STUDIES OF IN-VIVO AND IN-VITRO GERMINATION ABILITY OF DRAGON FRUIT (Hylocereus undatus)

Dragon fruit (Hylocereus undatus) is a well-popularized fruit species incountries like Thailand, China and have a great potential for cultivation insemi-arid regions of Sri Lanka. Plant propagation studies have not beencarried out in Sri Lanka, and hence objective of this research was to study thein-vivo and in-vitro germination of Dragon fruit seeds and to select a suitablemedia for in-vitro establishment. Wet filter papers, wet sand, and wet coirdust were used to study the in-vivo germination and Hormone free, MSmedium, Anderson's Rhododendron medium, and McCown Woody Plantmedium incorporated with 1 g/l of activated charcoal was used to study invitrogermination. In-vitro germination percentage was higher (lOa % inAnderson, 98.5 % in MS, and 96 % in WP) when compared to seedsgerminated in in-vivo conditions (50 %in Filter paper method, 45 % in Sand,and 35 % in Coir dust). Seedlings germinated in in-vitro conditions showedhealthy vigorous growth and 15, 14, and 11 mm seedling heights wereobserved with fully opened cotyledons at the end of second week inAnderson, MS, and WP medium respectively. Though similar plant heights(l5±2 mm) were observed, appearance of the seedlings was very weak, andcotyledons had not fully opened under in-vivo conditions. In both in-vivo andin-vitro conditions root system development was similar and root formationwas observed within 6 days with 4±2 mm root length. Germination, plantheight, and appearance of plants were best in Anderson medium. Resultsrevealed that seeds could be successfully germinated in in-vitro conditionsusing Anderson medium supplemented with 1 mg/l activated charcoal as theestablishment medium

IN-VITRO CALLUS FORMATION OF RED SANDALWOOD (Pterocarpus santalinus L.) AS AFFECTED BY EXPLANT TYPE AND DIFFERENT LEVELS OF 2,4-D AND BAP

Pterocarpus santalinus is a valuable medicinal plant, now included in red listof endangered plants under IUCN guidelines. Distribution of this plant in SriLanka is very limited and the local demand for ayurvedic purposes is stillunreached. As conventional propagation techniques are not satisfactory,possibilities in in-vitro techniques seem to be promising, and callus culture isone aspect that has to be studied. Leaf parts, cotyledon parts, root segments,inter-nodal segments, and nodal segments from in-vitro seedlings were usedas explants. 2,4-D and BAP were used separately in six differentconcentrations (1 mg/l - 6 mg/l) for callus initiation Full strength MS medium(Murashige and Skoog, 1962) was used with 30 g/l of sucrose and 8 g/l agaras the culture medium. Callus formation could be observed in every explant.However, large clumps of creamy white callus were obtained from nodalsegments. Callus formation in root segments was very poor and showedbrown color. In nodal segments, callus formation was started within twoweeks and large clumps of callus were observed while slight swellin~occurring on root segments, leaf parts and in cotyledon parts at the end of 41week. Callus formation was best when the culture medium was supplementedwith 3 mg/l of BAP. Though callus formation could be observed in 2,4-D,amount of callus formed was poor. Present studies revealed that MS mediumsupplemented with 3 mg/l BAP is ideal for callus induction in Pterocarpussantalinus and possibility of using nodal segments as initial explants

INVESTIGATION OF VASE LIFE PACKAGE ON Codiaeum Variegatum CUT DECORATIVE SHOOTS

Croton is one of the exportable type foliage species in Sri Lanka. However,wilting of the leaves is a major problem raised in the export of these foliagespecies. In order to full fill the demand in world market, it is essential toovercome such problems.In this study, seven experiments were conducted at Green Farms (Pvt) Ltd.Marawila, to maintain the vase life of Codiaeum varigatum cv. 'Batik','Pictum', and 'gold star' cut decorative shoots and to retain their exportquality characters. Sugar (0, 1, 2, 4 & 5%), NiCh (250, 500, 750 &1000ppm), combination of sugar (2%) + KMn04 2ppm and glycerol (1, 5 and10%) were tested as treatments (vase solutions) in separate experiments.Treatments were arranged in complete randomized design with 3 replicateseach. Data were analyzed using SAS statistical method with analysis ofvariances. Mean separation was done using LSD on parametric procedures.Croton had ability to maintain vase life up to 3 weeks in preliminary studies.To comparison of different packing methods for vase life of croton, wetpaper packing showed higher vase life and higher leaf freshness for croton.Sugar treatments applied to "Pictum" and "Gold star" were maintained 21days of vase life. "Batik" showed only 17 days vase life (C.V. =7.750323).NiCh gave 18 days of vase life for "Batik" (CV = 11.04419) however it isharmful to human. According to the re-cutting & water changes, 4 dayscutting interval and 2 days water change was the best. Combination ofsucrose & KMn04 was maintained vase life vase life up to 14 days.Combination of Sucrose 2% + KMn04 2 ppm & Cotton plug was bestamong all sugar concentrations (C.V. = 10.90617). For this could maintainexport quality up to 19 days. "Pictum" & "Gold Star" were tolerant cultivars.Pure glycerol gave negative effects. All dilute glycerol concentrations (1, 5and 10%) were good post harvest treatments. Among those, 5% couldmaintain export quality of "Batik" cuttings up to 20 days. Combination ofwax + KMn04 + sucrose treatment gave negative effect. Pure wax withcommercial preservatives did not enhance the quality.

