Auxin synergists

The physiological function of sterols has been reviewed by Grunwald (1975a). Apart from the stabilizing effect of free sterols on phospholipid-containing membranes, other functions suggested have been that the sterol derivatives are transport forms, that the sterols are precursors of hormones, and that sterol derivatives are auxin synergists. 

The problem of selectivity of detection has been a major aspect of plant hormone analysis since the early days of bioassay, as shown by the plethora of studies on naturally occurring auxin synergists and auxin antagonists . Two complementary approaches have been taken to improve the selectivity of detection. The first approach has been the application of high resolution techniques of separation science in order to purify the phytohormone away from interfering compounds. The second approach has been the use of selective detectors following chromatographic purification. The quality of an analytical method is dependent on the interplay of these two factors, resolution and detector selectivity. 

Synergistic Cross-Talk between Auxin Transport Inhibitor and Auxin Herbicide... 

Simultaneous Interaction. In the literature, the interaction of BR with auxin has been reported to be additive or synergistic depending on experimental systems and conditions (5). In cucumber hypocotyl sections, the interaction is definitely synergistic (5). The synergism is especially significant when the concentration of one of the two is suboptimal. The interaction at their optimal concentrations is synergistic only during the early period of incubation and becomes additive finally. A synthetic auxin, 2,4-D also interacts with BR similarly (8). 

Brassinosteroids (BRs) interact strongly with auxins. In some test systems, the response is synergistic. BRs, alone and in combination with auxins, induce the synthesis of ethylene. 

The mode of the germination-stimulatory action of coumarin on plant cells has been widely studied [106—110], and it is similar to the action of plant hormones which control different functions and processes of growth. The relationship between the effects of coumarins and auxins has been suggested [106, 107]. Coumarin in different concentrations stimulates stem and shoot elongation [108, 109] it also elicits a similar action [111] on substances which affect root initiation, cambial activity, and leaf expansion [108, 110]. The plant hormones and coumarin also stimulate the growth of roots. In low concentrations, coumarin exerts a synergistic action with plant growth substances, while with... 

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