Browsing by Author "Senanayake, S.P."

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Assessment of epiphytic lichen diversity in pine plantations and in adjacent secondary forest in Peacock Hill, Pussellawa, Sri Lanka
(2015) de Silva, C.M.S.M.; Senanayake, S.P.
Chemotaxonomy and medicinal properties of Sida spp: flavonoids
(University of Kelaniya, 2000) Perera, N.I.S.; Senanayake, S.P.; Jayasekara, L.R.
Cluster analysis of eight caryophyllids using structural and pigment characters
(Institute of Biology, Sri Lanka, 2011) Godagedara, G.L.T.; Senanayake, S.P.
Comparative study of foliar appendages and leaf flavonoid pigments in basal angiosperms and their evolutionary significance
(Sri Lanka Association for the Advancement of Science, 2013) Jayarathne, S.P.N.C.; Senanayake, S.P.
Comparative study of plant poisoning in ‘Kaduru’ plants of Sri Lanka with special reference to strychnine
(Sri Lanka Association for the Advancement of Science, 2009) Senevirathne, W.D.S.T.; Senanayake, S.P.
Development of suitable propagation systems for Tephrosia spp. and Flueggea leucopyrus in Sri Lanka
(University of Kelaniya, 2013) Priyadarshan, A.I.S.; Senanayake, S.P.; Jayetilleke, M.P.; Rajapakse, R.G.S.C.
Different species of both genera Tephrosia and Flueggea are commonly used as ingredients in traditional therapeutic preparations. Due to the increasing popularity of these plants as ingredients in traditional therapeutic systems, production of planting materials for commercial cultivation is a timely requirement. This research was carried out to develop suitable propagation systems for T. purpurea, T. villosa, T. noctiflora, T. pumila and F. leucopyrus. Though Tephrosia spp. seeds have shown higher viability, low germination percentage was observed within a week on wet filter paper as well as in different six potting media. Six potting media were prepared using five raw materials namely coir dust, sand, top soil, cow dung and compost with different compositions to evaluate the seed germination and growth performance of Tephrosia species. Water impermeability of seed coats was identified as the reason for the seed dormancy in Tephroisa spp. and soaking in Con. H2SO4: H2O; 3:1 for 25 mins and rubbing on sandpaper for 2 mins were determined as suitable seed dormancy breaking methods. Variation was observed in the growth performance of Tephrosia spp. in six different potting media. Soil medium was determined as a more suitable medium compared to the hydroponic solution for all four Tephrosia species. Due to less seed production in F. leucopyrus, stem cutting propagation methods in three different potting media (Coir dust, Sand, Coir dust: Sand 1:1) were applied to evaluate the efficiency in propagation. Semi hardwood and hardwood cuttings of F. leucopyrus were well established within a period of a week in sand potting medium. These findings can be used to establish suitable propagation systems for genera Tephrosia and F. leucopyrus for commercial cultivation.
Development of Suitable Propagation Systems for Tephrosia spp. in Sri Lanka
(University of Kelaniya, 2014) Priyadarshan, A.I.S.; Senanayake, S.P.; Jayatilleke, M.P.; Rajapakse, S.
