Germination of melon seeds under water and thermal stress

Abstract

Seeds vigor can influence seed performance under stress conditions. The objectives of this study were to evaluate the effect of water and thermal stress on germination and performance of melon seedlings, and to verify if germination under stress conditions is an efficient parameter to evaluate the vigor of these seeds. Four lots of ‘Golden Mine’ melon had their initial quality characterized by germination, first count, accelerated aging and seedling emergence tests. Germination under water stress was performed on a paper moistened with PEG 6000 solution at 0.06, -0.3, -0.6 and -0.9 MPa. The percentage and speed of germination, length and dry mass of the seedlings were evaluated. For the thermal stress experiment, cold test and germination at sub- (15 ºC) and supra-optimal (35 ºC) temperatures were performed, as well as at the ideal temperature (25 ºC). The germination of melon seeds under water stress induced by PEG 6000 at -0.3 and -0.6 MPa is an efficient method to detect differences in the physiological potential of lots of melon seeds, but these differences disappear under severe water stress (-0.9 MPa). Germination under sub-optimal temperatures also allows to identify differences in seeds performance and to classify them according to the vigor level.

Physiological quality of seeds and growth of seedlings of chickpea under salt stress

“…The reduction in germination due to the increase in water deficit caused by salt stress at -0.4 MPa was also observed in melon seeds by Pinheiro et al (2017). On the other hand, seeds of chia (Salvia hispânica L.) and sesame (Sesamum indicum L.) do not tolerate osmotic potentials of less than -0.15 and -0.2 MPa, respectively (Medeiros et al, 2015;Stefanello et al, 2017).…”

Salicylic acid in the physiological priming of onion seeds subjected to water and salt stresses

“…This reduction in germination, as the osmotic potentials become more negative, is explained by the water restriction, which decreases the velocity of the metabolic and biochemical processes, slowing or reducing seed germination percentage, interfering in the imbibition and in embryo cell elongation (Carvalho & Nakagawa, 2012). The reduction of germination due to the increase in water deficit was also verified in melon seeds by Pinheiro et al (2017), who observed germination close to 50% at the potential of -0.4 MPa. By contrast, chia and sesame seeds do not tolerate osmotic potentials lower than -0.15 and -0.2 MPa, respectively (Medeiros et al, 2015;Stefanello et al, 2017).…”