The present study reports a simple protocol for in vitro regeneration of Aglaonema ‘Valentine’ using axillary shoot explants for rapid multiplication and production of true-to-type plants. Different concentrations of benzyladenine (BA; 0, 1, 3, 5, and 7 mg·L−1), kinetin (Kin; 0, 1, 3, 5, and 7 mg·L−1), thidiazuron (TDZ; 0, 0.5, 1.0, 1.5, and 2.0 mg·L−1), naphthalene acetic acid (NAA; 0, 0.5, and 1.0 mg·L−1), and indole-3-butyric acid (IBA; 0, 0.5, and 1.0 mg·L−1) were used for shoot regeneration. The highest shoot proliferation (5.0) was obtained on Murashige and Skoog (MS) medium supplemented with 1.5 mg·L−1 TDZ and 1 mg·L−1 NAA. In vitro rooting was easily achieved with 100% at all concentrations of NAA and IBA supplemented to half- or full-strength MS medium. Regenerated plantlets were acclimatized in greenhouse with 100% survival rate. Randomly amplified polymorphic DNA (RAPD) analysis confirmed the genetic fidelity of the regenerated plantlets and mother plant.
Mohammed Elsayed El-Mahrouk, Yaser Hassan Dewir and Yougasphree Naidoo
Antar Nasr El-Banna, Mohammed Elsayed El-Mahrouk, Mohammed Eraky El-Denary, Yaser Hassan Dewir and Yougasphree Naidoo
For the first time, genetic diversity among 14 ornamental palm accessions originating from different countries and grown in different regions in Egypt were examined. Identification of genetic variation and phylogenetic relationships in ornamental palms would be useful for its genetic identification, improvement, and conservation. Genetic polymorphism was analyzed using the randomly amplified polymorphic DNA (RAPD) as well as protein markers. The electrophoretic pattern of protein analysis produced 21 bands distributed in all accessions with molecular sizes ranging from 11.8 to 99.3 KDa. Some accessions possessed some bands, which were absent in other accessions and could be used for their identification. Furthermore, 10 RAPD selected primers were employed to determine genetic variation among the 14 palm genotypes as well as to test the effectiveness of RAPD primers as a genetic marker. RAPD analysis revealed a high level of polymorphism (100%) among the studied accessions. A total number of 310 amplified bands were generated across the studied genotypes with an average of 30 bands per primer. Cluster analysis using sequence alignment was done to generate a dendrogram verifying the relationship among the 14 studied ornamental palms, with an average similarity matrix range of 0.00 to 0.08 and 0.39 to 0.93 for RAPD and protein markers, respectively. It is concluded that, both SDS-protein and RAPD markers are equally important for genetic analysis and are suitable for the characterization of ornamental palm collection.
Yaser Hassan Dewir, Abdulhakim A. Aldubai, Salah El-Hendawy, Abdullah A. Alsadon, Mayada Kadry Seliem and Yougasphree Naidoo
A method for micropropagation of Conocarpus erectus through axillary shoot proliferation is presented. Shoot tips were excised from adult donor tree and cultured for 4 weeks on Murashige and Skoog’s (MS) medium supplemented with 3 mg·L−1 gibberellic acid (GA3) to induce sprouting of shoots and formation of axillary shoots. Conocarpus erectus shoots were cultured for 6 weeks on MS medium supplemented with different concentrations and combinations of plant growth regulators (PGRs) and proliferation of the shoots was monitored. The type and concentration of cytokinins applied had a significant influence on shoot proliferation responses. Supplementation with 6-benzylaminopurine (BAP) increased the rate of shoot proliferation compared with other cytokinins. The use of BAP in combination with auxins such as indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA) resulted in an increased number of shoots per explant compared with treatment with BAP alone. A combination of 2 mg·L−1 BAP and 0.5 mg·L−1 IBA produced the highest number of axillary shoots (7.8 shoots/explant). The best rooting medium was full-strength MS medium supplemented with 1 mg·L−1 IBA; this treatment yielded 80% rooting with an average of 3.5 roots per plantlet. All regenerated plantlets were successfully acclimatized to greenhouse conditions.
Asma Alhussein Alawaadh, Yaser Hassan Dewir, Mona S. Alwihibi, Abdulhakim A. Aldubai, Salah El-Hendawy and Yougasphree Naidoo
The present study aimed to optimize the micropropagation of lacy tree philodendron using shoot tip explants. Axillary shoot regeneration was investigated in Murashige and Skoog (MS) medium with different types and concentrations of plant growth regulators, varied levels of MS medium salt strength, sucrose concentration, and light intensity and culture type. Adding 6-benzylaminopurine (BAP; 1 mg·L−1) significantly increased shoot multiplication compared with other cytokinins, and the combination of cytokinins and auxins [indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA)], yielded more shoots than cytokinins alone, with the greatest number of axillary shoots (11.4 per explant) obtained using both BAP (1 mg·L−1) and IBA (0.5 mg·L−1). In addition, the use of half-strength salt concentrations significantly reduced shoot multiplication, and high sucrose concentrations (>30 g·L−1) reduced explant growth. High light intensity also reduced shoot multiplication and growth, owing to photoinhibition, and shoot multiplication was more efficient in gelled culture, whereas shoot growth was greater in liquid/bioreactor culture. The best rooting success (100%) and greatest root number and fresh weight were obtained using MS medium supplemented with NAA (1–2 mg·L−1). The resulting plantlets were successfully acclimatized, with a survival rate of 100%, and were morphologically similar to the mother plant.
El-Sayed Mohamed El-Mahrouk, Eman Abdel-Hakim Eisa, Mahmoud Abdelnaby Hegazi, Mohamed El-Sayed Abdel-Gayed, Yaser Hassan Dewir, Mohammed Elsayed El-Mahrouk and Yougasphree Naidoo
Phytoremediation is an environmentally friendly and effective method of reducing contaminating ions to very low levels. In this study, the effects of different concentrations of cadmium (Cd), copper (Cu), and lead (Pb) on vegetative growth and the chemical and biochemical compositions of Salix mucronata as well as the potential for phytoextraction of these metals by plant organs were investigated. S. mucronata had the highest survival percentage (100%) in the presence of CdCl2, CuCl2, and Pb acetate up to 80, 200, and 850 mg·kg−1 in soil, respectively. A negative influence of these metals on vegetative and chemical parameters was observed relative to the control plants. The potential role of antioxidant enzymes in protecting plants from oxidative injury was examined by analyzing the antioxidant enzyme activities of plants grown in contaminated and control soils. Enzymatic activities and electrolyte leakage were higher in the plants grown in soil with increasing heavy metals than in the control plants. The bioconcentrating efficiency of Cd, Cu, and Pb in plant organs was estimated to be medium [bioconcentration factor (BCF) of 1–0.1]; an exception was the BCF of Cu in the roots, which was estimated to be intensive (BCF < 1). Concentrations of 60 mg·kg−1 CdCl2, 50 mg·kg−1 CuCl2, and 650 mg·kg−1 Pb acetate caused significantly higher translocation compared with other levels of each pollutant. The biomass tolerance index was less than 1. Additionally, S. mucronata accumulated Cd, Cu, and Pb in the following order: roots > stems > leaves. Therefore, the risk of contamination through leaf fall can be minimized. Therefore, S. mucronata could be a good candidate for phytoremediation of Cd-, Cu-, and Pb-contaminated soil.