Water availability is one of the main environmental factor able to influence the germinative process of seeds. In these conditions, the ability of seeds to maintain their viability during the storage can be an adaptive advantage of species found in differents biomes, especially in the Caatinga. The objective of this work was to assess the influence of storage on tolerance of seed of catingueira (Caesalpinia pyramidalis Tul.) to water restriction, using polyethyleneglycol 6000 (PEG 6000) as osmotic agent. Seeds of catingueira were stored for 0, 3 and 6 months at room temperature and packed in kraft paper bags, assessing the influence of different osmotic potentials (0.0; -0.2; -0.4; -0.6; -0.8; -1.0 and -1.2 MPa) of PEG 6000 solutions on percentage of germination (G%), average time of germination (AvT), average speed of germination (AvS) and speed rate of germination (SRG) of seeds. It was observed that the interaction between storage and osmotic treatments significantly influenced the evaluated germination kinetic variables, except AvS. In all evaluated months, reduction of available water in the medium affected decrease of G%, AvT and it affected increase of AvT of the seeds. The tolerance to water deficit in the seeds of catingueira was relatively high, and the limit was within the range from -0.8 to -1.0 MPa. The identification of environmental factors that rule seed germination, as the water availability, represents an important tool in the interpretation of the ecological behavior of the species under conditions of natural habitats.
Catingueira; Tolerance; Germination; PEG 6000
