Date palm (Phoenix dactylifera L.) plants demand reclamation of new areas or renewal of the oldest trees. Different methods to produce these plants as seeds that gave only 50% of seedlings will be female. The dates from seedling plants are often smaller and of poorer quality, so the propagation of date palm plantlets will occur with different methods. In vitro culture produced true-to-type huge numbers of plantlets under control conditions that led to many differences in morphology, physiology, and anatomy characteristics. The acclimatization was done to modify these abnormalities, and the plantlets after acclimatization need to improve growth by different treatments. Offshoots are the other method for propagation. These offshoots that grow from the base of the tree need to improve new rooting at the trunk base by growth regulators substances. This work shed light on the different methods of date palm propagation, the crucial role of the acclimatization greenhouse stage, and improved plantlets planted in the open field.
TopIntroduction
Date palm (Phoenix dactylifera L.) is a dioecious propagated by seeds which are not used as the commercial method for reasons;
The production plants are not true to type mother plants
Only 50% of seedlings will be female
The dates from seedling plants are often smaller and of poorer quality. So, these methods have done not in the research aspect (Khaled et al. 2017)
Date palm tissue culture technique is the considerable tool can be produce the huge numbers of plants to farmers in order to increasing dates which have high nutritional value, in vitro technique become used for large scale due to
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Annihilation of genetic variation by sexual propagation
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Production of large number of genetically true –to type plantlets
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Disease-free plants especially Bayoud (lethal disease)
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important for scientific purpose (Junaid and Khan, 2009; Bhattacharjee 2006, Fki 2011, Rajmohan 2011 and Zaid et al. 2011)
Several factors can be affecting successfully in vitro technique i.e.
Type of explant
Nutrients and growth regulators
Culture conditions as temperature, light intensity and light duration (Muthukrishnan et al. 2013).
These culture conditions contribute to different morphological, physiological and anatomical characters
TopIn Vitro And Ex Vitro Plantlets Differences
Morphological Effects
In vitro shoots and plantlets are tiny compared to the open field plants, this tiny shape refers to a high concentration of cytokinins specially in the shooting stage. Saturated water, plants in vitro have increasing water contents and high concentration of cytokinins, this makes reducing dry matter accumulation per area, all of the organs more fragile. Plantlets from in vitro have shortest shoots and roots and lowest numbers of leaves and roots than ex vitro, plant height, number of leaves, total dry mass and leaf mass area ratio of Nicotiana tabacum (Pospisilova et al.1999), Curled dark leaves of date palm derived in vitro condition (El- Bahr et al. 2003). Leaf length and shoot number and shoot and root dry weights were increased after ex vitro than in vitro of sea oats (Uniola paniculata L.) (Aracama et al. 2008). Stem diameter, shoots numbers of Alpinia purpurata were increased in ex vitro compared to in vitro (Medina et al. 2007), ex vitro survived-plantlets when acclimatized had varied survivability from 73-93% with 82% in average and increasing in leaf and root number and length and height of shoots of Ruscus hypophyllum L. (Winarto and Setyawati 2014), after 45 days from acclimatization stage in the greenhouse the roots numbers, mean root length and shoot height of Teak (Tectona grandis) were increased (Yasodha et al. 2005), numbers of leaves and axillary shoots, fresh and dry weights of leaves and shoots of Malus hupehensis were increased under glasshouse (Ur-Rahmanet al. 2007), in ex vitro of Pterocarpus santalinus L. the plant height, number of leaves/plant, fresh and dry weight of leaves and shoot and root/plant were increased (Rajeswari and Paliwal 2008), 12 weeks of acclimatization is the best treatment for increasing roots length which penetrated out from the pots through the holes at the bottom of the pots or grew in circle on the bottom of the pots, and also highest shoot height, leaf number an shoot diameter of oil palm plantlets Elaeis guineensis Jacq in ex vitro condition was by dipping the basal end of the plantlets in 2 -8 mM IAA,IBA and NAA solution (Sumaryono and Riyadi 2011), Pineapple (Ananas Comosus.L.Meer.cv.Del Mont) plantlets grown in culture medium containing only peat moss was significantly increased in plant length, number of leaves /plant, fresh weights of vegetative growth and roots (AL-Taha 2013).