Osmolyte Accumulation and Sodium Compartmentation Has a Key Role in Salinity Tolerance of Pistachios Rootstocks

Physio-biochemical responses of pistachio varieties including Pistacia vera L. ‘Ghazvini’ (GH), P. vera ‘Ghermez-Pesteh’ (GP) and P. atlantica subsp. mutica (M) were assessed under salt stress to understand the common mechanisms of salt tolerance in two popular Pistacia species. In the experiment, half-sib seedlings of the varieties were subjected to high (100 mM) and severe (200 mM) levels of NaCl-induced salinity for 90 days. Growth, physiological, biochemical and ionic parameters in the roots and shoots of plants were measured in the experiment. Salinity markedly declined plant growth, and increased the number of necrotic leaves (NL) and leaf abscission. In terms of physiological responses, salinity reduced the relative water content (RWC), membrane stability index (MSI) and the concentrations of photosynthetic pigments, but increased carbohydrates and proline content in the leaves. MSI of the leaves was positively correlated with the concentrations of anthocyanins and carotenoids. Salinity increased sodium content in root and shoot tissues of the plants, and decreased potassium concentration and K/Na ratio. Among the rootstocks, GH had better performance on all parameters. Despite the high concentration of Na+ and low K/Na ratio in the shoots, the lowest number of NL was found in GH under both salinity levels. The results indicated that salt tolerance in GH was most likely related to compartmentation of Na+ ions. Finally, accumulation of osmolytes and sodium compartmentation were considered to be the most important mechanisms in the salt tolerance of pistachio rootstocks.

ASSESSMENT OF GENETIC VARIATION AMONG PISTACIA ATLANTICA DESF. REGARDING SEXUAL GENOTYPES (MALE, FEMALE AND HERMAPHRODITIC) USING ISSRS. MARKERS

All Pistacia species are dioecious, male and female flowers are born on separated trees. Our recent studies identified new hermaphroditic genotypes of P. atlantica with different structure of racemes and flowers at the south of Syria. Therefore, the current research aimed to assess genetic variation among 11 genotypes (3 female, 5 hermaphroditic, 3 male) across fifteen ISSRs primers in Sweida Research Center (2018-2019). All of the primers were able to detect the polymorphism, which revealed 214 bands, 205 of them were polymorphic (95.79%). The number of bands for each primer ranged from 6 to 33, with an average 14.27 bands for each Primer. Genetic similarity among all studied genotypes ranged from (0.27) between hermaphroditic genotype (PA52) with female genotype (FA3) as well as between MA3 male genotype and FA2 female genotype, while the highest genetic similarity was 0.77 between two hermaphroditic genotypes (PA37and PA52). Cluster analysis grouped all studied genotypes into three main clusters according to their sexual structure; the first cluster contained all of the hermaphroditic genotypes and the second cluster comprised of all male genotypes, while the third cluster included all female genotypes. The results demonstrated the importance and the efficiency of ISSR technique by revealing the genetic variation among P. atlantica genotypes and separating all of them into detached clusters according to their sexual structure. Farther more, some primers were able to detect common bands in each sexual structure which might help to understand the mechanism of sexual inheritance within the studied species.

Determination of Phenolic Compounds’ Extraction Conditions from Pistacia palaestina Leaves at Two Different Stages of Maturity

Background: Phenolic compounds are distributed throughout the plant kingdom. Numerous investigations have proved that Pistacia species have secondary metabolites, and these contain different classes of bioactive phenolic compounds. Objective: The objective of the present work was to optimize the extraction conditions of phenolic compounds from Pistacia palaestina leaves cultivated in Syria and find out the effects of the solvent type, extraction time, and temperature on total phenolic content (TPC) and in vitro antioxidant activity% (AA%). Two different growth stages were studied. Methods: Antioxidant activity and total phenolic content values were estimated using 2,2’-diphenyl- 1-picrylhydrazyl and Folin-Ciocalteu methods, respectively. Results: The highest TPC and AA% were found in fresh leaves (14.32g/100g and 92.69%, respectively). The optimum extraction solvent for phenolic recovery and antioxidant capacity was acetone 40%. Changes both in temperature (25, 40, 60 and 80°C) and time (15, 30, 45 and 60 min) had no significant influence on TPC and AA% of Pistacia extracts. Conclusion: Phenolic compounds could be extracted in a short time at a low temperature and could be used as natural antioxidant agents.

The Effect of Oleander (Nerium oleander L.) Extracts on Seed Germination and Seedling Growth of Four Pistacia Species

In this study, the effects of the extracts obtained from flower, stem, leaf, branch and their mixture of Nerium oleander L. on the seed germination and seedling growth of four Pistacia species (Pistacia terebinthus L., P. vera L., P. khinjuk Stocks., P. atlantica Desf. and P. terebinthus L.) were investigated. Five hundred grams of N. oleander was taken from the plant parts and the extracts were mixed with distilled water (1.5 L). The extracts were applied to Pistacia species for 24 and 48 hours. The results showed that the extract had positive effects on their germination and growths of the species mentioned above. The highest germination rate for all the Pistacia species was obtained from the extracts of flower, while the lowest germination rate was recorded in the mixture of all parts of N. oleander mentioned above. Moreover, the treatment time was found to reduce the germination ratio. It was also found that the extracts from the stem of N. oleander were the most effective on the stem height of the Pistacia species studied. It was followed by the extracts from branches, leaves and flower, respectively. Furthermore, the findings indicated that the extracts from the stem of N. oleander had pronounced effect on the stem diameter of the Pistacia species studied. It was followed by the extracts from flower, leaves, and branches, respectively. In general, the effects of the extracts from several parts of N. oleander on the germination and other growing parameters were found to be almost comparable to those of synthetic promoter, Gibberellic Acid (GA3).