Blue light made soybean stems thicker by increasing the water-conducting tissue area and shortening the cells, which stopped them from growing taller.

When soybean plants were exposed to blue light, their height dropped by about two-thirds compared to plants grown in the dark, with both tall and short varieties showing similar reductions.

Blue light raised the stress hormone jasmonic acid by about 15% in tall soybeans and 38% in short soybeans compared to plants grown in the dark.

Blue light made the levels of a key growth hormone (GA3) drop by about 14% in tall soybeans and 20% in short soybeans when grown in the dark versus under blue light.