ISHS Acta Horticulturae 517: XXV International Horticultural Congress, Part 7: Quality of Horticultural Products
DETECTION OF ROOT DYSFUNCTION BY MEASURING ELECTRIC POTENTIAL IN TEA PLANTS |
| Authors: | T. Homma, H. Matsuoka |
| Keywords: | tea plant, xylem potential, root dysfunction, excessive fertilisation, NH4-N concentration, respiration activity |
| Abstract:
In tea fields, fertiliser is applied excessively compared with other crops in order to increase tea quality. This repeated excessive fertilisation affects root functions. Once planted in a field, it is hard to check root conditions. This study discussed about possibility of electric potential of woody and perennial tea plant (Camellia sinensis (L.) O. Kuntze) to be an useful parameter for non-destructive evaluation of root conditions. In order to change root conditions, potted young (4- and 1-years-old) tea plants were dipped in hydroponic solutions containing different concentrations of ammonium sulfate. Xylem potential was measured by liquid junction system which consisted of unpolarizable Ag/AgCl electrode, 3M KCl-filled reservoir, salt bridge, 10mM KCl-filled reservoir and injection needle for inserting into xylem apoplast via the stem. With increasing NH4-N (ammonium sulfate) concentration in the hydroponic solution, xylem potential changed to the positive direction (depolarization). On the other hand, when the respiration activity, which was selected as one of many root functions examined for checking the root conditions, was measured after the xylem potential recording, the activity change was smaller than the xylem potential variation. These results suggests that the xylem potential measurement at the stem might be promising for the root conditions detection without digging the roots. | |
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