Abstract
Transpiration rates, automatically monitored, provide a basis for investigating factors that affect the movement of water through plants and are particularly useful for demonstrating the role of leaf stoma. A transpiration balance is described which permits monitoring of transpiration rates by continuously recording the weight loss from a potted plant. It is based on the use of a displacement transducer to obtain a signal voltage output from an ordinary mechanical balance. Since it mainly incorporates equipment common to most laboratories, construction of the balance may involve relatively little expenditure. Experiments using the transpiration balance are presented and discussed.