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Abstracts - Elaine Fernanda dos Santos

ALLELOPATHIC ACTIVITY OF THE ROOT EXTRACTS OF ERAGROSTIS PLANA NEES

Ana Paula P. K. Hendges1* , Elaine Fernanda dos Santos1 , Sirlei D. Teixeira2 , Michelangelo M. Trezzi2 e Beatriz Helena L. N. Sales Maia1 1UFPR; 2UTFPR; *Correspondence: anakleinhendges@gmail.com

Secondary metabolites exhibit diverse applications in many areas,2 in the specific case of plants, it can be said that these compounds are used as a form of communication or response to external stimuli.1 Some species may release secondary metabolites into the environment, which are capable of influencing the normal metabolic processes of other plants, including respiration, cell division, growth, development, productivity and enzyme activity, a phenomenon known as allelopathy.3 Within this context, the secondary metabolism compounds are of interest for research of a new bio-herbicide due to the great variability of chemical structures,4 thus, the objective of this work is to test the allelopathic potential of the crude extracts of Eragrostis plana Nees roots collected in spring and summer. For the allelopathic tests, seeds of I. grandifolia and E. heterophylla were used as recipient species. The first trials were carried out with salicylic acid as standard in order to evaluate the behavior of the recipient species. The standard aqueous solutions used in the germination bioassays were 5, 12.5, 31.25, 78.1, 195.2 and 488 ppm, and distilled water as blank. The germination was monitored for a period of 7 days, and on the last day, evaluated by measuring the growth of the radicle and shoot of the seedlings of the recipient species. Aqueous solutions of each crude extract (petroleum ether, ethyl acetate and methanol) of the roots collected in spring and summer were used in varying concentrations (100, 200, 300, 400 and 500 ppm), distilled water as blank and Tween 80, necessary for solubilizing the extracts, plus water and solvent as Control. The germination bioassay using the crude extracts followed the same methodology as the standard assay. The data was treated and analyzed using the generalized linear model to determine which variables (GP, TMG, GSI, shoot growth and radicle growth) were affected by the extracts tested. The tests showed that the recipient species presented different behaviors against salicylic acid, whereas E. heterophylla presented lower GP (germination percentage) for all treatments and germination of I. grandifolia was more affected by the concentration solution equal to 488 ppm. The other concentrations presented similar profiles. The spring petroleum ether extract caused a negative effect on the seeds of the receptor species in relation to the variables TMG (average germination time) and radicle growth. The summer methanol extract negatively affected the species in relation to the variables GSI (germination speed index) and GP. Therefore, it is essential to fractionate the crude extracts that had the best allelopathic activity (petroleum ether and methanol) for further tests with the pure substances isolated from them. 1. PAVARINI et al., Animal Feed Science and Technology, 176, 5– 16, 2012. 2. VAISHNAV; DEMAIN. Biotechnology Advances, 29, 223 – 229, 2010. 3. DASTAN et al., Industrial Crops and Products, 55, 43–48, 2014. 4. TUR; BORRELA; PASTORINI, Revista Biotemas, 23, 2, 2010.