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- Author or Editor: Antar Nasr El-Banna x
In vitro ovule culture could be used to generate homozygous lines through the production of haploid plants. The present study reports on in vitro regeneration and production of haploid plants through ovule cultures and identification of the regenerated haploids using flow cytometry. The ovules were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of 6-benzyladenine (BA), kinetin (Kin), 2,4-dichlorophenoxyacetic acid (2,4-D), and naphthalene acetic acid (NAA) at 0, 0.5, 1, and 2 mg·L−1 for their gynogenesis. Among different plant growth regulators (PGRs) tested, 2,4-D at 2 mg·L−1 produced direct gynogenesis. The highest callogenesis percentage (100%) was obtained on MS medium containing 1 mg·L−1 2,4-D and 2 mg·L−1 NAA. Flow cytometry analysis was used to identify the regenerated haploids. It also confirmed gynogenic occurrence at 1 and 2 mg·L−1 2,4-D with percentages of 21.7% and 41%, respectively. Therefore, 2,4-D proved effective for the induction of haploids in black cumin. The regenerated haploids were developed on MS medium without PGRs. The obtained results of in vitro gynogenesis and haploid plant production can tremendously facilitate breeding programs of black cumin.
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.
Black cumin (Nigella sativa) is an important medicinal plant in the pharmacological industry. It is cultivated on a commercial scale, but its seeds have a slow, unsynchronized germination rate. Enhancing seed germination is crucial for improving the production of black cumin. The influence of presowing treatments [gibberellic acid (GA3), potassium nitrate, salicylic acid, and stratification at 4 °C] on seed germination was assessed. Seed germination was determined daily for 30 days, and germination parameters, including final germination percentage (FGP), corrected germination rate, number of days to reach 50% of FGP, and seedling length vigor index, were evaluated. Endogenous contents of GA3 and abscisic acid (ABA) in nonstratified and stratified seeds were estimated using high-performance liquid chromatography (HPLC) and seedling growth was determined in 45-day-old seedlings. All presowing treatments tended to boost early germination for the first 10 days compared with the control. Low concentrations of GA3 at 0.25 g·L−1 also increased FGP (80%) compared with the control group (65.55%). Stratification for 4 weeks provided the greatest FGP value at 95.56%, and stratification for 3 weeks proved to be the most effective treatment for optimal seedling growth. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis patterns of stratified seeds revealed the alteration in intensities of 13 bands and the appearance of a new band (180 kDa) indicating a change in the synthesis of proteins during stratification. Moreover, stratification modulated the endogenous GA3 and ABA contents of black cumin seeds, which alleviated the physiological dormancy and resulted in high and synchronized seed germination.