Impact of developmental stage on CAM expression and growth in an Aechmea hybrid under greenhouse conditions.

摘要

Besides environmental factors, expression of crassulacean acid metabolism (CAM) and the related production of malic acid may depend on plant developmental stage. This topic has not yet been investigated under commercial greenhouse conditions. In CAM plant cultivation, malic acid is a central determinant of plant growth, but can also cause physiological leaf damage problems. Here, we present data on diurnal leaf malic acid contents, relative water content dynamics, and measurements of growth at four stages of the plant growth cycle (i.e., ex vitro-acclimated plantlets, 6-month, 12-month, and 18-month-old plants) of Aechmea 'Maya'. The results obtained showed that Aechmea 'Maya' was an obligate CAM plant at all developmental stages during cultivation. Nevertheless, there was some developmental control on the expression of CAM. Under the same environmental conditions, 6-month-old plants accumulated significantly higher amounts of malic acid in their leaves, thus supporting higher growth rates, than in the other growth stages. This larger malic acid pool implied a higher risk of physiological leaf damage, but since remobilisation of malic acid in the early morning remained unaffected during growth, physiological leaf damage might occur throughout vegetative growth.