Ácido salicílico como atenuador de estresse hídrico nas fases de germinação e crescimento inicial em gergelim

Abstract

The study of germination response of seeds subjected to the condition of artificial stress is an important tool in understanding the survivability and adaptation of crops under stressful conditions, may contribute to the development of management strategies. In this sense, the objective was to evaluate salicylic acid as attenuator water stress induced by polyethylene glycol (PEG 6000) on germination and initial growth of sesame. To this end the experiment on the germination stage was developed in the laboratory to evaluate the effect of different water potentials in the substrate (0.0 witness; -0.2, -0.4, -0.6 and -0.8 MPa) and three treatments of pre-soaking seeds (pre-soaking in distilled water, pre-soak in salicylic acid and without pre - soaking) and six sesame genotypes (BRS Seda, CNPA-G2, CNPA-G3, G4CNPA,

LAG -Branquinha and LAG-Pretinha). It was adopted a completely randomized design with four replications and 50 seeds per repetition. We evaluated the germination percentage (%), the relative frequency of germination (%) and germination speed index, shoot length (cm), root length (cm) and biochemical variables (activities of catalase - CAT, ascorbate peroxidase - APX and superoxide dismutase - SOD and also the content of soluble proteins). The reduction of the osmotic potential of the substrate reduced the length of sesame seedlings and salicylic acid concentration (10 -5 mol / L -1 ) used in pre-soaking the seeds promoted the induction of tolerance to drought stress during germination and further growth root in BRS-Silk genotypes; CNPA-G2, G4 and CNPA-LAG-Branquinha, as also observed an increase in the activity of the enzymes evaluated as a result of water stress. The CNPA-G2 genotype had better performance for traits, demonstrating high potential for adaptation to water deficit.