he·li·ot·ro·pism /hE-lE-o-trO-piz-m noun
-phototropism in which sunlight is the orienting stimulus —
growth or orientation of a sessile organism, especially a plant, 
toward or away from the light of the sun.
-an orienting response to the sun
-an adaptation that permits leaves to reorient as the
sun moves through the sky

he·lio·tro·pic / hE-lE-o-trOp-ik adjective
-orientated towards the sun
-soulful debut album by Belgian artist Lalalover;
music inspired by the solar radiation