Date Palm Plantlets Research Articles

Application of Bacilli Phages for Controlling Bacillus Subtilis Associated Date Palm Plantlets Malformation in Tissue Culture

Application of Bacilli Phages for Controlling Bacillus Subtilis Associated Date Palm Plantlets Malformation in Tissue Culture

Comparison between nitrogen biofertilizers source (blue green algae and bacteria) on growth of date palm plantlets (Phoenix dactylifera ‘Malacabe’) during acclimatization stage

Comparison between nitrogen biofertilizers source (blue green algae and bacteria) on growth of date palm plantlets (<i>Phoenix dactylifera</i> ‘Malacabe’) during acclimatization stage

Design and Evaluation of a Smart Ex Vitro Acclimatization System for Tissue Culture Plantlets

One of the technological advancements in agricultural production is the tissue culture propagation technique, commonly used for mass multiplication and disease-free plants. The necessity for date palm tissue culture emerged from the inability of traditional propagation methods’ offshoots to meet the immediate demands for significant amounts of planting material for commercial cultivars. Tissue culture plantlets are produced in a protected aseptic in vitro environment where all growth variables are strictly controlled. The challenges occur when these plantlets are transferred to an ex vitro climate for acclimatization. Traditional glasshouses are frequently used; however, this has substantial mortality consequences. In the present study, a novel IoT-based automated ex vitro acclimatization system (E-VAS) was designed and evaluated for the acclimatization of date palm plantlets (cv. Khalas) to enhance their morpho-physiological attributes and reduce the mortality rate and the contamination risk through minimal human contact. The experimental findings showed that the morpho-physiological parameters of 6- and 12-month-old plants were higher when acclimatized in the prototype E-VAS compared to the traditional glasshouse acclimatization system (TGAS). The maximum plant mortality percentage occurred within the first month of the transfer from the in vitro to ex vitro environment in both systems, which gradually declined up to six months; after that, no significant plant mortality was observed. About 6% mortality was recorded in E-VAS, whereas 18% in TGAS within the first month of acclimatization. After six months of study, an overall 14% mortality was recorded in E-VAS compared to 41% in TGAS. The proposed automated system has a significant potential to address the growing demand for the rapid multiplication of tissue culture-produced planting materials since the plant survival rate and phenotype quality were much higher in E-VAS than in the conventional manual system that the present industry follows for commercial production.

Zinc Oxide Nanoparticles and Fe-Modified Activated Carbon Affecting the In Vitro Growth of Date Palm Plantlets cv. Medjool

The survival and growth of in vitro plantlets are still problematic for the date palm; thus, the application of nanotechnology may provide date palm plantlets that develop faster with enhanced growth and biochemical parameters. Moreover, the usage of Fe-modified activated carbon (Fe-AC) prepared from date palm pits instead of activated charcoal (AC) in tissue culture media during the current investigation can be considered an innovative approach. Furthermore, the effect of zinc oxide nanoparticles (ZnO-NPs) and bulk particles (ZnO-BPs) on the rooting and growth of date palm plantlets and on some physiological indices was also investigated. X-ray diffraction, dynamic light scattering, scanning electron microscopy, and transmission electron microscopy were used to characterize Fe-AC and ZnO-NPs. As detected from the characterization, the particle size was 720 nm for Fe-AC and 60 nm for ZnO-NPs. The obtained results indicated that AC significantly enhanced plantlet growth, plantlet height, number of leaves/plantlet, root length, number of roots/plantlet, and the concentrations of IAA, chlorophyll a and chlorophyll b compared with Fe-AC. On the other hand, sugars and phenols concentrations, and POD and PAL activities were highly increased with Fe-AC. There was no significant difference in terms of plant fresh weight (FW), leaf length, leaf width, protein, amino acids, and carotenoids. ZnO nanoparticles significantly improved plant height, leaf length, leaf width, root length, and the concentrations of IAA, chlorophylls a and b, and carotenoids; in contrast, the bulk form increased roots/plantlet, amino acids, and total sugars. Supplying the MS medium with combinations of ZnO-NPs or ZnO-BPs and AC or Fe-AC significantly increased all growth and physiological parameters. Plant height, leaf length, leaf width, root length, and the concentrations of IAA, protein, and chlorophylls a and b significantly increased when ZnO-NPs were combined with AC. Amino acids, total sugars, carotenoids, and phenols concentrations and the activities of POD and PAL increased when ZnO-BPs and Fe-AC were added together.