Genus Tephrosia (Fabaceae) commonly known as ‘Pila’ in Sri Lanka. Some Tephrosia spp. are used in many traditional therapeutic preparations in Sri Lanka and also in other countries. Increased use of Tephrosia in traditional therapeutic systems has developed a great demand for these species. Thus production of planting materials for commercial cultivation has become a timely requirement. Therefore, this research was conducted to determine suitable propagation systems for four selected Tephrosia spp.; T. purpurea, T. villosa, T. noctiflora and T. pumila. Even though seeds of Tephrosia spp. showed high viability, lower germination percentage was observed on wet filter paper as well as in six different potting media [M0 (Coir: dust: Sand; 1:1:1), M1 (Coir dust: Sand: Top soil; 1:1:1), M2 (Coir dust: Sand: Top soil: Compost; 1:1:1:1), M3 (Coir dust: Sand: Top soil: Compost: Cow dung; 1:1:1:1:1), M4 (Coir dust: Sand: Compost; 1:1:1), M5 (Coir dust: Sand: Top soil: Cow dung; 1:1:1:1)] during a period of one week. Water impermeability of seed coats was identified as the main reason for the seed dormancy in Tephrosia spp. and soaking seeds in Con. H2SO4: H2O; 3:1 for 25 minutes and rubbing seeds on sandpaper for 2 minutes were determined as suitable dormancy breaking methods. Variation was observed in the growth performance of Tephrosia spp. in six different potting media. Growth performances of seedlings of Tephrosia spp. in hydroponic solution and soil medium were observed and soil medium was selected as the most suitable medium for the growth of Tephrosia species based on their growth performances.
Effect of growth regulators on in vitro regeneration of Gerbera jamesonii.
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Perera, H.S.M.; Swarnalatha, K.D.S.; Senanayake, S.P.
Gerbera jamesonii (Gerbera), belongs to the family Asteraceae, is considered as one of the important cut flowers in the global floriculture industry. The propagation process of Gerberas require improvements to fulfill the commercial demand and in vitro propagation was considered as a suitable solution to overcome this problem. The aim of the present study was to determine the effect of various concentrations of growth regulators on callus formation and shoot regeneration of Gerbera using leaves as explants. Healthy mature leaves were taken from Gerbera grown in the plant house, University of Kelaniya for obtaining suitable explants. Excised explants were washed with teepol (0.1%) solution for 06 mins followed by washings pre-treated with 10% (w/v) captan and sterilized distilled water (SDW). The explants were surface sterilized with Clorox solution (5%) with addition of Tween 20, followed by washing with SDW. Sterilized leaves were cut into 5-10 mm pieces. Callus induction, shoot proliferation and root regeneration were accomplished on Murashige and Skoog (MS) basal medium supplemented with different concentrations (0, 0.5, 1.0, 1.5 and 2.0mg/L) of 6-benzylaminopurine (BAP) and (0, 0.5 and 2mg/L) of naphthaleneacetic acid (NAA). For rooting, MS medium was supplemented with different concentrations of BAP (0, and 2.0 mg/L) and NAA (0, 2.0 mg/L). The highest callus initiation was observed in MS medium with 2 mg/L NAA and 1.0 mg/L BAP (60 days) while highest shoot initiation was obtained in MS medium with 2 mg/L BAP and 0.5mg/L NAA. Number of shoot formation per explant was 80% and shoots were visible after 26 days. When BAP was used as the sole growth regulator in the culture medium without NAA, limited shoot proliferations and translucent short shoots were observed (54%), whereas, NAA alone as the sole growth hormone did not initiate any shoot proliferation. With up to 2 mg/L NAA in the medium, BAP had a negative effect on shoot development, multiplication rate and the height of the shoots. MS medium supplemented with, 2 mg/L NAA, was identified as the best response for rooting initiation and number of roots per explant were 23.2±1.34. The first roots appeared after 1–2 weeks of culturing and a well developed root system was noted in 4–5 weeks. Subsequently, plants were removed from the medium and transferred to coir dust for acclimatization. The findings indicate that above three media compositions could be utilized for callus initiation, shoot proliferation and root formation from leaf explants of Gerbera jamesonii.
Estimation of total phenolic content on stem bark extracts of selected Sri Lankan medicinal plants
(National Centre for Advanced Studies in Humanities and Social Sciences Sri Lanka, 2015) Jayasiri, A.P.A.; Paranagama, P.A.; Senanayake, S.P.; Amarasinghe, A.P.G.
Evaluation of anti-inflammatory and antioxidant properties of Genus Piper in Sri Lanka. International Research Symposium on Pure and Applied Sciences,
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Athapattu, R.S.K.; Jayarathna, S.P.N.C.; Paranagama, P.A.; Senanayake, S.P.
