To begin, grow homozygous transgenic Arabidopsis thaliana plants bearing ERL1-YFP and a red fluorescent protein, or RFP-labeled marker protein RFP ARA7 side-by-side in a growth room until flowering. On the young inflorescence of plant A, remove all the older flowers and calyx, except for one recently opened flower. Carefully remove the younger flowers and floral merostems.
In the recently opened flower, remove the sepals, petals, and stamen using a pair of sharp tweezers, leaving only the pistil on the inflorescence. From plant B, take mature stamen from an opened flower and deposit the pollen grains into the stigma of the dissected pistil of plant A.Label this manually crossed flower, indicating its parents and the date of the genetic cross. When the calyx turns yellow or brown, harvest the F1 seeds to check for a successful F1 plant having yellow fluorescent protein, or YFP, and RFP signals.