Variations in bark thickness and sapwood density of Calophyllum inophyllum provenances in Australia and in Sri Lanka

Sapwood density and bark thickness of Calophyllum inophyllum L. （a multipurpose durable timber species） were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4–15 mature trees having girth at breast height over bark （GBHOB） at 100–150 cm were selected on the basis of the population size. Significant （p0.05） hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influenced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sapwood density are likely to be governed by genotypic variations.

Effects of variation in seed sources and pre-sowing treatments on seed germination of Tamarindus indica: a multi-purpose tree species in Bangladesh

We investigated the morphology and germination of Tamarindus indica seeds in order to discover the ef- fects of variation in seed sources and pre-sowing treatments on germination. The experiment was carried out in the nursery of the Forestry and Wood Technology Discipline, Khulna University, Bangladesh. Seeds were collected from different but healthy trees from various locations in Bangladesh and subjected to four pre-sowing treatments, i.e., control, immersion in cold water （4℃ for 24 h）, immersion in hot water （80℃ for 10 min） and scarification with sand paper. Seed germination was carried out in poly-bags with a mixture of topsoil and cow dung in the ratio of 3：1. The average length of the fresh seeds was 1.35 ＋ 0.26 cm, their width 1.07 ＋ 0.20 cm and thickness 0.69 ＋ 0.11 cm. The results revealed that pre-sowing treatments affected the germination process of seeds, which significantly increased the germination percentage with the cold water （81.67%） and scarification with sand paper （82.33%） treatments, compared with those in the control （58.33%） and hot water treatment （59.00%）. In all treatments germination started on average within 5 to 7 days after the start of the treatments and were completed from 13 to 19 days later. The greatest success in germination （82.33%） was found in scarification with sand paper, followed with 81.67% in the cold water treatment. The results of analyses of variance （ANOVA） showed significant differences （p 〈 0.05） in germination closing dates, seed germination periods and germination percentages among the treatments but no significant difference among seed sources. However, the effect of the interaction between seed source variation and pre-treatment differed significantly in seed germination closing dates and germination percentages. We recommend cold water treatment （submersion of seed at a temperature of 4℃ for a 24-h period） for seed germination of T. indica in rural Bangladesh.

Seed germination of Albizia procera(Roxb.)Benth.in Bangladesh:a basis for seed source variation and pre-sowing treatment effect

An experiment in seed morphology and seed germination techniques of Albizia procera was carried out in the nursery of the Forestry and Wood Technology Discipline, Khulna University, Bangladesh in order to discover the source variation in seeds and pre-sowing treatment effects on seed germination. Mature seeds ofA. procera were collected from healthy trees in home garden plan- tations from five different districts in Bangladesh and treated with four pre-sowing treatments, i.e., control, immersion in cold water （4~C for 24 h） and immersion in hot water （80~C for 10 min and 100~C for 1 min）. The average length, width and thickness of seeds were calculated as 0.502 ＋ 0.485, 0.420 ~ 0.060 and 0.191 ~ 0.118 cm, respectively. Germination was conducted in poly-bags with a mixture of topsoil and cow dung in a ratio of 3：1. The results revealed that pre-sowing treatments affected the rate of germination of seeds, which significantly increased the germination percentages of seeds in hot water treatments compared with those in control （60.60%） and the cold water treatment （4℃ for 24 h, 63.53%）. The highest germination success was 82.07% in the treatment of im- mersion in hot water （80℃） for 10 min, followed by 79.00% in immersion in hot water （100℃） for l rain. Germination started 4 to 6 days after seed sowing and completed in a period of 22 to 25 days in all treatments. ANOVAs showed statistically significant dif- ferences （p 〈 0.05） in seed germination starting dates, closing dates, germination percentages and rates of germination among treat- ments, but no significant differences in seed germination starting dates, closing dates, germination period, germination percentages and rates of germination among the seed sources. The study also revealed that the interaction between seed source variation and treat- ment effect significantly differed in seed germination starting dates, closing dates, germination percentages and rates of germination. The hot water （100℃ for 1min） treatment is recommended for seed germination ofA. procera in rural Bangladesh.

Differentiation of Seed Germination and Early Seedling Growth in Ten Provenances of Eucalyptus Microtheca

An investigation of seed germination and early seedling growth of Eucalyptus microtheca was based onseed collection from 10 widely,separated provenanes in Australia. Genetic variation of seed germination and carly seedling growth was observed among a series of provcnances whose natural habitats range from different climatic condition Inthe ten provenances, both the model of seed relative germination percentage and the model of seed total germination percentage fitted Logistic regression [y=a/(1+exp(-cx+b))]. In comparison with provenanccs from four high temperature (meanannual maximum temperature >30.0 ℃: mean annual minimum temperature > 17.0 ℃) areas, six low temperature (meanannual maximum temperature <30℃, mean annual minimum temperature <17.0 ℃) areas showed the thst genninationrate and the high total germination percentage, For each provenance we have 45 seedlings equally divided into three watering levels (100%, 50%. and 25% of field capacity), and studies on relationship between early seedling growth and climaticfactors of the natural habitat of provenance. In control treatment. height growth of the seedling has beeb associated with intrinsically the driest quarter precipitation in the seed collection areas of provenance. In all the treatments, length growth ofthe biggest Ieaf of the seedling was related to mean annual maximum temperature and mean annual minimum temperaturein origin of provenance. In contrast, basal diameter growth of the seedling was related to mean annual minimum temperature of the seed collection areas in water stress treatment. From an ecological viewpint, the fast germination rate and thehigh total germination perecntage of the seed and rapid early grouth of the seedling appear to bc favourable adaptations tothe climatic conditions prevailing in the natural habitat of provenance.