Plant growth, accumulation and solute partitioning of four forest species under salt stress

Abstract

Under NaCl-salinity Na+ and Cl- accumulation of shoot and root vary greatly among glycophyte plants; this is mostly due to genetic diversity and has been utilized to distinguish between plant responses to salinity. The current study aimed to evaluate the accumulation and Na+ and Cl- tissue partitioning and its effect on dry mass gain and K+ accumulation in one-month-old Prosopis juliflora, Leucaena leucocephala, Piptadenia macrocarpa and Mimosa hostilis seedlings grown for 30 days, in sand watered with nutrient solution loading 100 mol m-3 of NaCl, in greenhouse. The Na+ and Cl- accumulation, but not partitioning between shoot and root, depended on plant species. All the plants accumulated Cl- over Na+ both in shoot and root. The K+ content of plants did not significantly vary in shoot but decreased in root due to salinity. The ability of these plants to avoid damaging the metabolism due to salinity may result, in part, from a high shoot-K+ to Na+ ratio. Leucaena leucocephala had the higher decrease of total dry matter (60%) and lower shoot-K+ to Na+ ratio (0.40), while Prosopis juliflora had lower decrease of total dry matter (15%) and had K+ to Na+ ratio of shoot about 3 times more. Evidence is presented supporting a role for increased K+ to Na+ ratios in adaptation of plants to osmotic and ionic stresses.