Papers by Syed Summar Abbas
Journal of Essential Oil-Bearing Plants, 2012
The present study was focused on unexplored Pakistani citrus species viz. sweet oranges (Citrus s... more The present study was focused on unexplored Pakistani citrus species viz. sweet oranges (Citrus sinensis Vars. Jaffa, Blood Red and Mosambi), Mandarins (Citrus reticulata Var. kinnow) and grapefruits (Citrus paradisi Var. Shamber) for peel oil yield, chemical composition and antipathogen activities. The chemical composition of citrus peel oil was analyzed through gas chromatographic -mass spectrometric analysis. Six compounds viz. D-limonene, d-carvone, Z-5-nonadecane, thujol, trans-P-mentha-2,8-dienol and heneicosane were commonly present in all cultivars. However, D-limonene (40.9-76 %) was a major compound in all citrus peel oils. The high amounts of phenolic compounds were recorded in the peel oil with a maximum amount in grapefruit (8.58 mg/g) and minimum in Kinnow mandarin (5.20 mg/g). Jaffa orange cultivar showed a highest radical scavenging activity (70.14 %). Furthermore, peel oils were tested for their antimicrobial activities against five pathogenic bacterial strains viz. Staphylococcus aureus, Eschrichia coli, Salmonella typhi, Proteus vulgaris, Staphylococcus epidermidis and two pathogenic fungal strains viz. Aspergillus flavus and Trichophyton alba. Citrus peel was found effective against all tested micro-organisms and in particular Jaffa orange essential oil was highly effective against all microbial strains growth and Salmonella typhi was the most inhibited strains among all.
In the present study the effect of different biochemical attributes on date fruits at their three... more In the present study the effect of different biochemical attributes on date fruits at their three different edible stages were studied in Aseel, Dhakki (Pakistan) and Deglet Nour (Algeria) cultivars. The results depicted that total phenolic contents, antioxidant activity (DPPH), antioxidant enzymes (CAT, POD) and protein decreased gradually from khalal to tamar stage during date fruit development in all selected cultivars. Despite, the amount of glucose (23.89-32.31%) and fructose (20.34-30.45%) increased significantly during ripening process among examined cultivars. The characterization of fibers of date fruits at three edible stages by Fourier transform infrared spectroscopy (FTIR) showed lignin (1514 cm-1), amide (1649 cm-1), cellulose-I and cellulose-II (1635 and 1420 cm-1), respectively, whereas, Scanning Electron Microscopy (SEM) revealed crystalline surface morphology of date fruit fibers at last three edible stages. Furthermore, our results revealed that variation in chemic...
Sixteen Pakistani date palm cultivars from diverse origins were characterized morphologically to ... more Sixteen Pakistani date palm cultivars from diverse origins were characterized morphologically to assess the similarity
level, the overall point of polymorphism and important agronomic traits existing in the germplasm present in Pakistan. Forty
two qualitative and quantitative features were explored and subjected to multivariate analyses. The results brought out
important differences in phenotypic characters in all date palm cultivars. Principal component analysis (PCA) indicated that
trunk length and diameter, total number of leaves, rachis length, leaflets length and width, number of leaflets per side,
number of pinnae planes, length and grouping of spines were highly divergent. Similarly cluster analyses (CA) also revealed
phenotypic diversity among date palm cultivars and, some close association or heterogeneity was also observed within
cultivars of the same origin.
Background and Aims Date palms (Phoenix dactylifera, Arecaceae) are of great economic and ecolo... more Background and Aims Date palms (Phoenix dactylifera, Arecaceae) are of great economic and ecological value
to the oasis agriculture of arid and semi-arid areas. However, despite the availability of a large date palm germplasm
spreading from the Atlantic shores to Southern Asia, improvement of the species is being hampered by a lack of information
on global genetic diversity and population structure. In order to contribute to the varietal improvement of
date palms and to provide new insights on the influence of geographic origins and human activity on the genetic
structure of the date palm, this study analysed the diversity of the species.
