I've had plants recover when they were in a vigorous growing stage. If I know a hot day is coming, I'll give the roots a good watering in the morning...

that dark mulch may be too much-mine this year have had a couple of 106 days and come through fine but are growing with corn, beans tomatoes and peppers-they seem to like the companionship

if the ends have burnt , and they were as said in a vigor stage of growth, the mother plant will shoot side vines from the leaf junctions. and with good ground watering will also root. plants are amazing!!! good luck!!!