___________ function as multisensory hydraulic valve?

Explanation

Guard cells surround each stomatal pore and act as a turgor-controlled hydraulic valve, opening or closing the pore as water enters or leaves them. Lenticels and hydathodes are other plant structures involved in gas exchange or water release, but they do not regulate a pore through paired turgid cells in this way. Students may choose hydathodes because they are associated with water, but hydathodes release liquid water and are not the main controllers of stomatal opening.