65ª Reunião Anual da SBPC

E. Ciências Agrárias - 1. Agronomia - 4. Fitotecnia

INFLUENCE OF DIFFERENT SOURCES OF POTASSIUM ON CHLOROPHYLL A IN EGGPLANT (Solanum melongena L.). "tags"

Jamille de Melo Pinho - Universidade Federal Rural da Amazônia- UFRA Odyone Nascimento da Silva - Universidade Federal Rural da Amazônia - UFRA Argemiro Pereira Martins Filho - Universidade Federal Rural da Amazônia - UFRA Douglas José Marques - Departamento de Ciência do Solo, Universidade Federal de Lavras Fernando Broetto - Departamento de Química e Bioquímica, Universidade Estadual Paulista Allan Klynger da Silva Lobato - Universidade Federal Rural da Amazônia - UFRA

INTRODUÇÃO:

Eggplant (Solanum melongena L.) is a horticultural species that has been largely consumed in world due to medical and nutritive potentials. Astudying of antocyanin extracted of Solanum melongena L.reported that this fruit promotes reduction of the total cholesterol in rats.Other aspect of potassium is linked to assimilation, because under adequate supplement in soil, the plant absorption of potassium can be four times higher than that of phosphorus, and equal to or greater than nitrogen, in which there are three macronutrients absorbed in large amounts in higher plants. Studiesdescribed beneficial effects of application of K+in Helianthus annuus plants induced to salt stress.Growth and adaptation of a species to environment is related with your reproductive efficiency, and this aspect also is linked to photosynthetic pigments, adequate work of photosynthetic apparatus can produce greater number flowers and consequently fruits. Researches have used chlorophyll level to evaluate plant nutritional state in relation to nitrogen (N), because chlorophyll molecule is constituted by nitrogen, and there is high relationship between chlorophyll and nitrogen level. "tags"

OBJETIVO DO TRABALHO:

The aim of this study was to investigate the influence of different sources and levels of potassium on chlorophyll a.

MÉTODOS:

Study was conducted in Departamento de Produção Vegetal, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil. The eggplant seeds of cv. Embu were placed to germinate in containers with sterile substrate denominated Plantmax®and watered with distilled water. The seedlings were transplanted from container to pot in 35thday, in which 3 or 4 definitive leaves were present.The experimental design used was factorial scheme with randomized blocks (2 x 4), 2 potassium sources (KCl and K2SO4) combined with 4 potassium levels (250, 500, 750 and 1000 kg K2O. ha-1). This experiment was composed of 5 replicates and 40 experimental units.The fertilization of surface started on 15thday after transplanting and promoted in constant intervals of 15 days. The fertilization of surface was performed using as N source calcium nitrate in amount of 22.8 g pot-1 divided in 14 applications.Chlorophyll awas determined using leaf disk with 1.04 cm2 of diameter. Tissue samples were homogenized with 1 mL of dimetilformamide and storage in dark at 10°C by 48 hs. Chlorophyll awas quantified using a spectrophotometer according to the methodology described by Lee et al. (1987). The leaf pigments were expressed in µg cm2.

RESULTADOS E DISCUSSÃO:

Results on chlorophyll a level in leaf were not showed significant difference in sources KCl and K2SO4. However, in samples collected in 60th day after transplanting and exposed to KCl, presenting value lower.These results on photosynthetic pigments suggest that potassium levels studded affect partially chlorophyll a in eggplant. In other words, reductions showed in this species under salt stress can be strongly related with lower capacity of synthesis or higher chlorophyll degradation. Results on photochemical damages showed in this research are similar with found in others similar studies, in which there are strong evidences that cells subjected to salt stress presented lower rate of electron transport between photosystems. Minor electron transport possibilities reduced ATP and NADPH productions, in which are essentials to biochemical fixation of carbon compounds, and these modifications in metabolism induced by salinity are consequences of several plant physiological responses such as changes in ionic balance, stomatal behavior, and photosynthetic efficiency. In addition, reduction in photosynthesis produced by salinity is derived of stomatal closing and produces as consequence also inhibition in carbon fixation.

CONCLUSÕES:

This study revealed that eggplant exposed to potassium excess presented not interference negative under chlorophyll a.

Palavras-chave: nitrogen, chlorophyll, potassium.