In Sri Lanka, the genus Piper is represented by ten species including five wild and two cultivated species. Most of the species of the genus Piper are important as medicinal plants and used in various systems of medicine.This study aims to evaluate the bioactivity (anti-inflammatory and antioxidant properties) of the selected five Piper spp. (P. nigrum L., P. longum L., P. betle L., P. chuvya (Miq.) and P. sylvestre). Specimens of leaves and fruits were collected from their natural habitats and cultivations, and were subjected to the extraction of essential oils by steam distillation. Three replicates were done for each concentration and data were analyzed using the MINITAB 17 statistical package. Antioxidant activity was tested using 2,2-diphenyl-1- picrylhydrazyl (DPPH) free radical scavenging assay and ferric reducing antioxidant power assay. The isolated essential oils of Piper species exhibited remarkable DPPH free radical scavenging ability at different concentrations. The results revealed that the essential oil of P.betle exhibited the highest radical scavenging activity (92.8% at 1 mg/mL) and the value is higher than even of the standard, Butylated Hydroxy Toluene (BHT), (74.5% at 1 mg/mL). Further, essential oils of P. chuvya and P. longum have shown 91.8% and 63.1%inhibition percentages at 1 mg/mL. Essential oil isolated from P. betle has showed remarkable ferric reducing antioxidant power (mean absorbance, 1.89at 1 mg/mL) compared to the standard, BHT, (2.01at 1 mg/mL). Further, it was observed that its antioxidant activity increased with the increment of the concentration of essential oil (0.03-1 mg/mL). These results suggested the potential of using essential oils of leaves of P.betle, P. chuvya (1.31) and P. longum (1.28) as sources of natural antioxidants. This study also focused on evaluating anti-inflammatory activity by using Human Red Blood Cell (HRBC) membrane stabilizing method.Higher mean inhibition percentage was observed for the essential oil of P. betle leaves (79.6%at 1 mg/mL) compared to the standard (aspirin) and the activity significantly increased with higher concentrations (76.4% at 0.5 mg/mL and 79.6% at 1 mg/mL). Further, 62 % and 58.3 % of inhibitions percentages were shown by essential oils of P. chuvya and P. longum respectively. According to the findings of this study, bioactivity properties of the leaves and fruits of these Piper species can be used in future perspectives for developing novel pharmaceuticals.
Evaluation of nutrient and fiber content of selected invasive plants in Sri Lanka with a potential for preparing compost
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Hewavitharana, N.; Kannangara, B.T.S.D.P.; Jayasekera, L.R.; Senanayake, S.P.
Based on availability, the amount of above ground bio-mass and the degree of use as compost in traditional farming systems Tithonia diversifolia, Chromolaena odorata, Mikania scandens, Lantana camara, Wedelia trilobata, Mimosa pigra and Panicum maximum were selected for nutrient analysis, with an attempt to investigate their potential to be utilized in preparation of cost effective, organic potting medium for cultivation of selected vegetables and ornamental plants. According to the preliminary surveys, Anuradhapura, Madawachchiya, Kandy, Gampaha, Kalutara and Kurunegala areas were selected for sample collection. Leaves and immature stem parts of the selected plants were analyzed by two samples per one location with three replicates. The total N, P and K contents were determined by Kjeldahl, vanadomolybdate and flame photometric methods respectively. Atomic absorption spectrophotometry was used for quantitative analysis of Mg, Ca, Cu Zn, and Fe. Crude fiber content was determined gravimetrically after chemical digestion and solubilization of the materials. Results obtained were statistically analyzed using SPSS statistics-22 software. The nutrient contents of T. diversifolia; N (3.28%), P (0.37%), K (2.50%), Mg (0.83%), Ca (4.92%), Cu (10 mg/kg), Zn (517 mg/kg) Fe (296 mg/kg) and M. scandens; N (3.44%), P (0.35%), K (3.30%) Mg (1.33%), Ca (3.39%), Cu (34 mg/kg), Zn (671 mg/kg), Fe (393 mg/kg) were significantly higher than that of other selected weeds. However, they showed significantly lower crude fiber contents 4.85% and 3.50% respectively. Although the nutrient content in P. maximum was significantly low N (1.27%), P (0.24%), K (1.44%) Mg (0.5%), Ca (1.55%), Cu (9 mg/kg), (Zn 181 mg/kg), Fe (267 mg/kg) and its crude fiber content (20.42%) was significantly higher than that of others. It can be concluded, T. diversifolia and M. scandens as plant materials which have higher amounts of nutrients. P.maximum which has higher content of crude fiber also can be incorporated in preparing compost in order to improve the physical properties of the potting medium.
