Alterações na qualidade fisiológica de sementes de tomateiro expostas ao nitrato e nitrito de sódio

Abstract

The productivity of the cultures is greatly determined by the interaction between the metabolism of carbon and nitrogen. These two processes are straightly connected, once the necessary energy for the nitrogen assimilation comes directly or indirectly from the photosynthesis. The diverse agricultural and industrial activities contribute to the conversion of nitrate into nitride, causing toxicity to the environment, and, as a consequence, accumulation in the soil. Therefore, this work has as objective evaluate and describe the alterations in the physiological quality of the seed, and the characteristics of tomato plants growth when exposed to growing concentrations of nitrate and sodium nitride. Cv. Gaúcho tomato seeds, harvest of 2002, were submitted to nitrate and sodium nitride solutions with different concentrations (zero; 100; 200; 300 and 400mg Kg -1 ). Afterwards the seeds were submitted to the following analysis: germination test, first germination counting, germination speed index, plantule emergence in green house, emergence speed index, length of the shoot and root, fresh mass and dry of the shoot and root, electrical conductivity, chlorophyll total content and of carotenoids and leaf area. Based on the results we can conclude that the viability and the vigor of the seed are positively affected by the sodium nitrate . On the other hand, the sodium nitride negatively affects the viability, but it does not seem to have effect on the vigor of the tomato plant seeds.