Nymphaea rubra Roxb. ex Andrews in Sri Lankan Fresh Waters

Native water lilies are wide spread in aquatic ecosystems in Sri Lanka and the RevisedHandbook to the Flora of Ceylon has recognized only two native water-lilies, Nymphaeanouchali Burm. f. and N. pubescens Willd. However, another night blooming Nymphaeaspecies with red flowers that is not either taxonomically described or recognized in the Floraduring the revision occurs in many parts of the country. A detailed taxonomic investigationwas carried out with field collected samples of all Nymphaea species occurring in local waterbodies. Forty eight morphological characters were studied in detail and coded into a datamatrix. Data were analysed using PAST software version 2.17.The multivariate analysis separated this group of Nymphaea from the other native Nymphaeaspecies as a separate phenetic group. Larger leaves (25-48 cm) with reddish purple abaxialand green adaxial surfaces, red petals and a larger number of stamens (62-103), and creamcolour stigmatic head are important characters that separates the group from its closeresemblance, N. pubescens. Comparing the morphological features of the individuals in thisphenetic group with taxonomic descriptions of N. rubra, confirmed their identity as N. rubra.A complete morphological description and an identification key to separate the differentNymphaea species occurring in Sri Lanka were constructed.

Beyond aesthetics: Integration of textural groups of tropical ornamental shrubs into urban planting designs

Shrubs are popularly incorporated to establish green infrastructure in urban spaces. We argue that the functions provided by shrubs could be further enhanced by giving due consideration to their leaf morphological characters. Therefore, our objective was to recognise how the different morphological characters of leaves, listed as contributing to determining the plant texture in literature, would collectively contribute to recognizing textural groups of plants, and further, to define each of these groups into either coarse, medium, or fine textural categories using ornamental shrubs. We investigated the quantitative and qualitative leaf morphology of 30 tropical ornamental shrubs in the Peradeniya area. According to our analysis, leaf area, petiole length, and internodal distance have significantly contributed to the separation of shrubs into three textural groups; fine, medium and coarse, and were considered as preliminary characters that determine the texture. Leaf hair related characters viz., hair densities on upper and lower surfaces, and the length of hairs on both surfaces, together with qualitative morphological characters, viz., leaf margins, leaf arrangement, and prominent venation were identified as secondary characters that contributed to defining textural groups. Shrubs with coarse texture possess significantly larger leaves, longer petioles and internodal distances compared to fine textured group. Our recommendation is to consider plant textural groups as a criterion in the selection of plants for planting designs during the establishment of green infrastructure in urban spaces, enabling the obtaining of benefits beyond aesthetics, which include other functional, health and environmental benefits, to improve the quality of life of city dwellers under the context of limited urban green spaces

Taxonomy and Systematic Analysis of the Two Genera Alpinia and Amomum of the Family Zingiberaceae in Sri Lanka

Alpinia and Amomum are the largest two genera that list the highest number of endemics offamily Zingiberaceae in Sri Lanka. The family is recognized as a least studied plant group inthe country, justifying the need for a thorough study. Hence, it is timely that the family istaken into consideration of molecular and systematic studies given new techniques areavailable. As a pioneering step, in this study, we addressed several taxonomic issues,phylogenetic relationships and conservational status of Alpinia and Amomum. In order tocollect more morphological data to address species boundaries with better insights, over 130morphological characters were studied and analysed using multivariate statistical methods.Molecular phylogenetic analysis was done using two Chloroplast gene regions (trnL-trnF andtrnS-trnfM). Results of the morphological analysis revealed the segregation of species ratherdepending on both vegetative and floral characters than only on floral characters. Study alsoidentified a group of Amomum with a new character combination which needs to berecognized as a new species or subspecies along with a new addition to genus Alpinia (A.zerumbet) in Sri Lanka. Furthermore, in our efforts to make a field key for easy identificationof species, results of this study also highlighted the difficulty in using only vegetativecharacters to differentiate species. Hence, the study has resulted in identifying a different andan easy set of morphological characters for species identification for Sri Lankan species.Evolutionary analysis of the two genera confirms that the Sri Lankan members of the twogenera Alpinia and Amomum have a monophyletic origin. Although the genus Alpinia has amonophyletic lineage, two members (A. abundiflora and A. fax) show a polytomy within thegenus. This was evident in both phylogenetic analysis and the morphological analysis.According to trnL-trnF and trnS-trnƒM data analysis, all the studied members of the genusAmomum have an exclusive monophyletic origin. Illumination of an immediate need forconservation efforts of these species is another important finding of the current study

