Improvement of hydrothermal response of corn seed under drought stress using abscisic acid, gibberellic acid, and salysilic acid

In order to evaluate the effect of temperature, drought and priming on the percentage and rate germination of corn seeds, a factorial experiment based on a completely randomized design with four replicates was conducted. Treatments included eight temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 ºC), four drought potential (0, -0.4, -0.8 and -1.2 MPa), and five priming (control, hydroprimin, GA priming, ABA priming and, SA ptiming). Both percentage and rate of germination were inhibited at osmotic potentials ≤−0.8 MPa PEG. At 35 ºC temperature. Germination percentage of unprimed seeds was reduced from 94 to 36% in −1.2 MPa. Under these conditions, gibberellic acid hormone treatment improved seed germination. The effect of temperature on germination can be defined in terms of cardinal temperatures. We compared three non-linear regression models (Dent-like, segmented and beta). The outcome revealed that the Dent-like function was suitable for use in describing seed germination response to temperature. The base, optimum 1, optimum 2 and ceiling temperature were estimated to be 9.51, 24.12, 35 and 44.62 °C, respectively. The response of germination rate to both temperature and water potential can be described as a non-linear function of the hydrothermal model. According to the results of this study, hydropriming, gibberellic acid, and salicylic acid increased the mean deviation of the base temperature compared to non-priming treatment, increasing the standard deviation of the base temperature indicates the ability of seed germination in different osmotic potentials.