Osmoproteção na germinação da chia (salvia hispanica l.) Com atenuadores dos estresses hídrico e salino

Abstract

Salvia hispanica L. is an annual herbaceous species whose main means of propagation is by seeds. In Brazil, the cultivation of S. hispanica is recent and the information about crop management, especially regarding seed germination under adverse environmental conditions, is scarce. Thus, different attenuating substances have been studied because they present potential in mitigating the effects of the abiotic stresses in the germination, being essential for the establishment and adaptation of this crop to the Brazilian climatic conditions. Thus, the objective of this study was to evaluate the action of different agents as attenuators of water and saline stress on germination and initial development of S. hispanica. The work was divided in two experiments, the seeds being previously soaked with different attenuating substances and submitted to water stress (Experiment I) and salt stress (Experiment II). In both experiments, the experimental design was completely randomized in a 5 x 5 factorial scheme (5 stress attenuators and 5 osmotic potentials). The work was carried out using four replicates of 50 seeds for each treatment. The treatments consisted of pre-soaking the seeds in salicylic acid (1 mM.L-1), gibberellic acid (0.4 mM.L-1), hydrogen peroxide (20 mM.L-1), distilled water and without imbibition (control). After 4 hours of inbibition, the seeds were seeded on two sheets of blotting paper previously moistened with solutions of PEG 6000 (Experiment I) and NaCl (Experiment II) under osmotic potentials 0.0; -0.1; -0.2; -0.3 and -0.4 MPa. The analyzed variables were germination percentage, IVG, shoot length and primary root length, total dry mass, total soluble sugars, total free amino acids and proline. Data were submitted to analysis of variance (p <0.05) and Tukey's test (p <0.05) for the attenuators and polynomial regression (p <0.05) for the osmotic potential and for interaction. For the experiment I, the gibberellic and salicylic acids mitigated the effect of water stress in the germination and early development stages of S. hispanica. In saline stress (Experiment II), we observed attenuating effect only of salicylic acid. For the two experiments, the gibberellic and salicylic acids provided increases in germination, vigor and biochemical composition of seedlings, being efficient in mitigating the effects of saline and water stress on S. hispanica seeds