Assessing the effect of antimycin A on morphophysiological parameters in Triticum aestivum L. exposed to high temperature

Abstract

The present study was conducted to investigate the evaluation of antimycin A (AA) as a modulator of the alternative respiratory pathway (AP) on the intensity of growth processes and some physiological parameters of etiolated wheat seedlings, such as maximum length of root, length of first leaf and coleoptile, fresh and dry weights at the whole plant level, leaf area as well as relative water content, saturation water deficit, degree of leaf succulence and sclerophylly.Generally, exposure to heat stress (HS) alone caused a noticeable reduction in root length (59%), leaf length (30%), plant fresh mass (10%), dry mass (14%), and leaf area (25%) which was consistent with the progressive alteration in water relations. Furthermore, the degree of leaf succulence and degree of leaf sclerophylly were severely affected by HS in wheat seedlings. However, the results demonstrated that the application of AA did not induce such a significant reduction in the leaf length (23%), coleoptile length (5%), plant fresh weight (7%), plant dry weight (3%), and leaf area (21%) as well as water relations in etiolated wheat seedlings compared to heat-stressed plants. Taken together, the activation of AP promoted a mitigating of the damaging effect of HS in wheat seedlings supporting growth processes.

Physiological Response of Some Wheat Cultivars to Thermal Stress

“…These results were supported by researchers [25] who observed that heat-tolerant genotypes of wheat seedlings had insignificant root lengths in response to thermal stress. However, results from the previous experiments indicated that prolonged high-temperature exposure completely inhibited the growth of the root [16]. Thermal stress is assumed to reduce root growth of heat-stressed wheat plants by inhibiting root formation, branching, and growth of the existing roots.…”

“…On the other hand, the inhibition of wheat growth characteristics under hightemperature stress would also be due to the reduction in net assimilation rate which is also another reason for the reduced relative growth rate [15]. It has been previously reported that the length of the first leaf and the maximum length of roots significantly declined in etiolated wheat seedlings exposed to prolonged high-temperature stress [16]. Wheat coleoptiles are cylindrical organs that function for a relatively short period at the early stage of ontogenesis that sheath the first leaf [17].…”

“…Furthermore, our previous studies have shown that prolonged high-temperature exposure did not significantly affect the coleoptile length at the early and late stages of Triticum aestivum L. development (cv. Harmony) [16]. Wheat seedlings adapt to stress environments by different mechanisms, including changes in the morphological and developmental patterns as well as biochemical and physiological processes.…”