Crescimento de mudas de jatobá com uso de bioestimulante e sombreamento

Abstract

This research evaluated the emergence and initial growth of treated jatobá (Hymenaea coubaril L.) seedlings with vegetable biostimulant (Stimulate®) and under shading. After scarifi cation, seeds were treated with biostimulant in doses of 15, 25 and 35 mL for every 0.5 kg of seeds, besides the control. The sowing was carried out in cell trays with substratum composed by soil + sand + plantimax® according to the proportion 1:1:1(v:v). The emergence speed index, diameter, leaf area, stem height, root lenght, leaf dry mass, root and total dry mass, stem/root dry mass ratio, stem /diameter ratio and Dickson Quality Index were evaluated. The seedlings were transplanted 100 days after sowing to 10 x 20 cm polyethylene bags with the same substratum and they were kept under 50 and 30% of light and full light. Height, diameter, chlorophyll were evaluated 162, 178, 194, 210 e 226 days after the sowing and stomatal conductance, photosynthetic and transpiration rate were evaluated 226 days after the sowing. The Stimulate doses used inhibited the seedlings emergence and initial growth. The emergence was higher without the use of the biostimulant. The greatest contents of chlorophyll were observed under 30% of light, and the lowest photosynthesis under full sun. The biostimulant highest doses inhibited the metabolic process, leading to the lower growth of the seedlings that in this phase can be cultivated in shadow conditions.