research Arabinogalactan Proteins Are Involved in Root Hair Development in Barley 32 citations, December 2014 in “Journal of experimental botany” Certain proteins are essential for the growth of root hairs in barley.
research Extracellular Vesicles from Activated Dermal Fibroblasts Stimulate Hair Follicle Growth Through Dermal Papilla-Secreted Norrin 37 citations, June 2019 in “Stem cells” Special particles from skin cells can promote hair growth by activating a specific growth signal.