Methods Genetic diversity levels and population genetic structure were investigated through the genotyping of a
collection of 295 date palm accessions ranging from Mauritania to Pakistan using a set of 18 simple sequence repeat
(SSR) markers and a plastid minisatellite.
Key Results Using a Bayesian clustering approach, the date palm genotypes can be structured into two different
gene pools: the first, termed the Eastern pool, consists of accessions from Asia and Djibouti, whilst the second,
termed the Western pool, consists of accessions from Africa. These results confirm the existence of two ancient
gene pools that have contributed to the current date palm diversity. The presence of admixed genotypes is also
noted, which points at gene flows between eastern and western origins, mostly from east to west, following a
human-mediated diffusion of the species.
Conclusions This study assesses the distribution and level of genetic diversity of accessible date palm resources,
provides new insights on the geographic origins and genetic history of the cultivated component of this species, and
confirms the existence of at least two domestication origins. Furthermore, the strong genetic structure clearly established
here is a prerequisite for any breeding programme exploiting the effective polymorphism related to each
gene pool.
Key words: Date palm, Arecaceae, genetic diversity, genetic structure, nuclear microsatellite, Phoenix dactylifera,
plastid minisatellite, SSR markers.
Date palm is a dioecious monocotyledonous plant which belongs to Arecaceae family. Date palm poll... more Date palm is a dioecious monocotyledonous plant which belongs to Arecaceae family. Date palm pollen retains
viability for a single growing season. Air dried pollen was enclosed in sealed capsules and stored at 4°C, -20°C and -80°C
for different storage periods (1, 3, 6, 12 months). Pollen viability of fresh and stored pollen was determined by in vitro
germination and staining test. After thawing, stored pollens werecultured in petri dishes and incubated at three different
temperature i.e., 20°C, 25°C and 30°C for different time periods (3, 6, 12 and 24 hours). Pollen grains looking normal and
stained red were considered viable, whereas weakly stained or colorless were recorded as non viable. Germination test
showed that pollen of cultivar Khadrawy stored at -20°C had higher germination (71.22%) when incubated at 30°C for 24
hours after 12 months of storage while least was in Hillawi i.e. 34.86%
The date fruit is a primary component of the human diet in many countries with arid and semiarid ... more The date fruit is a primary component of the human diet in many countries with arid and semiarid climates. The
present study reflects the relationship of different biochemical attributes with progressive date fruit
developmental stages. The study involved eight date palm (Phoenix dactyliferaL.) cultivars from Pakistan
examined at three different edible stages of dates (khalal, rutab and tamar). The antiradical efficiency (2.14–
0.36), antioxidant enzymes (catalase and peroxidase), total phenolic contents (468.99–108 mg GAE/100g, FW)
and the soluble protein contents (5.73–2.75 g/100g) were higher in higher at khalal and thereafter, but declined
at fully ripened (tamar) stage. Moreover, glucose (16.92–31.66%) and fructose (15.25–30.58%) have lower
quantity at khalal and higher quantity at tamar stage, whereas non-reducing (sucrose) sugars were present only
at khalal and rutab stage fruits. Makran and Chohara cultivars revealed best overall values in examined
compounds. Our results revealed that variation in different biochemical attributes is mainly depended on the
difference in fruit maturity stage and cultivar. Cultivars exhibiting high values of beneficial biochemical
attributes may be considered for the expansion of date palm cultivation.
In the present study the effect of different biochemical attributes on date fruits at their three... more In the present study the effect of different biochemical attributes on date fruits at their three different edible
stages were studied in Aseel, Dhakki (Pakistan) and Deglet Nour (Algeria) cultivars. The results depicted that total
phenolic contents, antioxidant activity (DPPH), antioxidant enzymes (CAT, POD) and protein decreased gradually
from khalal to tamar stage during date fruit development in all selected cultivars. Despite, the amount of glucose
(23.89-32.31%) and fructose (20.34-30.45%) increased significantly during ripening process among examined
cultivars. The characterization of fibers of date fruits at three edible stages by Fourier transform infrared
spectroscopy (FTIR) showed lignin (1514 cm-1
), amide (1649 cm-1
), cellulose-I and cellulose-II (1635 and 1420 cm-
1
), respectively, whereas, Scanning Electron Microscopy (SEM) revealed crystalline surface morphology of date
fruit fibers at last three edible stages. Furthermore, our results revealed that variation in chemical composition and a
significant variability in all the characterization techniques were recorded of date fruit fibers during ripening process.