THE STRUTURE AND COMPOSITION OF NATURAL VEGETATION TYPES IN LOWER WALAWE BASIN IRRIGATION EXTENTION AREA

Sri Lanka has experienced a tremendous boost in large-scale irrigation development. TheUdawalawe irrigation extension project of the Mahawelli Authority will result in theconstruction of a left bank main canal from the Walawe River and the establishment of anirrigation system spanning an area of approximately 15.000 ha. A systematic study onbiodiversity was carried out in the Lower Walawe Irrigation extension area, from February toAugust 2001. This paper summarizes the structure and composition of natural vegetation typesin the study area, during the pre-development stage. A total of 45 transects (each 50mx5m) weredemarcated within 16 sites along the dry to arid zone climatic gradient in the study area. Eachtransect was divided into 10IILx5m sub plots to facilitate sampling and individual plants overlOcm in girth were recorded. The data was analysed using ecological indices (Shannon-Wienerindex and Simpson's Index) and multivariate analyses using the PCORD4 softwareThe area consists of 3 major natural vegetation types; dry thorny scrubland (DTF), rock outcropforests (ROF).and degrade dry zone forest (DDF). A total of 151 plant species, belonging to 52families were recorded from the above vegetation types. The most diverse families wereFabaceae [Relative Diversity (RD)=l1.3], Poaceae (RD=9.3) and Euphobiaceae (RD=8). Interms of density, the most abundant species in the study area were Flueggea leucopyrus(Euphobiaceae) (23.3%) and Phyllanthus polyphyllus (Euphobiaceae) (8.6%)Comparisons of the diversity among vegetation types showed that the degraded dry zone forest"vas high in diversity (Simpson's diversity index; D=17.6, Shannon-Wiener diversity indexH'=3.6) than rock outcrop forests (D=10.7,H=3.1) and scrubland (D=9.9,H=304). Consideringthe species composition and density of flora, a Detrended Correspondence Analysis (DCA)showed the DDF as a distinct cluster, while the ROF exhibited an overlap with the DTS. ATWINSPAN cluster analysis showed that the DTS and DDF separate into two distinct clusters,which correspond to the dry and arid climatic zones. However, the ROF remained as a singlemajor cluster.

Determination of the scale of pattern and distribution in Helicteres isora L (Sterculiaceae)

Helicteres isora L. is a traditional multipurpose plant used by indigenous community and villagers inall the three major climatic zones in Sri Lanka. It naturally occurs in the edges of forests and indisturbed secondary vegetation. It is fastly disappearing in the wet zone due to land clearing and highextraction rates. The present study was conducted to understand the pattern and the scale of distributionof H. isora in order to provide information for biodiversity conservation and further to enable thesustainable use.Twelve natural populations were identified in wet, intermediate and dry zones and the distribution ofindividuals was studied using gradient directed transect method. The t test was performed for eachpopulation to detect the pattern of distribution and pattern analysis was carried out to determine thescale of pattern.Out of twelve populations surveyed, only five populations showed contagious distribution (p < 0.05)while seven populations showed random pattern of distribution. This indicates that the populations ofH isora do not fall into a particular pattern of distribution in nature. This may be due to the highdisturbance present in and around the populations.The results of the pattern analysis reveal more peaks in smaller block sizes (2m2) and larger blocksizes (32m2) indicating aggregated pattern in respective block sizes. Peaks in smaller block sizes aredue to the morphology of the plant as it produces new plants from roots. Peaks at larger block sizesare due to the extrinsic factors and these results could be utilized in the in- situ conservation of Hisora .

