Growth Behaviour of Three Species of Rajasthan in Relation to Salinity and Changes in Ionic Composition of Leaves

For rehabilitation of soils rendered barren owing to salinity, adaptation to site conditions and multiple uses form important criteria of tree selection. Seeds of preferred multipurpose tree species Acacia nilotica, Albizzia lebbeck,and Prosopis cineraria were sown in pots to study the growth behavior of seedlings during the initial year of establishment. Germination, Survival, height, stem diameter and biomass production were determined at three levels of saline water irrigation. Acacia nilotica showed moderate tolerance under medium levels of salinity of irrigation water whereas Albizzia lebbeck and Prosopis cineraria showed moderate tolerance upto low salinity level. Under different levels of saline water irrigation response breadth for height growth and total biomass was widest for A. nilotica followed by A. lebbeck. This pattern indicates that A. nilotica can grow in wider range of saline water conditions compared to other two species. The leaf sodium, calcium and magnesium content increased with increasing salinity conditions in Albizzia lebbeck and Acacia nilotica being maximum in Acacia nilotica, however K, Ca and Mg content decreased in Prosopis cineraria with increasing salinity levels. The ratios of Na/K, Na/Ca and Na/Mg increased with increasing salinity levels but in case of Acacia nilotica Na/ Mg increased upto medium level and decreased thereafter. At the end of experiment, the soil Na+ , K+ , Ca+ and Mg + content increased with increasing salinity levels and was maximum in Prosopis cineraria, whereas the organic carbon content in the soil was maximum under Albizzia lebbeck at highest level of salinity of irrigation water. These results suggests that the growth of Acacia nilotica and Prosopis cineraria seedlings was greatly promoted under the stress conditions of salinity and resulting much more balanced growth in terms of biomass, which is vital for plants growing in the harsh arid environments where concentration of salts is much more.