗科,柞树的"种"名应统一称为"栎";壳斗科在中国分布有7个属;青冈类植物应归为栎属的一个亚属———青冈亚属。     

正交试验对佛甲草屋顶建坪基质的筛选

应用正交试验对深圳屋顶绿化新种——佛甲草的屋顶建坪基质进行了研究。结果表明,佛甲草屋顶建坪基 质的最优组合是A3B3C3D1,即泥炭:花泥:沙:椰糠为3:3:3:1(体积比)的配方是佛甲草屋顶建坪的最优基质。     

柞蚕场蒙古栎冠层结构与光合生产力研究

柞蚕场的树冠类型和冠层结构是影响蚕场光合生产力的主要因素之一。通过测定现有三种树冠型的叶面积指数、叶量分布、光能分布等冠层结构特点,表明中干型结构优于无干型,“阶梯”树型优于中干型,表现出更合理的叶量和光能分布格局,具有最大的叶面积指数和较大的光合生产力。     

不同分离方法对甘肃瑞香叶提取物灭蚜活性的影响

瑞香的叶提取物对月季长管蚜有较强毒杀作用。用水提醇沉法和醇提水沉法获得的提取物对蚜虫的致死中浓度(LC50)3963mg/L和6397mg/L。水提醇沉提取物的乙酸乙酯萃取物对月季长管蚜的毒力较其它萃取物强,其LC50为1953mg/L,结果表明:瑞香叶含有杀虫活性物质主要存在于乙酸乙酯萃取物中。对水提醇沉提取物进行硅藻土柱层析分离,得到的第三组分得率和灭蚜效果均优于氧化铝柱层析离到的第三组分。     

辽河源国家森林公园的蒙古栎林

对辽河源国家森林公园蒙古栎林的结构、林木蓄积、死地被物贮量及其最大持水量等进行了调查与研究。结果表明:蒙古栎林的植物种数为22种;林木蓄积量为47.955 m3/hm2,死地被物贮量为25.3 t/hm2;最大持水量为72.2t/hm2。     

卷丹百合脱毒快繁技术研究

对卷丹百合脱毒苗组培快繁技术体系进行研究。以带LSV病毒的卷丹百合珠芽为材料,通过36℃高温预处理10天,剥取0.2mm大小的茎尖在MS＋2.5mg/L6-BA＋1.5mg/LGA＋0.5mg/LNAA＋0.1g/L活性炭＋0.6%琼脂＋3%白糖的培养基中进行芽诱导培养,经过一次继代培养后,用RT-PCR检测LSV病毒,脱毒率达100%。将脱毒百合苗在MS＋2.0mg/L6-BA＋2.0mg/L2,4-D＋0.1mg/LNAA培养基中诱导愈伤组织及丛生芽,诱导率达100%;在1/2MS＋2.5mg/L6-BA＋0.2mg/LNAA培养基中进行分化、增殖培养,增殖倍数达到4.31;采用MS＋1.2mg/LNAA＋0.5g/L活性炭培养基进行生根培养,产生的根系多而粗壮,移栽时最易成活。     

沈阳天柱山油松栎林群落结构调查与研究

油松栎林群落是具有沈阳地域特色的地带性植物群落,城市园林在构建植物配置时,要遵循地带性植物群落结构的规律。因此,研究油松栎林群落的结构对城市园林建设有一定的指导意义。采用典型样地调查法对油松栎林群落的结构进行研究,得出对其产生影响的相关指标。沈阳天柱山油松栎林群落有种子植物122种,分属38科74属,通过对重要值大小的分析比较,得出乔木层的主要优势种为油松、蒙古栎、辽东栎和花曲柳,灌木层的主要优势种为胡枝子、榛子、花木兰和接骨木;对油松栎林群落生活型进行分析,可知地面芽植物所占比例最多（38.12%）,其余依次为高位芽植物（27.64%）、隐芽植物（22.87%）、1年生植物（8.1%）和地上芽植物（3.27%）;油松栎林群落分为乔木、灌木和草本3个基本层,其中灌木层的优势较差;油松栎林群落水平结构的特点是同类植物成片状均匀分布,各物种间混交性差,其中乔木层的平均郁闭度为0.75,灌木层的平均盖度为0.27,草本层的平均盖度为0.46。     

山药汁对糖尿病大鼠血糖的影响

探讨山药汁对糖尿病大鼠血糖的影响,为山药的精深加工与产品开发提供实验参考。以大鼠静脉注射四氧嘧啶(40 mg.kg-1bw)建立糖尿病模型,以山药块茎、山药水煎剂、山药汁高、中、低剂量为不同处理,每日灌胃一次,持续9周,测定空腹血糖和胰岛素及糖化血红蛋白率。山药汁可显著降低糖尿病大鼠的血糖水平和糖化血红蛋白率,并使胰岛素分泌水平具有明显的恢复性升高;山药块茎和水煎剂虽然也有上述功能活性,但显著低于山药汁。