Screening of some indigenous herbal dyes for use in plant histological staining

The efficacies of some indigenous herbal dyes for use in staining plant materials were examined to obtain non-toxic, eco-friendly and cheap stains for use in plant histology. Dye extracts from Bixa orellana, Curcuma domestica, Lonchocarpus cyanescens and Pterocarpus osun were used to stain wood sections using the existing standard staining procedures with little modification. All the extracts had affinity for the fibre and vessel elements except the extract from L. cyanescens. The extracts from C. domestica and B. orellana had higher selectivity than those ofP. osun for fibre. From the results of the absorbance curves, each of the dye extracts from all speciese had minimum of two peaks, indicating that they had two or more colour imparting chromophores except dye extract from C. domestica. All the dye extracts were acidic with pH range of 3.77 to 6.77. Therefore, this study shows that dye extracts from B. orellana, C. domestica and P. osun could be solitarily or in combination with artificial dyes for plant histological staining.

Rate of timber production in a tropical rainforest ecosystem of Southwestern Nigeria and its implications on sustainable forest management

Timber harvesting data are very essential for sustainable management of forest resources.These data are very scarce in developing countries.Therefore,we collected and analyzed data on the rate of timber production of the free areas and the forest reserves in Ondo State,Nigeria.The data collected from the State Department of Forestry＇s official records,annual reports and files were on the species,volume and number of different economic timbers exploited on monthly basis between 2003 and 2005.Analyses were done with the student t-test and one-way analysis of variance.Results reveal that the highest numbers of species,families and stems were exploited in the free areas when compared with what was exploited from the reserves for the three-year period.However,the total volume of trees removed from the reserves was significantly higher（p〈0.05） than what was removed from the free areas.A total 60 different indigenous hardwood species in 25 families were exploited from the free areas,and 57 in 23 families from the reserves.The total number of stems exploited from the forest ecosystem of Ondo state during the three-year period stood at 111377 with an estimated volume of 295089.67 m^3.While the mean number of stems and volume exploited per annum is 37125 and 98363.22 m^3,respectively.The monthly average number of stems and volume is 3094 and 8196 m^3,respectively.The t-test results show that there were significant differences（p〈0.05） in number of stems and volume removed from the free areas and the reserves.The ANOVA results reveal a significant increase（p〈0.05） in logging activities between the years of 2003 and 2004 but there was a decline in year 2005.This trend reveals that economic timber species were disappearing from the forests and the ecosystem was seriously disturbed during logging activities.Principles for achieving the goals of sustainable forest management（SFM） and urgent conservation measures to mitigate the consequences of forest degradation were suggested.