Growth, Carbon Dioxide Exchange, Transpiration, and Transpiration Ratio of Pineapple

Abstract

Measurements of growth, carbon dioxide exchange, transpiration, and transpiration ratio were made for pineapple (Ananas comosus [L.] Merr.) plants. During the experimental period, their growth rate was 0.015-0.018 g increase in dry weight per day per 100 cm² of average leaf area. Carbon dioxide exchange was recorded for 24 hr. During the first part of the light period, CO₂ was given off, but uptake began in mid-afternoon and continued through the dark period. This pattern of uptake is common in plants exhibiting a crassulacean type of acid metabolism. From the same measurements, the calculated theoretical rate of net photosynthesis for pineapple was 0.5-0.7 mg/hr per 100 cm² of leaf area. Transpiration proceeded at a rate of 0.02-0.05 g/hr per 100 cm². Both these values are lower than those for several crop plants. The transpiration ratio for pineapple, 50, was determined from values for gain in dry weight and water loss during the experimental period of 80 days. This also is considerably less than the values for other crop plants and for trees. Since its transpiration ratio and rate of water loss are low, pineapple probably can maintain high levels of productivity in regions where water is limited.