Phylogeny and mycotoxin profiles of pathogenic Alternaria and Curvularia species isolated from date palm in southern Tunisia.

Date palm (Phoenix dactylifera L.), is a widely cultivated crop across North Africa, with about 300 thousand tons of fruits produced per year, in Tunisia. A wide range of fungal pathogens has been associated with leaf spots of date palm, Alternaria species being the most frequently reported. Symptomatic leaves of Deglet Nour variety were randomly collected in six localities in Tunisia. We used a polyphasic approach to identify 45 Alternaria and five Curvularia strains isolated from date palm, confirming their pathogenicity. Sequencing of allergen Alt-a1, glyceraldehyde-3-phosphate dehydrogenase (gpd) and calmodulin genes allowed us to group 35 strains in Alternaria Section, and 10 strains in Ulocladioides section. Based on sequencing analyses of Internal Transcribed Spacer, gpd and elongation factor genomic regions, all Curvularia strains were identified as Curvularia spicifera. All Alternaria and Curvularia species tested on date palm plantlets proved to be pathogenic, fulfilling Koch's postulates. Although no significant differences were observed among the species, the highest mean disease severity index was observed in A. arborescens, while the lowest corresponded to C. spicifera. The capability of these strains to produce mycotoxins in vitro was evaluated. None of the A. consortialis strains produced any known Alternaria mycotoxin, whereas more than 80% of the strains included in Alternaria section Alternaria produced variable amounts of multiple mycotoxins such as alternariol, alternariol monomethyl ether, altenuene, tenuazonic acid and tentoxin. Curvularia spicifera strains produced detectable traces of fumonisins B. This work reports a first comprehensive multidisciplinary study of mycotoxigenic Alternaria species and C. spicifera associated with leaf spot disease on date palm.

Efficacy of Bacillus subtilis (Ehrenberg1835) Cohn1872, in suppressing Fusarium oxysporum Schlecht. emend. Snyder &amp; Hansen, the causal agent of root rot of date palm offshoots (Phoenix dactylifera L.) in Iraq

Date palm root rot disease is one of the most important diseases of date palms and offshoots. It is caused by many soil-borne pathogenic fungi. Pathogenicity assays of the isolated fungi showed that the major causative agents of root rot disease in date palm plantlets were Fusarium oxysporum Schlecht. emend. Snyder &amp; Hansen, F. proliferatum (Matsush.) Nirenberg ex Gerlach &amp; Nirenberg S1, F. proliferatum S2, Gibberella fujikuroi (Sawada) Wollenw., and Rhizoctonia solani J.G. Kühn. The most virulent fungus was F. oxysporum with a severity index of 82.16 % of root rot, while R. solani was the least harmful with a disease severity rate of 12.42 %. In laboratory tests, Bacillus subtilis reduced the radial mycelial growth of F. oxysporum on PDA medium by 86.6 %. The application of B. subtilis in combination with F. oxysporum substantially inhibited the severity of root rot disease relative to plantlets treated with only F. oxysporum. In addition, B. subtilis application in the presence or absence of F. oxysporum improved the plant physiology of plantlets, including total chlorophyll, total carotenoid, antioxidant enzyme levels (catalase and peroxidase), and total proline content.

