BIOCHEMICAL ASPECTS OF GREENHOUSE TOMATO ROOTS RESPONSE AND RESISTANCE TO NEMATODES (MELOIDOGYNE INCOGNITA)
When nematodes were absent, diferences between resistant and sensitive roots depend on the growth stage of the respective plants and are sensibly higher with fruit setting on the 4-th flowering.
Thus at the 5 leaves stage, free aminoacids, polyphenols and prevailing organic acids, contents in cellulose and lignine were higher in the more resistant variety.
Root response to infestation depends on plant age and sensitivity. Differences between the two kinds of roots are higher in younger plants. In contrast with what occurs in sensitive roots, sugar content and free acidity decrease while oxidable KMnO4 substances, lignine and prevailing organic acids contents increase in resistant roots. At the 4-th flowering fruit setting, other biochemical differences of the studied factors may occur between resistant and sensitive roots.
While both kinds of roots exhibit an increase of chlorogenic acid and prevailing polyphenols contents, increases are much higher in resistant roots.
Marked differences appeared in the chemical composition of roots with and without galls, depending on soil nature.
However, for all the experimented varieties the oxidable KMnO4 substances content increased in roots with galls, while glucose, maltose and saccharose contents decreased.