Rootstocks and wild grapevines responses to salinity

A study of the effects induced by salt solutions applied on in vitro cultures and potted vines comparing five widely used rootstocks in Romania and six wild accessions from five populations of Vitis vinifera L. ssp. sylvestris (Gmelin) Hegi was performed. For in vitro test, all genotypes were analyzed for toxicity symptoms appearance in media containing 17, 32 and 49 mM NaCl. The same accessions, as potted plants, were subjected to salt treatments with 51, 68 and 102 mM NaCl, and were evaluated in terms of growth reduction and toxicity symptoms emergence after one month of salt treatment. P, K and Na contents were detected in in vitro plantlets and potted plants. Results showed significant differences among genotypes and between the in vitro and potted treatments. The wild grapevine individuals, in comparison to the rootstocks, expressed a higher ability to adapt to the salt stress in both type of treatments. In comparison with the rootstocks, the wild grapevine individuals were characterized by a higher content of P and lower contents of K and Na, which could be directly correlated with their ability to uptake and accumulate a higher level of Na and Cl into their tissues

Changes in chlorophyll fluorescence parameters and oxidative stress responses of bush bean genotypes for selecting contrasting acclimation strategies under water stress

Drought resistance of bean landraces was compared in order to select genotypes with either high morphological or high biochemical-physiological plasticity. The lines in the former group exhibited fast reduction in fresh and dry mass, decreased the water potential in primary leaves after irrigation withdrawal and the biomass mobilized from the senescent primary leaves was allocated into the roots. These genotypes had high frequency of primary leaf abscission under water stress. The genotypes with plasticity at the biochemical level maintained high water potential and photochemical efficiency, i.e. effective quantum yield, high photochemical (qP) and low non-hotochemical (NPQ) quenching in primary leaves under drought stress. While superoxide dismutase activity was not influenced by the drought and the genotype, catalase activity increased significantly in the primary leaves of the genotypes with efficient biochemical adaptation. Lines with high morphological plasticity exhibited higher quaiacol peroxidase activity under drought. Proline may accumulate in both cases, thus it may be a symptom of protein degradation or a successful osmotic adaptation. On the basis of contrasting responses, the genetic material cannot be screened for a large-scale breeding program by a single physiological parameter but by a set of the methods presented in this work