Evaluation of phenetic diversity of selected orchid cultivars with ornamental value
(The Institute of Biology, Sri Lanka, 2016) Farook, F.; Attanayake, R.N.; Senanayake, S.P.
Evaluation of the Survival of Dendrobium crumenatum Swartz. Pollen Stored at Different Temperatures
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Silva, W.E.R.; Attanayake, R.; Ratnayake, S.; Senanayake, S.P.
Dendrobiums have a high demand in the Sri Lankan floriculture industry as cut flowers and potted plants. Most Dendrobium cultivars found in the Sri Lankan market are imported from countries like Thailand, Singapore and Malaysia. Development of new cultivars and commercial cultivation of orchids has become a billion-dollar profitable industry in the world. In order to uplift the local orchid industry, cultivars with Sri Lankan identity should be developed. As Sri Lankan Dendrobiums have high floral diversity with economically important characters like fragrance, patterns and shapes, such characters could be introduced to the popular cultivars through breeding programs. Pollinia of these species and cultivars may not be always available throughout the year. Therefore, a suitable pollen storage method that maintains pollen viability and germinability, should be developed. The objective of this study was to develop a pollen preservation technique for Dendrobium crumenatum (E: Pigeon orchid, S: Sudu pareyi mal) by storing at different temperatures in order to use them in breeding programs. Pollen were collected into 0.2 mL tubes from fully opened fresh flowers at the onset of the anthesis around 7.00 – 8.00 am in July 2019. A set of pollen was dried in silica for 24 hours before storage and the other set was directly stored at -80 °C, -20 °C, -1 °C, 9 °C and 28 °C temperatures. Cryopreservation of pollen at -80 °C and -20 °C were also conducted in modified Murashige and Skoog medium (pH 5.7). Treatments were performed in triplicates. Samples of stored pollen were removed after 1, 3, 7, 14, 30 and 60 days and in vitro germinability and viability were tested in 10% sucrose and 2,3,5-Triphenyltetrazolium chloride (TTC) respectively. To confirm pollen viability and germinability, pollen of D. crumenatum stored at 9 °C were used in controlled cross pollination with Dendrobium ‘Pink Stripe,’ Dendrobium ‘Sonia Red’ and Dendrobium ‘Pink New Splash’. D. crumenatum had 54.97±12.22 % germinability and 76.0±4.58 % viability prior to storage. Pollen stored at subzero temperatures or subjected to cryopreservation lost viability and germinability. Pollen stored at 9 °C without drying, were viable for 14 days and produced pollen tubes (8.63±0.71 %). Although, percent in vitro germination of D. crumenatum pollen reduced to less than 20% after 7 days of storage (19.57±6.55 %) at 9 °C, pollination of stored pollen resulted in fruit set in Dendrobium ‘Pink Stripe,’ and Dendrobium ‘Pink New Splash’. This study found that seasonally flowering D. crumenatum pollen can be stored for short periods at 9 °C while maintaining their viability and germinability and can be used for cross pollination in breeding programs. However, subzero temperatures and cryopreservation may not be appropriate for storage of D. crumenatum pollen
Germinability and Viability of Pollen of Selected Commercial Dendrobium Hybrids
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Kahagalla, T.H.; Herath, H.M.; Attanayake, R.N.; Senanayake, S.P.