Population-specific selection on standing variation generated by lateral gene transfers in a grass

Evidence of eukaryote-to-eukaryote lateral gene transfer (LGT) has accumulated in recent years [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14], but the selective pressures governing the evolutionary fate of these genes within recipient species remain largely unexplored [15, 16]. Among non-parasitic plants, successful LGT has been reported between different grass species [5, 8, 11, 16, 17, 18, 19]. Here, we use the grass Alloteropsis semialata, a species that possesses multigene LGT fragments that were acquired recently from distantly related grass species [5, 11, 16], to test the hypothesis that the successful LGT conferred an advantage and were thus rapidly swept into the recipient species. Combining whole-genome and population-level RAD sequencing, we show that the multigene LGT fragments were rapidly integrated in the recipient genome, likely due to positive selection for genes encoding proteins that added novel functions. These fragments also contained physically linked hitchhiking protein-coding genes, and subsequent genomic erosion has generated gene presence-absence polymorphisms that persist in multiple geographic locations, becoming part of the standing genetic variation. Importantly, one of the hitchhiking genes underwent a secondary rapid spread in some populations. This shows that eukaryotic LGT can have a delayed impact, contributing to local adaptation and intraspecific ecological diversification. Therefore, while short-term LGT integration is mediated by positive selection on some of the transferred genes, physically linked hitchhikers can remain functional and augment the standing genetic variation with delayed adaptive consequences

Key changes in gene expression identified for different stages of C4 evolution in Alloteropsis semialata.

C4 photosynthesis is a complex trait that boosts productivity in tropical conditions. Compared to C3 species, the C4 state seems to require numerous novelties, but species comparisons can be confounded by long divergence times. Here, we exploit the photosynthetic diversity that exists within a single species, the grass Alloteropsis semialata, to detect changes in gene expression associated with different photosynthetic phenotypes. Phylogenetically-informed comparative transcriptomics show that intermediates with a weak C4 cycle are separated from the C3 phenotype by increases in the expression of 58 genes (0.22% of genes expressed in the leaves), including those encoding just three core C4 enzymes: ASP-AT, PCK, and PEPC. The subsequent transition to full C4 physiology was accompanied by increases in another 15 genes (0.06%), including only the core C4 enzyme PPDK. These changes likely created a rudimentary C4 physiology, and isolated populations subsequently improved this emerging C4 physiology, resulting in a patchwork of expression for some C4-accessory genes. Our work shows how C4 assembly in A. semialata happened in incremental steps, each requiring few alterations over the previous one. These create short bridges across adaptive landscapes that likely facilitated the recurrent origins of C4 photosynthesis through a gradual process of evolution

Revealing the Functions of the Transketolase Enzyme Isoforms in Rhodopseudomonas palustris Using a Systems Biology Approach

