Ahmed M . W . Al-Mayahi

Date palm is propagated by the offshoots, the number of which is limited. Therefore, adult date palms produce shoot tips and axillary buds meristems through the use of tissue culture. The micropropagation of the date palm also still faces many obstacles. Here, we established an efficient plant-regeneration system for (Phoenix dactylifera L.) cv. Ashgar by tissue culture. Murashige and Skoog medium containing 6-benzyladenine (BA) (2.0 and 5.0 mg L− 1) and a-naphthaleneacetic acid (NAA) or phenylacetic acid (PAA) (0.05–2.00 mg L− 1) was used to initiate shoot formation from callus tissues. The maximum number of shoots per jar was produced on a medium containing 5.0 mgL− 1 BA and 0.5 mg L− 1 PAA. The medium supplemented with 2.0 mgL− 1 BA in combination with 0.05 m L− 1 PAA gave the highest callus induction (+++). A decrease in browning percentage was observed in the tissue cultured in the media supplied with BA in combination with NAA or PAA compared to the media provided with BA alon...

Embryogenic suspension cultures of Date palm (Phoenix dactylifera L.) allow mass propagation of somatic embryos; Partial desiccation (0, 1, 2, 3 and 4 hours) and low temperature (0 °C for 2 hr, 0 °C for 4 hr, 4 °C for 24 hr and 4 °C for 48 hr) treatments were applied to improve germination of somatic embryos in vitro of date palm cultivar Berhi with or without AC. The highest germination percentage was achieved when embryos were desiccated for three hours as well as treatment of low temperature in 4 °C for 24 hr. Also, the results proved that found activated charcoal (AC) in liquid media produced the highest somatic embryos number and weight and improving percentage of germination. Further, Partial desiccation and low temperature increased embryos proline content. The improvement of the germination of somatic embryos via low temperature and especially via partial desiccation embryos somatic is successful can be used for the purpose of commercial propagation especially for Berhi cult...

There are some limitations in the practical applications of in vitro date palm tissue culture, such as low multiplication efficiency, low rooting rate, and high mortality experienced by in vitro raised plantlets during laboratory to soil transfer. The objective of the present study is to determine the effect of polyamines (putrescine "PUT" and spermidine" SPD") and silver thiosulfate (STS) on enhancing propagation of date palm cv Quntar in vitro. Media supplemented with 75 mg L-1 SPD in combination with 10 mgL-1 STS gave the highest percentage of callus producing buds (83.34%) and average bud formation (16.3) per jar. The addition of PUT and STS to the medium was most effective in root regeneration and the number of roots per shoot, where the best result 91.67% and 6.37 roots per shoot, respectively, were obtained using 75 mgL-1 PUT and 10 mgL-1 STS, resulting in fast-growing plantlets during acclimatization phase, reaching 90% of plant survival. The genetic fide...

This study was carried out to investigate the effects of silicon (Si) 3.6 mM (as calcium silicate) under drought stress induced by polyethylene glycol "PEG" at 15% (MW 8000), in addition to the control treatment on growth and some biochemical constituents of date palm cv. Barhee cultured in vitro. Drought stress (15% PEG) depressed the growth of shoot and decreased protein content and chlorophyll concentration. Addition of 3.6 mM Si could improve the growth of shoot and increase the protein content and leaf chlorophyll concentrations of stressed plants. The inclusion of Si to the PEG containing medium significantly increased the catalase (CAT) and superox-ide dismutase (SOD) activity in regenerated shoot, compared to other treatments. As well as drought stress 15% PEG induced significant accumulation of shoots proline, which were decreased by added silicon. Moreover, the results were also supported by the observation that PEG stress-induced decrease the response percentage of root induction and root lengths was reversed by added silicon. Addition of Si obviously significantly increased the wax content in leaves, response percentage of root induction and root lengths of plantlets under drought stress. The results of this study indicate that the application of silicon improved growth attributes, effectively mitigate the adverse effect of drought, and increase tolerance of date palm plants for drought stress during the course of date palm tissue cultures.

