The effect of fluridone (or flurochloridone), the inhibitor of carotenoid, chlorophyll and abscisic acid synthesis, on the abscission of Ligustrum vulgare leaves was investigated. Both forms of fluridone inhibited the abscission of petioles when they were applied as a 1.0% concentration in lanolin to the leaf blade. Fluridone was capable of inhibiting abscission even when it was applied to the petiole as late as 7 hours after the blade was cut off. Fluridone applied in lanolin to the apical part of intact pea seedlings or on the cut surface after decapitation of the epicotyl caused albinism of the stipules. The degree of albinism decreased according to the concentration of applied flurodine (from the highest -0.5% to the lowest -0.03%) and was higher in intact than in decapitated plants. Albinism also appeared in pea seedlings grown from seeds swollen in differently concentrated solutions of flurochloridone, particularly in the basal part of the shoots. Complete albinism occurred only in plants cultivated from seeds swollen in high concentrations (0.06-0.12%). The lowest concentration (0.007%) stimulated root growth of the pea seedlings, but inhibited epicotyl growth.

No abstract

Flax seedlings were decapitated above the cotyledons. After one cotyledon was removed the growth of the bud of the remaining cotyledon was stronger in 90% of the plants. However, the application of the cytokinin benzyladenine (BA) to the bud of the removed cotyledon caused a growth correlative reversal and, by contrast, in 65% of the plants the bud of the removed cotyledon grew out. On the other hand, in sunflower seedlings, which have epigeal cotyledons similar to flax, after the removal of one cotyledon the growth of the axillary of the removed cotyledon was more intensive in 59% of the plants. Not even an application of BA to the remaining cotyledon of sunflower resulted in more intensive growth of the axillary of this cotyledon. When both cotyledons were left on the seedling, BA applied to one of the cotyledons of decapitated flax plants resulted in a highly significant stimulation of growth of the axillary of this cotyledon; in sunflower; however, the effect of the BA was insignificant. After decapitation of the stem of pea seedlings where both cotyledons remained, both axillaries grew out, but after a certain period of time one of them (the dominant one) achieved a growth correlative dominance over the other (inhibited). The present study is focused on whether an application of plant hormones onto the inhibited shoot is able to cause a growth correlative reversal, i.e. to change the inhibited shoot into a dominant one. The application of 0.12% BA can cause such a reversal virtually in all plants if the original difference in the length between the inhibited and dominating axillaries is 12–24 mm. A 0.12–0.5% concentration of gibberellin causes a reversal in 13–75% of the plants, but only if the difference between the dominant and inhibited shoot is 1–12 mm. A 0.03–0.25% concentration of IAA causes a reversal in 34–57% of the plants, if the difference in the length of the axillaries is 1–4 mm.

No abstract

No abstract