Authors: ESSAM E. M. ABO-KASSEM
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 CaSO_4. High salinity delayed radical emergence and decreased germination percentage in all plants. Combined CaSO_4 reduced inhibition of seed germination in B. vulgaris, S. oleracea, and A. hortensis, but increased it in C. quinoa and A. occidentalis. CaSO_4 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 CaSO_4 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 CaSO_4 enhanced its activation in all plants, except B. vulgaris. Salinity increased endonuclease activity, except in S. oleracea and A. occidentalis. Addition of CaSO_4 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 CaSO_4 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.
Keywords: Chenopodiaceae, growth, nucleic acid, DNase I, endonuclease, RNase A and RNase T
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