Vegetation zonation along the geological and geomorphological gradient at Eastern slope of Sulaiman range, Pakistan

The vegetation of gypsiferous strata of Sulaiman range (30°33/ N to 30°41/30// north latitude and 70°32/ E to 70°41/30// east longitude, annual rainfall more than 100 mm) was analyzed using ordination (DECORANA) and classificatory cluster analysis techniques. Four plant associations were recognized in the study area. The application of the classification to the ordination allowed an interpretation of vegetation distribution in terms of topography and redistribution of rainwater, the nature of soil, bed rock and geological strata. The pattern of plant communities along the first ordination axis suggested that beside the landscape, substrate plays an important role in determining the boundaries between the plant communities. The assessment of the floristic suggested that there were three classes of plants: first there are plants of alluvial sandy plains (psymophytes), secondly; those of permanent water courses (hydrophytes) and thirdly, there are plants that grow on rocky hard strata (xerophytes/lithophytes). The observed pattern in available soil calcium seems related to long term redistribution of water that occurs during rainfall events because soil calcium, magnesium and moisture content have similar distributions along the transect. High calcium content for rocky strata was due to its parent geological gypsiferous formation. Although the boundaries across the landscape were associated with down slope movement of water, soil particles and cations, it was difficult to assess the relative importance of these factors in comparison with landscape level. The vegetation patterns revealed are discussed in relation to environmental factors and problems of plant assemblage in vegetation of the area.Key words: Vegetation analysis, plant communities, Sulaiman range, Pakistan

Consistent association of fungus Fusarium mangiferae Britz with mango malformation disease in Pakistan

Mango malformation disease (MMD) deforms the natural shape of panicles and shoots. The disease incitant is of great concern due to its complexity and mode of infection. Recently, a new species Fusarium mangiferae Britz was confirmed as the etiological agent of MMD in African and Asian clade. There was a need to confirm the fungus in other Asian countries. We investigated the association of F. mangiferae with malformed branches of five exotic and five indigenous cultivars of Mangifera indica L. in Pakistan. F. mangiferae proved to be the dominant fungus hosting majority of the malformed tissues. Among the indigenous cultivars, maximum tissue infection of 96.66% was found in cultivar Anwar Rataul and minimum was found in cultivar Late Chaunsa (48.33%). In exotic ones, maximum and minimum infections of 97.33 and 70.67% were noted in the cultivars Sensation and Pop, respectively. Light and transmission electron microscopy proved helpful in investigating the morphological matrix and ultrastructure of the propagules of fungus F. mangiferae.Key words: Mangifera indica, microconidium, Pakistan, tissue assay, transmission electron microscopy