SEED ECOLOGY OF SOME SELECTED DRY FOREST SPECIES OF SRI LANKA

This study examines seed ecology of ten native dry zone forest species: Manilkarahexandra, Drypetes sepiaria, Salvadora persica, Bauhinia racemosa, Cassia fistula,Cassia siamea, Schlechera oleosa, Oroxylum indicum, Randia uliginosa, Dichrostachyscineria and in one alien invasive species: Prosopis juliflora.Seed samples were collected from the dry zone of Sri Lanka (in Anuradhapura,Polonnaruwa, Monaragala and Hambanthota districts). Morphology (colour, width,length of seeds) and the weight of 60 seeds per each species were recorded in threereplicates. Viability of seeds was tested using standard TIC test while the percentagegermination of seeds was recorded in moist petridishes laid according to RandomizeComplete Block Design. Rate of water absorption of seeds and seed coat widths were alsomeasured, while the presence of water-soluble growth inhibitors were examined througha bioassay using Brasica juncea seeds. Hot water treatments, Hot air treatments,Gibberalic acid treatments, Manual scarification and combinations of above treatmentswere tested to break the seed dormancy of these species. Seed and plant characteristicswere observed to determine the ecological state (Climax or Pioneer) of study species.Seed predation and dispersal mechanisms were observed during field visits.P.jutiflora and 0. indicum seeds are recalcitrant, while the remaining species showedseed dormancy. D.cineria Cfistula, Csiamea and B.racemosa seeds appeared to bedormant due to its water impermeable seed coat and the dormancy can be overcome bymanual-scarification. S.persica seeds contain underdeveloped embryo and hot watertreatment (at 45°C for 5 days) was found to be the best treatment to break the seeddormancy. D.sepiaria, S.oleosa and R.uliginosa seeds seem to be dormant due to thepresence Of a growth inhibitor and the hard seed coat. Manual scarification together withGibberalic acid (4000ppm) treatment was found to be suitable to break the seed dormancyof the species. M.hexandra seeds too have an undeveloped embryos and hard seed coats,which may cause seed dormancy, but seed germination can be improved by hot watertreatment (at 85°C for 15minutes) fallowed by manual scarification. o'indicum andR. uliginosa can be described as Pioneer species. Other 8 natural forest species can bedescribed as climax species, which mainly dispersed by animals. High seed predationcan be observed in these species. Especially insects including termites and several larvaeof insects attack the seeds of tbese species.

Physiological Epicotyl Dormancy and Recalcitrant Storage Behaviour in Seeds of Two Tropical Fabaceae (Subfamily Caesalpinioideae) Species

BACKGROUND AND AIMS: Physiological epicotyl dormancy in which the epicotyl elongates inside the seed before the shoot emerges has been reported for only a few tropical rainforest species, all of which are trees that produce recalcitrant seeds. In studies on seeds of Fabaceae in Sri Lanka, we observed a considerable time delay in shoot emergence following root emergence in seeds of the introduced caesalpinioid legumes Brownea coccinea and Cynometra cauliflora. Thus, our aim was to determine if seeds of these two tropical rainforest trees have physiological epicotyl dormancy, and also if they are recalcitrant, i.e. desiccation sensitive. METHODOLOGY: Fresh seeds were (i) dried to various moisture levels, and (ii) stored at -1 and 5 °C to determine loss (or not) of viability and thus type of seed storage behaviour (orthodox, recalcitrant or intermediate). To identify the kind of dormancy, we tested the effect of scarification on imbibition and monitored radicle emergence and epicotyl growth (inside the seed) and emergence. PRINCIPAL RESULTS: FRESH SEEDS OF BOTH SPECIES HAD HIGH MOISTURE CONTENT (MC): 50 % for C. cauliflora and 30 % for B. coccinea. Further, all seeds of C. cauliflora and the majority of those of B. coccinea lost viability when dried to 15 % MC; most seeds of both species also lost viability during storage at -1 or 5 °C. Intact seeds of both species were water permeable, and radicles emerged in a high percentage of them inHowever, shoot emergence lagged behind root emergence by 77 ± 14 days in B. coccinea and by 38 ± 4 days in C. cauliflora. Further, plumule growth inside seeds of C. cauliflora began almost immediately after radicle emergence but not until ∼30-35 days in B. coccinea seeds. CONCLUSIONS: Seeds of both species are recalcitrant and have physiological epicotyl dormancy. The kind of physiological epicotyl dormancy in seeds of C. cauliflora has not been described previously; the formula is C(nd) (root)-[Formula: see text] (epicotyl)

