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Effects of salinity: Calcium interaction on growth and nucleic acid metabolism in five species of chenopodiaceae

Seed germination, seedling growth, and some enzyme activity of nucleic acid metabolism were studied in 5 members of Chenopodiaceae [Beta vulgaris L., Chenopodium quinoa Willd., Spinacea oleracea L., Allenrolfia occidentalis (S.Watson) Kuntze, Atriplex hortensis L.] under NaCl salinity alone or combined with 0.5 mM CaSO4. | Turk J Bot 31 (2007) 125-134 © TÜB‹TAK Research Article Effects of Salinity: Calcium Interaction on Growth and Nucleic Acid Metabolism in Five Species of Chenopodiaceae Essam El-Deen Mohaned ABO-KASSEM* Botany Department, Faculty of Science, Tanta University, Tanta, EGYPT Received: 06.06.2005 Accepted: 11.12.2006 Abstract: Seed germination, seedling growth, and some enzyme activity of nucleic acid metabolism were studied in 5 members of Chenopodiaceae [Beta vulgaris L., Chenopodium quinoa Willd., Spinacea oleracea L., Allenrolfia occidentalis (S.Watson) Kuntze, Atriplex hortensis L.] under NaCl salinity alone or combined with 0.5 mM CaSO4. High salinity delayed radical emergence and decreased germination percentage in all plants. Combined CaSO4 reduced inhibition of seed germination in B. vulgaris, S. oleracea, and A. hortensis, but increased it in C. quinoa and A. occidentalis. CaSO4 reduced plant growth to a greater degree than high salinity did. High salinity decreased total nucleic acid content in all plants, except C. quinoa. Combined CaSO4 enhanced this effect in B. vulgaris, S. oleracea, and A. hortensis, but alleviated it in C. quinoa and A. occidentalis. Salinity progressively activated deoxyribonuclease (DNase I) and CaSO4 enhanced its activation in all plants, except B. vulgaris. Salinity increased endonuclease activity, except in S. oleracea and A. occidentalis. Addition of CaSO4 increased endonuclease activity in C. quinoa, S. oleracea, and A. occidentalis. Salinity inhibited ribonuclease A (RNase A) activity, but increased it in C. quinoa and S. oleracea, whereas CaSO4 alleviated such inhibition in A. occidentalis and A. hortensis. Salinity increased ribonuclease T (RNase T) activity in all plants, especially in C. quinoa, S. oleracea, and A. occidentalis. Key Words: Chenopodiaceae, growth, nucleic acid, DNase I, endonuclease, RNase A and RNase T Introduction Osmotic stress is one of the effects of salinity on plants. It is induced by a decrease