Zea mays
corn was planted with four individual weeds (canola) surrounding a corn seed in the center of an 8 pot. The weeds were planted in conetainers that penetrated through the bottom of the pot so that there was no chance for direct root-to-root contact between the corn and the canola. No opaque plastic cone-shaped barrier were used, and thus weed-generated light quality (increased far-red light due to reflection from the canola) signal could impact the corn seedling. The plants were grown under greenhouse conditions with diffuse light and an 18 Hr photoperiod at about 25 C for 3 months (until the plants were at the V12 stage of growth). Plants were watered daily and fertilized weekly by additional watering with 20:20:20. Plant root (including roughly equal amount by weight of support roots and horizontal roots) and leaf tips (the distal 10 cm of the top-most fully expanded leaf) were harvested separately into liquid nitrogen for future RNA extractions.