Impact of Antioxidants on in vitro Rooting and Acclimatization of Two Egyptian Dry Date Palm Cultivars.

BACKGROUND AND OBJECTIVES: Date palm (Phoenix dactylifera L.) is propagated vegetatively via offshoots, which is limited by either the offshoots numbers produced from a superior selected plant, or the occurrence of these offshoots only during the juvenile phase of the date palm life cycle. As a result, the in vitro propagation could be considered an alternative technique for large scale propagation of date palm. Obtaining well-developed root system is considered the most important step in establishment of reliable protocol for successful production of date palm and subsequently successful acclimatization of the in vitro derived plants. The aim of this study is to obtain a well-developed root system through using different antioxidants, with detecting the similarity between the in vitro derived plants and the mother plants using RAPD, long RAPD and ISSR techniques. MATERIALS AND METHODS: Individual plantlets obtained from maturation of somatic embryos in vitro of about 5-7 cm in length with 2-3 leaves were used as plant material. Plantlets were cultured on half strength MS liquid medium supplemented with 0.5 mg L-1 thiamine-HCl+2.0 mg L-1 glycine+0.1 mg L-1 biotin+40 g L-1 sucrose+ 0.1mg L-1 NAA with different concentrations from either AgNO3 or citric or ascorbic acids (0.0, 0.5, 1, 2 mg L-1). Growth development, root number and root length (cm) were evaluated at the end of the second subculture (12 weeks). Data were reported as Mean±Standard deviation (SD). Data were subjected to one way-analysis of variance (p<0.05). Results were processed by Excel (2010). RESULTS: Among the different antioxidants with different concentrations used, generally it was found that 2 mg L-1 of each agent gave the highest values of growth development, roots number and roots length. However, using 2 mg L-1 AgNO3 gave the best results with all parameters. Regarding the response of date palm cultivar, it was remarkable that Bartamoda showed relatively better results than Sakkoty cultivar. According to PCR reactions, the results of RAPD, long RAPD and ISSR profile of tissue culture-derived plantlets grown on a medium supplemented with 2 mg L-1 AgNO3 obviously revealed high similarity to mother plants. CONCLUSION: It could be concluded that using 2 mg L-1 AgNO3 gave the best results for growth development, root numbers and length of the two cultivars but Bartamoda showed relatively better results than Sakkoty cultivar. The tissue culture-derived plantlets on this medium (2 mg L-1 AgNO3) revealed high similarity to mother plant as a result to RAPD, long RAPD and ISSR profiles.

Impact of Zeatin and Thidiazuron on Phenols and Flavonoids Accumulation in Callus Cultures of Gardenia (Gardenia jasminoides).

BACKGROUND AND OBJECTIVE: Gardenia (Gardenia jasminoides) has many pharmacological actions such as anti-inflammatory, antioxidant and fibrolytic activities and cytotoxic effects, etc. This study was conducted to recognize the effect of zeatin and thidiazuron (TDZ) on callus proliferation, total phenolic content, total flavonoids and DPPH scavenging activity of gardenia callus cultures. MATERIALS AND METHODS: Calli were cultured on Murashige and Skoog (MS) medium supplement with different concentrations (2, 4 or 6 mg L-1) of zeatin or TDZ individually as well as combination of 2 mg L-1 zeatin+4 mg L-1 TDZ. Cultures contained 4 mg L-1 TDZ gave the highest callus fresh weight followed by those contained 2 mg L-1 zeatin then that cultured on 4 mg L-1 zeatin. Data reported as Mean±Standard Deviation (SD). Data were subjected to one-way analysis of variance (p< 0.05). Results were processed by Excel (2010) and SPSS Version 17.0. RESULTS: It was found that callus growing on medium supplemented with 4 mg L-1 zeatin gave the maximum value (14.93%) of yield extract. Callus cultured on 4 mg L-1 zeatin recorded the maximum total phenol (268.33 mg GAE/100 g FW of callus) and total flavonoids (2703.33 µg QE/100 g FW of callus) accumulation. The antioxidant activity of each extract was determined through DPPH radical scavenging activity. Callus cultured on 4 mg L-1 TDZ showed the highest antioxidant activity then those cultured on 4 mg L-1 zeatin. The HPLC analysis for phenolic acids showed that chlorogenic acid, rosmarinic acid and cinnamic reached their highest contents with callus cultured on 4 mg L-1 TDZ (123.24, 322.14 and 278.22 µg g-1, respectively). Regarding flavonoids and using HPLC analysis, rutin, apigenin-7-glucoside and kaempferol were detected. Callus cultured with 4 mg L-1 TDZ gave the highest rutin and kaempferol contents (287.76 and 10.38 µg g-1, respectively). However, apigenin-7-glucoside was detected with high content (129.86 µg g-1) in callus culture with 4 mg L-1 Zeatin. CONCLUSION: The HPLC analysis recommended that TDZ is more effective in accumulation of individual phenolic and flavonoid than Zeatin. The present study provided a useful system for further study on in vitro culture of G. jasminoides as alternative and new source for important secondary products.