Recovery and germinative response of Amaranthus deflexus L. seeds under different levels of water stress and luminosities

Abstract

Article AbstractThe objective of this work was to evaluate, in two experiments, the effect of water stress and luminosity on the germinative behavior and vigor of Amaranthus deflexus L seeds. The seeds were sown in Petri dishes containing two sheets of filter paper moistened with distilled water, in the control treatment. Using this treatment-control configuration, as a standard of comparison, two assays were performed using subsamples from the same A. deflexus seed population. In the first experiment (experiment 1), solutions of polyethylene glycol 6000 (PEG 6000) were used, providing osmotic potentials of -0.3; -0.6; -0.9; -1.2 and -1.5 MPa; however, in the second trial (experiment 2) osmotic potentials of -0.1; -0.2; -0.3; -0.4 and -0.5 MPa were used. At the end of the test, the ungerminated seeds for each treatment were washed and germinated on a filter paper moistened with water. The germination and vigor of the seeds were evaluated through the first germination count, germination test, germination speed index and average germination time. The experimental design was completely randomized, in a 2 x 6 factorial scheme, totaling twelve treatments, with four replicates of 50 seeds each, in both trials. Water stress negatively affects the performance of A. deflexus seeds, reducing germination and vigor from -0.1 MPa. Seed germination was compromised by the absence of light, regardless of the applied stress levels. There was an increase in seed germination after application of the same at higher levels of water stress.

Germinação de sementes de Amaranthus deflexus L. submetidas a diferentes condições de tempera-tura e estresse salino

“…Vigna unguiculata seeds showed a germination percentage of less than 80% when cultivated under osmotic potentials lower than -0.35 MPa (Gomes et al, 2019). Water stress negatively affects the performance of Amaranthus deflexus seeds, reducing germination and vigor, just as the absence of light compromised germination for seeds of this species regardless of the stress level applied (Fontes et al, 2019). This reduction in germination parameters may be associated with the fact that when there is an increase in the concentration of ions in the substrate and, consequently, a reduction in osmotic potential, water absorption by the seeds is reduced and the germination phases are delayed (Santos et al, 2016).…”

“…2022 alternating temperatures, which correspond to the environmental conditions found in the natural environment (Ribeiro et al, 2016). Fontes et al (2019) evaluated the influence of light and water stress on the germination behavior and vigor of Amaranthus deflexus and found that water stress negatively affects seed performance, reducing germination and vigor, whereas the absence of light completely compromised germination, regardless of the stress level applied. M. L. M. D. Silva et al (2016) also reported that water stress was harmful at any level, regardless of temperature, for the germination of Chorisia glaziovii.…”