As hot as it is, and being in a smallish pot, I think the plant might be dropping leaves to conserve water since the majority of the leaves look OK. I know of a trick used by some folks who train Bonsai when they want to keep their plants watered in hot weather. As you may know, the method used to miniaturize woody plants for Bonsai is cropping the roots to minimize nutrient intake. In hot weather, this also limits the amount of water they can take in at one time as well. To give them a long, slow drink without the benefit of a drip irrigation system, they put a chunk of ice on top of the soil in the Bonsai pot where it slowly melts and waters the plant. It also has the benefit of cooling the soil and slowing evaporation.
  Just my .02... not chiseled in stone or anything...
  Just my .02... not chiseled in stone or anything...