This study was carried out to investigate the antioxidant effects of salicylic acid (SA) and ascorbic acid (ASA) under two stress levels (75 and 150 mM NaCl) on growth and some biochemical constituents of date palm cv. Nersy cultured in vitro. Micro-propagated shoots of cv. Nersy at length 2.5-3 cm was excised from the proliferation medium and were separately cultured on MS medium. The data indicated that maximum growth and chlorophyll content of shoots was observed after 75 days of culturing in the medium supplemented with 50 mgl-1 salicylic acid and 100 mgl-1 ascorbic acid in both stress and non-stress conditions. It was also observed that the in vitro-grown plants resulted increased activities of antioxidant enzymes SOD and APX in medium containing of salicylic acid (75 mgl-1) and ascorbic acid (100 mgl-1) with increasing salt stress (up to 150 mM of NaCl) compared with other treatments. The study of shoot protein patterns using SDS-PAGE showed some remarkable changes in protein expression. The results suggests that the stress induced the synthesis of proteins bands with MW of 15, 29, 43 kD and 15, 22.6, 35 and 46 kD in medium supplement with 75 and 150 mM NaCl, respectively, compared with control treatment (20.9, 28.39, 37, 40 and 48.6) kD. Supplementing salicylic acid (75mgl-1) and ascorbic acid (100 mgl-1) under salt stress condition induced the synthesis of additional protein bands with MW of 19.28, 28.50, 32.61, 59.12 and 72.00 KD at 75 mM NaCl; and 17.96,22.6, 31.95 54.50 and 68.0 at 150 mM NaCl.

The establishment of an efficient protocol for plantlets regeneration and micropropagation from leaf cultures of date palm cv. Quntar is reported. The two types of leaflet segments used in the experiment (First piece of leaf base which have white color, and second piece of leaf tip which have green color), were taken from micro propagated shoots of date palm cv. These leaf segments were in vitro culture on MS media containing various concentrations of 2,4-dichlorophenoxyaceticacid at 1.0 mgl-1 and benzyl adenine (BA). Maximum induction of callus was obtained from piece of leaf base (white) in medium supplemented with 5.0 mgl-1 2,4-D and 1.0 mgl-1 (BA), as compare with [piece of leaf tip (green)] which did not show response for callus formation. Using culture system with temporary tissue immersions "bioreactor" in Somatic embryo production enriched with 1.0 mgl-1 2,4-D + 500 mgl-1 active charcoal (AC) gave the highest number of somatic embryos (172 embryos). These embryos formed from 500 mg initial callus. As well as, the short immersions frequently repeated, 1 min immersions every 4 h, led to the largest quantities of embryos. Indirect shoot organogenesis was achieved from the embryogenic callus using 3.0 mgl-1 2iP + 1.0 mgl-1 NAA, where highest number of shoots (8.28 ± 0.71) with maximum frequency (58.34%) was regenerated. The addition of 3 gml-1 Gelrite to medium was optimal for the shoots proliferation. The balance of auxin to cytokinin in medium affected on the growth of the date palm tissue. The shoots were successfully rooted (80%) with rapid elongation when cultured on MS medium containing 0.5 mgl-1 GA 3 + 1.0 mgl-1 NAA. Rooted shoots were successfully acclimatized when planted in plastic pots containing a mixture of peat moss and perlite (2:1) with 80% success.

This study was carried out to investigate the effects of copper sulphate and cobalt chloride on propagation of date palm cv. Ashgar in vitro. The rate of callus proliferation was significantly higher in the medium supplemented with 2 µM copper sulphate and 2 µM cobalt chloride together (p<0.05). Addition of copper sulphate and Cobalt chloride to the medium was most effective for shoots regeneration from callus and enhanced regeneration frequency as well as number of shoots obtained per explant, the best result (7.12 shoot/explant) was obtained by using copper sulphate and Cobalt chloride at 2.0 µM. Also the results of this experiment indicates that the maximum induction of roots can be achieved in the media containing both additives at 0.5 µM. The callus exhibited a decline in carbohydrate contents, proteins, whereas total phenol content increased at high concentration of Cu and Co. The greatest formation of chlorophylls a, b and total chlorophyll was obtained in plantlets grown in the media containing both additives at 0.5 µM. As well as Maximum survivability was noticed for plants cultured in media that containing both copper sulphate and Cobalt chloride at 0.5 µM.