Helen Porter
... that Helen Porter helped to pioneer the use of radioactive tracers in botany?
... that <b id="mwrw"><a href="./Helen_Porter" id="mwsA" rel="mw:WikiLink" title="Helen Porter">Helen Porter</a></b> helped to pioneer the use of <a href="./Radioactive_tracer" id="mwsQ" rel="mw:WikiLink" title="Radioactive tracer">radioactive tracers</a> in botany?