SUPERIORITY OF NANO-SILVER NITRATE AND NANO-CHITOSAN IN CONTROLLING BACTERIAL CONTAMINATION AND PROMOTING GROWTH OF In vitro DATE PALM CULTURES

Date palm (Phoenix dactylifera L.) a perennial monocotyledonous tree it’s have an ecological importance and economical role in several countries of Middle East and North Africa, date palm can’t be propagate by seeds, meanwhile the offshoots produced low numbers of offshoots for the given period, so tissue culture technique become a great important for produced the huge demand plantlets, the in vitro technique facing a problem as the contamination by bacterial and fungus that lead to loss the cultures, for eliminate this problem many treatments were used as chitosan 5 and 15 ml/l, AgNO3 4.0 and 7.0 ml/l, Zn 4.0 and 7.0 mg/l and cu 0.5 and 1.0 mg/l. as the main forms or as a nanoparticles NPs in addition to streptomycin 40 and 50 mg/l and AgNO3 + Sodium thiosulfate 0.5 and 1.0 ml/l were added to rooting stage medium for 3 subcultures for each, then these plantlets were acclimatized under greenhouse condition. Collected data were subjected to analysis of variance (ANOVA) and the means were compared following t-test using LSD values at 5%. The percentage of cultures contamination was to be found zero % with the treatments chitosan, silver nitrate AgNO3, in addition to the combination of Chitosan + AgNO3, chitosan + Zn and finally chitosan + Cu at all tested levels produced, while the treatments Zn and Cu at two tested levels produced 11% contamination, the observation of the vegetative growth and leaves contents of indoles and amino acids mg/g f.w. were found highest values under chitosan and AgNO3 and the combination in between as the main forms or as NPs treatments, as well as, the acclimatization stage presented the great survival percentage % under Chitosan and AgNO3 and combination in between as the main form or as NPs. The present study have been suggest that NPs chitosan, AgNO3 and the combination in between might be a promising method for reduced or eliminate the in vitro microbes, reduced the harmful effects on the valuable date palm plantlets and increasing growth parameters.

Optimizing Tissue Culture Protocol for In Vitro Shoot and Root Development and Acclimatization of Date Palm (Phoenix dactylifera L.) Plantlets

Optimizing Tissue Culture Protocol for In Vitro Shoot and Root Development and Acclimatization of Date Palm (Phoenix dactylifera L.) Plantlets

PRIMITIVE EFFECTS OF CULTURE SYSTEM, SORBITOL AND SALICYLIC ACID ON GROWTH OF TISSUE CULTURE DERIVED DATE PALM PLANTS (PHOENIX DACTYLIFERA L.) AMRI CV. DURING ACCLIMATIZATION STAGE

Date palm plantlets produced in vitro using tissue culture technique in a greenhouse face a great challenge that may lead to their death due to different ambient environmental conditions, moreover the slow growth rate of the survived tissue culture derived date palm plants during acclimatization are critical problems facing the tissue culture as a commercial technique of date palm propagation. ​Therefore, the success of date palm micropropagation is strongly linked to the success and quality of plantlets in the greenhouse. This study aimed to evaluate the effect of three different cultural systems on survival percentage, plant length, number of leaves and estimation photosynthetic pigments in greenhouse in the first experience as well as effect of foliar spray and watered three concentrations of Sorbitol (0, 15, 30 and 45 g l-1) and salicylic acid at concentrations (0, 20, 40 and 60 mg l-1) on some vegetative growth parameters such as survival percentage, leaf width and growth vigor in the secondary experience. Findings indicated that using both the hydroponic (first culture system) and the traditional systems, with the addition of Barbary-Plante (third culture system) during the acclimatization stage gave highest values of survival percentage, plant length, number of leaves and chlorophyll a+b content compared to the second culture system, where the lowest values were recorded. Also spraying and irrigation with sorbitol at 30 gl-1 plus salicylic acid at 40 mg l-1 giving the highest values of survival percentage, leaf width and growth vigor (91%, 2.73 cm, 4, respectively) compared to other treatments.

Cost analysis of date palm (cv. Mejhoul) plantlets produced by organogenesis in Morocco

