Developmental changes in nitrogen and protein of tall and dwarf tomato seedlings Lycopersicon esculentum Mill

Abstract

Tris-soluble protein and total nitrogen of tall and dwarf tomato (Lycopersicon esculentum Mill.) seedlings were determined by the method of Lowry et al. and a modified micro-Kjeldahl direct Nesslerization technique.

The tall tomato 'Fireball' differs from the dwarf 'Md. 412-4' in several ways: (1) the tall has more total nitrogen and protein; (2) it exhibits a significant increase in protein during the initial 48-hours of seeds imbibition; (3) it has a higher amount of protein in the roots; (4) the rate of decline of total nitrogen is faster than the dwarf, and (5) the tall tomato is more efficient in the utilization of plant nitrogen and protein.

The greater growth of the tall resulted in a more rapid decline in nitrogen. However, in 10-18 day-old seedlings, growth was still rapid while nitrogen and protein did not change appreciably. The tall was more efficient and utilized a lesser amount of nitrogen and protein in the production of a comparable amount of fresh weight.

It is suggested that the roots have considerable influence(s) on the growth of the shoot and that the decline in nitrogen and protein is a resultant of growth. It is indicated that the differences in growth may be more dependent on the manner in which nitrogen and protein are utilized rather than their absolute content.