Salt resistant plants are able to exclude Na+ in a selective manner from their plasma membrane during initial phase of salinity which is encountered during first phase . Cell membranes are selectively permeable and can undertake transport of ions against the gradient. When the plants encounter salinity , a signal is percieved in plants and they try to accummulate osmolytes to balance the higher concentraions outside the call cytoplasm and also undertake exclusion of Sodium through cell membrane . ATPase plays an important role in this process as demonstrated by Professor Dr Sven Schubert and his group from Institue of Plant Nutrition Giessen Germany. However how do the plants perceive that the salinity outside the plant has increased.

Sodium promotes life activities and its low levels cause loss of memory in humans . In C4 plants its needed for metabolism also. How does sodium regulate in positive and negative manner. Can it replace Calcium I dont know may be you can tell

Cell membrane composed of lipids is impermeable to glucose which is a polar compound. Transport of glucose across the cell membrane requires a carrier protein located in cell membrane. In plant system it is triose phosphate which is transported across the chloroplast . Availability or lack of Pi determines the transport of metabolites across chloroplast besides other factors. Cell membrane also has Na anti-porters. ATPase have some important role to play in it.

If only you could visit the new Barcelona airport and see the shops you will hardly notice any signs of recession. I was much impressed by the designs of ladies purses displayed in window which had some freshness and mixture of clours.

Bacteria perhaps have smallest chromosomes in organized fashion though they lack nuclear membrane.

Nature has well knit system of biodiversity. Microbes that thrive on dead organic matter and decompose it to its elements are a sort of sanitary inspectors of nature. Dead animals, plants, organic food remains are acted upon by such microbes. Due to their differential activity on organic food they have also been tamed to undertake selective degradation, up gradation modification of food items turning them into cheese, vinegar, alcohol etc. Other microbes are helpful in nitrogen fixation, phosphorus solubilization, and mineralization of elements. Nitrogen fixing bacteria in symbiotic and non symbiotic mode are important for agriculture.