Dual internal clocks keep plant defenses on schedule. Duke Today, June 22, 2015. Time management isn’t just important for busy people — it’s critical for plants, too. A new study in the journal Nature shows how two biological clocks work together to help plants deal with intermittent demands such as fungal infections, while maintaining an already-packed daily schedule of activities like growth. The researchers also identified a gene that senses disturbances in the “tick-tock” of one clock, and causes the other clock to tighten its timetable.