Effects of Pollinator Loss on Endemic New Zealand Mistletoes (Loranthaceae)

Abstract: The endemic mistletoes Peraxilla colensoi and P. tetrapetala (Loranthaceae) have declined considerably in New Zealand since 1840, reputedly because of introduced herbivores but coincident with a major decline in native bird densities. We show that at two South Island sites ( Craigieburn and Ohau) there are too few bird pollinators visiting the flowers to allow full fruit set. We studied pollination rates in P. colensoi at Wakefield and P. tetrapetala at Craigieburn over four flowering seasons and P. tetrapetala in one season at Ohau. Supplemental hand pollination increased fruit production 1.25–5.3 times at Craigieburn and Ohau but not at Wakefield. Excluding birds by covering mistletoes with mesh bags decreased fruit set significantly at Wakefield but had little effect at Craigieburn and Ohau. Bellbirds ( Anthornis melanura ) and Tuis (   Prosthemadera novaeseelandiae ) visited flowers significantly more often at Wakefield than at Craigieburn. A lack of pollen tubes in the style, not self-incompatibility or resource shortage, caused the low fruit production in unmanipulated flowers at Craigieburn. Thus, at the two P. tetrapetala sites (Craigieburn and Ohau) fruit set was chronically pollen limited, whereas P. colensoi at Wakefield was not pollen-limited. Data from other Peraxilla sites also suggest pollination failure. Our study suggests that the conservation of Peraxilla species will require maintenance of native bird populations. Tuis and Bellbirds are important pollinators and dispersers of many other New Zealand plants, and the breakdown of such mutualistic relationships may have widespread consequences.     

用单个特异引物扩增桃ACC氧化酶cDNA及其在大肠杆菌中的表达

用单个特异引物和通用引物ｏｌｉｇｏ（ｄＴ）１５从桃受伤叶片ｃＤＮＡ中扩增出１．３ｋｂ左右大小的片段．将该扩增产物克隆并对重组克隆作酶切分析发现至少可分为３类．用桃ＡＣＣ氧化酶基因组ＤＮＡ为探针进行点杂交表明,４,７,９,１０,１１,１２重组质粒能与之杂交,其中７,９,１０,１１,１２号重组质粒酶切图谱与已报导的桃果实成熟相关的ＡＣＣ氧化酶ｃＤＮＡ基因基本一致,而４号克隆则不同．ＤＮＡ序列分析和ＰＣＲ鉴定表明,插入片段均由５′端特异引物单个引物扩增出来,对７号重组克隆插入片段ＤＮＡ全序列分析表明,７号重组克隆插入片段全长１１４６ｂｐ,包含了除启始密码子外的全部编码区和１９２ｂｐ的３′端非编码区．通过补上起始密码子ＡＴＧ构建重组表达载体,在大肠杆菌中表达出３５×１０３的非融合蛋白     

从长江洪水看土壤环境保护的重要性

从１９９８ 年长江流域发生的特大洪水说起,分析从汉代到清末２０００ 年间及近４０ 年来长江流域水旱灾害的变化趋势,认为造成长江洪水灾害的原因主要是气候异常,但也与生态环境遭到破坏有关,其中土壤侵蚀、水土流失是最重要的因素。探讨了防治长江水患的对策;基于对土壤的吸水和贮水功能主要靠地被层和土壤有机质层,而水土流失是从植被破坏、地被层消失开始的,以及对古今治水、治土正反两个方面的认识,提出了治水的同时应治土的观点及５ 条有效的途径。     

耐氨固氮菌对蔬菜作物生长的促进作用研究

研究并探讨了蔬菜作物在施用耐氨固氮菌后的生长、生理反应及增产的效果和原因。试验结果表明： 施用耐氨固氮菌显著增加了蔬菜苗期生物量、叶面积和叶片的叶绿素含量, 同时还增强了植株的根系活力, 并有明显的增产效果。耐氨固氮菌促进增产的作用不仅与其本身的固氮作用有关, 还可能与其分泌出某些生长刺激物 （ 或激素） 有关。     

架空管道震害预测实用方法的研究

根据震害调查分析和试验研究结果,建立了由环境因素和管道结构参数组成的,对架空管道震害预测进行二级多因素模糊综合评判的方法。文中给出了计算、评价构成二级评判因素地震烈度、场地类型、工作状态和结构种类各档次正态模糊数范数ａｋ的参数和对实际情况如何确定的方法。本文为面广量大的已建架空管道的震害预测工作提供了一套科学性强,方便实用的计算方法。     

Thermogravimetric analysis and kinetic study on pyrolysis of representative medical waste composition

To obtain detailed information on the pyrolysis characteristics, a thermogravimetric study on the pyrolysis of 14 typical medical waste compositions was carried out in thermogravimetric analysis (TGA) equipment using dynamic techniques in a stream of N(2). An index representing pyrolysis reactivity of waste was presented. Kinetic parameters were obtained by Coats-Redfern method and used to model the TG curve. The results showed that: (a) Plastic, protein, cellulosic material, synthetic fibre, and rubber entered pyrolysis process in succession. (b) There was one decomposition stage in the pyrolysis of one-off medical glove, operating glove, cellulosic waste, absorbable catgut suture and adhesive plaster, while other components had two obvious weight loss stages. (c) The obtained apparent activation energy for second stage pyrolysis was comparably higher than that for first stage. (d) Each stage was controlled by only one kinetic mechanism, in which kinetic parameters were constant. (e) The degradation kinetics of medical waste may be affected by special physical and chemical treatment in the product manufacturing process. (f) Among 13 waste samples, the pyrolysis index of cellulosic matter was the highest, which indicated cellulosic matter had strong pyrolysis reactivity. (g) With increasing heating rate, TG curve and DTG peak shifted to high temperatures and main reaction interval of the sample became longer.     

Adsorption of arsenate on soils. Part 2: modeling the relationship between adsorption capacity and soil physiochemical properties using 16 Chinese soils

An attempt has been made to elucidate the effects of soil properties on arsenate adsorption by modeling the relationships between adsorption capacity and the properties of 16 Chinese soils. The model produced was validated against three Australian and three American soils. The results showed that nearly 93.8% of the variability in arsenate adsorption on the low-energy surface could be described by citrate-dithionite extractable Fe (Fe(CD)), clay content, organic matter content (OM) and dissolved organic carbon (DOC); nearly 87.6% of the variability in arsenate adsorption on the high-energy surface could be described by Fe(CD), DOC and total arsenic in soils. Fe(CD) exhibited the most important positive influence on arsenate adsorption. Oxalate extractable Al (Al(OX)), citrate-dithionite extractable Al (Al(CD)), extractable P and soil pH appeared relatively unimportant for adsorption of arsenate by soils.