The present study was focused on unexplored Pakistani citrus species viz. sweet oranges (Citrus s... more The present study was focused on unexplored Pakistani citrus species viz. sweet oranges (Citrus sinensis Vars. Jaffa, Blood Red and Mosambi), Mandarins (Citrus reticulata Var. kinnow) and grapefruits (Citrus paradisi Var. Shamber) for peel oil yield, chemical composition and antipathogen activities. The chemical composition of citrus peel oil was analyzed through gas chromatographic -mass spectrometric analysis. Six compounds viz. D-limonene, d-carvone, Z-5-nonadecane, thujol, trans-P-mentha-2,8-dienol and heneicosane were commonly present in all cultivars. However, D-limonene (40.9-76 %) was a major compound in all citrus peel oils. The high amounts of phenolic compounds were recorded in the peel oil with a maximum amount in grapefruit (8.58 mg/g) and minimum in Kinnow mandarin (5.20 mg/g). Jaffa orange cultivar showed a highest radical scavenging activity (70.14 %). Furthermore, peel oils were tested for their antimicrobial activities against five pathogenic bacterial strains viz. Staphylococcus aureus, Eschrichia coli, Salmonella typhi, Proteus vulgaris, Staphylococcus epidermidis and two pathogenic fungal strains viz. Aspergillus flavus and Trichophyton alba. Citrus peel was found effective against all tested micro-organisms and in particular Jaffa orange essential oil was highly effective against all microbial strains growth and Salmonella typhi was the most inhibited strains among all.
The genus Phoenix (Arecaceae) comprises 14 species distributed from Cape Verde Islands to SE Asia... more The genus Phoenix (Arecaceae) comprises 14 species distributed from Cape Verde Islands to SE Asia. It includes the economically important species Phoenix dactylifera. The paucity of differential morphological and anatomical useful characters, and interspecific hybridization, make identification of Phoenix species difficult. In this context, the development of reliable DNA markers for species and hybrid identification would be of great utility. Previous studies identified a 12 bp polymorphic chloroplast minisatellite in the trnG(GCC)-trnfM(CAU) spacer, and showed its potential for species identification in Phoenix. In this work, in order to develop an efficient DNA barcode marker for Phoenix, a longer cpDNA region (700 bp) comprising the mentioned minisatellite, and located between the psbZ and trnfM(CAU) genes, was sequenced. One hundred and thirty-six individuals, representing all Phoenix species except P. andamanensis, were analysed. The minisatellite showed 2-7 repetitions of the 12 bp motif, with 1-3 out of seven haplotypes per species. Phoenix reclinata and P. canariensis had species-specific haplotypes. Additional polymorphisms were found in the flanking regions of the minisatellite, including substitutions, indels and homopolymers. All this information allowed us to identify unambiguously eight out of the 13 species, and overall 80% of the individuals sampled. Phoenix rupicola and P. theophrasti had the same haplotype, and so had P. atlantica, P. dactylifera, and P. sylvestris (the "date palm complex" sensu Pintaud et al. 2013). For these species, additional molecular markers will be required for their unambiguous identification. The psbZ-trnfM(CAU) region therefore could be considered as a good basis for the establishment of a DNA barcoding system in Phoenix, and is potentially useful for the identification of the female parent in Phoenix hybrids.
