Mosses of Mt. Trus Madi, Sabah, Malaysia

A species list of mosses collected in Mt. Trus Madi, Sabah, between 10 September and 10 October 1996 is presented. A total of 153 taxa were collected, of which 11 are new to Borneo and five new to Sabah

Effect of Salicylic Acid on the Early Development of the Chick Limb-Bud

Transplanted hind limb-buds of chick embryos were treated with salicylic acid. Treatment with this chemical caused reduction in length, weight and volume of the developing limb-buds. A side effect observed was an apparent loosening of the basal membrane and examined with regard to length, weight, and volume. The above observations are discussed in relation to the different hypotheses of the ectoderm-mesoderm interaction. The physiological role of the basal membrane, as well as the possible implications of the basal findings to the question of limb development and morphogenesis, are also discussed

Effect of water temperatures and seed weights on the germination of black plum (Vitex doniana sweet) seeds

Vitex doniana is an underexploited indigenous tree species with enormous potentials. Investigation was conducted in Federal College of Forestry Mechanization, Afaka, Kaduna during dry season of 2018 to overcome problems associated with germination of Vitex doniana seeds. Effect of temperatures of water (27, 56, 73 and 96oC) and seed weights (3.3, 1.4 and 1.2 g) on the germination of V. doniana was laid down in a split-plot experimental design with five replications. Interaction of temperatures of water and seed weights significantly (P<0.05) enhanced the germination of V. doniana seeds. A significant germination percentage of 46.67 % was recorded in seeds soaked in 56 oC water. Germination percentage among the seed weights were not significantly (P<0.05) different. The least mean germination time of 12 days was recorded in 1.2 g seeds soaked in 73 oC water for 45 minutes. A significant germination percentage value of 80 % was recorded in 3.3 g seeds soaked in 96 oC water. Soaking of 3.3 g seeds in 96 oC water enhanced the germination of V. doniana. The study therefore recommends soaking of 3.3 g seeds in 96 oC water for 45 minutes.Keywords: Temperature of water, Seed weights, Germination, Indigenous fruit tree specie

Effect of periods of hydro-priming and seed weights on the germination of Vitex doniana sweet seeds

There is paucity of information on breaking the dormancy of Vitex doniana through hydro-priming. Hydropriming is the method of ensuring uniform and high germination percentage, by soaking seeds in water and follow by drying of seeds, while the emergence of radicle is prevented. There is need to determine the appropriate periods of hydropriming to prevent over or under hydro-priming of seeds. In light of this, investigation was conducted on the effect of periods of hydro-priming and seed weights on the germination of V.doniana seeds. To assess the effect of periods of hydropriming (0, 6, 12, 18, 24 and 36hrs) and three seed weights (1.2, 1.4 and 3.3g) on the germination of V.doniana seeds, a split-plot experimental design with five replications was employed. Result revealed that periods of hydropriming significantly (P<0.05) enhanced the germination of V.doniana. A significant germination percentage value of 50% was recorded in seeds hydroprimed for 36hours. Germination percentage of seeds increased with the increasing periods of hydropriming. Highest germination percentage value of 40% was recorded in average seed size of 1.4g A significant germination percentage of 100% was recorded in 1.4g seeds hydro-primed for 36hours. Least mean germination time of 8days was recorded for 1.4 and 3.3g seeds. Hydro-priming of 1.4g for 36hours enhances the germination percentage of V.doniana seeds. The study therefore recommends hydro-primng of 1.4g seeds for 36hours for mass production of its seedlings for agro-forestry systems.Keywords: Dormancy, Soaking and drying of seeds, Pre-sowing treatment, Germination, Agro-forestry specie

MAT-720: EFFECT OF PORE STRUCTURE ON CONCRETE DETERIORATION BY PHYSICAL SULPHATE ATTACK

Repeated crystallisation of salt minerals has been considered as the driving force for surface scaling of concrete exposed to physical sulphate attack. This damage is initiated when stresses induced by the internal pressure created via repeated salt crystallisation exceed the tensile strength of the concrete. The degree of such damage will depend mainly on the structure and connectivity of pores, which control the penetration of sulphates into the concrete. Several factors affect the pore structure including the concrete constituents, mixture proportions and the curing process. Therefore, in this paper, the effect of the pore structure on concrete deterioration by physical sulphate attack was investigated. Results show that the durability of concrete against physical sulphate attack can be controlled by tailoring the pore structure of the concrete surface

Energetic proton spectra in the 11 June 1991 solar flare

The June 11, 1991 gamma-ray flare seen by the Compton Gamma-ray Observatory (CGRO) displays several features that make it a dynamic and rich event. It is a member of a class of long duration gamma-ray events with both 2.223 MeV and greater than 8 MeV emission for hours after the impulsive phase. It also contains an inter-phase between the impulsive and extended phases that presents a challenge to the standard gamma-ray line (GRL) flare picture. This phase has strong 2.223 MeV emission and relatively weak 4.44 MeV emission indicative of a very hard parent proton spectrum. However, this would indicate emission greater than 8 MeV, which is absent from this period. We present the application of new spectroscopy techniques to this phase of the flare in order to present a reasonable explanation for this seemly inconsistent picture