Plant pore (5)
I believe the answer is:
stoma
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">plant pore</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stoma that I've seen before include "surgical opening" , "Pore in plant" .)