Luiz Antônio Gallo

ENRAIZAMENTO DE CRAVO (Dianthus caryophyllus L.) IN VITRO E EX VITRO

Plantlets of carnation (Dianthus caryophyllus L.) micropropagated through several generations during one year, were observed with respect to rooting in vitro, in the presence of IAA , NAA and IBA, at the following concentrations: 0,0; 0,25; 0,5 and 1,0 mg/l. All treatments promoted root formation, however no differences were detected in comparison to control. As far as the lenght of the aerial part is concerned no difference was observed between in vitro rooting. in the presence or absence of IAA 0,5 mg/l, and ex vitro rooting. Plantlets which were rooted in vitro conditions showed higher production of fresh matter then those rooted ex vitro. The root system had a synergistic effect on the growth of the aerial part.

INFLUENCE OF NITROGEN FERTILIZATION ON NICKEL ACCUMULATION AND CHEMICAL COMPOSITION OF COFFEE PLANTS DURING FRUIT DEVELOPMENT

Nutritional and physiological significance of micronutrients in coffee plants, especially with regard to nickel (Ni) is still unknown. The dynamics of nitrogen (N), phosphorus (P), potassium (K) and Ni accumulation in coffee fruits, as well as their relationships with total soluble protein, amino acids, reducing sugars, and starch content during coffee fruit development (green, ripe, and dry fruits), were investigated. Coffee trees received three N fertilizer rates (0, 150, and 300 kg of N ha−1) as ammonium sulfate split into three applications per year. Nitrogen fertilization increased reducing sugars and starch concentrations in ripe fruits. In contrast, green fruits showed the highest amino acid and Ni concentrations. Fruit Ni concentration decreased in both green and ripe fruits as N rates increased; thus, indicating the possibility of either a N-associated dilution effect on Ni concentration or that Ni uptake by roots and/or transport to developing fruit was limiting. Plant nutritional status and fruit development stage influenced the coffee grain chemical composition. Furthermore, the variation in reducing sugars and starch content was more closely linked to the stage of fruit development than to N supply. A supposed relationship among the decreased of caffeine, starch, amino acids, and proteins with Ni content during green fruit development suggests a fundamental role for Ni in coffee fruit ripening. The interaction between N and Ni metabolism during fruit ripening might influence the chemical parameters involved in the coffee grain quality. This is the first report documenting changes in Ni concentrations of coffee fruit as a function of N fertilization rates and the development stage, but further research is needed to better understand the significance of N-Ni interaction in developing coffee fruit.

Influence of potassium nutrition and the nitrate ammonium ratio on the putrescine and spermidine contents in banana vitroplants

Univ Sao Paulo, Ctr Agr Biotechnol, CEBTEC, FEALQ,ESA Luiz de Querioz, BR-13416145 Piracicaba, SP, Brazil