The influence of a reduced gibberellin biosynthesis and nitrogen supply onthe morphology and anatomy of leaves and roots of tomato (Solanum lycopersicum)

We investigated how the differences in growth and morphology between fast-g rowing wildtype (Wt) tomato (Solanum lycopersicum L.) plants and slow-growi ng gibberellin (GA) deficient W335 mutants were reflected in cell numbers a nd cell sizes. We also studied whether the differences between the Wt and t he low-GA mutant would persist at a growth-limiting supply of nitrate. Both a low endogenous GA concentration and a low supply of nitrate reduced the number and size of leaf cells, whereas they increased the size and number o f root cortex cells. The effects of low N supply on the size and number of leaf and root cells did not depend on endogenous GA concentrations. The mut ant's higher allocation to roots seemed to he the result of the strongly re duced growth of the shoot.