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Evidence exists that Cd and certain nutrient elements, such as Fe and Mg, could share similar mechanisms of plant uptake and accumulation. Here we report that Mg and Fe deficiency in mature plants ofSalix viminalis, grown in hydroponic solutions containing 5 µg ml−1of Cd, caused a significant increase in Cd accumulation in roots, stems and leaves. Cd (µg g−1dry weight) was determined following three treatments: 1) Cd treatment in complete nutrient solution; 2) Cd treatment with Fe deficiency; and 3) Cd treatment with Mg deficiency, yielding, respectively: in young leaves (65.3, 76.1, and 92.2), mature leaves (51.5 to 76.3 and 87.1), upper stems (80.6, 116.8, and 130.6) lower stems (67.2, 119, and 102.3), roots (377.1, 744.8, and 442,5). Our results suggest that Cd utilizes the same uptake and transport pathways as Mg and Fe. Evidence exists that Mg and Fe uptake and translocation could be further facilitated by plants as an adaptive response to deficiency of these elements. Such physiological reaction could additionally stimulate Cd accumulation. Although Cd uptake was mostly confined in roots, high Cd content in aerial plant parts (51.5–130.6 µg g−1) indicates that the analysedSalix viminalisgenotype is suitable for phytoextraction. [ABSTRACT FROM AUTHOR]

Five black poplar clones were subjected to three different soil water regimes (well-watered and two water-stressed treatments) to evaluate their morpho-physiological and biochemical responses to water deficits. Plants were grown in a semi controlled environment (greenhouse) by soil culture method. The three-month-old plants were exposed to 90-70% of maximum soil water saturation - control, mild drought followed by recovery of optimal soil water saturation (90-40%) and severe drought (50-40% of soil water saturation) for 21 days. Prolonged drought caused reduction in photosynthetic (A) and transpiration (E) intensity in all clones, but after recovery these parameters were enlarged considerably. Instantaneous water use efficiency (WUEi) was significantly increased under conditions unfavorable for A and E, where genotypes IX/30 and I/2 showed the highest values. The best recovery of A and WUEi exhibited genotype I/2. Proline accumulation in leaves was increased with the increasing intensity of drought, whereas VII/25 and I/2 showed better osmotic adjustments and higher drought tolerance than the other examined clones. No direct correlation was found between water deficit level and malondialdehyde (MDA) content in genotypes IX/30 and X/32, while the other clones showed significant MDA accumulation in one or both drought treatments. Water deficits significantly slowed down apical growth and shoot height growth in all clones except in X/32, while VII/32 and X/32 showed similar number of leaves during all treatments with no significantly differences among values per clone. The obtained results provide clear evidence for clonal differentiation in their responses to water deficiency in all examined parameters. [ABSTRACT FROM AUTHOR]

Environmental factors like temperature and soil humidity are recognized as influencing factors on photosynthetic response and organic productivity, distribution and biochemical characteristics of plants. Here we present measurements of gas exchange parameters, water-use efficiency (WUE) and nitrogen-use efficiency (NUE) of field-grown invasive species Ambrosia artemisiifolia L., Ambrosia trifida L. and Iva xanthifolia Nutt., in order to define their potentials as colonizers. Biogenic volatile organic compounds (BVOC) in leaves and flowers depending on soil humidity were also investigated. Results indicated species A. artemisiifolia as the colonizer with the highest physiological potential because of its high WUE in its vegetative phase and also the highest NUE and the highest photosynthesis/dark respiration ratio in its flowering phenological phase. It was found that the volatile compounds of Ambrosia species and Iva xanthifolia consist mainly of terpenic compounds. There was a significant difference among the species regarding qualitative composition of monoterpens and sesquiterpens and specific qualitative and quantitative ratio of monoterpens in flowers and leaves of A. artemisiifolia. [ABSTRACT FROM AUTHOR]

In order to determine their phytoextraction potential, four clones of Salix (1. Salix alba - clone 68/53/1; 2. Salix alba - clone 106/54/0; 3. Salix matsudana - clone SM 4041; and 4. Salix nigra - clone 0408) were exposed to elevated concentrations of Cd, Ni and Pb-EDTA in a water culture solution. The translocation ratio to upper plant parts was very low for all applied heavy metals and, therefore, the metal uptake was restricted to the roots, especially regarding Pb. The ability of the clones to extract and translocate Cd, Ni and Pb differed depending on the quantity of metal content in the nutrient solution and of the willow genotype. The ability of the investigated clones to accumulate Cd in leaves is to our knowledge among the highest so far recorded compared to other hydroponic trials in literature. The preference for Cd-stimulated root growth was determined. This genotype-specific response could be part of a mechanism for Cd resistance. [ABSTRACT FROM AUTHOR]

This study tried to evaluate the influence of high temperatures (HT) on carbon assimilation of two oak species (Quercus cerris and Quercus robur). The screening of their populations, which are assumed to have a different resistance and acclimatization potential to adverse environmental conditions, can provide essential information for its implementation in reforestation strategies. By employing principal component analysis, the aim was to determine the most variable physiological characteristics of plants exposed to extremely HT during vegetation periods. After 2 d of HT treatment, a significant decline of photosynthetic and transpiration rates, and stomatal conductance were observed in plants of all investigated populations. The decrease of photosynthetic parameters after 2 d of HT treatment was regulated by the stomatal closure which caused the limitation of CO2 assimilation. Contrary, a chronic HT stress led to an increase in gs and inhibition of photosynthesis at the level of carboxylation. [ABSTRACT FROM AUTHOR]