Morphological parameters and nutritional quality of seedlings of Jacaranda cuspidifolia mart. In response to brightness and different substrate combinations

Abstract

Jacaranda cuspidifolia Mart. is a forest species native to Brazil, with wide geographic distribution. It is classified as heliophyte, apicultural and pioneer, with potential for use in urban afforestation, civil construction and ornamentation, and there are few studies regarding the appropriate environmental conditions for the production of its seedlings. Thus, the objective of this work was to evaluate the effect of shading and different alternative substrates on seedling production. The experimental design was completely randomized in a 2 x 6 factorial scheme (two shading and six substrates) with 15 replications per treatment, and the experimental unit consisted of one plant. The substrates used were: T1: commercial; T2: sand + soil + chestnut shell (1:2:1) sand + soil + rice straw (1:2:1); T3: sand + soil (1:2), T4: sand + soil + rice husk + coffee straw (1:2:1:1); T5: sand + soil + sugarcane bagasse (1:2:1); T6: sand + soil + rice husk (1:2:1). The types of shading were: full sun (0% shading) and 50% shading, obtained with a shade screen. The characteristics evaluated were height, stem diameter, stem height/diameter ratio, root length, aerial dry mass, root dry mass, total dry mass, and Dickson's Quality Index. There was interaction for practically all the variables analyzed, except root length and the relationship between weight of dry mass area and weight of root dry mass. The seedlings at 50% shading in the commercial substrate followed by the one formulated with chestnut shell had the highest values in all biometric parameters in relation to the other alternative substrates in full sun. Results observed in the nut shell demonstrate potential for development in the field, so it is necessary to carry out follow-up studies of the seedlings in the field. J.cuspidifolia Mart seedlings grown at 50% shading in an alternative substrate formulated with chestnut husk, as well as commercial substrate that met the biometric, morphological and nutritional parameters.