ISHS Acta Horticulturae 736: III International Date Palm Conference
EVALUATION OF IN VITRO SCREENING TECHNIQUES FOR SALT TOLERANCE IN DATE PALM |
| Authors: | T.A. Al Mansoori, M.N. Alaa El-Deen, P.D.S. Caligari |
| Abstract:
The date palm is an important source of income and nutrition in a number of countries. It is considered a salt tolerant plant species. However, very limited information is available concerning variation in salt tolerance among the cultivars currently growing. This investigation aimed to evaluate the potential of employing tissue culture techniques to screen date palm genotypes for salt tolerance. The effect of NaCl on calli derived from immature embryos of four local date palm cultivars was examined at two distinct stages, which were dedifferentiation and fast growing stages. The results suggest that employing callus induction might be more efficient than using the fast growing stage to identify variation in salt tolerance among date palm genotypes. The fast growing callus system was unable to detect significant differential performance, whereas the callus induction system was capable of detecting variation among the genotypes. Salinity affected date palm immature embryos significantly and complete inhibition occurred when 3.0% (w/v) NaCl was incorporated into the induction medium. In both cases, callus growth retardation was clearly evident with increasing salinity. Both types of calli also exhibited tissue dehydration symptoms, which were recorded as a significant increase in callus dry weight ratio. Callus Na+ content increased dramatically with increasing NaCl level, whereas K+ content decreased causing a significant reduction in callus K+/Na+ status. Proline, which is considered a compatible osmoticum, increased significantly in both types of calli in response to salinity. During the induction stage, the increase in endogenous free proline content was more pronounced in the progeny of the cultivar, which exhibited higher percentage of callus induction. Therefore, the better dedifferentiation process could be related to proline content, which adjusts the intracellular osmotic pressure between the cytoplasm and the vacuole. | |
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