Sex identification in Pistacia species during the long juvenile stage is an economically desirable objective. Due to the lack of morphological methods to identify sex at this stage, the application of molecular markers is expected to facilitate breeding programs. The aim of our study was to identify a marker closely linked to sex loci in Pistacia atlantica Desf subsp. mutica, P. khinjuk, and P. vera subsp. Sarakhs. Samples were collected from both male and female plants of each species, and their band patterns were analyzed according to the presence or absence of specific bands. Thirty random amplified polymorphic DNA (RAPD) primers and a pair of sequence characterized amplified region (SCAR) primers were tested as potential markers of sex in wild Pistacia species. Among the RAPD primers, only BC 1200 was found to amplify a specific sex band present in female plants. Based on our analysis of all individual samples, a fragment of approximately 300 bp was amplified in female trees but absent in male ones. Although sex determination mechanisms in Pistacia are still unknown, they may be controlled by a single locus that acts as a trigger. The SCAR technique has proved to be a reliable technique in gender determination of pistachio genotypes at the seedling phenophase. This method could reduce both the time and costs associated with breeding programs.

ABSTRACT. The genus Juniperus L. (Cupressaceae), an aromatic evergreen plant, consists of up to 68 species around the world. We classified five species of Juniperus found in Iran using molecular markers to provide a means for molecular identification of Iranian species. Plants were collected (three samples of each species) from two different provinces of Iran (Golestan and East Azarbayejan). The DNA was extracted from the leaves using a Qiagen Dneasy Plant Mini Kit. Amplification was performed using 18 ten-mer RAPD primers. Genetic distances were estimated based on 187 RAPD bands to construct a dendrogram by means of unweighted pair group method of arithmetic means. It was found that J. communis and J. oblonga were differentiated from the other species. Genetic distance values ranged from 0.19 (J. communis and J. oblonga) to 0.68 (J. communis and J. excelsa). Juniperus foetidissima was found to be most similar to J. sabina. Juniperus excelsa subspecies excelsa and J. excelsa subspecies polycarpos formed a distinct group.

No abstract

Pollution by heavy metals such as cadmium (Cd) is hazardous to soil microbial function, including enzyme activities. However, the addition of clay to soils may control the negative effect of Cd by both adsorption of the metal ion onto the clay and stabilization of the soil enzymes. We investigated the effects of clay addition on the activities of soil proteases in the presence of Cd using a short-term laboratory incubation experiment. The clays were separated from the soil samples used in the study. Our experiment was done at three levels of clay and Cd addition (0, +5 and +10% of original clay content, and 0, 10 and 50 mg Cd kg )1 soil, respectively) to two surface soil samples of Andosols obtained from a forest and a cultivated field in an upland area of Japan's Kanto district. We determined the protease activities, protein content, soil pH and exchangeable Cd in both soil samples after 0, 2, 10 and 40 days of incubation. Mineralogical analysis by dissolution with acid ammonium oxalate solution on the clay fractions from both the forest and the cultivated field soil samples showed that they were largely composed of allophane (probably including imogolite) and ferrihydrite. Allophanic clay had a significant positive effect on proteases activities even in the presence of Cd, although the addition of Cd decreased protease activities, protein contents and soil pH in both soil samples in all clay treatments during incubation. Protease activities were negatively correlated with the amounts of exchangeable Cd, but the addition of clay did not have a significant recovery effect on inhibition by Cd. These results indicate that allophanic clay enhances the activity of proteases owing to stabilization of the enzyme, and that allophanic clay has little capacity to adsorb Cd 2+ .

Cadmium (Cd) is considered to be the metal with the most serious adverse effects on microbial and enzyme activities in soils polluted with heavy metals. To investigate its effects, we conducted a short-term laboratory experiment at five levels of Cd addition to the soils (0-, 5-, 50-, 100-, and 250-mg of Cd kg j1 soil) using surface soil samples from Andosols obtained from a forest and a cultivated field in an upland area of Japan's Kanto District. We determined the activities of Aglucosidase and proteases in the soils after 0, 2, 10, 20, 40, and 80 days of incubation. Availability of Cd was determined by measuring watersoluble Cd. We also measured these enzyme activities after the addition of Cd to commercial crude A-glucosidase and proteases and after the addition of these crude enzymes and Cd to autoclaved soils to evaluate the stability of the enzymes and to detect their changes in response to Cd. During the incubation experiment, Cd inhibited protease activity by up to 47% in the forest soil and 31% in the cultivated soil, where negative correlation was found between soluble Cd content and protease activity on each incubation day. In contrast, A-glucosidase activity showed little or no significant inhibition. For crude enzyme experiments, Cd did not significantly affect A-glucosidase activity, but the four proteases we tested were strongly inhibited at different levels of Cd concentrations. Thus, the responses of the A-glucosidase and protease activities of the crude enzymes to Cd addition were similar to the results for the Andosols with Cd addition. As a result, the apparent direct inhibitory effect of Cd on protease stability would result in a greater decrease in N mineralization than in cellulose decomposition by A-glucosidase.