Physiological response of ornamental tree species to induced salinity

Abstract

An experiment was conducted to explore the possibility about saline irrigation water may be used to grow ornamental tree species in pots under sub tropical condition of Punjab for two years (2015-16). Five salinity treatments of NaCl (analytical reagent) as 0 mM, 30 mM, 40 mM, 50 mM and 60 mM were given to one year old seedlings planted in earthen pots (10”) containing soil : FYM (2:1). These concentrations were given till October. After October month, i.e. in first week of November the treatments of NaCl as 0 mM, 30 mM, 60 mM, 90 mM and 120 mM were given. The results indicated that the increased salinity concentration in Bauhinia purpurea and Milletia ovalifolia significantly reduced the total chlorophyll, carotenoid and relative water content, whereas increased the cell membrane injury during both years. In Acacia auriculiformis and Cassia fistula, total leaf chlorophyll and carotenoids were maintained or slightly increased during first year and after that decreased, whereas relative water content increased with increase in salinity concentrations in first year and after that decreased. Electrolyte leakage in Acacia auriculiformis and Cassia fistula were maintained or slightly decreased during first year and during second year increased. It has been concluded that depending on the physiological responses, viz. total chlorophyll content, carotenoid content, relative water content and membrane permeability index, maximum salt tolerance was observed in Acacia auriculiformis followed by Cassia fistula, Bauhinia purpurea and Milletia ovalifolia.