Hetero-polysaccharide mucilage was extracted from the seed coats of different citrus rootstocks v... more Hetero-polysaccharide mucilage was extracted from the seed coats of different citrus rootstocks viz. Rough lemon, Sachtion citrumelo and Yuma citrange for investigating its biochemical and molecular properties. Investigations showed that the mucilage contained (mg/g) starch 3.13-5.04; maltose 3.23-4.31; glucosamine 0.017-0.289; d-xylose 0.059-0.107 and total soluble sugars 8.13-11.82. Specific enzyme activities were 16. 98-35.96, 30.60-98.45, 42.00-73.98, 660.98-738.35 and 7.660-19.27 IU mg −1 of protein for protease, amylase, catalase, peroxidase and superoxide dismutase, respectively. Proximate analysis showed 12.85-13.94% moisture, 11.25-14.06% crude protein, 0.31-0.86% crude lipid, 1.31-2.69% crude fibre, 2.95-3.45% ash and 81.48-91.49 kJ 100 g −1 energy. The comparative characterization of the extractable proteins was profiled by SDS-PAGE and quantified using Bradford assay. Structural properties of samples were analyzed and compared using Fourier transformation infrared (FT-IR) spectroscopy.
Some date palm cultivars grown in Pakistan were biochemically characterized and the effect of fru... more Some date palm cultivars grown in Pakistan were biochemically characterized and the effect of fruit maturity on radical scavenging capacity (DPPH), total phenolic contents (TPC), specific activity of antioxidant enzymes, sugars profile and soluble protein contents was assessed. Higher range of differences in composition of studied phytochemicals was recorded among different cultivars. Antiradical efficiency (AE), TPC, antioxidant enzymes and soluble protein contents were recorded higher at khalal stage thereafter, declined at rutab then finally at tamar stage. The amount of glucose (11.32-32.50%) and fructose (10.95-32.41%) started accumulation from khalal stage and were in higher composition at tamar stage due to hydrolysis and inversion of sucrose (10.82-3.1%) contents. The results concluded that variation in biochemical attributes primarily influenced by type of cultivars and different fruit developmental stages.
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Papers by Syed Summar Abbas
level, the overall point of polymorphism and important agronomic traits existing in the germplasm present in Pakistan. Forty
two qualitative and quantitative features were explored and subjected to multivariate analyses. The results brought out
important differences in phenotypic characters in all date palm cultivars. Principal component analysis (PCA) indicated that
trunk length and diameter, total number of leaves, rachis length, leaflets length and width, number of leaflets per side,
number of pinnae planes, length and grouping of spines were highly divergent. Similarly cluster analyses (CA) also revealed
phenotypic diversity among date palm cultivars and, some close association or heterogeneity was also observed within
cultivars of the same origin.
to the oasis agriculture of arid and semi-arid areas. However, despite the availability of a large date palm germplasm
spreading from the Atlantic shores to Southern Asia, improvement of the species is being hampered by a lack of information
on global genetic diversity and population structure. In order to contribute to the varietal improvement of
date palms and to provide new insights on the influence of geographic origins and human activity on the genetic
structure of the date palm, this study analysed the diversity of the species.
Methods Genetic diversity levels and population genetic structure were investigated through the genotyping of a
collection of 295 date palm accessions ranging from Mauritania to Pakistan using a set of 18 simple sequence repeat
(SSR) markers and a plastid minisatellite.
Key Results Using a Bayesian clustering approach, the date palm genotypes can be structured into two different
gene pools: the first, termed the Eastern pool, consists of accessions from Asia and Djibouti, whilst the second,
termed the Western pool, consists of accessions from Africa. These results confirm the existence of two ancient
gene pools that have contributed to the current date palm diversity. The presence of admixed genotypes is also
noted, which points at gene flows between eastern and western origins, mostly from east to west, following a
human-mediated diffusion of the species.
Conclusions This study assesses the distribution and level of genetic diversity of accessible date palm resources,
provides new insights on the geographic origins and genetic history of the cultivated component of this species, and
confirms the existence of at least two domestication origins. Furthermore, the strong genetic structure clearly established
here is a prerequisite for any breeding programme exploiting the effective polymorphism related to each
gene pool.