Dendrobium is one of the highly demanding ornamental orchid genera in Sri Lankan floriculture industry. The assessment of functional quality of the pollinium on the basis of germinability and viability is useful for the development of breeding programs for crop quality improvement and pollen storage protocols in conservation. This research was carried out to determine in vivo and in vitro pollen germinability and pollen viability of eight commercial Dendrobium hybrids (A-H). Percentage of pollen viability was studied by placing crushed pollinia on a cavity slide with 1% 2,3,5-triphenyltetrazolium chloride solution and incubating at dark for 12 hours. Pollinia of Dendrobium flowers were placed on the stigma of the same flower on the second day after opening. After three days, pollinia were stained with lacto phenol cotton blue and percentage of in vivo pollen germination was calculated. In vitro pollen germination of the Dendrobium hybrids was studied in three different media. Pollinia were removed from the anthers on the second day after flower opening and placed in (i) 5%, 10%, 15%, 20% and 25% sucrose solutions and (ii) a semi solid medium containing 10% sucrose, 100 mgL-1 H3BO3, 300 mgL-1 Ca(NO3).2H2O, 200 mgL-1 MgSO4.7H2O, 200 mgL-1 KNO3, 8 gL-1 agar and stigmatic fluid of Dendrobium flower and incubated at room temperature. Pollinia of Dendrobium hybrids A, G and H placed in a (iii) semi solid medium containing 1%, 2%, 3% sucrose, 75 mgL-1 H3BO3 and 0.5%, 1%, 2% agar were incubated at 24 oC, 26 oC, and 28 oC. After 48 hours, percentage of in vitro pollen germination was calculated. Means were compared using one-way ANOVA with Tukey’s pairwise comparison test in IBM SPSS Statistics 22 software. As the percentage values of pollen germination and viability were not normally distributed, the values were transformed to arcsin square root values prior to statistical analysis. There was no significant deference in pollen viability of different hybrids which varied between 94% and 77%. The highest percentage of in vivo pollen germination was found in Dendrobium cultivar D (67%) and there was a significant deference in in vivo pollen germination among the hybrids. Correlation analysis was performed using IBM SPSS Statistics 22 software to determine the relationship between pollen viability and in vivo pollen germination and found that there was no significant relationship (�= 0.237). The percentage of in vitro pollen germination was low and the highest in vitro pollen germination (7.2%) was observed in the semisolid medium containing 1% sucrose, 75 mgL-1 H3BO3, 1% agar and incubated at 26 oC for Dendrobium cultivar H.
Host tree specificity and seed germination of Dendrobium aphyllum (Roxb.) C.E.C.Fisch. in Sri Lanka
(Journal of the National Science Foundation of Sri Lanka, 2013) Harshani, H.B.C.; Senanayake, S.P.; Sandamali, H.
Tree species can be considered as hosts for many epiphytes. Orchids as epiphytes display a biased distribution among hosts. It is possible that the barks of these hosts have some chemical and physical characteristics that influence for the seed germination of orchids. Dependence on symbiotic fungi for the seed germination is also a crucial factor for orchid distribution. Dendrobium aphyllum is an orchid species with restricted distribution in sub montane region of Sri Lanka. Aims of this study were (1) to determine the host tree specificity of the epiphytic D. aphyllum using physical and chemical bark characteristics of the host (2) to isolate and identify the symbiotic fungi in D. aphyllum roots and (3) to determine the effect of tree bark extracts on symbiotic seed germination of D. aphyllum. Methanol, dichloromethane, hexane and water were used to extract the chemical compounds in tree barks. Aqueous and organic bark extracts of non host species (Erythrina sp. ,Erythrina berteroana, Eurya accuminata, Semecarpus marginata, Symplocaceae cochinchinensis ) inhibited seed germination of D. aphyllum. However, the effect of host tree species (Eurya ceylanica, Actinodaphne stenophylla, Eurya sp., Antidesma zeylanicum, Citrus maxima, Semecarpus nigra-viridis and two Syzygium spp.) on seed germination fluctuated with the concentration of host bark extracts. Bark physical characteristics such as bark texture, peeling behavior and bark thickness showed positive correlation with host tree specificity of D. aphyllum.. Symbiotic fungus Rhizoctonia sp. was isolated as the associate in D. aphyllum roots.
