Alternative Substrate with Cupuaçu Bark Promotes Morphophysiological Quality in Yellow Passion Fruit Seedlings

Abstract

The use of agricultural residues for the production of alternative substrate is essential to reduce seedling production costs, as well as to reduce the environmental impacts resulting from the use of commercial substrates. Thus, the objective of this study was to evaluate the morphological and physiological performance of Passiflora edulis fruit seedlings as a function of alternative Theobroma grandiflorum bark substrates. The experiment was carried out in a screened nursery with sombrite of 50%, with a randomized block design with three replications and five plants per plot. The treatments consisted of the combination of ground and crushed cupuaçu bark in percentages of 20%, 40%, 60% and 80%. Liquid photosynthesis, stomatal conductance, internal CO2 concentration, transpiration, plant height, stem diameter, main root length, number of leaves, dry and fresh shoot and root weight and Dickson Quality Index were evaluated. The morphological and physiological performance of passion fruit plants was influenced by the cupuaçu bark concentration. Substrates containing 20 to 40% cupuaçu bark resulted in better seedlings, as they promoted increased net photosynthesis, gas exchange, leaf number, higher root growth and development, and larger stem diameter and shoot height. Consequently, the Dickson quality index showed excellent values, which shows an improvement in the biometric and physiological characteristics of the passion fruit seedlings produced with substrates based on cupuaçu bark.