Key words: Date palm, Arecaceae, genetic diversity, genetic structure, nuclear microsatellite, Phoenix dactylifera,
plastid minisatellite, SSR markers.
viability for a single growing season. Air dried pollen was enclosed in sealed capsules and stored at 4°C, -20°C and -80°C
for different storage periods (1, 3, 6, 12 months). Pollen viability of fresh and stored pollen was determined by in vitro
germination and staining test. After thawing, stored pollens werecultured in petri dishes and incubated at three different
temperature i.e., 20°C, 25°C and 30°C for different time periods (3, 6, 12 and 24 hours). Pollen grains looking normal and
stained red were considered viable, whereas weakly stained or colorless were recorded as non viable. Germination test
showed that pollen of cultivar Khadrawy stored at -20°C had higher germination (71.22%) when incubated at 30°C for 24
hours after 12 months of storage while least was in Hillawi i.e. 34.86%
present study reflects the relationship of different biochemical attributes with progressive date fruit
developmental stages. The study involved eight date palm (Phoenix dactyliferaL.) cultivars from Pakistan
examined at three different edible stages of dates (khalal, rutab and tamar). The antiradical efficiency (2.14–
0.36), antioxidant enzymes (catalase and peroxidase), total phenolic contents (468.99–108 mg GAE/100g, FW)
and the soluble protein contents (5.73–2.75 g/100g) were higher in higher at khalal and thereafter, but declined
at fully ripened (tamar) stage. Moreover, glucose (16.92–31.66%) and fructose (15.25–30.58%) have lower
quantity at khalal and higher quantity at tamar stage, whereas non-reducing (sucrose) sugars were present only
at khalal and rutab stage fruits. Makran and Chohara cultivars revealed best overall values in examined
compounds. Our results revealed that variation in different biochemical attributes is mainly depended on the
difference in fruit maturity stage and cultivar. Cultivars exhibiting high values of beneficial biochemical
attributes may be considered for the expansion of date palm cultivation.
stages were studied in Aseel, Dhakki (Pakistan) and Deglet Nour (Algeria) cultivars. The results depicted that total
phenolic contents, antioxidant activity (DPPH), antioxidant enzymes (CAT, POD) and protein decreased gradually
from khalal to tamar stage during date fruit development in all selected cultivars. Despite, the amount of glucose
(23.89-32.31%) and fructose (20.34-30.45%) increased significantly during ripening process among examined
cultivars. The characterization of fibers of date fruits at three edible stages by Fourier transform infrared
spectroscopy (FTIR) showed lignin (1514 cm-1
), amide (1649 cm-1
), cellulose-I and cellulose-II (1635 and 1420 cm-
1
), respectively, whereas, Scanning Electron Microscopy (SEM) revealed crystalline surface morphology of date
fruit fibers at last three edible stages. Furthermore, our results revealed that variation in chemical composition and a
significant variability in all the characterization techniques were recorded of date fruit fibers during ripening process.
level, the overall point of polymorphism and important agronomic traits existing in the germplasm present in Pakistan. Forty
two qualitative and quantitative features were explored and subjected to multivariate analyses. The results brought out
important differences in phenotypic characters in all date palm cultivars. Principal component analysis (PCA) indicated that
trunk length and diameter, total number of leaves, rachis length, leaflets length and width, number of leaflets per side,
number of pinnae planes, length and grouping of spines were highly divergent. Similarly cluster analyses (CA) also revealed
phenotypic diversity among date palm cultivars and, some close association or heterogeneity was also observed within
cultivars of the same origin.
to the oasis agriculture of arid and semi-arid areas. However, despite the availability of a large date palm germplasm
spreading from the Atlantic shores to Southern Asia, improvement of the species is being hampered by a lack of information
on global genetic diversity and population structure. In order to contribute to the varietal improvement of
date palms and to provide new insights on the influence of geographic origins and human activity on the genetic
structure of the date palm, this study analysed the diversity of the species.