Interspecific Relationships of Piper Species in Sri Lanka as Revealed by DNA Barcode ITS
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Jayarathna, N.; Senanayake, S.P.; Rajapakse, S.; Jayasekera, R.; Paranagama, P.A.
The genus Piper which is the largest genus in the family Piperaceae is economically important as it comprises with valuable crop species as well as several wild species. Although ten species of genus Piper are recorded in Sri Lanka, their interspecific relationships were not well studied. Therefore, the aim of this study was to determine interspecific relationships of Piper species in Sri Lanka using internal transcribed spacers from nuclear ribosomal DNA )ITS(. Ten varieties of Piper nigrum L., two varieties of each P. betle L.and P. longum L., P. chuvya )Miq.( C. DC., P. siriboa L., P. sylvestre Lam., P. walkeri Miq. and P. zeylanicum Miq. were used for the study. The genomic DNA was extracted from tender leaf samples using CTAB method, PCR amplified using ITS primer pair and subjected to DNA sequencing. The DNA sequence alignment analysis was carried out and a dendrogram was constructed using the multiple sequence alignment programme MUSCLE. According to the dendrogram clear formation of two major clusters can be seen and ten P. nigrum varieties were clustered together however, variety Kuching has shown a separation from the main cluster. P. longum, P. walkeri, P. sylvestre, P. siriboa, P. betle, P. chuvya and P. zeylanicum formed the other cluster in which P. siriboa has shared close similarities with P. betle, while P. sylvestre and P. walkeri displayed close relationships and clustered together with P. longum varieties. Interspecific relationships between wild species and cultivated species )P. nigrum, P. betle and P. longum( indicated the potential of using the wild species in breeding programs for crop improvement. However, further studies to reveal genetic and phenetic relatedness of those species are needed to deepen the knowledge on interspecific relationships of Piper species.
Intraspecific Variation of Flueggea leucopyrus Willd. Grown in Sri Lanka and Establishing a Suitable Propagation System
(University of Kelaniya, 2014) Priyadarshan, A.I.S.; Senanayake, S.P.; Jayatilleke, M.P.; Rajapakse, S.
Flueggea leucopyrus belongs to family Phyllanthaceae, commonly known as ‘Katupila’or ‘Heen katupila’ and has become increasingly popular as an ingredient in several traditional therapeutic systems in Sri Lanka as well as in other Asian countries. A questionnaire survey was carried out using a hundred population sample to determine the awareness of the distribution and therapeutic uses of F. leucopyrus in Sri Lanka as a preliminary survey. The aims of the present study were to interpret the phenetic variation and determine the variation of phenolic composition in leaf extracts of F. leucopyrus in different climatic zones in Sri Lanka and to develop a suitable propagation system for F. leucopyrus. Eleven floral and vegetative characters of F. leucopyrus were observed and cluster analysis was carried out to infer phenetic relationships among populations collected from localities, Colombo, Kurunegala, Puttalam and Hambanthota, .representing different climatic zones. Medicinal value of most of plants lies in phytochemicals such as phenolics, flavonoids and anthocyanidins. Thus, leaf samples were extracted into ether, and ether extracts were used to isolate phenolic compounds using 2-Dimensional paper chromatography in solvent systems, butanol: acetic acid: water; 6:7:3 and sodium formate: formic acid: water; 10:1:200. Colors of the spots were observed under UV (366nm), and Rf values were calculated. Intra specific variations were observed in the distribution of phenolics in leaves and phenetic characters of F. leucopyrus with respect to their habitats in different climatic zones. Due to low seed production in F. leucopyrus, stem cuttings (Semi-hardwood, hardwood and softwood) in three different potting media were used to evaluate the successfulness in propagation. Semi hardwood and hardwood cuttings of F. leucopyrus were well established within a period of one week in sand potting medium while softwood cutting has not responded in any of the media during the period. Medium with only coir dust was also not successful in establishing the cuttings.
