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Influence of copper on root-growth and morphology of Pinus-pinea L. and Pinus-pinaster Ait. seedlings
No full textWe assessed the effects of Cu on root growth and morphology of stone pine (Pinus pinea L.) and maritime pine (Pinus pinaster Ait.) seedlings grown in culture solutions supplied with 0.012 (control), 0.1, 1 or 5 mu M CuSO4. The presence of 5 mu M Cu in the nutrient solution completely inhibited root growth of both species within 3 days. In both species, taproot elongation was reduced in the presence of 1 mu M CU, although partial growth recovery occurred after 7 days of treatment. The presence of 0.1 mu M Cu in the culture solution slightly enhanced root elongation in P. pinnster, but did not significantly influence root elongation in P. pinea. In both species, root weight per unit length increased in response to Cu exposure, and in P. pinaster, root diameter was significantly increased. The Cu treatments also affected lateral root number and length. In the presence of 1 mu M Cu, both species formed only short lateral primordia. The 1 mu M Cu treatment increased the lateral root index (number of roots per cm of root length) of P. pinaster, but decreased that of P. pinea, compared with control values. Neither the 0.1 nor 1 mu M Cu treatment had a significant effect on the mitotic index of either species. We conclude that cell elongation is more sensitive to Cu than cell division. Cell membrane damage, as indicated by Trypan blue staining, occurred after 10 days of exposure to 1 mu M Cu
Cadmium and copper change root-growth and morphology of Pinus-pinea and Pinus-pinster seedlings
No full textHeavy metal loads in forest soils have been increasing over time due to atmospheric inputs. Accumulation in the upper soil layers could affect establishment of seedlings and forest regeneration. Mediterranean species show a high initial root development, allowing seedlings to reach the moisture of deeper soil layers. In the present work seedlings of stone pine (Pinus pinea L.) and maritime pine (Pinus pinaster Ait.), were grown in culture solution supplied with 0.0, 0.1, 1 or 5 mu M CdSO4 or with 1 mu M CdSO4 and 1 mu M CuSO4 combined. In both species tap-root elongation was drastically reduced in the 5 mu M Cd2+ and in the (Cd2+ + Cu2+) treatments. A supply of 0.1 or 1 mu M Cd2+, however, enhanced root elongation in Pious pinea without significantly influencing root elongation in Finns pinaster. In both species the root density (weight per unit length) and the width of the cortex increased in response to Cd2+ exposure. In Pinus pinaster the mitotic index decreased at the higher Cd2+ concentrations and when Cd2+ and Cu2+ were combined. The data suggest that cell elongation is more sensitive to Cd2+ than cell division. The number and length of the lateral roots were also affected by Cd2+ treatment to a higher degree in Pinus pinaster than in Pinus pinea, reflecting the different Cd-tolerance of the two species
Cadmium and copper uptake and distribution in Mediterranean tree seedlings
No full textCopper and cadmium uptake and distribution in 2-week-old seedlings of stone pine (Pinus pinea L.), maritime pine (Pinus pinaster Ait.) and ash (Fraxinus angustifolia Vahl.) were investigated. Seedlings were grown in culture solution at increasing concentrations of CuSO4 (0.012-5 mu M) and CdSO4 (0.0-5 mu M). All species accumulated copper in a larger amount than cadmium, Translocation to the shoot was strongly restricted for both metals, though higher cadmium mobility within the plant could be evidenced. A strong relationship between root content and growth inhibition was detected in the roots in response to copper but not to cadmium treatments, Among species P. pinea seemed to be more tolerant to cadmium, whereas F: angustifolia was highly sensitive to both cadmium and copper. X-ray microanalysis of root tip sections showed that copper and cadmium only accumulated in the root tips of F. angustifolia, copper mostly in the cell walls of the cortex layer, cadmium in the inner compartments of the cortex cells. It is suggested that in the two Pinus species the well developed root cap plays a protecting role against metal uptake at the root-tip zone
Metal pollution and forest decline
No full textThe chapter presents an overview on the antrophogenic sources of heavy metal pollution and the patterns of distribution of these contaminnats in natural environments. It presents authors' researches on the different sensitivity of forest species to heavy metals and on the role of mycorrhiza. Finally amelioration techniques are discussed
pH influence on root growth and nutrient uptake of Pinus pinaster seedlings
No full textTwo-week old Pinus pinaster seedlings were grown at four pH values ranging from 3.5 to 6.5. Root elongation rate progressively decreased with the duration of treatment at 3.5 and 6.5 pH. After 4 weeks 3.5 pH grown roots showed the lowest length and the highest biomass because of their marked thickening. The pH of the culture solution did not influence lateral root initiation, whereas it affected their length, that was highest at 3.5 pH and lowest at 6.5 pH. Mineral nutrition was affected by the pH of the culture solution. The P, Fe and Al concentration in roots was higher in the 3.5 and 4.5 pH solutions. On the contrary, a lower K, Ca, Mg and especially Mn content of roots was measured in the 3.5 pH grown seedlings. These results suggest that P. pinaster is able to grow on a wide range of acidic soils changing the morphology of the root system in relation to soil conditions
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