MICROCALORIMETRY: AN ACCURATE TOOL FOR EXPEDITE DETERMINATIONS OF PLANT TISSUE METABOLISM

This report includes examples of uses of microcalorimetric techniques applied to horticultural topics.
Among them, a comparison of metabolic heat production of dormant apple shoot and root meristems, confirming results that during dormancy, roots maintain a higher metabolic activity than shoots.
Also, the application of TDZ –a budbreaking agent- in ecodormant ‘Golden Delicious’ apples, rose flower bud metabolism from 4.98, 5.01. 5.05 and 5.22 µW.mg dw^-1, when sprayed with 0, 300, 500 and 700 ppm, respectively.
Measurements were made fifteen days after the chemical was applied.
By following bud metabolism in actual time, it was possible to compare the effect of evaporative cooling on ‘Red Chief Delicious’ flower buds.
A highly significant delay in bud metabolism was detected at any given sampling date.
An exothermal freezing compound in apple flowers was partitioned by second derivative analysis showing that different compartments froze at different times.
Finally, a comparison between in vitro and in planta tissues showed that microorganisms may play a significant role in contributing to higher metabolic rates as compared to axenic tissues.
We emphasize the advantages that this technique offers to horticulturist for quick and accurate insights in plant metabolism.

VI International Symposium on Temperate Fruit Growing in the Tropics and Subtropics

J. Llamas, E. Carvajal-Millán, A. Rascón-Chu, J.A. Orozco, A.A. Gardea

apple, TDZ, bud metabolism, evaporative cooling

https://doi.org/10.17660/ActaHortic.2001.565.12