Drought tolerance was evaluated in twelve cultivars of three ornamental Tagetes species (T. patula, T. tenuifolia and T. erecta). A stress treatment was performed by completely stopping watering of plants maintained in controlled greenhouse conditions. After three weeks, several plant growth parameters (stem length (SL), fresh weight (FW) and water content (WC)), photosynthetic pigments (chlorophylls and carotenoids (Car)), osmolytes (proline (Pro), glycine betaine (GB) and total soluble sugars (TSS)), an oxidative stress maker (malondialdehyde (MDA)) and antioxidants (total phenolic compounds (TPC) and total flavonoids (TF)) were measured. Considerable differences in the evaluated traits were found among the control and drought-stressed plants. Drought stress generally caused a marked reduction in plant growth and carotenoid pigments, and an increase in soluble solutes and oxidative stress. For most cultivars, proline levels in stressed plants increased between 30 and 70-fold compared to the corresponding controls. According to the different measured parameters, on average T. erecta proved to be more tolerant to drought than T. patula and T. tenuifolia. However, a considerable variation in the tolerance to drought was found within each species. The traits with greater association to drought tolerance as well as the most tolerant cultivars could be clearly identified in a principal components analysis (PCA). Overall, our results indicate that drought tolerant cultivars of Tagetes can be identified at early stages using a combination of plant growth and biochemical markers.

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.

In recent years, quinoa (Chenopodium quinoa Willd.) has attached the interest as a multi-purpose crop. A 3-year field experiment was conducted to determine the effects of tillage systems and fertilization on nitrogen uptake and use efficiency of quinoa crop. The experiment was laid out in a split-plot design with two replicates, two ) were found in N2. Nitrogen harvest index and nitrogen utilization efficiency were up to 60% lower and 40% lower, respectively, in inorganic treatments than in the control. Rates of nitrogen higher than 100 kg N ha -1 (N1) did not increase the nitrogen agronomic efficiency. Regarding apparent nitrogen recovery efficiency, the higher values observed under inorganic fertilization and being greater than 100%. The highest rates of change of nitrate reduction in soil (-0.108 to -0.188 N% day -1 ) and nitrogen increase in plant (0.025 to 0.027 N% day -1 ) were observed under N2 treatment. As a conclusion, quinoa has a high capacity to take up nitrate from the soil, but presents lower nitrogen remobilization from the vegetative parts into the seeds under high nitrogen supply.

Larix decidua, the European larch, is not normally affected by drought or salinity in its natural habitats, but it may be when grown as an ornamental tree, by the widespread practice of winter de-icing of mountain roads with NaCl, and because of global warming-induced environmental changes. The responses of two-month-old larch seedlings to 30 days water deficit (withholding irrigation) or salt stress (150 mM NaCl) treatments were studied by determining stress-induced changes in several growth parameters and biochemical markers (ion and osmolyte contents, level of oxidative stress, activation of enzymatic and non-enzymatic antioxidant systems). Both treatments caused the inhibition of growth, degradation of photosynthetic pigments, a small increase in malondialdehyde (MDA, an oxidative stress biomarker), and the activation of antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR). In all cases, salinity appeared to have stronger effects on the seedlings than water deficit. The presence of relatively high concentrations of glycine betaine, both in control and stressed plants, may represent a constitutive mechanism of defence against stress in European larch. Additionally, other responses were specific for salt stress and included the activation of K + transport from roots to shoots and the accumulation of Pro as an osmoprotectant.

Norway spruce is a native European coniferous species distributed from the Carpathian Mountains and the Alps to northern Scandinavia. In the coming decades, spruce forests will need to cope with increasing climate changes which are already threatening their natural habitats. European forest policy should adapt to the changing climate by deploying drought-tolerant genotypes in regions expected to experience increased stress in the future. To identify reliable water stress biomarkers in this species, which may be eventually used to select populations responding better to forecasted drought events, we studied the physiological responses to severe water stress treatments of spruce seedlings originating from several locations in the Romanian Carpathian Mountains. Oneyear old seedlings were denied irrigation for six weeks in order to generate severe water stress in controlled conditions. Variations in the levels of the studied photosynthetic pigments, osmolytes, and non-enzymatic antioxidants were detected across the spruce populations. Several of the determined parameters in seedling needles, such as the decrease in water content (nearly 40% decrement in the most sensitive studied populations), the degradation of chlorophylls, or a low increase of proline levels (up to seven-fold increment in the most sensitive populations in comparison to no change in the most tolerant ones), could be employed as biomarkers for an early assessment of water stress at this stage. Furthermore, seedlings from two of the populations under study (Sudrigiu and Gioristea-Calimanut) apparently responded better to water stress than the other populations, as shown by their lower reduction in needle water content, no degradation of chlorophyll a and carotenoids, and less proline accumulation, suggesting a relatively higher 2 resistance to drought. These populations also seemed to be the least affected by osmotic stress at the seed germination stage. Therefore, we consider that the use of biochemical markers of stress at early seedling stages could represent a useful tool for the initial screening of populations that have relatively high tolerance to drought, warranting further research for potential use in reforestation.