EFFECT OF DIFFERENT SUGARS ON FLOWERING OF CHENOPODIUM-RUBRUM L IN DEPENDENCE ON CONDITIONS OF GERMINATION AND INITIAL GROWTH

Flowering of C. rubrum seedlings fed different sugars at a concentration of 0.6 and 0.4 M, respectively, during a single inductive cycle was stimulated or inhibited depending on the conditions of germination and initial growth. Plants allowed to germinate at alternating temperatures of 28.degree. C and 5.degree. C showed a slower initial growth, and their development was stimulated by some sugars as compared to controls induced in the absence of sugars. Plants germinated at alternating temperatures of 32.degree. C and 5.degree. C exhiibited a rapid initial growth and flowering was inhibited after induction in the presence of sugars. Development proceeded more rapidly in control plants induced in the absence of sugars after germination at the higher temperature than after germination at the lower one. The differences between the 2 variants could also be observed after induction by two 16 h dark cycles. Glucose and sucrose were most effective in stimulating flowering under appropriate conditions of germination. Fructose was less effective, and the action of maltose was very weak. Xylose, ribose and galactose were innocuous, while arabinose, G-6-P and mannitol were toxic. The sugars inhibited root growth in all cases and lead to an increase in starch accumulation in the underground and overground plant organs. At a concentration of 0.6 M they mostly inhibited the length of the cotyledons and, especially, of the first leaf; at a concentration of 0.4 M growth of the overground organs was stimulated. The possible changes in photoperiodic sensitivity brought about by the rate of initial growth are discussed.