5种荒漠植物幼苗对模拟降水量变化的响应

以5种荒漠植物红砂、泡泡刺、花棒、白刺和沙拐枣为研究对象,根据当地生长季节内60 d的平均降水量最大为91.2 mm,平均约为50.7 mm,最小约为35.9 mm等基本情况,人工控制了4种降水量处理水平(29、58、88、117 mm)来模拟幼苗生长对生长季节内降水量变化的响应.结果表明,每种植物都以自己的生长策略表现出独特的对降水量变化的响应格局.红砂幼苗的生长高度和高度生长率随着降水量的增加而显著减小,但降水量变化对其生物量和生物量分配及相对含水量影响不显著;降水量显著影响了泡泡刺和白刺幼苗的生长高度、高度生长率、生物量及其分配和相对含水量,但二者在生物量及生物量分配和相对含水量方面的趋势存在差异.泡泡刺幼苗的生长高度、高度绝对生长率、生物量及其分配等都随着降水量的增加而呈抛物线趋势;白刺幼苗以萎蔫老叶、发出新芽的方式来适应干旱环境.降水量显著影响了花棒幼苗的绝对高度生长率、生物量干重、生物量分配和相对含水量,但对生长高度和相对高度生长率影响不明显;沙拐枣幼苗的相对高度生长率和生物量干重对降水量的响应不敏感,但从其幼苗的生长高度和绝对高度生长率来看,沙拐枣幼苗的存活需要较多的水分.花棒和沙拐枣在不同降水量处理下对地上、地下生物量的分配方式相反,但降水量偏少限制了二者的生长.红砂和白刺幼苗更适合于在适宜在降水量为29 mm的环境中生存,泡泡刺幼苗阶段适宜在降水量为58~88 mm的环境中生长,而花棒和沙拐枣在幼苗阶段的生长更偏向于降水量多于88 mm的条件.     

A new species of the genus Haloschizopera Lang, 1944(Copepoda,Harpacticoida, Miraciidae,Diosaccinae) from the East China Sea

A new species belonging to the genus Haloschizopera Lang, 1944 (Copepoda, Harpacticoida, Miraciidae, Diosaccinae) was identifi ed based on the samples collected from the East China Sea, near the off shore of Zhejiang Province, East China. The new species is closely related to H . pygmaea Norman & Sccot T., 1905 and shares a combination of the following features: A1 eight-segmented;A2 exp-2 with one distal seta, exp-3 with three setae;P1 endopodal segments subequal, enp-1 not exceeding exp-2;exp-3 of P3 with one inner seta, of P4 with two inner setae. The new species is characterized by the presence of one inner seta on P2 exp-3 of both sexes. It can also be distinguished from its congeners by the characters of female: P5 exopod subcircular, endopodal lobe extending beyond half-length of exopod;genital doublesomite ornamented with three dorsolateral rows of spinules on anterior part.     

Preliminary description of a new species of Paraw aldeckia (Crustacea Amphipoda: Lysianassidae) from New Zealand (note)

A preliminary diagnosis is given for Parawaldeckia stephenseni from New Zealand, and the genus is briefly reviewed.     

Effect of the herbicide triclopyr on the abundance and species composition of benthic aquatic macroinvertebrates in the Ahuriri River,New Zealand

Abundance and species composition of aquatic benthic macroinvertebrates were compared between an area sprayed with the herbicide Grazon (active ingredient triclopyr), and an upstream control site (no triclopyr). Five Surber samples were collected from each of three riffles in control and treatment sites on eight occasions over a 1‐month period. Aquatic invertebrate species composition was similar in treatment and control sites, and did not change over time. The five taxa that made up 91–95% of all invertebrates by abundance did not vary significantly in treatment compared to control riffles. Abundance of three of the 15 most common taxa (>10 individuals per riffle) differed significantly between treatment and control sites over time. However, none of these fluctuations correspond to the presence of known concentrations of triclopyr in water samples, and it is unlikely that the declines resulted from triclopyr. These results are discussed with reference to known lethal concentrations of triclopyr for some invertebrates, and to the effect of floods on invertebrate populations.     

西北荒漠区6种珍稀濒危植物的种子微形态特征

首次报道了我国沙区6种珍稀濒危植物的种子微形态结构的光镜及扫描电镜观察结果。实验结果表明:沙冬青、四合木、半日花等6种珍稀濒危植物的种子微形态特征呈现出丰富的多样性,且大多具有复杂精细的表面纹饰。     

矿产勘查发展趋势与科研勘查一体化

矿产勘查商业化、市场化与全球化发展趋势和未来激烈的竞争局面,以及行业的高投资高风险决定了找矿成功率和成果的经济价值是矿产勘查企业生存和发展的基础。为提升找矿成功率和企业经济效益必须坚持科研与勘查一体化模式,坚持科研与找矿勘查紧密结合,加强科研对找矿勘查的指导。     

中国北方晚侏罗世晚期—早白垩世早期的 新叶肢介化石

新叶肢介化石共有3属5种,其中2属4种产自新疆准噶尔盆地早白垩世早期的清水河组,包括Shiheziestheria pangi Wang（gen.et sp.nov.）,Nestoria jungarensis Wang(sp.nov.),Nestoria shawanensis Wang(sp.nov.),Nestoria donggouensis Wang( sp. nov.);另1属1种 Eosestheria yaozhanensis sp.nov.,产自冀北围场县腰站乡晚侏罗世晚期的大北沟组。     

喀斯特石漠化区不同优势树种根际土壤有机碳及氮磷的变化

通过对贵州中部喀斯特石漠化区典型植被及土壤进行调查,探讨森林退化过程中不同群落优势树种根际土壤有机碳及氮磷含量的变化。结果表明:根际土壤有机碳及氮磷含量均高于非根际土壤;在不同植被类型之间,林木根际对土壤有机碳及氮磷的累积效应存在明显的差异性,其中土壤有机碳的累积效应表现最明显,其次是土壤磷素,而土壤氮素累积效应的差异性较小。在树木根基0～30cm水平范围内,根际土壤总有机碳、易氧化有机碳、全氮、有效氮和有效磷含量都明显高于30～90cm外围根际区。不同群落优势树种之间,根际土壤碳及氮磷总量的差异性表现为总有机碳＞全氮＞全磷,而碳及氮磷的生物有效态含量则表现为有效磷＞易氧化有机碳＞有效氮。森林退化过程中,群落优势树种根际土壤总有机碳、易氧化有机碳及有效磷含量出现显著的下降,从而明显地影响土壤的肥力水平。