DISCONTINUOUS HYDRATION ON THE GERMINATION OF Mimosa caesalpiniifolia AND Pityrocarpa moniliformis SEEDS UNDER WATER STRESS

Josefa Patrícia Balduino Nicolau,Mauro Vasconcelos Pacheco,Salvador Barros Torres,Francival Cardoso Felix,Francisco Eudes Da Silva,Márcio Dias Pereira

doi:10.1590/1983-21252020v33n228rc

Josefa Patrícia Balduino Nicolau, Mauro Vasconcelos Pacheco + Show 4 more

Open Access

https://doi.org/10.1590/1983-21252020v33n228rc

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Abstract

ABSTRACT The use of discontinuous hydration cycles can act in improving seed germination and seedling initial growth under water stress. In this context, the objective of this study was to evaluate the effect of discontinuous hydration on the germination of Mimosa caesalpiniifolia and Pityrocarpa moniliformis seeds under water stress. For this, seeds of these species were subjected to 0 (without hydration), 2 and 4 hydration cycles (18 h) and dehydration (12 and 18 h, respectively), with subsequent germination under water stress simulated for osmotic potentials of 0.0 (distilled water), -0.2, -0.4, -0.6 and -0.8 MPa. Seedlings were evaluated using tests of germination, germination speed index, mean germination time and seedling length. Discontinuous hydration in M. caesalpiniifolia and P. moniliformis seeds hampers germination and vigor of seedlings under water stress up to -0.6 MPa. However, the use of two cycles in P. moniliformis favors germination under more severe water stress (-0.8 MPa).

Highlights

Mimosa caesalpiniaefolia Benth. and Pityrocarpa moniliformis (Benth.) Luckow & R
Jobson (Fabaceae) are small, fast-growing tree species that occur in States of Northeast Brazil and in part of Minas Gerais, popularly known as ‘sabiá’ and ‘catanduva’, respectively
M. caesalpiniifolia and P. moniliformis fruits came from populations (10 trees each), respectively, of the Experimental Area of the Escola Agrícola de Jundiaí (Macaíba/RN) (5° 53’ 35.12” S and 35° 21’ 47.03” W) and the Experimental Farm of the Universidade Federal Rural do Semiárido (Mossoró/ RN) (5o 03’ S and 37o 24’ W), Rio Grande do Norte State, Brazil

Summary

Introduction

Mimosa caesalpiniaefolia Benth. and Pityrocarpa moniliformis (Benth.) Luckow & R. W. Jobson (Fabaceae) are small, fast-growing tree species that occur in States of Northeast Brazil and in part of Minas Gerais, popularly known as ‘sabiá’ and ‘catanduva’, respectively. Jobson (Fabaceae) are small, fast-growing tree species that occur in States of Northeast Brazil and in part of Minas Gerais, popularly known as ‘sabiá’ and ‘catanduva’, respectively The former is used for reforestation, recovery of degraded areas and manufacture of posts (SOUSA et al, 2018), while the latter is used for beekeeping and forage purposes (AZERÊDO et al, 2016). In dry forests, such as in Caatinga ecosystem, low rainfall, high temperatures and irregular rains throughout the year are common (AZERÊDO et al, 2016). The momentary availability of water, caused by rapid and irregular rains, associated with high evaporation from the surface soil layers, directly affects seed germination in hydration and dehydration cycles, which prevents germination from being completed (LIMA; MEIADO, 2017)

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