Effect of salinity on seed germination of Vigna marina a wild relative of crop Vigna species using hydrotime modelling

Vigna marina (Fabaceae) is a wild relative of cultivated Vigna species. Crop wild relatives are important genetic source, which can be utilized in developing desired crop varieties. V. marina is a vine, growing naturally in sandy seashore with high saline soil conditions and have the different threshold water potential effects on germination pattern rather non-salt tolerant Vigna species. Thus, salinity tolerant traits of V. marina can be utilized to develop salinity tolerant crop Vigna varietiesThe objective of the study was to study the salinity stress tolerance of V. marina seeds during germination using a hydrotime model. Healthy seeds of V. marina were extracted from randomly selected plants from coastal area of Southern Province of Sri Lanka. Germination and imbibitions of untreated and chemically scarified seeds were studied. Several acid scarification treatments were conducted to determine the best dormancy breaking treatment. Acid scarified seeds of V. marina and V. radiata were separately germinated in series of salt concentrations to develop a hydrotime model.Chemically scarified seeds of V. marina increased mass > 62% while, untreated seeds increased mass <21%. Chemically scarified seeds germinated 100% whereas, untreated seeds germinated 67% both at light and dark conditions. Results revealed that 5% of V. marina seeds have physical dormancy. Chemically scarified seeds for 5 minutes showed the highest germination which was > 85% and confirmed that chemical scarification for 5 minutes was the best dormancy breaking treatment. In Na2SO4 base water potential is [ψ b(60%)] -5.47 MPa and – 5.43 MPa for V. marina and V. radiate respectively. In KNO3 base water potentials are – 5.65 MPa and – 5.59 MPa for V. marina and V. radiata respectively. Lower base water potentials of V. marina seeds compared to base water potential of V. radiata indicate the salt tolerance ability of V. marina than the V. radiata. Therefore V. marina can be utilized to develop salt tolerant crop Vigna specie

Cross-amplification of EST-derived markers among 16 grass species

The availability of a large number of expressed sequence tags (ESTs) has facilitated the development of molecular markers in members of the grass family. As these markers are derived from coding sequences, cross-species amplification and transferability is higher than for markers designed from genomic DNA sequences. In this study, 919 EST-based primers developed from seven grass species were assessed for their amplification across a diverse panel of 16 grass species including cereal, turf and forage crops. Out of the 919 primers tested, 89 successfully amplified DNA from one or more species and 340 primers generated PCR amplicons from at least half of the species in the panel. Only 5.2% of the primers tested produced clear amplicons in all 16 species. The majority of the primers (66.9%) were developed from tall fescue and rice and these two species showed amplification rate of 41.6% and 19.0% across the panel, respectively. The highest amplification rate was found for conserved-intron scanning primers (CISP) developed from pearl millet (91%) and sorghum (75%) EST sequences that aligned to rice sequences. The primers with successful amplification identified in this study showed promise in other grass species as demonstrated in differentiating a set of 13 clones of reed canary grass, a species for which very little genomic research has been done. Sequences from the amplified PCR fragments indicated the potential for the transferable CISP markers for comparative mapping purposes. These primer sets can be immediately used for within and across species mapping and will be especially useful for minor grass species with few or no available molecular markers

