Flowering event of Johannesteijsmannia lanceolata: An understorey palm in the Angsi Forest Reserve, Malaysia

The flowering event of an understorey palm; Johannesteijsmannia lanceolata J. Dransfield was investigated in the Angsi Forest Reserve, Malaysia for a total period of 18 months. The study commenced from the appearance of the inflorescence until the fall of mature ripe fruits. Results showed that the flowering phase lasted between 8.7 to 9.4 months and of the 1086 - 2150 fruit sets produced per inflorescence, only 5 - 8 fruits (of 3.5 - 5.0 cm diameter) reached maturity. 71% of the 24 adult trees produced new inflorescences within the study period, with 1.4 inflorescences per plant per year which gives 7 - 11 fruits per plant per year

In vitro induction and proliferation of protocorm-like bodies (PLBs) from leaf segments of Phalaenopsis bellina (Rchb.f.) Christenson

An in vitro culture procedure was established to induce protocorm-like bodies (PLBs) from leaf segments of the Phalaenopsis bellina (Rchb.f.) Christenson directly from epidermal cells without intervening callus on ½ strength modified Murashige and Skoog (MS) (in Physiol Plant 15:473–497, 1962) medium supplemented with 1-Naphthaleneacetic acid (NAA; 0, 0.1, 1 mg/l) and Thidiazuron (TDZ; 0, 0.1, 1, 3 mg/l). The best response was established at 3 mg/l TDZ which induced 78% of leaf segments to form a mean number of 14 PLBs per explant after 16 weeks of culture. No PLBs were found when leaf segments were cultured on ½ strength modified MS media supplemented with 0.1 and 1 mg/l NAA. The best induction percentage for auxin: cytokinin combination was at the combination of NAA and TDZ at 1.0 and 3.0 mg/l which gave 72% induction with 9 PLBs per explant. Semi-solid ½ strength MS and liquid Vacin and Went (VW) (in Bot Gaz 110:605–613, 1949) medium were used in order to find the highest survival and number of PLBs proliferation after 3 months in culture. Half strength MS showed an average of 9 PLBs in comparison with VW with an average of 5.3 PLBs per explants. Histological observations revealed that the regenerated PLBs were generally formed from the epidermal layers of the posterior regions of the leaf segments. Scanning electron micrograph of PLBs showed the origin of newly formed PLB from the peripheral region of leaf segments

Direct pathway for sticking/desorption of H2 on Si(100)

The energetics of H2 interacting with the Si(100) surface is studied by means of ab initio total energy calculations within the framework of density functional theory. We find a direct desorption pathway from the mono-hydride phase which is compatible with experimental activation energies and demonstrate the importance of substrate relaxation for this process. Both the transition state configuration and barrier height depend crucially on the degree of buckling of the Si dimers on the Si(100) surface. The adsorption barrier height on the clean surface is governed by the buckling via its influence on the surface electronic structure. We discuss the consequences of this coupling for adsorption experiments and the relation between adsorption and desorption.

Association of seed colour with germination, physical and physiological growth of oil palm (Elaeis guineensis) seedlings

In commercial Dura x Pisifera (DxP) seed production, white-coloured seeds are perceived as abnormal despite lack of scientific evidence to support this. This study evaluates different seed colour (black, semiwhite and white) during germination and nursery evaluation. Four replications of 10 seeds were used for the evaluation of seed characteristic. Seed germination was conducted using four replications of 100 seeds by subjecting the seeds to 60 days of heat-treatment followed by germination at 30ºC. Thirty pre-germinated DxP seeds per replication were then transferred into the nursery for morphological, physiological and growth assessment at three months interval until 12 months after sowing. Germination test shows all seed types indicated similar germination percentage (more than 78%) and speed (13-15 days of mean germination time). Nursery assessment shows black seed indicated higher overall biomass within the first three months, however, no differences in growth were observed from six until 12 months after sowing. Physiological evaluation including net photosynthesis (5.3-18.13 µmol CO2 m–2 s–1), stomatal conductance and transpiration rate were similar among the seedlings produced by seeds differing in colour. Hence, seed colour does not implicate abnormality and should not be discarded for the purpose of seed production