Allelopathic potential of five species of the Annonaceae family

Abstract

Allelopathy refers to the ability that certain plant has to interfere in the metabolism of another by substances released into the environment, causing harmful or beneficial effects. The aim of this work was to evaluate the allelopathic effects of metanolic extracts from shoots (leaves and stems) of Annona crassiflora, A. coriacea, A. dioica, A. sylvatica and Duguetia furfuracea (Annonaceae), at 1% (m/v) concentration on germination and early growth of lettuce seedlings. Treatments consisted of three replicates of 25 lettuce seeds distributed in Petri dishes containing two sheets of germitest paper and 3 mL of extracts, maintained at 25ºC with white light. The control treatment was only watered with distilled water. The counting of normal seedlings, time of germination and length of radicle and hypocotyl were evaluated at four and seven days after sowing. Extracts were characterized about pH and phytochemical prospection. The methanolic extracts from Annonaceae altered all the parameters analyzed, significantly reducing the germination percentage and vigor of lettuce seeds and affecting adversely the time of germination in relation to the control. Extracts also caused radicle and hypocotyls growth inhibition.