Mitogen Activated Protein Kinase: Function and Responses to Different Stresses in Plants

Mitogen Activated Protein Kinase (MAPK) pathway is the most commonly studied signaling mechanisms, consisting of different groups of protein kinases that participate in regularly connecting interpretation of external stimuli that can change in gene expression or cellular organization within eukaryotic systems. The MAP kinase pathways functions in plants cell signaling (intra- and extra). MAPK cascades follow a response system. MAP kinases are the component of kinase constituents that deliver signals from sensors to responders in eukaryotes including plants. Several pathways are activated under different environmental stresses. Stimulating agents may be biological (biotic) like microbial infections or environmental (abiotic) like temperatures threshold, high salt concentration, drought, heavy metal, Ultra-violet radiation, ozone gases and reactive oxygen species (ROS). The involvement of MAPK signaling pathway in different stresses has been widely studied. In this review we also try to highlight MAPK cascades, its regulation, functions and recent findings in various cellular processes against stress conditions.

Phytosociological Attributes of Different Vegetational Zones of Nandiar Khuwar Catchment Area

This dissertation communicates an analytical exploration of the vegetational profile of Nandiar Khuwar Catchment area, District Battagram, Pakistan. The Nandiar Khuwar Catchment starting from the alpine pastures in the east and stretches towards the famous Indus River in the west. The area provides a variety of geo-climatic regimes within a sharp relief of 525-3817m with total land area of 1301km2. Based upon physiognomy of the vegetation, the study area was divided into 80 stands. Sum 324 vascular plants species belong to 97 families were recorded among which, 157 plant species medicinally important. The most diverse stand was Rajmira followed by Jaro in term of Shannon Diversity Index and Species Richness. The widely distributed species in the study area were Fragaria nubicola and Adiantum capillus-veneris recorded in 53 stands out of 80 stands. With respect to phenology, the maximum plant species flowered in April-July (68.5%) and maximum plant species showed fruiting in May-August. Among life form classes, phanerophytes were dominant with 118 (36.4%) followed by therophytes group with 82 (24.05%) species. The leaf size spectra were dominated by microphyll with 137 (40.2%) followed by mesophyll having 103 species i.e. 30.2%. The TWINSPAN classification sorted out vegetation of the area into 13 plant communities. Six sub communities were identified in subtropical zone, 4 in mixed Pinus roxburghii and Pinus wallichiana forests, 5 in pure Pinus wallichiana forests, 4 in western mixed coniferous forests, 3 in pure Abies pindrow and Picea smithiana forests and 2 plant communities were identified in alpine zone. The index of similarity was maximum (35.7%) for Wikstroemia, Viburnum, Androsace and Juniperus, Sibbaldia, Primula communities. Ordination analyses of the data provided a compositional response with a gradient of 6.4 SD units long. The total variance (inertia) in the species data was 7.07. Bray-Curtis ordination score was maximum for axis 1 (0.96) having regression coefficient -54.1 and variance in distance were 2.5. Detrended Correspondence Analysis (DCA ordination) produced a maximum gradient length of 6.3 recorded for axis 1 with eigenvalue of 0.71. DCA clustered xv different species having similar habitats and different stands having common species. The Canonical Correspondence Analysis (CCA ordination) showed that plant species and stands were in linear combination with environmental variables. Acacia modesta and Ficus carica was positively correlated with temperature. Betula utilis, Juniperus communis, Ciminalis karelinii and Wulfenia amherstiana species were negatively correlated with temperature. Conservation status of the plants species recorded for the area showed that 10 species fall under critically endangered and 12 more species fall under endangered categories. Major threats recorded for the flora were habitat losses, excessive logging, selective and unscientific collection of herbs, over grazing, erosion, environmental changes and introduction of exotic taxa. We concluded that Nandiar Khuwar Catchment has great potential for conservation of the native species of the Western Himalayan Ecoregion. The conservation issues needs to be addressed through devising strategies for protection, recovery and rehabilitation of the threatened species within their respective stands.