Effect of Light, Temperature, Salinity, and Halopriming on Seed Germination and Seedling Growth of Hibiscus sabdariffa under Salinity Stress

Abstract

Salt stress is a serious and current global problem for crops. Due to climate change, the soil today has higher salinity levels than in past decades. Identifying temperature, light, and salinity that allow plants to germinate and grow is an ambitious challenge for the future. Hibiscus sabdariffa (H. sabdariffa) is a plant that undergoes abiotic stress during all stages of growth. The aim of this work was to identify the best conditions in terms of light, temperature, and salinity during the germination and growth phases of H. sabdariffa. To improve the germination of H. sabdariffa seed, the effects of abiotic stress were investigated in three experiments. In the first experiment, the factors included light at two levels (light and dark cycles) and temperature at eight levels (5, 10, 15, 20, 25, 30, 35, and 40 °C). In the second experiment, the effect of salinity was examined at seven levels (0, 30, 60, 90, 120, 150, and 180 mM NaCl). In the third experiment, the factors consisted of seed halopriming at two levels (0 and 180 mM NaCl for 24 h) and salinity at seven levels (0, 30, 60, 90, 120, 150, and 180 mM NaCl). The highest germination rate (GR), seedling dry weight, and uniformity of germination were obtained at 30 °C in dark conditions, as reported by one-way Anova analysis. Germination was restricted by temperatures lower and higher than 5 and 30 °C, respectively. By increasing the salinity, all the germination characteristics were decreased, but these effects were less pronounced by halopriming. The most suitable planting date was in the spring, when the temperature was in the range of 25–35 °C. During the germination stage, Hibiscus tea is sensitive to low salinity soils. Halopriming can be performed for enhancing GR and emergence percentage.

Enhancing Bean (Phaseolus vulgaris L.) Resilience: Unveiling the Role of Halopriming against Saltwater Stress

“…Considering the economic importance of this cultivar, we focused the next experiment on the physiological response of Borlotto, starting from sowing germinated seeds, either primed or not, in saline soil. Despite reports from the literature [62][63][64][65], priming was not sufficient to support plant growth in such conditions. This outcome had already been observed in our previous study on tomato plants [32], where an improvement in salt tolerance was observed when priming was followed by an acclimation phase to salinity.…”

Seed Priming for Mitigating Salinity Stress Effects in Plants: A General Review

“…Additionally, it increased water use efficiency in field conditions compared to the control, which was significant in mitigating the adverse effects of water scarcity (El-Sanatawy et al, 2021). Halopriming has also been applied to Hibiscus sabdariffa seeds under salt stress conditions, leading to an increased germination rate and emergence percentage (Taghvaei et al, 2022).…”

Comparative study of dormancy breaking efficiency in Terminalia mantaly seeds using microorganisms and conventional pre-treatment methods

“…The germination of seeds is one of the most critical stages of plants. Seeds tend to germinate when provided with favorable environmental conditions and factors necessary for germination such as; light, water, oxygen, and temperature (Taghvaei et al, 2022; Ankalaiah & Reddy, 2022a & 2022b; Rohini Latha, 2022). Nevertheless, some seeds fail to germinate even when the above favorable environmental conditions are provided, such seeds are said to be dormant (dormancy) (Guo et al, 2020;Luo et al, 2022).…”