BACKGROUND: Rhodopseudomonas palustris (R. palustris) is a purple non-sulfur anoxygenic phototrophic bacterium that belongs to the class of proteobacteria. It is capable of absorbing atmospheric carbon dioxide and converting it to biomass via the process of photosynthesis and the Calvin-Benson-Bassham (CBB) cycle. Transketolase is a key enzyme involved in the CBB cycle. Here, we reveal the functions of transketolase isoforms I and II in R. palustris using a systems biology approach. METHODOLOGY/PRINCIPAL FINDINGS: By measuring growth ability, we found that transketolase could enhance the autotrophic growth and biomass production of R. palustris. Microarray and real-time quantitative PCR revealed that transketolase isoforms I and II were involved in different carbon metabolic pathways. In addition, immunogold staining demonstrated that the two transketolase isoforms had different spatial localizations: transketolase I was primarily associated with the intracytoplasmic membrane (ICM) but transketolase II was mostly distributed in the cytoplasm. Comparative proteomic analysis and network construction of transketolase over-expression and negative control (NC) strains revealed that protein folding, transcriptional regulation, amino acid transport and CBB cycle-associated carbon metabolism were enriched in the transketolase I over-expressed strain. In contrast, ATP synthesis, carbohydrate transport, glycolysis-associated carbon metabolism and CBB cycle-associated carbon metabolism were enriched in the transketolase II over-expressed strain. Furthermore, ATP synthesis assays showed a significant increase in ATP synthesis in the transketolase II over-expressed strain. A PEPCK activity assay showed that PEPCK activity was higher in transketolase over-expressed strains than in the negative control strain. CONCLUSIONS/SIGNIFICANCE: Taken together, our results indicate that the two isoforms of transketolase in R. palustris could affect photoautotrophic growth through both common and divergent metabolic mechanisms

Evidence for interspecific hybridization between exotic ‘Dam manel’ (<em>Nymphaea × erangae </em>) and native ‘Nil manel’ (<em>Nymphaea nouchali </em>Burm. f.) in Sri Lanka

Biological invasions are considered a serious threat to the biodiversity, and second only to habitat loss, but predicted to soon become the key cause of environmental degradation globally. In addition to competing with natives in natural habitats, another serious threat possessed by Invasive Alien Species (IAS) is their ability to hybridize with natives. The exotic violet flowered Nymphaea × erangae has been introduced to the country for ornamental purposes where it has got naturalized.  Now it is recognized as a silent invader in wetlands of the country. The revealing of Nymphaea populations with intermediate characters, both of the native N. nouchali and Nymphaea × erangae in the wetlands of the island raised the question of the occurrence of natural hybridization. The present study was carried out to investigate the event of natural hybridization between the native and the exotic using morphological data. Data collected from putative hybrids and pure populations of the two parents were subjected to multivariate statistical analyses. The results confirmed the identity of the populations with intermediate characters as hybrids between the native N. nouchali and Nymphaea × erangae, highlighting the importance of conserving the natural populations of the native, as hybridization with the exotic pose a threat to its genetic purity

Molecular characterization of <i>Colletotrichum</i> species causing <i>Begonia</i> anthracnose in Sri Lanka

Anthracnose disease is known to affect many tropical and subtropical fruits, vegetables and also certain cut-flowers and foliage plants. The disease was known to be caused by Colletotrichum gloeosporioides or C. acutatum which are presently accepted as species complexes. The present study was conducted with the main objective of identifying Colletotrichum species causing begonia anthracnose using morphological and molecular data. Begonia is an ornamental foliage plant grown worldwide. Anthracnose symptoms appear in begonia leaves as brownish, irregular, necrotic lesions. Colletotrichum was isolated from three Begonia species showing anthracnose symptoms, collected from three Provinces of Sri Lanka. Thirty isolates were obtained in the study of which 29 formed oblong conidia and the remainder produced falcate conidia. Six randomly selected isolates forming oblong conidia and the isolate with falcate conidia were sequenced for Internal Transcribed Spacer (ITS) and β-tubulin 2 (TUB2) regions. Considering &gt;98% similarity with NCBI GenBank database for both sequences, the isolates with oblong conidia were identified as C. siamense and the isolate with falcate conidia as C. truncatum. Newly generated sequences were subjected to phylogenetic analysis with the closely related ex-type and authenticated isolates sequences. Phylogenetic analysis confirmed the species as C. siamense and C. truncatum. Koch’s postulates were performed to establish whether the fungi isolated from anthracnose lesions were actually causing anthracnose disease in Begonia leaves. This is the first report of C. siamense causing Begonia anthracnose