The ideal temperature for growing marijuana plants is between 68° Fahrenheit and 77° Fahrenheit. Learn how to regulate grow temperature here.
www.ilovegrowingmarijuana.com
"Marijuana plants won’t usually die from being too hot, but their growth can slow from it.
High external temperatures (above 80 degrees) while flowering
will not only slow down bud growth but also reduce their smell and potency. If you care about growing buds with plenty of cannabinoids, you need to be sure the external temperature is kept under control during the
flowering stage. "
Hardly the extreme "reduce growth at 45°C" or 113F which would fry the plants quickly I think
@Kassiopeija but please cite a translation of your German research? Does that book even refer to Cannabis?