Aspectos fisiológicos de sementes de Piptadenia moniliformis Benth

Abstract

With the increasing demand for seeds of high quality native forest species, mainly to support the work of mixed reforestation, it is fundamental that the methods of quality evaluation of the seeds are efficient, so the present work aimed to evaluate aspects pertinent to the physiological quality of seeds of Piptadenia moniliformis Benth. (calico angus). Two experiments were carried out: experiment 1 -Use of seed dormancy overcoming treatments, where they were immersed in concentrated sulfuric acid by (zero -intact seeds, 5, 10, 15, 20 and 25 minutes). The design was a completely randomized design, with six treatments and five replicates of 20 seeds per treatment. Experiment 2 -Evaluation of the methodology of the accelerated aging test, that is, traditional methodology and that employing the use of saturated NaCl solution at 41ºC with periods of zero exposure; 24; 48; 72 and 96 h. Before and after each aging period, regardless of the method, the water content of the seeds was determined. After each treatment the seeds were submitted to electrical conductivity and germination tests. The design was completely randomized, in a 2x5 factorial scheme (methodology x exposure times), with four replicates of 25 seeds per treatment. To overcome seed dormancy there was no statistical difference between the times of 5; 10; 15; 20 and 25 minutes of immersion in sulfuric acid, but the time of 20 minutes provided a larger number of seeds with protrusion of the primary root. The different methods of accelerated aging, conventional and saturated solution, affected the physiological quality of seeds of Piptadenia moniliformis Benth., With the reduction of the germinative potential after 24 hours of exposure. Regarding the methodology employed, the use of the saturated solution generally gave the best results, as the water content of the seeds was lower, thus reducing fungal growth. The results obtained in the biochemical test of electrical conductivity showed that the increase of the aging period, independent of the methodology, caused the increase of the deterioration of the seeds. It is soon concluded that the seeds of P. moniliformis Benth. had their dormancy overcome when immersed in concentrated sulfuric acid for periods of 5; 10; 15; 20 or 25 minutes; and that the different methodologies of accelerated aging, traditional and saturated solution, affected the physiological quality of the seeds.