DORMANT RUPTURE AND HORMONES LEVELS IN Jatropha curcas L. AND Jatropha macrocarpa GRISEB SEED

TAVECCHIO N; TERENTI O; OLMEDO SOSA L; ESCUDERO E; A. VIGLIOCCO; PEDRANZANI H.

Otro; IV Reunión Conjunta de Sociedades de Biología de la República Argentina; 2020

IV Reunión Conjunta de Sociedades de Biología de la República Argentina

Jatropha curcas L. and Jatropha macrocarpa Griseb are perennial shrub with the greatest importance mainly from its biofuel potential. Seeds of both species present a hard seminal covering that encloses the endosperm and the embryo. Several authors consider that this tegument is one of the factors that induce dormancy. The aim of the work was to study the role of tegument and abscisic acid (ABA) y jasmonic acid (JA) in dormancy and germination in these species. J. macrocarpa present dormancy since it does not germinate by traditional methods. The seeds of J. macrocarpa were subjected to different treatments to break seed dormancy: (T1) Control; (T2) Scarification with sandpaper; (T3) Total elimination of the tegument; (T4) Immersion in boiling water for 1 min and then immersed in cold water for 24 h; (T5) Alternating hot and cold water for 5 min, each one; (T6) Immersion in concentrated H2SO4 for 15 min; (T7) Immersion in concentrated H2SO4 for 30 min; (T8) Stratification in wet and cold paper (4°C) for 90 days; (T9) Stratification in moist sand and cold (4°C) for 90 days. After each treatment the seeds were placed in Petri dishes containing 3 mL of distilled water at 30°C temperature. The test was conducted under dark condition. Germination percentages (GP) were determined for 30 days. We used 20 seeds by treatment, with three replications each one. The seeds of J. curcas don?t were subjected to different treatments scarification and stratification because they have no dormancy. ABA and JA were extracted and purified from both Jatropha species tegument. These hormones were identified and quantified from tissue using reverse-phase high-performance liquid chromatography (HPLC)-mass spectrometry (MS). Analysis of variance (ANOVA) was applied, and data were subjected to the Multiple Range Duncan Test, using the software INFOSTAT-UNC. The total removal of tegument showed a 50% increase in germination percentage, with the other treatments achieved between 0?10%. ABA and JAs were detected in tegument of J. macrocarpa and J. curcas seeds. JAs were the most abundant compound. ABA level was higher in J. curcas (628%) than in J. macrocarpa. This would indicate that the tegument ABA level is not directly linked to germination and/or dormancy of these Jatropha species. In contrast, level of JAs was higher in J. macrocarpa (101%) than in J. curcas. In effects JA could have a roll in inhibition of germination of J. macrocarpa seeds.