THE ADVANSE EFFECT OF GA3 (GIBBERELLIC ACID) ON MEDIUM SALINITY OF Phoenix dactylifera L. PLANTLETS In vitro ROOTING STAGE

Abstract

The effect of an application of GA3 to in vitro rooting culture medium (MS + 30 g/l sucrose + 6 g/l agar +0.1 mg/l kinetin + 3.0 mg/l IBA + 0.5 g/l AC) of date palm for 6 months (1month interval) to adverse the salinity effects was studied. The plantlets were cultured on a medium with different concentrations of GA3 (0,20,25 and 30 mg/l) combined with various levels of salinity (0,10000,14000 and 16000 ppm NaCl + CaCl 2 2:1 by weight ) .The plantlets were incubated under controlled laboratory conditions (27 ± 2 C 0 and 6000 lux).These plantlets were transferred to the liquid culture medium as a pre acclimatization treatment (1/4 MS +3.0 mg/l IBA) for two weeks before transferring to the greenhouse. The results showed that salinity has a depressing effect on various growth parameters (shoot and root length, number of leaves and number of roots), in contrast salt stress increased proline which is considered a (compatible osmoticums), Na, Ca, Cl and total sugars contents. GA 3 application had a stimulated effect on the adverse effect of salinity stress on the growth parameters and survival percentage at the acclimatization stage. The advantage of GA 3 application under salinity levels is discussed.