A Study into the Effect of Jasmonic and Humic Acids on Some Germination Characteristics of Rosselle (Hibiscus sabdariffa) Seed under Salinity Stress

An experiment was conducted to investigate the effects of jasmonic and humic acids on some seed germination characteristics of Roselle under the salt stress condition in a factorial experiment, adopting a completely randomized design with three replications. Treatments included four different levels of salinity stresses: 0, 70, 140 and 210 mM; four levels of Jasmonic Acid: 0, 50, 150 and 200 mM and three levels of humic acid: 0, 40 and 80 mM. The results showed that the effect of salinity on all the traits studied was significant except the ratio of the length of root and shoot. With an increase in salinity stress condition from 70 to 210 mM, there were 39% decrease in germination percentage, 55% in germination rate, 45% in fresh and dry weight, 30% in root length, 42% in shoot length, 37% in seedling length, 67% in longitudinal index and 61% in the weighted power, as compared with the control. However, the longitudinal power index increased. In addition, the use of jasmonic acid and humic acids had a significant effect on the traits studied. The interaction of the salt and hormones had a significant impact on plant fresh and dry weight, the length of the root, germination percentage, power weight index and average time needed for 50 percent germination. Given that the highest rate of root length and plant fresh and dry weight belonged to the interaction of humic and jasmonic acid in the absence of salinity, that in the presence of humic acid (with 80 mM concentration), Rosselle can bear salinity up to 140 mM and maintain stamina root length and that the germination rate of Rosselle increases by adding jasmonic acid up to 200 mM, one can conclude that the interaction of jasmonic and humic acids not only improves germination rate, but it also contributes to root length because, with an increase in root length, Rosselle can bear water stress conditions.
Highlights: 1. Jasmonic acid and humic acid increase the Rosselle germination in salinity condition.
2.Jasmonic acid and humic acid increase Rosselle the root length in salinity condition.