VASE LIFE STUDIES ON Dracaena reflexa CUT DECORATIVE SHOOTS

Wilting and color change of Dracaena leaves are major post harvestproblems in exportation. This study is an attempt to overcome these problemsand to improve vase life of Dracaena cut stems. Experiments were done atGreen Farms Ltd. Marawila to investigate post harvest handling of Dracaenareflexa to maintain export quality and freshness. Series of experiments wereconducted to investigate management practices; effect of glycerol solution(pure glycerol in 1,3 & 5hrs); effect of immersing one hour (using KMn04 2,5 & 10pmm); effect of sucrose solution (2, 5 & 10%); effect of KMn04 (2, 5& lOppm) for cultivars of Dracaena reflexa "Reflex a Green", "Song ofJamaica" and "Song of India". Treatments were arranged in completerandomized design with 4 replicates each. Data were analyzed using SASstatistical programme with analysis of variances. Mean separation was doneusing LSD on parametric procedures.The results revealed that wilting, color change and rotting, of Dracaenareflexa cultivars were not significantly affected by post harvest solutions ofKMn04 and sucrose compared to the control (tap water). However, pureglycerol (dipped for 1hr) and tap water maintained vase life of "Song ofJamaica" for 21days. Damaged cuttings showed Erwinia infection after 10-12days during vase period (CV = 05.628813). Results in general show avoidinginjury to specimens, and this helps to maintain the quality of the products.Many infections can be avoided by keeping the specimens dry. Experimentsproved that maximum vase life of Dracaena cuttings could be achieved bymaintaining proper management practices and sanitation conditions in a coldroom.

Costing of a Blended Course at the Open University of Sri Lanka: An Empirical Study

In a viable Open and Distance Learning system, providing immediate access to learning resources and fostering effective teacher-learner interactions are essential components while balancing the cost of the course without compromising quality. Owing to the advancement of ICT across the globe, the Open University of Sri Lanka has initiated integrating online components into the existing print-based courses and offering them as blended courses. The gauging costs for these blended courses are also vital to determine the various costs components. Hence, an empirical study was conducted to estimate total costs and cost per student of a blended course. In this empirical study, costing was carried out, based on five major costs categories; course materials design and development, course materials production, course delivery, student evaluation, overhead and infrastructure. Th

A Study of Time-Dependent CP-Violating Asymmetries and Flavor Oscillations in Neutral B Decays at the Upsilon(4S)

We present a measurement of time-dependent CP-violating asymmetries in neutral B meson decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The data sample consists of 29.7 ${\rm fb}^{-1}$ recorded at the $\Upsilon(4S)$ resonance and 3.9 ${\rm fb}^{-1}$ off-resonance. One of the neutral B mesons, which are produced in pairs at the $\Upsilon(4S)$, is fully reconstructed in the CP decay modes $J/\psi K^0_S$, $\psi(2S) K^0_S$, $\chi_{c1} K^0_S$, $J/\psi K^{*0}$ ($K^{*0}\to K^0_S\pi^0$) and $J/\psi K^0_L$, or in flavor-eigenstate modes involving $D^{(*)}\pi/\rho/a_1$ and $J/\psi K^{*0}$ ($K^{*0}\to K^+\pi^-$). The flavor of the other neutral B meson is tagged at the time of its decay, mainly with the charge of identified leptons and kaons. The proper time elapsed between the decays is determined by measuring the distance between the decay vertices. A maximum-likelihood fit to this flavor eigenstate sample finds $\Delta m_d = 0.516\pm 0.016 {\rm (stat)} \pm 0.010 {\rm (syst)} {\rm ps}^{-1}$. The value of the asymmetry amplitude $\sin2\beta$ is determined from a simultaneous maximum-likelihood fit to the time-difference distribution of the flavor-eigenstate sample and about 642 tagged $B^0$ decays in the CP-eigenstate modes. We find $\sin2\beta=0.59\pm 0.14 {\rm (stat)} \pm 0.05 {\rm (syst)}$, demonstrating that CP violation exists in the neutral B meson system. (abridged)Comment: 58 pages, 35 figures, submitted to Physical Review

Measurement of the Branching Fraction for B- --> D0 K*-

We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

Study of e+e- --> pi+ pi- pi0 process using initial state radiation with BABAR

The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18 +/- 0.19)% has been measured.Comment: 21 pages, 37 postscript figues, submitted to Phys. Rev.

Measurement of the B+ --> p pbar K+ Branching Fraction and Study of the Decay Dynamics

With a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the BaBar detector, we study the decay B+ --> p pbar K+ excluding charmonium decays to ppbar. We measure a branching fraction Br(B+ --> p pbar K+)=(6.7+/-0.5+/-0.4)x10^{-6}. An enhancement at low ppbar mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate Theta*++ decaying into pK+ in the mass range 1.43 to 2.00 GeV/c2 and set limits on Br(B+ --> Theta*++pbar)xBr(Theta*++ --> pK+) at the 10^{-7} level.Comment: 8 pages, 7 postscript figures, submitted to Phys. Rev. D (Rapid Communications

Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays

We present measurements of the branching fractions for the three-body decays B0 -> D(*)-/+ K0 pi^+/-$and their resonant submodes$B0 -> D(*)-/+ K*+/- using a sample of approximately 88 million BBbar pairs collected by the BABAR detector at the PEP-II asymmetric energy storage ring. We measure: B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4} B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 10^{-4} From these measurements we determine the fractions of resonant events to be : f(B0-> D-/+ K*+/-) = 0.63 +/- 0.08(stat) +/- 0.04(syst) f(B0-> D*-/+ K*+/-) = 0.72 +/- 0.14(stat) +/- 0.05(syst)Comment: 7 pages, 3 figures submitted to Phys. Rev. Let