BIOLOGIA PLANTARUM 49 (2): 285-288, 2005 285 BRIEF COMMUNICATION Growth and ion uptake in Annona muricata and A. squamosa subjected to salt stress V.M. PASSOS*, N.O. SANTANA*, F.C. GAMA*, J.G. OLIVEIRA**, R.A. AZEVEDO*** and A.P. VITÓRIA**** 1 Departamento de Ciências Biológicas, Horto Florestal, Universidade Estadual de Feira de Santana, Feira de Santana CEP 44031-460, BA, Brasil* Laboratório de Melhoramento Genético Vegetal, Centro de Ciência e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, CEP 28013-600, RJ, Brasil** Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba CEP 13418-900, SP, Brasil*** Laboratório de Ciências Ambientais, Centro de Biociência e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, CEP 28013-600, RJ, Brasil**** Abstract The effects of treatment with NaCl (3, 100 and 300 mM) for 1, 2, 3 and 7 d on plant growth and ion accumulation were analyzed in 2-week and 8-week-old Annona muricata and A. squamosa plants. Fresh mass and root growth inhibition were directly related to the increase in salinity, particularly for A. squamosa. Two-weeks old seedlings were sensitive to 100 and 300 mM NaCl particularly after 7 d, whereas 8-week-old plants were shown to be more resistant to NaCl even at 300 mM NaCl. Na + and Cl - mostly accumulated in young leaves. Our results suggest that A. squamosa is more sensitive than A. muricata to salt stress and that older seedlings of both species are more tolerant than younger seedlings. Additional key words: abiotic stress, ion translocation, NaCl. ⎯⎯⎯⎯ Plants may tolerate salt concentrations of approximately 100 mM NaCl without any damage (Serrano 1996). Salt stress involves two main components, the first is related to the decrease in the osmotic potential in the soil solution (ψ s ), and an ionic component, which is related to the accumulation of toxic ions and to the decrease of essential elements, such as K + and Ca 2+ . An excess of salt can cause various modifications of plant metabolism, such as changes in phosphorylation state, inhibition of enzyme activity, or production of reactive oxygen species (Allakhverdiev et al. 2000, Blumwald et al. 2000). The identification of salt tolerant species that can be cultivated under high salinity is particularly important (Latha et al. 2004). Annonaceae plant species are particularly important in semi-arid regions in terms of agro-economic aspects and food alternative and certain aspects related to salt stress have been studied (Marler and Zozor 1996). Salt stress in A. squamosa has been shown to decrease gas exchange, chlorophyll a fluorescence, and the uptake of water and nutrients, suggesting that A. squamosa is sensitive to salt stress (Marler and Zozor 1996). Ebert (1998) also observed a significant growth reduction of A. cherimola by NaCl, with both ions being accumulated in all tissues, ⎯⎯⎯⎯ Received 19 April 2004, accepted 27 August 2004. Acknowledgements: We wish to thank Prof. Peter Lea (Lancaster University, U.K.) for critical reading of the manuscript. The authors gratefully acknowledge the financial support of this work provided by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Grant no. 99/06429-0) and the Universidade Estadual de Feira de Santana (BA-Brazil). R.A.A. and F.C.G. received a research fellowship from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq-Brazil). 1 Corresponding author; fax: (+55) 019 34336706, e-mail: apvitoria@uenf.br