Integration of physio-biochemical processes at different phenological stages of wheat (Triticum aestivum L.) plants in response to heat stress

A study was conducted to assess the influence of heat stress imposed at different growth stages of wheat (triticum aestivum l.) plants. four wheat cultivars namely s-24,saher-2006,lasani and aari-10 were subjected to high temperature (ht) stress at tillering and booting phenological phases. under stress conditions,root and shoot fresh weights,membrane thermostability (mts) and non-photochemical quenching (npq) were significantly perturbed in all four wheat cultivars at both developmental stages. however,ht stress did not influence all the other attributes significantly including shoot fresh weight,chlorophyll a and b pigments,photosynthetic rate (a),leaf water (ψw),internal co2 (ci),osmotic (ψs) and turgor (ψp) potentials,transpiration rate (e),water-use-efficiency (a/e),stomatal conductance (gs) as well as fv/fm ratio. among all wheat cultivars,cv. lasani performed better in shoot and root fresh weight,and chlorophyll a contents at the tillering stage,while in mts at the booting phase,cv. s-24 in shoot fresh weight,e,and gs at the boot stage and highest mts and wue at the tillering stage. however,cv. aari-10 performed well in root fresh weight,ψw,ψs,ψp