Drought effects on buds growth and dynamic of Tunisian cork oak populations

Forest species have adapted to their local climate by changing some of their phenological characteristics. Differential phenological responses may modify tree chance of survival by altering the competitive balance between them. The study of key phenological stages (budding, budburst, flowering, falling leaves ...) knew a renewed interest these last years for climate changes consequences researches. Characterizing the phenological variability response, of five Tunisian cork oak populations from contrasting climatic situations, in front to water deficit, has been the subject of this study. Large differences between populations from highest and coldest sites as well as those of lowest and warm sites were detected and adaptative responses specific to some populations were founded

Identification of Salt Stress Biomarkers in Romanian Carpathian Populations of Picea abies (L.) Karst

The Norway spruce (Picea abies), the most important tree species in European forests, is relatively sensitive to salt and does not grow in natural saline environments. Yet many trees are actually exposed to salt stress due to the common practice of de-icing of mountain roads in winter, using large amounts of NaCl. To help develop strategies for an appropriate use of reproductive seed material on reforestation sites, ensuring better chances of seedling survival in salt-affected areas, we have studied the responses of young spruce seedlings to salt treatments. The specific aim of the work was to identify the optimal salt stress biomarkers in Picea abies, using as experimental material seedlings obtained by germination of seeds with origin in seven populations from the Romanian Carpathian Mountains. These responses included general, conserved reactions such as the accumulation of ions and different osmolytes in the seedlings needles, reduction in photosynthetic pigments levels, or activation of antioxidant systems. Although changes in the contents of different compounds involved in these reactions can be associated to the degree of stress affecting the plants, we propose that the (decreasing) levels of total phenolics or total carotenoids and the (increasing) levels of Na+ or K+ ions in Picea abies needles, should be considered as the most reliable and useful biomarkers for salt stress in this species. They all show very high correlation with the intensity of salt stress, independently of the genetic background of the seeds parental population, and relatively easy, quantitative assays are available to determine their concentrations, requiring simple equipment and little amount of plant material.Funding: Sorin Schiop is a PhD student at the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. This paper was published under the frame of European Social Found, Human Resources Development Operational Programme 2007-2013, project no. POSDRU/159/1.5/S/132765. Mohamad Al Hassan is a recipient of an Erasmus Mundus pre-doctoral scholarship financed by the European Commission (Welcome Consortium).Schiop, ST.; Al Hassan, M.; Sestras, AF.; Boscaiu Neagu, MT.; Sestras, RE.; Vicente Meana, Ó. (2015). Identification of Salt Stress Biomarkers in Romanian Carpathian Populations of Picea abies (L.) Karst. PLoS ONE. 10(8). doi:10.1371/journal.pone.0135419Se013541910

Drought effects on buds growth and dynamic of Tunisian cork oak populations

Forest species have adapted to their local climate by changing some of their phenological characteristics. Differential phenological responses may modify tree chance of survival by altering the competitive balance between them. The study of key phenological stages (budding, budburst, flowering, falling leaves ...) knew a renewed interest these last years for climate changes consequences researches. Characterizing the phenological variability response, of five Tunisian cork oak populations from contrasting climatic situations, in front to water deficit, has been the subject of this study. Large differences between populations from highest and coldest sites as well as those of lowest and warm sites were detected and adaptative responses specific to some populations were founded

Effects of Heavy Metals on Growth and Bioaccumulation of the Annual Halophytes Atriplex Hortensis and A. Rosea

Abstract: Heavy metals such Zn, Pb, Cu and Cd can cause a non-degradable pollution in numerous sites in France as well as in Tunisia, or elsewhere. This pollution resulting from various human polluting activities, related to industry or mining, is often diffuse in soils. Vegetation can play an important role in decontaminating these soils, their rehabilitation, and making their environment safer. For a better understanding of metal reactivity, a review of general knowledge concerning this kind of polluting metals and plant tolerance mechanisms is presented. A study was also conducted on the accumulation of the following metals: Cd, Cu, Zn, Pb and Ni, in their localisation in plant tissues and their induced toxic effects. The most general visible, but nonspecific symptom of heavy metal stress is growth inhibition, which has been investigated in many plants, including Atriplex. A cultivation of annual Atriplex plants was conducted according to hydroponic experimental design. The experimental approach consisted of hydroponic cultures using simplified medium represented by a nutritive solution. Results showed that plant final biomass, leaf area and metal accumulation, all varied with the metals level of toxicity and the plant species considered. Hence, the plants of the three annual arroach species or varieties used, all showed an intermediate level of tolerance according to the imposed treatments. Metal induces a number of physiological changes, such as growth inhibition, a significant reduction in biomass production was observed in metal treated plants compared with the control plants. The bioaccumulation factor decreased at the highest metal level, the low transfer of metal from solution to above-ground organs at higher solution metal concentrations indicates an exclusion mechanism. Trace element accumulation in shoots and the bioconcentration factors were proportional to the initial concentration of individual metals in the growth medium and the duration of exposure. Annual orach : A. hortensis seem to have a good capability for tolerance and phytostabilisation areas containing heavy metals

Physiological and biochemical responses of Suaeda fruticosa to cadmium and copper stresses: growth, nutrient uptake, antioxidant enzymes, phytochelatin, and glutathione levels

Environmental pollution by trace metal elements (TMEs) is a serious problem worldwide, increasing in parallel with the development of human technology. The present research aimed to examine the response of halophytic species Suaeda fruticosa to oxidative stress posed by combined abiotic stresses. Plants have been grown for 1 month with an irrigation solution supplemented with 200 mM NaCl and 400 μM Cd2+ or 400 μM Cu2+. The level of glutathione (GSH), phytochelatins (PCs), and antioxidant enzyme activities [ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT)] as well as lipid peroxidation was studied to see the stress exerted by the TME and the level of tolerance and detoxification strategy adopted by S. fruticosa. Relative growth rate (RGR) decreased under Cd2+ stress in this species, whereas Cu2+ did not have any impact on S. fruticosa performance. Cd2+ or Cu2+ enhanced malondialdehyde, suggesting reactive oxygen species-induced disruption of membrane integrity and oxidative stress in S. fruticosa. On the other hand, the activities of the antioxidant enzymes CAT, APX, and GPX diminished and mineral nutrition was disturbed by metal stress. S. fruticosa was able to synthesize PCs in response to TME toxicity. However, data indicate that GSH levels underwent a significant decrease in roots and leaves of S. fruticosa stressed by Cd2+ or Cu2+. The GSH depletion accompanied by the increase of phytochelatin concentration suggests the involvement of GSH in the synthesis of phytochelatins.info:eu-repo/semantics/publishedVersio