Organogenesis is an in vitro regeneration method used for rapid and large-scale propagation of a number of plant species. During the last decade, organogenesis has been used as a tool to rehabilitate date palm groves in Morocco, and resulted in the production of millions of date palm plantlets. In the present study, the production cost of date palm plantlets (cv. Mejhoul) obtained through direct organogenesis was estimated. The organogenesis protocol used was based on previously published studies. The cost analysis included the costs of offshoots, culture medium components, chemicals, equipment maintenance, water, fuel and electricity consumption as well as staff salaries and all the consumables used during in vitro work and plantlet acclimatization. The hardware (infrastructure, laboratory equipment and vessels) cost was not included. During the production process, the loss of plant material due to endophytic bacteria, tissue browning and hyperhydricity was taken into account. At the end of the organogenesis process, an average of 947.6 plantlets were produced from one offshoot. It was found that staff salaries (46.05%) and electricity consumption (26.16%) account for the majority of expenses. The production cost of one plantlet was estimated to be US$ 3.84. The findings of the present study highlight the economic feasibility of using organogenesis for date palm propagation. The production cost of date palm plantlets through organogenesis was estimated. The economic feasibility of this technique was highlighted when compared with conventional propagation through offshoots.

In-site and Ex-site Date Palm Exposure to Heavy Metals Involved Infra-Individual Biomarkers Upregulation.

As a tree of considerable importance in arid regions—date palm, Phoenix dactylifera L. survival in contaminated areas of Sfax city has drawn our attention. Leaf samples of the plants grown in the study area showed high levels of cadmium (Cd), copper (Cu), and chromium (Cr). On the basis of this finding, the cellular mechanisms that explain these metal accumulations were investigated in controlled conditions. After four months of exposure to Cd, Cr, or Cu, high bioconcentration and translocation factor (TF > 1) have been shown for date palm plantlets exposed to Cd and low TF values were obtained for plantlets treated with Cr and Cu. Moreover, accumulation of oxidants and antioxidant enzyme activities occurred in exposed roots to Cu and Cd. Secondary metabolites, such as polyphenols and flavonoids, were enhanced in plants exposed at low metal concentrations and declined thereafter. Accumulation of flavonoids in cells may be correlated with the expression of the gene encoding Pdmate5, responsible for the transport of secondary metabolites, especially flavonoids. Other transporter genes responded positively to metal incorporation, especially Pdhma2, but also Pdabcc and Pdnramp6. The latter would be a new candidate gene sensitive to metallic stress in plants. Expressions of gene coding metal chelators were also investigated. Pdpcs1 and Pdmt3 exhibited a strong induction in plants exposed to Cr. These modifications of the expression of some biochemical and molecular based-markers in date palm helped to better understand the ability of the plant to tolerate metals. They could be useful in assessing heavy metal contaminations in polluted soils and may improve accumulation capacity of other plants.

Influence of Polyethylene Glycol on Leaf Anatomy, Stomatal Behavior, Water Loss, and Some Physiological Traits of Date Palm Plantlets Grown In Vitro and Ex Vitro.

Few reports explain the mechanism of PEG action on stomatal behavior and anatomical structure and analyze the photosynthetic pigments of in vitro date palm plantlets for better tolerance to ex vitro exposure. The main challenge for in vitro micropropagation of date palm techniques remains restricted to high survival rates and vigorous growth after ex vitro transplantation. In vitro hardening is induced by Polyethylene glycol PEG (0.0, 10, 20, 30 g L−1) for 4 weeks. Leaf anatomy, stomatal behavior, water loss %, photosynthetic pigments, and reducing sugars were examined in date palm plantlets (Phoenix dactylifera L.) cv. (Sewi) after 4 weeks from in vitro PEG treatment and after 4 weeks from ex vitro transplanting to the greenhouse. Leaf anatomy and the surface ultrastructure of in vitro untreated leaves showed a thin cuticle layer, wide opened malfunctioning stomata, and abnormal leaf anatomy. Furthermore, addition of PEG resulted in increasing cuticle thickness, epicuticular wax depositions, and plastids density, improving the stomatal ability to close and decreasing the stomatal aperture length while reducing the substomatal chambers and intercellular spaces in the mesophyll. As a result, a significant reduction in water loss % was observed in both in vitro and ex vitro PEG treated leaves as compared to untreated ones, which exhibited rapid wilting when exposed to low humidity for 4 h. PEG application significantly increased Chlorophylls a, b and carotenoids concentrations, especially 10, 20 g L−1 treatments, which were sequentially reflected in increasing the reducing sugar concentration. However, leaves of plantlets treated with PEG at 30 g L−1 became yellow and had necrosis ends with death. In vitro hardening by 20 g L−1 PEG increased the survival rate of plantlets to 90% after ex vitro transfer compared to 63% recorded for the untreated plantlets. Therefore, this application provides normal date palm plantlets developed faster and enhances survival after ex vitro transfer.

