Abstract
In two experiments with young barley plants, respiration rate, carbohydrate content and growth rate of the whole plant were measured. When 18-day-old plants were darkened the rate of respiration and the levels of soluble carbohydrate fell in parallel over the following 30 h. When the dark respiration rate of plants was followed from 7 to 24 days respiration rate and soluble carbohydrate levels did not change together, nor did the respiration rate (R) follow the empirical relationship with photosynthesis (P) and d. wt (W) R = aW + bP, suggested by McCree.