StatusThe thesis was presented on the 18 March, 2010
Approved by NCAA on the 3 June, 2010
Abstract– 0.50 Mb / in romanian
The peculiarities of adaptation to the dry weather of some plants of iso – and anisohydric type and the effect of the salicylic acid ”. Thesis of doctor in Biology, Chisinau, 2010. 90 pages. Thesis structure: introduction, 4 chapters, conclusions, practical recommendations, 294 bibliography sources, 14 tables, 30 figures and 6 annexes. Obtained results have been published in 16 scientifical works.
The aim of the work was to outline the peculiarities of regulation of the status of the water of the plants with different adaptation strategies to dryness and to determine the mechanisms which contribute the efficiency of the water under the conditions of insufficiency of humidity.
Methodology of scientific research: the complex approach of the processes that take part to the self-regulation of the water to different level of organization of the plants (cops), as well as outlining the conditions of external optimization of the functional status, of the growth and productivity of the plants under the conditions of dry season.
Scientific innovation: We established distinct differences in the capacity of self-regulation of the status of the water of isohydric (Zea mays L.) and anisohydric (Sorghum bicolor L. Moench) plants under dry conditions. The physiological basis of tolerance to dryness of the anisohydric plants is determined by the high capacity of water homeostasis, insured by the compensation of the consumed water at transpiration from the account of the absorption activity of the radicular system, by maintaining the hydraulic conductibility and the flux of the water to the leaves, the osmotic potential, the hydrostatic pressure, the high capacity of retaining the water into the tissues, the conductance of the stomatal apparatus. There were stated relevant differences according to the morphologic character which are adaptable to iso- and anisohydric plants: the reduction of the surface of evaporation through the senescence of the inferior leaves (the corn) and of the lateral scions (sorgho), the rolling leaves (corn), cutinization and exhudation to the silicium oxides (sorgho). We proved that the salicylic acid and the salicylates (NH4+ , K+ , Mg++ ) take part in the regulation of the status of the water and also induction of the mechanisms of plants of tolerance to dry weather by modulating the absorption, the hydraulic conductibility, increasing the resistance of the stomata and the intensity of transpiration. These adaptive modifications are oriented to the maximum efficiency of water consume in the productiviry. The processing of the seeds before sowing and sprinkling of plants foliar apparatus with salicylates induce the increasing of organism tolerance to the negative factors that are acting in the future, fact that is accompaned with increasing plants growth and productivity.
Theoretical significance: The finding of the mechanisms of water status selfregulation in iso- and anysohidric type of plants is completing the scientific knowledge in the field of the physiology of stress, adaptation, and resistance of vegetal organisms in a non-favorable environment. This can serve as a scientific basis for elaboration the diagnostic programs and procedures of exogene control of the tolerance, growth and development, and as well increasing plants productivity.
The applicative value of the research. On the grounds of the established principles concerning the effect of the salicylates on the parameters of the water status in plants under dry conditions, five procedures of optimization the resistance, growth and productivity of plants under the conditions of deficiency of humidity have been elaborated (MD no. 3391, 3438, 3439, 3466, 3495).
The application of the scientific results The elaborated procedures can be applied in agriculture for increasinge the plants resistance productivity to non-favorable conditions