Respiratory metabolism of Agave angustifolia Haw. clonal lines at different temperatures

Abstract

We used isothermal microcalorimetry to evaluate the effect of temperature on the production of metabolic heat and the respiratory characteristics of four clonal lines of Agave angustifolia Haw. Seedlings were subjected to a temperature range from 15 to 45 °C at intervals of 10 °C. The results showed that the maximum production of metabolic heat and CO2 in the four clonal lines was at 35 °C. Metabolic heat rate decreased significantly at 45 °C, with the exception of the clonal line CL26b, while CO2 production decreased significantly in all clonal lines. The substrate to carbon conversion efficiency and heat loss decreased and increased with the increase in temperature, respectively, for all the clonal lines. Clonal line CL24b showed the highest efficiency. Moreover, the number of leaves, dry weight of the seedlings and the multiplication factor were higher in CL24b. These results suggest the existence of genotypes with different efficiencies of energy utilization, which can be a valuable tool for early selection of clonal lines of agave.