THE IMPACT OF XENOTOXIC SUBSTANCES ON SOME ECOPHYSIOLOGICAL INDICES DURING THE FLOWERING PHASE OF BROAD BEAN CROP (Vicia faba L. var. major Harz) IN THE ECOLOGICAL CONDITIONS OF THE NORTH OF SUCEAVA COUNTY

Abstract

The research was carried out at SCDA Suceava, in the pedoclimatic conditions of the Pojorâta Center during 2017- 2018, on a lithic alluvial soil, located on the first terrace of the Moldova River, at an altitude of 700 m. One of the main factors in this experience, constituted the use of a xenobiotic product, called Tender 960 EC, herbicide from the IV toxicity group and its implications on the microbiological activity of the soil. The following research variants were pursued:V 1- untreated unsown; V2 - manually sown; V3- treated 1 l/ha before sowing; V4- 1.5 l/ha before sowing; V5- 1 l/ha before the plants sprouting; V6- 1.5 l/ha before the plants sprouting; V7- 1 l/ha after sprouting; V8- 1.5 l/ha after sprouting, sown at 50 cm between rows; V9- untreated unsown; V10- manually sown; V11- 1,5 l/ha before sprouting, sown at 30 cm between rows. This paper analyzes the action exerted by the herbicide mentioned above in the fight against weeds in broad beans culture on some ecophysiological indices (the content of dry matter, total water and carbohydrates) in the flowering phenophase of the plants. It was found that the accumulation of dry matter, in the flowering phase of the broad bean, in the pedoclimatic conditions of normal years, varies between 20.35 and 32.28%. The highest values of the dry matter content were recorded in the plants of the uncultivated variant not treated with herbicide (31.84-32.28%), and the lowest in the sowed but untreated variants (20.35-21.05% ). The rest of the variants show an average accumulation in dry matter between 22.89 and 30.42%. The analysis of the broad bean carbohydrate content, by form and total, was done using the Bertrand-Iljin titrimetric micromethod. The directly reducing carbohydrates (glucose-fructose), the water-soluble carbohydrates (sucrose) and the water-insoluble polysaccharide (starch) were analyzed. Organ analysis of carbohydrates by form and total, indicates an increased content of carbohydrates in reproductive organs and leaves and a lower content in roots and stems. In the varieties treated with herbicide, the lowest content of soluble carbohydrates and the highest content of water-insoluble carbohydrates were achieved.