Germinação, crescimento, estaquia e idades de cortes do mentrasto (Ageratum conyzoides L.)

Abstract

Mentrasto (Ageratum conyzoides L.) plants have been used as phytotherapy medicine in many states of Brazil, the majority of technological and commercial aspects need to be further studied. In order to increase the knowledge about this species this work had the focus in the germination process, plant growing and development, seedling development, asexual propagation and different court ages. There were performed two distinct germination tests, the first one used Ageratum seeds, in the florific form, obtained from Cachoeira Dourada-GO, Botucatu-SP, Fortaleza-CE and Pentecoste-CE counties, combined with three different GA3 concentrations (0, 50 and 100 mg/L). In the second test, were used Ageratum seeds, in the florific form, after immersion in different concentrations of giberelic acid (50, 100 and 200 mg/L) and water. To study the vegetative form of Ageratum plants, ten plants were cultivated using the 1.0 x 1.0 m-distance and analysed every 15 days, starting 41 days and finishing 176 after sowing. The experiment, which analysed Ageratum plants in the florific form, used seven treatments (38, 45, 59, 66, 73 and 80 days after sowing) and four repetitions with ten plants each plot. In the experiment with Ageratum cuttings, in the vegetative form, that analysed the capacity of the cuttings in producing roots were used two different cuttings (apical and basal) combined with three substrates Plantagro®, Plantagro® + vermiculite in the 1:1 (v/v) proportion; Plantagro® + vermiculite + soil in the 3:2:2 (v/v) proportion, with four repetitions and 12 cuttings per parcel. Ageratum plants in both florific and vegetative forms were used for analysing the best age for making the cuttings. In the florific form treatments the cuttings were removed every 15 days, starting at 50 days and finishing at 140 days after sowing. In the vegetative form treatments the cuttings were removed every 15 days, starting at 90 days and finishing at 150 days after sowing_ According to the results, the origin of seeds in Ageratum plants in florific form influenced the seed germination and velocity index. The GA3 pre-treatments provoked an increased on germination of Ageratum conyzoides florific seeds. Ageratum conyzoides plants in the vegetative form not presented a reproductive stage during 240 days_ The period of October through May, on environmental conditions of Fortaleza-CE, the seedlings of Ageratum in florific form should be transplanted from 52 through 59 days after sowing; herb apical cuttings are useful for rooting Ageratum conyzoides in the vegetative form. The substrate Plantagro® + vermiculite (1:1 v/v) promoted seedlings production by rooting; as well as seedlings of good quality. The best period for Ageratum conyzoides cutting production using florific form and vegetative form occurred at 80 and 135 days after sowing.