Impact of K2SiO3 and Luminosity in the Nutrition and Growth of Genipa americana

Abstract

Considering the classification of Genipa americana L. in the ecological succession, excessive exposure to light can be stressful condition, and promotes changes on mineral metabolism and morphophysiology. Foliar application of potassium silicate (K₂SiO₃) has demonstrated to be a promising alternative for induced tolerance. We aimed to evaluate the effect of applying K₂SiO₃ on nutrition and growth of G. americana seedlings under two luminous ambiences. Four doses of K₂SiO₃ via foliar spray were tested: 0.0, 2.5, 5.0, and 10.0 mL L^–1, and cultivation under full sun or shade. Assessments of nutritional status, growth and quality of seedlings were carried at 45 and 90 days after 1st application of K₂SiO₃. We observed higher N content in seedlings under full sun at 45 days, and decreased with increased K₂SiO₃ doses in same ambience at 90 days, while P, K, Ca, and Mg were higher in shaded seedlings and with 10.0 mL L^–1 K₂SiO₃ at 45 and 90 days. The order of nutritional requirements for most seedlings, regardless of cultivation conditions, was K > N > Ca, with inversion of Mg to P requirement with 10.0 mL L^–1 K₂SiO₃. Shaded seedlings showed better growth characteristics at 45 and 90 days, but K₂SiO₃ contributed to photoassimilates accumulation under full sun. Foliar application 5.0 mL L^–1 K₂SiO₃ contributed to greater stem diameter, leaf area, and Dickson quality index. Foliar application of K₂SiO₃ alleviated the stressful effects of full sun and favored the nutrition and quality of G. americana seedlings.