Water use efficiency and nutrient uptake of rice under soil water stress condition

One obstacle that can limit the growth and production of rice is low water availability. Therefore, a comprehensive study of the response of rice plants to drought is very important. The study was conducted in the greenhouse of the Faculty of Animal Husbandry and Agriculture, Diponegoro University, from April to August 2016. The study used a 3 x 3 factorial design with 3 replications. The first factor is three types of rice (Sidenuk, Way Apo Buru, Pepe) and the second factor is water stress treatment (KA &lt;field capacity = enough water, field capacity (KL), water saturation (JA). The observed parameters are protein content, leaf levels rolling (number of leaves rolled), relative water content (RWC), water use efficiency (WUE), N, P, K uptake, rice protein content decreases with increasing water supply. The relative water content of rice plants decreases with increasing stress water that occurs in the limited water supply for the three types of rice Sidenuk rice has the lowest N seed content (2.1%) compared to Way Apo (3.0%) and Pepe (3.1%). The mineral content of P in both biomass and seeds is not really influenced by water stress, as well as K content of seeds. REFERENCES Badan Pusat Statistik. 2018. https://www.bps.go.id/dynamictable/2019/04/15/1608/luas-panen-produksi-dan-produktivitas-padi-menurut-provinsi-2018.html Darwesh, R, S,S. 2013. Improving growth of date palm plantlets grown undersalt stress with yeast and amino acids applications Annals of Agricultural Science (2013) 58(2), 247–256 Etienne P.I.D, S. Diquelou , M. Prudent, C. Salon., A. Maillard, and A.Ourry. 2018. Macro and Micronutrient Storage in Plants and Their Remobilization When Facing Scarcity: The Case of Drought. Agriculture 2018, 8, 14; 2-17. doi:10.3390/agriculture8010014 Farooq, M., S.M.A.Basra, A. 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Evaluation of optimum concentration of naphthalene acetic acid on &lt;i&gt;in vitro&lt;/i&gt; rooting and acclimatization of tissue culture date palm (&lt;i&gt;Phoenix dactylifera&lt;/i&gt; L.) plantlets

A major limitation in large scale application of micropropagation technology is high mortality experienced by in vitro raised plants during laboratory to land transfer. This study was aimed at investigating the best concentration of Naphthalene acetic acid (NAA) on in vitro rooting and also develop protocol for successful plant acclimatization with high survival rate. Date palm plantlets were rooted on Murashige and Skoog (MS) basal medium with different NAA concentrations (0.0, 0.1, 0.5 1.0, 1.5 and 2 mg/l) without activated charcoal. Result showed that all the NAA concentrations supported root formation. The optimal initiation and growth of roots of the plantlets were observed at NAA concentration of 1.0 mg/l (87 %) and least with Basal MS without NAA (47 %). Results also showed that root number and lengths increased with increasing NAA concentrations up to 1.0 mg/l and decreased thereafter. The culture mixture of peat moss + soil (2:1) gave the highest survival percentage of 80 % for plant acclimatization. This investigation had shown that accurate assessments of responses to medium at various stages should be considered as specific requirement for successful plant acclimatization. Keywords: date palm, in vitro , plantlets, acclimatization

Influence of cold pretreatment on shoot regeneration from callus in date palm (Phoenix dactylifera L.) cv. ‘Barhee’

Mass propagation of date palm through indirect somatic embryogenesis or organogenesis has attracted the interest of commercial producers. But, this technique still faces some problems that hindered the production of date palm plantlets in vitro. Tissue browning is one of the serious problems that reduce callus growth and shoot regeneration. So the objective of the present study is to investigate the effect of cold pretreatment on callus growth, shoot regeneration, and polyphenol oxidase (PPO) activity during the callus culture. Results showed that a high survival rate of callus cultures (100%) were obtained when cultures were incubated in low temperature (cold treatment) for 45 and 75 days. On the other hand, total amount on phenolic compounds was also reduced to 0.47 and 0.53 mg GAE/g after same period of incubation (45 and 75 days respectively) at low temperature. In additional, our results showed that the highest frequency of shoot formation (66.67 and 73.34, %) and the highest shoot numbers (7.8 and 8.6 shoots/100 mg) were obtained from callus treated with low temperature for 45 and 75 days, respectively.

