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581.
The strategy of biological reclamation of ecosystems in the zones of chemical pollution with asymmetrical dimethylhydrazine (ADMH), a highly toxic propellant, is proposed. The strategy is based on the results of comprehensive studies on trends in the interactions of soils, plants, and accompanying microorganisms with ADMH at rocket stage drop sites and in specially established test areas, under natural and controlled conditions.__________Translated from Ekologiya, No. 3, 2005, pp. 193–200.Original Russian Text Copyright © 2005 by Ermakov, Panova, Stepanova. 相似文献
582.
583.
水耕植物过滤法去除氮磷的影响因素及途径 总被引:2,自引:0,他引:2
采用水耕植物过滤法(hydroponic bio-filter method,HBFM)净化富营养化地表水的试验表明,在水力负荷为3.0 m3/(m2·d)的条件下,TN、TP年平均去除率分别为16.8%、30.8%,年平均去除速率分别为1.0、0.1 g/(m2·d).通过底泥沉积去除的氮、磷分别占系统氮、磷总去除量的62.2%和75.9%,是TN、TP最主要的去除途径.HBFM的最佳水力负荷为3.0~4.0 m3/(m2·d).西洋菜收割时的剪割强度影响其氮磷吸收速率,每次剪割长度不得超过10 cm.收割频率为1次/月时不会影响HBFM的氮磷去除效果. 相似文献
584.
Increasing atmospheric CO2 concentration is generally expected to enhance photosynthesis and growth of agricultural C3 vegetable crops, and therefore results in an increase in crop yield. However, little is known about the combined effect of elevated CO2 and N species on plant growth and development. Two growth-chamber experiments were conducted to determine the effects of NH4^+/NO3^- ratio and elevated CO2 concentration on the physiological development and water use of tomato seedlings. Tomato was grown for 45 d in containers with nutrient solutions varying in NH4^+/NO3^- ratios and CO2 concentrations in growth chambers. Results showed that plant height, stem thickness, total dry weight, dry weight of the leaves, stems and roots, G value (total plant dry weight/seedling days), chlorophyll content, photosynthetic rate, leaf-level and whole plant-level water use efficiency and cumulative water consumption of tomato seedlings were increased with increasing proportion of NO3- in nutrient solutions in the elevated CO2 treatment. Plant biomass, plant height, stem thickness and photosynthetic rate were 67%, 22%, 24% and 55% higher at elevated CO2 concentration than at ambient CO2 concentration, depending on the values of NH4^+/NO3^- ratio. These results indicated that elevating CO2 concentration did not mitigate the adverse effects of 100% NH4^+-N (in nutrient solution) on the tomato seedlings. At both CO2 levels, NH4^+/NO3^- ratios of nutrient solutions strongly influenced almost every measure of plant performance, and nitrate-fed plants attained a greater biomass production, as compared to ammonium-fed plants. These phenomena seem to be related to the coordinated regulation of photosynthetic rate and cumulative water consumption of tomato seedlings. 相似文献
585.
L. A. Ivanov L. A. Ivanova D. A. Ronzhina H. Ziegler K. Deigele P. D. Gunin V. I. P’yankov 《Russian Journal of Ecology》2007,38(3):155-160
The isotope ratios δ13C and δ15N and the contents of nitrogen, carbon, and mineral substances have been studied in the leaves of Ephedra sinica, Allium polyrhizum, and Stipa glareosa plants growing separately or together under arid conditions of the Gobi (Mongolia). The contents of nitrogen, mineral substances, and δ15N have proved to decrease when these species grow together, providing evidence that they compete for environmental resources. The nitrogen content decreases to the greatest extent in E. sinica due to the low competitiveness of this species. The direction of change in δ13C in E. sinica is opposite to that in A. polyrhizum and S. glareosa. Differences in physiological mechanisms of adaptation to stress between these species provides a basis for attributing them to different functional groups and for predicting the result of their competition upon changes in climatic conditions. 相似文献
586.
587.
考察了水芹、鱼腥草、香根草及对校园微污染景观水体的净化效果,分析了植物不同部位的氮磷含量分布.结果表明,水芹、鱼腥草和香根草对水中的TN、TP、CODcr和Chla的去除率范围分别为52.4%~64.3%、46.8%~ 58.4%、69% ~ 84%和48.1% ~60%,经7周净化可使听松湖水质由Ⅳ类水变为Ⅲ类水.组合植物对TN、TP、CODcr和Chla的净化效果相对于单种植物作用均没有显著增加(p>0.05).鱼腥草对水中氮磷的吸收效率最高,香根草次之,水芹最低.3种植物不同部位的植株含氮量为根>茎>叶,磷含量为根大于茎叶. 相似文献
588.
It has been shown that endomycorrhizas are found in the majority of herbaceous plants, but their adaptive significance is ambiguous. As a rule, the degree of development of plants and their parts, cenotic status of the species, and species diversity of plant community manifest no definitely positive correlation with the level of mycorrhiza development on root systems. Interactions between the partners in most cases can be classified as indifferent or negative. 相似文献
589.
Effects of Self-Compatibility on the Distribution Range of Invasive European Plants in North America
Abstract: Many plant species have been introduced to new continents, but only a small subset of these have become invasive. It has been predicted that self-compatible species, particularly those that do not need the services of pollinators, are more likely to establish and spread after long-distance dispersal. We tested whether this hypothesis, commonly called Baker's law, applies to 361 species that have invaded the United States from Europe. Species capable of autonomous seed production occurred in significantly more states than species requiring a pollen vector. Moreover, of the species that are not capable of autonomous seed production, self-compatible species occurred in significantly more states than those that are not self-compatible. The positive effect of autonomous seed production on the range of invasion was larger for abiotically pollinated species than for biotically pollinated species and for monocarpic species than for polycarpic species. These results support Baker's law, and we recommend that screening protocols for predicting invasiveness of species considered for introduction should include assessment of their breeding system. 相似文献
590.