Saline stress and different temperatures change physiology in seeds of Clitoria fairchildiana Howard

Abstract

Clitoria fairchildiana Howard, popularly known as sombreiro is a native tree widely used in urban landscaping due to its rapid growth and beauty of the its flowers. In addition, it provides excellent shade and its wood is used in many purposes. Thus, the work was carried out with the objective of determining the tolerance of the seeds of Clitoria fairchildiana Howard to salt stress on germination at different temperatures. The experiment was conducted in the Laboratory of Seed Analysis of the Center of Agricultural Sciences of the Federal University of Paraíba, Areia - PB state. To simulate the salt stress, sodium chloride (NaCl) diluted in distilled and deionized water to obtain the concentrations of 0.0 (control) was used as the solute; 1.5; 3.0; 4,5; 6.0; 7.5; 9.0 and 10.5 dS m^-1, at constant 25 and 30°C and alternating 20-30°C temperatures. In the evaluation of the effects of the treatments, the following characteristics were determined: percentage, first count and germination speed index (IVG), as well as length and dry mass of seedlings (root and shoot). The experimental design was completely at random, with treatments arranged in a 3 x 8 factorial scheme (temperatures and salinity levels), in four replications. The percentage of germination and vigor of the seeds reduced with the increasing in the salinity levels, however, for those submitted to a constant temperature of 25°C the percentage of germination was higher compared to the others. The decrease in the osmotic potentials of saline solutions (NaCl) in the germination medium causes a reduction in the germination and vigor of the seeds of Clitoria fairchildiana Howard, which are classified as glycophytes, with moderate tolerance to NaCl salt.

Keywords:
Sombreiro; Seeds quality; Forest species