Salinity effects on germination and growth

Prosopis chilensis, also named Chilean algarrobo, is a leguminous tree, described as highly tolerant to heat shock, water deficit, salinity and injury stress. The objective of this research was to investigate the germination and growth responses of seeds, seedlings and young plants of P. chilensis under increasing concentrations of N a Cl. Six groups of P. chilensis seeds were germinated. One group was watered with distilled water (control group) and the other five were treated with 0.3, 0.4, 0.5, 0.6, and 0.8 M NaCI. Control seeds germinated lOO% in 48 hours, while those imbibed in 0.3M and 0.4M NaCI reached lOO% after 21 days of imbibition. In 0.5M NaCl there was 66% germination after 28 days of imbibition. Above 0.5M NaCI there was no germination. Seedlings of 0.5 cm long germinated and maintained for 8 weeks in the same NaCI concentration used for germination grew less than the control seedlings. Seedlings and young plants of algarrobo coming from seeds germinated and grown for 14 days in distilled water could grow a lot better in 0.3 to 0.8 M NaCI. The seedlings reached a 69% growth of the control seedlings in 0.8M NaCl after 21 days of treatment, while plants showed 58% growth of the control group after 8 weeks of treatment at this concentration. It was also observed that the seedling cotyledonary expansion was delayed by salinity. Under salt treatment the number of leaves per plant was reduced with a tendency to become significantly different to the control with 0.8M NaCI after 8 weeks of treatment. The conclusion of this research is that algarrobo can be consider as a Prosopis spp. highly tolerant to salinity because plants and seedlings can grow in 0.8M NaCI.