Effect of seawater irrigation on germination and growth of Bauhinia variegate seedlings and seed treatment with gibberellins

Abstract

The sea height level along Libyan coasts is considered one of the environmental pressures that lives in soil vegetation characteristics. Therefore, two experiments were conducted (laboratory - pots) to find out the effect of irrigation with seawater at the concentration (10%, 20%, 40%, 60%) on germination of seeds and seedlings of Bauhinia variegate trees with an age of 6 months, and treated using pre-soaking in gibberellin acid ( GA3) 500ppm for 24 hours. The results showed that the exposure of seeds and seedlings of B.variegate trees to salinity led in two experiments to a significant decrease in percentage germination, an increase in means germination time, moreover, a decreased seedlings lengths, number of leaves/plant, shoot and root lengths, fresh and dry weight of seedlings compared with a control. The results also showed that the seeds and seedlings of B.variegate trees were able to germinate in different concentrations of seawater, except for 60% concentration which caused in death of seeds and seedlings, while pre-soaking treatment of seeds with gibberellin acid was not successful to overcome the salt stress, although slightly improved some studied traits. The results concluded that the possible seeds and seedlings agriculture of B.variegate trees in coastal locations in which seawater concentration did not exceed 40%, existed to be used in reforestation of degraded lands. Key words: Bauhinia variegata, seawater, GA3, Libyan coasts.