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41.
ABSTRACT Elsholtzia splendens Naki has been identified as a copper (Cu) geobotanical indicator. In this study, the effects of Cu supply levels (control, 100, 200, 400, 600, 800, 1000, 1200 mg kg1) on the growth and Cu accumulation in E. splendens were studied in one pot experiment. The results showed that no reduction in shoot height and dry weight was noted when the plants were grown at Cu supply levels up to 1000 mg kg?1 in soil. Slight stimulation on shoot growth was noted at Cu levels ≥ 100 mg kg?1. Copper concentration in shoots and roots increased with increasing Cu levels, and reached a maximum of 1751 and 9.45 mg kg?1 (DW) at 1200 mg Cu kg?1. The amount of Cu accumulated in the roots and shoots were 313 and 22 μ g plant?1 at external Cu levels of 1000 and 800 mg kg?1, respectively. The shoot/root Cu ratios ranged from 0.005 to 0.008 and more than 92% of the total Cu taken up by E. splendens was accumulated in roots. Furthermore, Cu concentrations in roots and shoots were significant and positively correlated with total soil Cu, water, ammonium nitrate (NH4NO3), ammonium (NH4)-acetate, and ethylenediaminetetraacetic acid (EDTA) extractable Cu. These results indicate that E. splendens can considered as a Cu tolerant and accumulated plant, and root is the major part for accumulation of Cu in E. splendens. 相似文献
42.
青藏高原东北部黄土区草本植物根系加筋土的抗剪特性 总被引:6,自引:3,他引:3
为了分析草本植物根系加筋土的抗剪特性,以青藏高原东北部黄土区生长时间为1a的芨芨草根系作为加筋土的筋材,通过将根系加筋土试样制成9组不同含根量的扰动试样,进行了直剪摩擦试验。结果表明,当含根量与含水量一定时,根系加筋土的抗剪强度与剪切面上的法向压力呈正比,抗剪强度随垂直压力的增加基本呈线性增大;当根系加筋土含水量与垂直压力一定时,抗剪强度随含根量的增加而呈增大趋势,其黏聚力c和内摩擦角φ均有不同程度的提高,c值明显增加,且c值与含根量之间呈指数函数关系,φ值变化不大;在20.5,61.5,102.5,和143.5kPa这4种垂直压力下,根系加筋土抗剪强度和含根量之间均呈指数函数关系。说明供试种芨芨草根系可以显著提高试验区土体的抗剪强度,同时有助于增强坡体稳定性。 相似文献
43.
J. C. J. van Zon 《国际虫害防治杂志》2013,59(2):179-185
Abstract Conventional methods of aquatic weed control meet increasing objections on economic and/or environmental grounds. An alternative approach is the use of grass carp (Ctenopharyngodon idella Val.), a herbivorous fish. This biological method has mainly been used in Europe and the USA, but since 1976 an Egyptian‐Dutch project has studied the potential of this approach for the Egyptian irrigation systems. All aspects of the production and use of grass carp have been studied and evaluated, Egyptian personnel have been trained, a large‐scale breeding station has been established and practical use of the technique has begun. The programme has shown that a stocked grass carp population not only provides effective weed control, but it also increases the protein production in Egyptian waterways substantially. If managed well, this production can provide continuous revenues that far outweigh the costs of weed control. The necessary management techniques developed are mainly based on yearly restocking with grass carp and cooperation between irrigation authorities and professional fishermen. The experience described in this paper will be of interest to many other countries. 相似文献
44.
青海湖芨芨草干草原植被退化对土壤温湿特征的影响 总被引:2,自引:0,他引:2
芨芨草(Achnatherum splendens)干草原目前退化严重,但对土壤温湿特征的驱动机理仍不清楚。利用2011年连续观测资料分析环青海湖区域的芨芨草干草原原生植被和典型退化区域的0 cm、5 cm、10 cm、20 cm、40 cm和80 cm土壤温度和5 cm、10 cm、20 cm、40 cm和80 cm土壤容积含水量。结果表明:植被退化直接导致0 cm和5 cm表层土壤温度日极大值显著升高了39.04%和13.91%,温度日极小值显著降低,温度日较差升高;而10 cm以下温度日特征无显著响应。原生植被区0 cm逐日土壤温度在植物生长季(5-9月)极显著降低,非生长季5 cm和10 cm则略高。芨芨草植被改变了土壤年均温度垂向扩散特征。植被退化间接导致土壤5 cm土壤容积含水量升高了35.20%,10 cm无差别,20 cm以下显著降低,同时降低了系统土壤含水量的时间稳定性。特征聚类分析结果表明,芨芨草干草原土壤温湿特征对植被退化的综合响应主要表现在7-8月。 相似文献
45.
46.
泰国斗鱼的胚胎发育及温度对胚胎发育的影响 总被引:1,自引:0,他引:1
观察了泰国斗鱼Betta splendens受精卵的形态和胚胎发育的过程,研究了温度对胚胎发育的影响。试验设置5个温度组(20、23、26、29、32℃),记录各温度下胚胎发育历时、孵化率和畸形率,共重复5次。结果表明:水温为20~32℃时,泰国斗鱼受精卵均能孵化,最适孵化温度为26~29℃。孵化温度T与孵化时间t呈负相关,相关方程为t=18878T-1.8528(R2=0.9811);泰国斗鱼胚胎发育的生物学零度为11.08℃,有效积温为659.39℃.h。 相似文献
47.
Sherif S. Ebada Victor Wray Nicole J. de Voogd Zhiwei Deng Wenhan Lin Peter Proksch 《Marine drugs》2009,7(3):434-444
Two new jaspamide derivatives 2 and 3, together with the parent compound jaspamide (1) have been isolated from the marine sponge Jaspis splendens collected in Kalimantan (Indonesia). The structures of the new compounds were unambiguously elucidated based on 1D and 2D NMR spectral data, mass spectrometry and comparison with jaspamide (1). The new derivatives inhibited the growth of mouse lymphoma (L5178Y) cell line in vitro with IC50 values of <0.1 μg/mL. 相似文献
48.
49.
[目的]明确引起广东省中山市一串红茎基部腐烂的病原菌种类及其主要生物学特性。[方法]对一串红病株进行了病原菌分离纯化,研究了其形态特征、致病性、主要生物学和分子生物学特性。[结果]该菌在多种培养基上均可生长;生长温度范围为5~30℃,最适生长温度为加~25℃。在供试碳源中,病原菌对葡萄糖利用最好;在供试的氮源中,对硫酸铵利用最好;菌丝在pH2—9均可生长,生长的最佳pH值为3~6;同时筛选出几种对病原菌有明显抑制作用的杀菌剂。[结论]引起一串红茎基腐菌核病的病原菌鉴定为核盘菌,这在中国大陆首次报道。 相似文献
50.