Methods Genetic diversity levels and population genetic structure were investigated through the genotyping of a
collection of 295 date palm accessions ranging from Mauritania to Pakistan using a set of 18 simple sequence repeat
(SSR) markers and a plastid minisatellite.
Key Results Using a Bayesian clustering approach, the date palm genotypes can be structured into two different
gene pools: the first, termed the Eastern pool, consists of accessions from Asia and Djibouti, whilst the second,
termed the Western pool, consists of accessions from Africa. These results confirm the existence of two ancient
gene pools that have contributed to the current date palm diversity. The presence of admixed genotypes is also
noted, which points at gene flows between eastern and western origins, mostly from east to west, following a
human-mediated diffusion of the species.
Conclusions This study assesses the distribution and level of genetic diversity of accessible date palm resources,
provides new insights on the geographic origins and genetic history of the cultivated component of this species, and
confirms the existence of at least two domestication origins. Furthermore, the strong genetic structure clearly established
here is a prerequisite for any breeding programme exploiting the effective polymorphism related to each
gene pool.
Key words: Date palm, Arecaceae, genetic diversity, genetic structure, nuclear microsatellite, Phoenix dactylifera,
plastid minisatellite, SSR markers.
viability for a single growing season. Air dried pollen was enclosed in sealed capsules and stored at 4°C, -20°C and -80°C
for different storage periods (1, 3, 6, 12 months). Pollen viability of fresh and stored pollen was determined by in vitro
germination and staining test. After thawing, stored pollens werecultured in petri dishes and incubated at three different
temperature i.e., 20°C, 25°C and 30°C for different time periods (3, 6, 12 and 24 hours). Pollen grains looking normal and
stained red were considered viable, whereas weakly stained or colorless were recorded as non viable. Germination test
showed that pollen of cultivar Khadrawy stored at -20°C had higher germination (71.22%) when incubated at 30°C for 24
hours after 12 months of storage while least was in Hillawi i.e. 34.86%
present study reflects the relationship of different biochemical attributes with progressive date fruit
developmental stages. The study involved eight date palm (Phoenix dactyliferaL.) cultivars from Pakistan
examined at three different edible stages of dates (khalal, rutab and tamar). The antiradical efficiency (2.14–
0.36), antioxidant enzymes (catalase and peroxidase), total phenolic contents (468.99–108 mg GAE/100g, FW)
and the soluble protein contents (5.73–2.75 g/100g) were higher in higher at khalal and thereafter, but declined
at fully ripened (tamar) stage. Moreover, glucose (16.92–31.66%) and fructose (15.25–30.58%) have lower
quantity at khalal and higher quantity at tamar stage, whereas non-reducing (sucrose) sugars were present only
at khalal and rutab stage fruits. Makran and Chohara cultivars revealed best overall values in examined
compounds. Our results revealed that variation in different biochemical attributes is mainly depended on the
difference in fruit maturity stage and cultivar. Cultivars exhibiting high values of beneficial biochemical
attributes may be considered for the expansion of date palm cultivation.
stages were studied in Aseel, Dhakki (Pakistan) and Deglet Nour (Algeria) cultivars. The results depicted that total
phenolic contents, antioxidant activity (DPPH), antioxidant enzymes (CAT, POD) and protein decreased gradually
from khalal to tamar stage during date fruit development in all selected cultivars. Despite, the amount of glucose
(23.89-32.31%) and fructose (20.34-30.45%) increased significantly during ripening process among examined
cultivars. The characterization of fibers of date fruits at three edible stages by Fourier transform infrared
spectroscopy (FTIR) showed lignin (1514 cm-1
), amide (1649 cm-1
), cellulose-I and cellulose-II (1635 and 1420 cm-
1
), respectively, whereas, Scanning Electron Microscopy (SEM) revealed crystalline surface morphology of date
fruit fibers at last three edible stages. Furthermore, our results revealed that variation in chemical composition and a
significant variability in all the characterization techniques were recorded of date fruit fibers during ripening process.