Nonperturbative renormalization group approach to frustrated magnets

This article is devoted to the study of the critical properties of classical XY and Heisenberg frustrated magnets in three dimensions. We first analyze the experimental and numerical situations. We show that the unusual behaviors encountered in these systems, typically nonuniversal scaling, are hardly compatible with the hypothesis of a second order phase transition. We then review the various perturbative and early nonperturbative approaches used to investigate these systems. We argue that none of them provides a completely satisfactory description of the three-dimensional critical behavior. We then recall the principles of the nonperturbative approach - the effective average action method - that we have used to investigate the physics of frustrated magnets. First, we recall the treatment of the unfrustrated - O(N) - case with this method. This allows to introduce its technical aspects. Then, we show how this method unables to clarify most of the problems encountered in the previous theoretical descriptions of frustrated magnets. Firstly, we get an explanation of the long-standing mismatch between different perturbative approaches which consists in a nonperturbative mechanism of annihilation of fixed points between two and three dimensions. Secondly, we get a coherent picture of the physics of frustrated magnets in qualitative and (semi-) quantitative agreement with the numerical and experimental results. The central feature that emerges from our approach is the existence of scaling behaviors without fixed or pseudo-fixed point and that relies on a slowing-down of the renormalization group flow in a whole region in the coupling constants space. This phenomenon allows to explain the occurence of generic weak first order behaviors and to understand the absence of universality in the critical behavior of frustrated magnets.Comment: 58 pages, 15 PS figure

Southeast Asia and the Politics of Vulnerability

The economic and political crises that have recently engulfed the countries of Southeast Asia provide a stark reminder of just how difficult the challenge of sustained regional development remains. In retrospect, the hyperbole that surrounded the 'East Asian miracle' looks overblown, and testimony to the manner in which rhetoric can outstrip reality, especially in the minds of international investors. Certainly, some observers had questioned the depth and resilience of capitalist development in Southeast Asia, but in the years immediately prior to 1997 such analyses tended to be in the minority. Now, of course, it is painfully obvious that much of Southeast Asia's economic and political development was extremely fragile. When seen in historical context, this outcome should not have been surprising since the countries of modern Southeast Asia, both as independent nations and as colonies of various imperial powers, have been highly vulnerable to the actions of powerful external political and economic forces. This paper will examine the economic bases and the political consequences of this vulnerablity, both domestically and at a regional level. I argue that the recent crisis has served as an unwelcome reminder of just how constrained, dependent and vulnerable the Southeast Asia region's development prospects remain, a situation that is exacerbated by, and which contributes to, domestic political crises

A origem das parcerias público-privada na governança global da educação

Durante a última década, a globalização da governança educacional por meio de parcerias público-privadas (PPP) tem gerado considerável debate quanto ao seu significado, propósito, status e resultados. Este debate é particularmente aquecido no setor da educação por causa da ampla aceitação da educação como atividade complexa, social e política que deve permanecer, em grande parte, se não totalmente, no setor público, servindo a interesses públicos. O artigo analisa a rápida expansão das parcerias público-privadas em educação (PPPE) articulada à introdução de regras de mercado no setor. Neste estudo nos concentramos sobre o papel de uma rede de desenvolvimento global, fundamental na globalização de um tipo particular de PPPE, indicando que a ideia de PPP encaixa-se em um projeto mais amplo de reconstituição da educação pública no âmbito do setor de serviços, a ser governada como parte da construção de uma sociedade de mercado.Over the past decade, the globalization and governing of education through Public Private Partnerships (PPPs) have generated considerable debate as to their meaning, purpose, status and outcomes. This debate is particularly heated in the education sector because of the widely-held view that education is a complex social and political activity that should remain largely, if not wholly, in the public sector serving public interests. The article analyses the rapid expansion of Education Public Private Partnerships (EPPPs) and the associated introduction of market rules into the education sector. We focus on the role of a key global development network in globalizing a particular kind of ePPPs, and show that the EPPP idea fi ts into a wider project of reconstituting public education as an education services industry to be governed as part of the construction of a market society