Carbon Allocation in Cotton Grown in CO₂ Enriched Environments

Many studies have used CO₂ -enriched environments to identify the factors limiting growth and productivity of the cotton crop. This review focuses on the allocation of carbohydrates within the plant in these environments. Three pools of carbohydrates have been shown to be altered significantly by CO₂ enrichment. 1) Leaf starch is increased during the day and mobilized for night utilization; 2) starch deposition in the stems increases during the juvenile period of growth and is utilized during the boll filling period, and 3) starch deposition is increased in roots during the juvenile and early fruiting period. This enables the roots to remain more active during the heavy demand of fruit maturation. The expansion of these three pools of deposition enables the cotton crop to utilize the higher photosynthetic rate to a greater degree than other crops. The activity in these pools determines the growth and productivity of the crop at ambient CO₂.