We show that in the same manner as with Ethrel® treatments, bark treatments of mature virgin trees of the PB217 rubber clone using synthetic auxin (4-chlorophenoxyacetic acid, 4-CPA), ABA or SA decrease the latex TSC and concomitantly increase the latex yield. All of these hormonal treatments induced similar marked differential expressions patterns in the aquaporin genes. In the case of ethylene, HbPIP2;1 and HbTIP1;1 were affected in the laticifers and in the inner liber cells, while HbPIP1;1 was poorly affected by the same treatments. We confirmed the poor efficiency of HbPIP1;1 in inducing plasmalemma water flux, at least in Xenopus laevis oocytes. Our results support that HbPIP2;1 and HbTIP1;1 are the major functional aquaporins that efficiently drive water fluxes across the membranes of inner bark and latex cells, especially in response to all of the bark plant hormone treatments tested here.