CHANGES OF GROWTH AND METABOLISM IN ONTOGENY OF MUSTARD PLANTS DURINGPROLONGED DEFICIENCY OF INORGANIC PHOSPHORUS

Inorganic phosphorus (P(i)) was excluded from the nutrient solution in 8-day mustard plants (Brassica juncea L.), and growth, photosynthesis , carbohydrate and nitrogen metabolism, and accumulation and distribut ion of biomass among the organs were studied in the course of ontogene sis. Plants at the stage of vegetative growth experienced a state of s tress during prolonged deficiency of phosphorus exceeding the norm of the response of the genotype (15 days on a solution without P(i)). The transition to reproductive development was accelerated in the test pl ants in the course of ontogenesis, growth was slowed in the process, a nd the bulk of assimilates moved into the reproductive organs. Coordin ation of photosynthesis and nitrogen assimilation and their interactio n with growth were restored. It is concluded that accelerated developm ent promotes the overcoming of stress during prolonged phosphorus star vation.