Leaf flavonoid glycosides as chemosystematic characters in Ocimum
(Biochemical Systematics and Ecology, 1993) Grayer, R.J.; Kitea, G.C.; Veitcha, N.C.; Eckerta, M.R.; Marin, P.D.; Senanayake, S.P.; Paton, A.J.
Abstract Thirty-one accessions of nine species belonging to three subgenera of Ocimum (basil, family Lamiaceae) were surveyed for flavonoid glycosides. Substantial infraspecific differences in flavonoid profiles of the leaves were found only in O. americanum, where var. pilosum accumulated the flavone C-glycoside, vicenin-2, which only occurred in trace amounts in var. americanum and was not detected in cv. Sacred. The major flavonoids in var. americanum and cv. Sacred, and also in all other species investigated for subgenusOcimum, were flavonol 3-O-glucosides and 3-O-rutinosides. Many species in subgenus Ocimum also produced the more unusual compound, quercetin 3-O-(6?-O-malonyl)glucoside, and small amounts of flavone O-glycosides. The level of flavonol glycosides produced was reduced significantly in glasshouse-grown plants, but levels of flavone glycosides were unaffected. A single species investigated from subgenusNautochilus, O. lamiifolium, had a different flavonoid glycoside profile, although the major compound was also a flavonol O-glycoside. This was identified as quercetin 3-O-xylosyl(1??2?)galactoside, using NMR spectroscopy. The species investigated from subgenus Gymnocimum, O. tenuiflorum (=O. sanctum), was characterised by the accumulation of flavone O-glycosides. These were isolated, and identified as the 7-O-glucuronides of luteolin and apigenin. Luteolin 5-O-glucoside was found in all nine species of Ocimumstudied, and is considered to be a key character for the genus.
Leaf flavonoids as chemotaxonomic characters in genus Sida L. (Bevila)
(Tropical Agricultural Research, 2001) Perera, N.I.S.; Senanayake, S.P.; Jayasekera, L.R.
Theflavonoid distribution pattern of five species of genus Sida was studied to identify the species since the existing classification was mainly based on morphological and anatomical characters. Four main flavonoids and one minor flavonoid were isolated by preparatory paper chromatography. Trace amounts of six flavonoids were observed in two-dimensional paper chromatography. The major flavonoid compounds in S. acuta. S. rhombifolia. S. alnifolia. and S. cordifolia were glycosylated and methylated flavonols where as S. humilis had minor flavonoids. There are remarkable variations in the substitution patterns of these flavonol compounds. The presence ofquercetin 3-methyl ether and the compound C is a common character to S. rhombifolia and S. cordifolia. and hence these two species may be considered as related taxa in the genus Sida. Kaempferol glycosides were the major Jlavonoids in the S. alnifolia in contrast to the S. rhombifolia. which was characterised by the presence of methylated quercetin. This is in agreement with the recent revision of the genus in which they are considered as different entities. The habit ofS. humilis. prostrate trailing, is different from other species, which are erect herbs. This dissimilarity of morphology agreed with its characteristic flavonoid pattern of possessing minor flavonoids.
Lesson 21: Weeds and Weed Management Methods
(Research Services Centre, Faculty of Science, University of Kelaniya, 2015) Senanayake, S.P.; Ratnayake, R.M.C.S.