Effect of exogenous application of anti-stress substances and elemental sulphur on growth and stress tolerance of tissue culture derived plantlets of date palm (Phoenix dactylifera L.) cv. 'Khalas' during acclimatization -
Department of Aridland Agriculture, College of Food and Agriculture, UAE University, P.O.Box. 17555 Al-Ain, United Arab Emirates. Permanent address: Faculty of Agriculture, Pomology Department, Mansoura University, El-Mansoura/Egypt.
DOI: https://doi.org/10.37855/jah.2006.v08i02.30
Key words: Tissue culture, acclimatization, elemental sulphur, gamma aminobutyric acid, salicylic acid, aspirin, vitamin E, oleic acid, ABG-3168, Phoenix dactylifera L.
Abstract: There is a high demand for date palm plantlets regenerated via tissue culture techniques. However, such plantlets require a long acclimatization period extending 12-18 months before transplanting in the open field. The effect of foliar and soil application of anti-stress substances and elemental sulphur, respectively, on growth and survival percentage of tissue culture-derived 'Khalas' date palm plantlets during acclimatization were studied. The results showed that application of salicylic acid, acetyl salicylic acid (aspirin), elemental sulphur, plantacur-E (a vitamin E formulation containing 25% ?-tocopherol) at 1%, and oleic acid at 100 ppm, significantly increased plantlet survival percentages compared to the control. In this respect, gamma aminobutyric acid (GABA) at 20 mM was the most effective treatment compared to 10 mM and the control. Salicylic acid, aspirin, elemental sulphur and plantacur-E (at 2%) significantly increased the concentrations of Fe, Mn, Zn, and Cu in leaflets compared to the control. However, the macro nutrients showed no clear response to the applied treatments. Application of 250 ppm of the ethylene biosynthesis blocker, ABG-3168 (ABG), inhibited the growth of plantlets, and completely suppressed growth at 500 ppm, suggesting the potential role of ethylene biosynthesis in subsequent plantlet development. Irrigation with 10,000 ppm sea water for two months decreased chlorophyll concentration and increased electrolyte leakage by 2-3 fold compared to the control and the other treatments. GABA at 20 mM significantly increased chlorophyll concentration and decreased electrolyte leakage of leaflets compared to all the saline water treatments. In contrast, ABG at 250 ppm significantly decreased chlorophyll concentration and increased electrolyte leakage of leaflets by about 3-fold compared to all the saline water treatments. These results show potential role of GABA, salicylic acid, aspirin and oleic acid conducive for improved survival percentage of plantlets and stress tolerance during acclimatization.
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