The effect of several environmental factors on germination of medicinal herb Centella asiatica was investigated. Freshly harvested seeds of C. asiatica did not germinate even after gibberellic acid (GA3) treatment and exposure to different treatments with light qualities, while two-three months old seeds exhibited germination (82%) without pre-treatment at warm environment (25 -30ºC). GA3 treatment induced germination by two weeks earlier than in control. Germination was significantly (p=0.001) higher in red and white light than in blue and far red light. In addition, germination of C. asiatica was sensitive towards the salt stress and was significantly inhibited at 6500 ppm NaCl. The leaf leachates from invasive weeds Chromolaena odorata, Ageratum conyzoides, Parthenium hysterophorus and Xanthium strumarium showed inhibitory effects on seed germination of C. asiatica. Parthenium hysterophorus had significant effect (p<0.001) on seed germination. These data contribute for the establishing of an efficient protocol for C. asiatica cultivation.

Centella asiatica is an important medicinal plant of subtropical to tropical region. It grows widely, in different habitats. In Nepal, it is distributed at an altitudinal range of 96-2200 m above sea level. A comparative quantitative analysis of chemical constituents in Centella asiatica samples collected from three different habitats in Nepal was carried out by HPLC to evaluate the variability in the important constituents. There was marked variability in asiaticoside, asiatic acid and quercetin 3-O-glucuronide content among the samples collected from different habitats. Samples collected from open agricultural land showed the highest asiaticoside (1.91%), asiatic acid (0.13%) and quercetin 3-O-glucuronide (0.35%) content. Therefore, open land is preferable for plantation of this species for high yield of secondary metabolites. Key-words: Asiaticoside; asiatic acid; Centella asiatica; HPLC; medicinal plants; quercetin 3-O-glucuronide. DOI: 10.3126/botor.v7i0.4372Botanica Orientalis – Journal of Plant Science (2010) 7: 43-47

Four community-managed Sal forests in Dadeldhura district of Nepal were selected for the assessment of carbon stock. The stratified random sampling method was applied to measure the field data from 105 sample plots of 100 m(2). The carbon stock of trees and shrubs was estimated using Chave allometric equations for moist forests. The study found that the community forests stored carbon stock ranging from 148.5 to 202.3 Mg ha(-1)(mean: 175.5 Mg ha(-1)). The community forests managed for a longer duration have higher carbon stock than the community forests managed for a shorter duration. From the study, it can be concluded that these forests have been acting as a storehouse of the carbon. So, we can infer that community management has had a positive impact on increasing the carbon stock of forests and thus on the mitigation of global climate change. This study contributes to the understanding of the role of community forests in mitigating the effects of global climate change.