RESPONSES OF DATE PALM (PHOENIX DACTYLIFERA L.) CALLUS TO BIOTIC AND ABIOTIC STRESSES
Keywords:Aspergillus niger, Callus, Culture filtrate, Date palm, NaCl
The in vitro responses of date palm (Phoenix dactylifera L.) callus of Hillawi cv. to Aspergillus niger culture filtrates (ACF) (10 and 20%) and sodium chloride (68.45; 137 and 205.34 mM) treatments were investigated at proliferation stage. Results indicated that both ACF and NaCl treatments at high concentrations led to an adverse effect on callus growth. Fresh and dry weights were significantly decreased, in contrast with control treatment (untreated callus).Growth reduction was accompanied with an increase of browning intensity. A stimulatory effect on callus growth was observed at low concentration of NaCl (68.45 mM). The exposed callus generally tends to accumulate a significant amount of free proline as well as hydrogen peroxide. This accumulation increased significantly with the increase of ACF and NaCl concentrations, whereas the opposite trend was seen in the activity of Catalase. Additionally, RAPD-PCR technique utilized to define any DNA rearrangements that may have been induced by ACF and NaCl treatments. Results of RAPD analysis detected DNA polymorphism usingOPA01-OPA03 primers which revealed appearance and disappearance of fragments compared to control profile. Thus suggesting genetic rearrangements which could be the cause of the observed morphological and biochemical variations in date palm callus exposed to biotic and abiotic stresses.