Musharaf Khan

Vegetation structure in summer of Tehsil Takht-e- Nasrati plains, district Karak, Pakistan

Community structure is a key marker of long-term vegetation change in ecosystem. In the present investigation, 11 plant communities were recorded in plains area. The cluster analysis gives rise to 5 groups on the basis of important value and 4 groups on basis of soil. The vegetation changed with change of distance. As a whole in plains, the CZS community was developed. There were 6 tree, 7 shrub and 19 herb species. The Importance value contributed by three dominants species was 79.5. The contribution by tree was 50.6, shrubs (IV = 62.06) and herbs (IV = 187.3). The soil texture was found from sandy clay to sandy clay loam. These results emphasize the continuous need for long-term groundbased ecological monitoring in conjunction with satellite-based monitoring of changes in vegetation cover.

Classification and ordination of vegetation in Tehsil Takht-e-Nasrati, District Karak, Khyber Pakhtunkhawa, Pakistan

Ordination techniques are commonly used in phytosocio-logy. This may be done either by arranging the points along the axis or by forming the scatter diagram with two or more axis. Detrended Correspondence Analysis (DCA) is an indirect gradient analysis technique in which the distribution of species is not controlled by environmental variables rather, it focuses on analyzing the pattern of species distribution. Environmental data for DCA is not required and species data is used to assume the gradi-ents (Sagers and Lyon, 1997). Ordination techniques are widely used by the ecologists to study the relationship between vegetation and environment. Khaznadar et al. (2009) conducted a study in Chott El Beida wetland, a RAMSAR site in Setif, Algeria to study distribution of plants community and environmental factors. The collec-tion was done from sixty vegetation plots. TWINSPAN and DCA were used as the analysis techniques. A similar study was conducted by Ahmad et al. (2010) along motorway (M-2), Pakistan using multivariate techniques, that is, DECORANA. Results showed two major and six-teen sub-communities from 397 quadrats. The study was helpful for implementation and conservation planning and for the improvement of road sides. To study the rela-tionship between vegetation and environment, a study was conducted by He et al. (2007) in the Alxa Plateau of Inner Mongolia, China which resulted in the detection of six characteristics vegetation groups by using the DCA. Ahmad (2009) studied the herbaceous vegetation in Margalla Hills National Park, Islamabad, Pakistan. Four vegetation groups were recognized by TWINSPAN. El-Bana et al. (2009) studied

Inhibitive effects of Chrozophora obliqua (del.) juss. on germination and seedling growth of cultivated species

The allelopathic influence of aqueous extracts of Chrozophora obliqua on the germination and seedling growth of Pennisetum typhoides (Bajra) have been determined. It was eminent that 10 g aqueous extracts of leaves and 48 h treatment present inhibitory effect on germination percentage, radical length and number of seminal roots and the cause was found significantly higher than that recorded in the stem and control treatment. The inhibitory effects were increased proportionally with increasing extract concentration and soaking duration. The only exception was observed in the 5 g concentration of leaves that decreased the plumule length. These findings indicate that P. typhoides sown in fields which had leaf and stem litter of C. obliqua will be adversely affected regarding germination, growth and ultimately resulting in lower yield.