Combined effects of salinity and temperature on germination, growth and gas exchange in two cultivars of Sorghum bicolor

Abstract

Excessive salinity in irrigation decreases crop's growth in arid regions such as Saudi Arabia. The aim of this research was to study the combined effects of salinity and temperature on germination, plant growth, F v /F m , gas exchange, chlorophyll and proline content in two Sorghum bicolor cultivars, Hindi and Jaizani. The treatments contained 3 temperatures (20°C, 30°C, 40°C) and 4 NaCl concentrations (0, 50, 100, 200 mM). The results presented that as NaCl increased, germination, growth, gas exchange and F v /F m of the two cultivars declined, with great effects at 40°C than at the other temperatures. Proline was higher in the Hindi and Jaizani cultivars at 20°C and 30°C under the different salinity conditions. On the other hand, the chlorophyll content was increased at 20°C under increased salinity in both cultivars. The interactions between salinity and temperature significantly affected most measurements of the two cultivars; however, Hindi cultivar showed more tolerance toward stress.

Effect of Salinity and Temperature on the Seed Germination and Seedling Growth of Desert Forage Grass Lasiurus scindicus Henr.

“…The results of our study indicated that the aRL, aSL, and SLA of L. scindicus seedlings decreased when incubated at T2 along with all the varying salinity concentrations. These results are in accordance with the findings of [59], where all the growth parameters of Sorghum bicolor showed a significant decline at the highest temperature of 40 • C. This is due to the increased detrimental impact of high temperatures on enzymic activities, protein synthesis, and ATP content, as well as the generation of reactive oxygen species (ROS) [27].…”

“…Also, the chlorophyll content of the seedlings showed an abrupt decline at the temperature T2 compared to the seedlings at T1 with all the salinity levels. These results indicate that the response to high salinity and temperature involves a drop in the chlorophyll content of L. scindicus plants, as also shown in the previous studies on L. scindius [8], Sorghum bicolor [59], and P. simonii [78].…”

“…However, the germination rate and/or the cumulative germination speed were higher in the case of seeds incubated at T2 under the non-saline or lower salinity concentration, which then showed a decline under the highest salinity levels. Similar results were reported by [41,42,59], where the germination of Medicago ruthenica; Lasiurus scindicus, Panicum turgidum; and Sorghum bicolor decreased at the highest temperature under the varying concentrations of NaCl. These results can be linked to the capacity of high temperatures to impede seed germination by inducing the production of large levels of endogenous abscisic acid (ABA) via transcriptional activation of ABA signaling genes [63,64].…”

“…In glycophytes and to a lesser extent in halophytes, increased salt stress has been demonstrated to cause a reduction in the percentage of seed germination as well as a delay in the germination process [51,[56][57][58]. Moreover, the ability of seeds to germinate through a wide range of salinities and temperatures is critical for the production of plants in varying environments [59]. Our findings revealed that ]increasing salt concentrations significantly decreased the GP, GR, and SVI at both the incubating temperature levels T1 and T2 (Figure 1).…”

Higher Temperature had Positive Effects on Seed Germination of Glycyrrhiza glabra under NaCl Stress

“…Temperature and salinity interactions significantly affect seed germination (Hadi et al, 2018;AL-Shoaibi, 2020;Piovan et al, 2019). Favourable temperature promotes seed germination under salinity stress; however, improper temperature aggravates salt stress on seed germination and even makes seeds lose vigour (Cardona et al, 2021).…”