Fig. 1

The intermittent immersion rocker system. Periodic wetting and drying of tissue was created when the shelving was gently rocked by the motor (1 rpm) (a). The paired shelves were tilted once a minute. Viewing the underside of the vessels on the top shelf (b), the shallow film of liquid medium barely covers the plant surface. Plants grow in the 2.5 L gaseous headspace of the vessels as seen on lower shelf