INHIBITORY AND STIMULATORY EFFECTS OF ROOT EXUDATES IN TWO VARIETIES OF RICE

Abstract

The (allelopathic) interaction between two varieties of rice (Oryza sativa) seedlings Subarna and Pankaj was studied. Root exudates (RE) of Subarna inhibit the germination and growth of the seedlings of Pankaj and vice-versa. RE of both Subarna and Pankaj contain phenolic compounds, amino acids and presumably a fatty acid. The putative fatty acid appears 15-20 days following germination and disappears after two months. Only one phenolic was detectable in the later stages and two others in young seedlings. The Rf values of these three putative phenolics show that none of these is among the eight standards, namely: syringic acid, caffeic acid, ferulic acid, 3-4 dihydroxy benzoic acid, vanillic acid, 4-hydroxy benzoic acid, coumaric acid, and sinapic acid. The synergistic effect is inhibitory but when chromatographically separated two inhibitors and three stimulators have been found in RE of two-month old Subarna.