For example, strong leaf antioxidant capacity was observed in PR-grafted plants although the leaf ABA content was decreased by heat stress with marginal significance ( P = 0.064), and root FRAP was the lowest in MA-grafted plants despite their high root ABA contents under heat stress conditions ( Figures 3E–H , 5A–D ).
‘Arkansas Traveler’ showed less heat susceptibility in chlorophyll fluorescence, which contradicts with the results from our previous cultivar screening in the growth chamber and open field study ( Bhattarai et al., 2021 ), possibly due to different plant developmental stage, soil type and temperature regimes, but leaf ROS contents were still lower in ‘Celebrity’ under heat stress at a marginally significant level ( P = 0.083).