Effect of organic fertilizer and commercial arbuscular mycorrhizal fungi on the growth of micropropagated date palm cv. Feggouss

Date palm is an important crop in Morocco, Tunisia and many other drylands of the world, but its growth is often limited due to the low soil fertility and harsh environmental conditions of oases ecosystems, which can hardly be compensated by the sole application of high dosages of chemical fertilizers. For the first time, we investigated the effects of compost application and inoculation with a commercial strain of the arbuscular mycorrhizal fungus (AMF), Glomus iranicum , on the growth of micropropagated date palm plantlets (cv. Feggous). After twelve months of growth, plantlets transplanted into compost amended substrate inoculated with AMF showed increased biomass production (root and shoot biomass), chlorophyll and mineral nutrient contents than plantlets transplanted into compost amended substrate or without compost addition. Thus, this inoculum reinforced the promoting effect of compost and was successful in colonizing the root system. According to our results, sandy substrate enriched with compost and inoculated with G. iranicum can be recommended for improving the growth and nutrition of micropropagated date palm plantlets.

Effect of Phloroglycinol and Different Planting Media on Rooting and Acclimatization Plantlets of Date Palm cv. Zaghloul

Date palm plantlets cv. Zaghloul derived from somatic embryogenesis were used to investigate factors affecting rooting and subsequent survival in acclimatization. Rooting formation was affected by phloroglcionl (PG) level (20, 40 and 80 per liter) added to rooting medium. Rooting medium supplemented with 40 mg/1 PG was statistically the superior and exhibited the tallest and greatest numbers of rootlets per each plantlet in addition 20 mg/l PG was statistically more effective as compared to either control medium or medium provided with 80 mg/1 PG. Plantlets were transferred to greenhouse to study the effect of different mixtures of media on survival percentage the most suitable mixtures were peatmoss sand at (3:1v:v); peatmoss sand vermiculit perlite at (1:1:1:1 v:v); and peatmoss perlite vermiculite (1:1:1v:v) as they exhibited 100 %,75% and 75% survival planlets (respectively) after three months of ex vitro acclimatization. The reverse was true with both peatmoss sand (1:3 v:v) and peatmoss perlite at 1:1 v:v where each one resulted the least survival percentage (25%). In addition the peatmoss sand mixture at equal proportion 1:1 by volume was in between the aforesaid two extremes 50% after three months of ex vitro acclimatization.

Micropropagation of some Sewa Oasis Date Palm (Phoenix dactylifera L.) Cultivars Grown in Egypt

Shoot tip and leaf primordial explants of Phoenix dactylifera L. cvs. (Sewi and Oshkingbeel) were cultured in modified MS medium supplemented with various combinations between different growth regulators cytokinins (2iP or BA) and Auxins (2, 4-D or NAA). Friable callus was produced from shoot tip and leaf primordial explants. The highest percentage of callus initiation was achieved on modified MS medium supplemented with 100 mg/L 2,4-D and 3 mg/L 2iP for shoot tip and leaf primordial explants. The highest percentage of embryogenic callus was achieved on modified MS medium supplemented with 10 mg/L 2,4-D, 5 mg/L NAA, 3 mg/L 2iP and 3.0 g/L activated charcoal which gave 87.5% and 75% for Sewi and Oshkingbeel cvs., respectively. Somatic embryos formation were obvious on modified MS medium plus 0.1 mg/L NAA which gave the highest average number (5.16, 4.94) for Sewi and Oshkingbeel, respectively after three subcultures. Greatest embryonic elongation resulted at 0.5 mg/L 2iP + 0.5 mg/L kinetin + 40 g/L sucrose in solid full strength MS medium. Also, the highest value of leaves number was shown on the same medium. The complete plantlets developed from individual embryos (5-10 cm) were transferred to rooting MS medium supplemented with 1 mg/L NAA with good growth in solid and liquid media. Rooted date palm plantlets from both cultivars were transferred to plastic pots (5cm diameter) containing peat-moss, sand and vermiculite at equal volume. Acclimatization percentage decreased gradually during four months in the first acclimatization stage. Date palm plantlets produced from the first acclimatization stage were transferred to plastic pots (20 cm diameter) containing peatmoss, washed sand and vermiculite at equal volume for more growth and development to be ready to cultivate in the field. Although survival percentage was low during the first acclimatization stage, it was very high in the second acclimatization stage and date palm survival percentage became constant after another six months with good growth.

