Physiological quality of seeds from Passiflora mucronata Lam. genotypes with nitric oxide donor and salt stress

Qualidade fisiológica de sementes de genótipos de Passiflora mucronataLam. com o doador de óxido nítrico e estresse salino

Abstract

The presence of salts in the soil solution reduces the osmotic potential, hindering water absorption by roots. However, plants have defense mechanisms against stresses, releasing signaling molecules, in which nitric oxide plays an important role in the abiotic stress. This study aimed to assess the physiological quality of seeds from Passiflora mucronata Lam. genotypes pre-conditioned with the nitric oxide donor Tadalafil kept under salt stress. Seeds from nine P. mucronata genotypes evaluated under four nitric oxide donor Tadalafil concentrations : 0.0, 1.5, 2.5, 5.0, 7.5, 10.0 and 12.5 mg L^-1, applied by soaking seeds for two hours, followed by washing in running water and germination in germitest® paper moistened with NaCl at -1.2 MPa. The experiment was carried out in a completely randomized design, with four replicates of 25 seeds. The nitric oxide donor Tadalafil, at concentrations of 1.5 and 2.5 mg L^-1, increased the germination speed, shoot length, and dry mass. Pre-conditioning of seeds with the nitric oxide donor Tadalafil at concentrations of 5.0, 7.5, 10.0, and 12.5 mg L^-1 determined the death of seeds. Seeds from genotype G3, pre-conditioned with Tadalafil at concentrations of 1.5 and 2.5 mg L^-1, presented higher germination, germination speed index, mean germination time, shoot length, root length and dry matter values. Genotypes presented distinct phenotypic responses, providing intraspecific divergence.

Index terms
Germination; Passifloraceae; Passion fruit; Tadalafil; Vigor