Pre-germination treatments of Paricá (Schizolobium amazonicum) seeds

Estefânia Martins Bardiviesso,Tiago Alexandre Da Silva,Natália De Brito Lima Lanna,Flávio Ferreira Da Silva Binotti,Edilson Costa,Thiago Barbosa Batista

doi:10.14393/bj-v36n4a2020-41791

Abstract

Paricá seeds have dormancy and, even after mechanical scarification, these seeds show slow and uneven germination. Pre-germination treatments can be used to increase seed germination performance. Thus, the aimed to evaluate the physiological potential and initial growth of paricá seeds after pre-germination treatments, using different substances as plant regulators and nutrients, in addition to mechanical scarification. The experimental design was completely randomized, in a 2x7 factorial scheme, consisting of the following pre-germination treatments: mechanical scarification (10% and 50% of the seed coat) and seed pre-soaking [control-water, KNO3 0.2%, Ca(NO3)2 0.2%, gibberellin 0.02%, cytokinin 0.02%, and mixture of gibberellin + cytokinin (1:1)] besides a control group without pre-soaking, with four replicates. The study evaluated germination and emergence rates, germination and emergence speed indices, collar diameter, plant height, seedling dry mass, hypocotyl and seedling length, and electrical conductivity. It was observed that pre-soaking the seeds in gibberellin after mechanical scarification at 50% as a pre-germination treatment resulted in seeds with higher vigor expression and greater initial seedling growth.

Highlights

Schizolobium amazonicum (Huber ex Ducke) Barneby, the Brazilian fern tree, locally referred to as paricá, is a forest species of the family Fabaceae (Leguminosae) and subfamily Caesalpinoideae (BARNEBY, 1996)
The experimental design was completely randomized in a 2 x 7 factorial scheme, consisting of mechanical scarification (10% or 50% of integument fragmentation) and seed pre-soaking with different chemical agents [, control-water, KNO3 0.2%, Ca(NO3)2 0.2%, 0.02% gibberellin, 0.02% cytokinin, and mixture of gibberellin + cytokinin (1:1)] besides a control group without presoaking, with four replicates
Seeds were pre-soaked in deionized water; potassium nitrate - KNO3 0.2%; calcium nitrate Ca(NO3)2 0,2%; gibberellin - GA3 0,02%; cytokinin6-benzylamino-purine 0.02%; and mixture of gibberellin + cytokinin (1:1)

Summary

Introduction

Schizolobium amazonicum (Huber ex Ducke) Barneby, the Brazilian fern tree, locally referred to as paricá, is a forest species of the family Fabaceae (Leguminosae) and subfamily Caesalpinoideae (BARNEBY, 1996). Paricá seeds have slow and reduced germination, but when subjected to scarification, germination rates rise above 90% (CRUZ; CARVALHO, 2006; CARVALHO, 2007) This prolonged time to germination is a strong evidence that the seeds of this species are affected by physical or integument dormancy capable of limiting the rapid and uniform germination of the seeds (CRUZ; MARTINS; CARVALHO, 2001). In intact seeds of this species, hydration does not occur even after they are immersed in water for 72 hours (SHIMIZU et al, 2011) Such dormancy, caused by restricted water entry, is typical of the family Leguminosae (PEREZ, 2004), and since they have dehiscent fruits, their seeds have lignified integument granting them greater protection (DAMIÃO FILHO; MORO, 2005)

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