Improving In Vitro Somatic Embryos Production of Medjool and Khalas Date Palm Cultivars via Modification of Ammonium and Potassium Nitrate

Date palm is one of the most economically powerful fruit tree grown in Egypt. Although Egypt tops the list of date's product in the world. Egyptian date palm industry suffers from many constraints. Low-quality varieties and limited conventional propagation methods are the main obstacles. Extension of date palm plantations in various areas of Egypt and replanting trees to compensate loss due to diseases or human factors are reduced expected to lack adequate planting materials. The knowledge of the interplay between some fundamental medium parameters allows not only the optimization of the micropropagation system but also gives models to investigate and rationalize the process of induction and development of somatic embryogenesis itself. In vitro growth and development of produced embryos and plantlets has been improved by using of full MS salt strength. MS medium modification of some nutrients concentrations, i.e. NH4NO3(1237.5 mg/l) which recorded (13.20 and 9.60 embryos/explant for Medjool and Khalas respectively) at the end of three subculture. KNO3 which gave a higher score of mature somatic embryos (14.40 and 10.00 embryo/culture for Medjool and Khalas respectively) was obtained with 1425 mg/l KNO3 after three subcultures as compared to those obtained from any other treatment combination. The morphological response of somatic embryos production is controlled by some internal factors that fall under the influence of the genetic make-up of the plant and specialized for each genotype that is responsible for the production of somatic embryos (Medjool and Khalas cultivars). The genetic make-up is a decisive factor during somatic embryos production. There are differences between the two cultivars named, Medjool and Khalas. The produced somatic embryos at germination stage were transferred from the two experiments namely ammonium nitrate and potassium nitrate to multiplication and rooting stages for more in vitro growth for 12 weeks at three re-cultures. Individual shoots were cultured on modified MS basal medium in addition to IBA (1.0 mg/l), sucrose (30 g/l) and solidified with phyto-agar (8.0 g/l) for more in vitro growth and development. In vitro plantlets were transferred to acclimatization stage in plastic pots 5*18 cm diameter containing peatmoss, perlite and washed sand at equal volume. In vitro date palm plantlets produced from rooting stage grow well in the greenhouse during acclimatization stage without morphological abnormality. The growth and development of Medjool cultivar were better than Khalas during in vitro culture and ex vitro acclimatization.

Improvement of In Vitro Date Palm Plantlet Acclimatization Rate with Kinetin and Hoagland Solution.

In vitro propagation of date palm Phoenix dactylifera L. is an ideal method to produce large numbers of healthy plants with specific characteristics and has the ability to transfer plantlets to ex vitro conditions at low cost and with a high survival rate. This chapter describes optimized acclimatization procedures for in vitro date palm plantlets. Primarily, the protocol presents the use of kinetin and Hoagland solution to enhance the growth of Barhee cv. plantlets in the greenhouse at two stages of acclimatization and the appropriate planting medium under shade and sunlight in the nursery. Foliar application of kinetin (20mg/L) is recommended at the first stage. A combination between soil and foliar application of 50% Hoagland solution is favorable to plant growth and developmental parameters including plant height, leaf width, stem base diameter, chlorophyll A and B, carotenoids, and indoles. The optimum values of vegetative growth parameters during the adaptation stage in a shaded nursery are achieved using planting medium containing peat moss/perlite 2:1 (v/v), while in a sunlight nursery, clay/perlite/compost at equal ratio is the best. This protocol is suitable for large-scale production of micropropagated date palm plantlets.