Impact of gibberelic acid and tebuconazole on formation of the leaf system and functioning of donor – acceptor plant system of solanaceae vegetable crops

Abstract

We studied the comparable effect of gibberelic acid and tebuconazole on morphogenesis, mesostructure formation and redistribution of flows in sweet peppers and tomatoes. It has been found that the use of gibberelic acid and tebuconazole retardant during budding leads to increased plant productivity due to optimization of the structure and operation of the plants’ leaf apparatus. It was established that both gibberelic and antigibberelic tebuconazole drug stimulated the formation and functioning of the photosynthetic apparatus of peppers and tomatoes, but the mechanisms of this regulation were different. Increased photosynthetic activity of plants under the influence of gibberellin was determined primarily by the formation of more leaves and total leaf surface. When using tebuconazole retardant there was a significant restructuring of the organization of leaf mezostructure: the leaves were thickened by chlorenchyma proliferation, there was an increase in the volume of columnar parenchyma cells and linear dimensions of spongy parenchyma leaf cells. The surface density of leaves significantly increased, the chlorophyll content and nitrogen content (especially protein) also increased, compared with control variants and variants using gibberelin. Such a profound restructuring of the photosynthetic apparatus in plants under the actions of tebuconazole led to a significant increase in donor leaves function of peppers and tomatoes, which is an indicator of the growth of net productivity of photosynthesis – the highest among all the variants of the experiment. The results also show that increasing the chlorophyll phytocenotic index was more significant than the increase of leaf index: the tomatoes under the action of tebuconazole had a lower leaf index than in control options, but due to a higher chlorophyll index the crop productivity increased.Since during the fruiting period the costs of assimilates to the growth of vegetative organs are greatly reduced, optimization of photosynthetic apparatus in pepper and tomato plants led to the laying of more fruit per plant and increasing crop yield. The analysis of the mass ratio of the researched vegetative and fruit plants shows that the mass fraction of fruit (an acceptor sphere of plants during fruiting) under the action of both drugs increased. Thus in both variants of the experiment both the mass fraction and donor assimilates of leaves were higher. Apart from the main source of assimilates – the processes of photosynthesis, which intensified due to the formation of a larger area of leaf surface (variant with gibberelin) or optimization of mesostructure (variant with tebuconazole) it is probable that the formation and growth of the embryo occurred in part due to reutilization of carbohydrates from the vegetative plant organs in carpogenesis processes.