Potassium Silicate in the Acclimatization of Arabica Coffee Seedlings under Shaded and Full Sun Conditions

Abstract

Aims: The objective of this study was to evaluate the effect of the application of potassium silicate (K2SiO3) on the acclimatization of arabica coffee seedlings, under shaded and full sun conditions. Study Design:  Randomized block design, with the treatments arranged in the subdivided portions scheme, with 13 replicates. Place and Duration of Study: The experiment was conducted from November 2016 to February 2017 in the greenhouse, at the State University of Norte Fluminense Darcy Ribeiro - UENF, in the municipality of Campos dos Goytacazes - RJ, Brazil. Methodology: The experiment was conducted in randomized blocks, with the treatments arranged in the subdivided portions scheme, with 13 replicates. The plots referred to two forms of acclimatization (shading and full sun), and the subplots were arranged to two nutrition conditions (application of K2SiO3 or not). The biometric, physiological and nutritional parameters of the plants were evaluated. The means of the collected data were submitted to analysis of variance and compared by the Tukey test at 5% of probability. Results: A significant interaction between the acclimatization and application of K2SiO3 was observed in the SPAD index and potassium contents in the leaves. The SPAD index was higher when K2SiO3 was applied in both the acclimatization methods; and K2SiO3 application resulted in higher potassium contents in the shaded seedlings. Regarding the biometric variables, an increase in the fresh and dry matter of the aerial part was observed, when the K2SiO3 was used. In relation to the physiology, there was a beneficial effect in relation to the gradual acclimatization of the seedlings for all the parameters evaluated; while K2SiO3 increased only the chlorophyll contents in the leaves. Conclusion: The application of K2SiO3 might be effective in making the seedlings rustic, thereby increasing the tolerance against insolation.