Water stress on germination and vigor of ‘mofumbo’ (Combretum leprosum Mart.) seeds at different temperatures

Abstract

Combretum leprosum Mart., commonly known as mofumbo, is used for medicinal purposes, recovery of degraded areas and apiculture. The objective of this study was to evaluate the effect of water stress on the germination and vigor of C. leprosum seeds as a function of different temperatures. For the formation of the treatments, the substrate used was the roll of paper that has been moistened with polyethylene glycol solutions (PEG 6000), the following levels of osmotic potential: 0.0; -0.1; -0.2; -0.2; -0.4; and -0.5 MPa, and placed in chamber at constant temperatures of 25, 30, 35 and alternating 20-30 °C, forming a 6 x 4 factorial. The seeds were submitted to the following evaluations: germination percentage, germination velocity index, root length, shoot length, dry root mass, dry mass of the aerial part. There was a significant interaction for all variables, with a negative effect for these, with a decrease in osmotic potentials. Thus, C. leprosum showed high sensitivity to low osmotic potentials, showing a steeper decrease from the potential of -0.2 MPa for all the evaluated temperatures. Initial germination and development of C. leprosum seedlings are negatively affected by low osmotic potentials, with a tolerance limit of -0.4 MPa. Temperatures of 25 and 35 °C accentuate the negative effect of the low osmotic potential of water on germination and early development of C. leprosum seedlings.