Physiological Quality in Leucaena leucocephala Seeds Conditioned with Potassium Nitrate Submitted to Saline and Water Stresses

Abstract

Leucaena leucocephala is a species that occurs in semi-arid regions capable of developing physiological and biochemical strategies under adverse environmental situations, such as saline soils and water deficiency. Even so, there are still losses in germination and initial development of plants, mainly due to abiotic stress effects, making it necessary to implement alternatives which are able to diminish the impact on the seeds with the use of potassium nitrate. The objective of this work was to evaluate the physiological quality in L. leucocephala seeds conditioned in potassium nitrate solution and subjected to saline and water stresses. After scarification, the unconditioned leucine seeds were separated and identified, and the conditioners were immersed in the 1.0 Mmol/L solution of potassium nitrate for 24 hours. The treatments were NaCl: 0; 30; 60; 90; 120 and 150 Mmol/L and the water potential: 0, 0; -0.2; -0.4; -0.6, and -0.8 MPa. The seeds were distributed over two Germitest® sheets, moistened with distilled water 2.5 times the dry weight and incubated in a B.O.D. at 25°C for 10 days. Then, the germination speed index, seedling length and seedling mass were measured for the normal seedlings. Eleven treatments with four replicates of 50 seeds were used. The design was completely randomized, and the statistical analyzes were performed in SAS. The use of potassium nitrate (KNO3) contributed to maintaining the physiological quality of L. leucochephala seeds under conditions of saline stress and water restriction.