The present study on the medicinally important species of Solanaceae from Pakistan has been carried out from biosystematics view-point. Seventeen medicinal species from six different genera Atropa, Capsicum, Datura, Hyoscyamus, Solanum and Withania were evaluated for Plant habits, stem structure and colour, petiole status, petiole pubescence, leaf shape, leaf margin, leaf apex, leaf base, flower shape, flower colour, fruit shape, fruit type and seed colour. Qualitative characters play a key role in the identification of species as compared to quantitative characters. Correlation coefficient, and cluster analysis were carried out to estimate the extent of genetic diversity present in the species of Solanaceae. Allelic variation was investigated by SDS-PAGE in ninety-three different samples of medicinal species of the family. Whereas nineteen accessions of various species were used for RAPD analysis. Germination in Solanaceae is suppressed by seed coat imposed dormancy. Methods for breaking dormancy of the species of this family were investigated.
The distinguishing morphological characters of Solanum surattense are prostrate plant habit, presence of spines on the whole plant and small yellow round fruit with persistent spiny sepals. Two different flower colours (white and purple) were observed in the specimens of this species. S. surattense with white flowers showed variation from the S. surattense with purple flowers not only morphologically but also based on protein profiles and DNA markers. However the high similarity index (82%) between them indicates that S. surattense (W) should be separated from S. surattense (P) as variety nova. S. nigrum complex has controversial taxonomic status. In Pakistan this complex is consists of S. nigrum, S. americanum and S. villosum. Our present study revealed that S. nigrum and S. americanum are two distinct species, whereas S. villosum is the subspp of S. nigrum. Similarity index (based on protein and DNA markers) of S. villosum and S. americanum was 53 % whereas it has similarity of 78% with S. nigrum. Similarity was 41 % between S. nigrum and S. americanum. Hyoscyamus is a uniregional genus having two (H. niger and H. pusillus) medicinally important species. A specimen of H. niger (accession no. 46322) and two specimens of H. pusillus (accession no 68182 and 68183) showed morphological variations. H. niger acc. 46322 having hairs on winged anthers and stigma, half of the fruit is covered with operculum and yellow colour seed. Whereas H. pusillus acc. 68182 and 68183 had cylindrical petiole, leaves with evenly distributed dense hairs and dentate margin. These specimens also exhibited certain variation in protein profile and DNA markers. Our study support to separate accession 46322 as new variety of H. niger and accession 68182 and 68183 as variety nova of H. pusillus.
Withania is a biregional genus with two species W. somnifera and W. coagulans. Leaf, flower, fruit and seed characters play key role to differentiate W. coagulans from W. somnifera. Few specimens of W. somnifera collected from Panjgur (Baluchistan), having the accession no 109717, 109718, and 109710 showed morphological difference from type specimen. These specimens have herbaceous habit, less hairs on younger parts and dense on older parts, small size leaf with evenly distributed hairs white solitary flower and winged conical seeds. A protein band of 66,47 and 42 Kda was observed in W. somnifera and absent from accessions 109717, 109718 and 109710. As this accession is geographically different from other specimens of Withania somnifera, having variation in morphological and protein markers suggested to separate these accessions as new sub species of W. somnifera. Lower order taxonomy of this family based on morphological, biochemical and molecular markers is entirely different from the orthodox taxonomy. Classification based on all the three markers predicts the division of family into two tribes Datureae and Solaneae. Tribe Solaneae will consist of two genera Solanum and Capsicum whereas Hyoscyamous, Withania, Atropa and Datura will be part of the tribe Datureae.
Seeds of species collected from different areas of Pakistan were subjected to various treatments viz; distilled water (control), pre-chilling, NaNO3 (1 % & 0.5%), CaNO3 (1 % & 0.5%), hot water treatment (3hrs, 24hrs) and 100ppm GA3. Treatments were given in germinating chamber and at the room temperature. Species showed different response to various treatments.
All the species responded well to 100ppm GA3 and 0.5 % CaNO3 However the percentage germination was low in case of 0.5 % CaNO3. Five species germinated by prechilling treatment, Solanum erianthum, S. melongena and S. incanum showed the 100% germination. Whereas 20% germination was observed in the case of Withania coagulans. Prechilling was not proved dormancy-breaking treatment for S. torvum, Datura innoxia and Hyoscyamous pusillus. Seeds of H. pusillus, S. surattense and D. innoxia were germinated when treated with calcium and sodium (0.5%) suggesting the presence of primary dormancy. No sign of germination was observed in species when treatments were given at room temperature with the exception of Solanum incanum. This species showed 10% germination following prechilling treatment.