Concerning the prospects of quantitative valuing of leaf surface functional activity for different plants

The following paper discusses the problem of ecophysiological indicators evaluation and comparison for trees foliage formed in dynamic environment conditions. In addition to the already used methods of leaf parameters screening we propose to use one more indicator, characterizing foliage functional activity. In these aims, after performing some analytical procedures with leaf mass samples, some calculations must be made allowing to determine the quantity of active components (for instance, photosynthetic pigments, ash, etc.), per unit of leaf surface area. The prospects of proposing parameter use seem to be fruitful for a variety of purposes, including: - analysis of the seasonal dynamics features of the leaf metabolic activity; - comparison of ecophysiological characteristics of various plants (species and varieties, local and introduced objects); - reactions to stress factors, a comparison of various objects in resistance to stress. The article bases on the original data relating to the vegetation period of 2013-2015. The leaf mass samples were taken: for wild tree or shrub species - in the Krasnosamarsky forests, for fruit crops - in the gardens of Samara regional research institute «Zhiguliovskye Sady», for exotic tree and shrub species - in the dendrarium of the Botanical Garden of the Samara University. The leaf samples treatment mass procedure was performed according to the algorithm previously developed. In general, all aforementioned objects demonstrated more smooth dynamics of pigments component content per surface area unit than per mass unit. This situation seems to be connected with age-related changes of the leaf blades, saturated during the vegetative period with a certain amount of «ballast» substances or osmotically active compounds during stress periods, and so forth. The screening of photosynthetic surface unit quality allows us to note that the plants maintain a certain level of the metabolic activity of the leaf during variable weather conditions, producing a rapid «adjustment» pool of photosynthetic pigments on the basis of specific and varietal characteristics of their ecological plasticity.