Cytogenetic Activity of Root Meristems of Rice in Response to Conditioning in Carrot Extract and Salinity

摘要

Aims: This study was conducted to evaluate the role of Daucus carota L. root extract in cytogenetic parameters of Oryza sativa L . seeds exposed to salinity. Study Design: The experiment installed was in a completely randomized design, in a 2x4 factorial scheme, with four replicates. Place and Duration of Study: The experiment was conducted between March and June 2017, at the Laboratory of Seed Physiology and at the Laboratory of Genetics both belonging to the Universidade Federal de Pelotas (UFPel), in Cap?o do Le?o, RS, Brazil. Methodology: Seeds of cultivars BRS Querência (indica subgroup) and BRS 358 (japonic subgroup) were soaked at concentrations of 0% (water), 25%, 50% and 100% of aqueous extract of carrot for 48 h. Then, were germinated on germitest paper moistened with solutions of 0, 25, 75 and 150 mM NaCl and placed in a germination chamber under a mean temperature of 25°C. The evaluation of mitotic index was performed in meristem cells of rice roots when they reached 0.5 to 1 cm in length. Results: An increase in mitotic index was observed with the use of increasing doses of extract for cv. BRS 358, mainly by increasing the number of prophase cells. The salinity affected the two cultivars differently, with increase in the mitotic index for cv. BRS Querência and decrease for cv. BRS 358, but in this, the use of 50% of extract increased the index of cell division even with the increase of salinity. In addition, salinity above 75 mM caused an increase in the number of chromosomal alterations when associated to use of 50% of extract. Conclusion: The results show that there is positive effect of the use of carrot extract on the mitotic index of root meristems of rice, cv. BRS 358, when germinated in the presence or absence of salt stress.