Effect of different sources of organic matter added to the substrate on physiological parameters of clonal plants of conilon coffee

摘要

Organic matter is a fundamental component of a substrate. However, different organic matter sources can provide differentphysiological responses from seedlings as a result of different types and concentrations of humic substances, which influence thefunctioning of the plant and the structuring of the soil. The objective of this work was to quantify photosynthetic pigments, gasexchange, and secondary metabolite indices in the abaxial and adaxial parts of leaves of Conilon coffee clonal plantlets grown indifferent sources of organic materials. The experiment was arranged in a randomized block design with five treatments and fivereplications. The treatments consisted of different sources of organic matter added to the substrate: 85% soil + 15% urban wastecompost; 85% soil + 15% mature cattle manure; 85% soil + 15% dairy residue; 85% soil + 15% tannery sludge; and a Control: 100%soil, without addition of organic material. The contents of chlorophylls a, b, and total, carotenoids, and their ratios were analyzed bydestructive methods. Indirect measurements of nitrogen and chlorophyll (SPAD) were performed by non-destructive methods.Fluorescence indices of flavonoids, anthocyanins, total chlorophyll, and nitrogen balance were estimated using a Multiplex? sensor.The substrate added with dairy residue provided the highest chlorophyll a production in the adaxial part, which was confirmed bythe SPAD index. Tannery sludge provided the highest production of flavonoids. The comparison between the two forms ofevaluation showed that the abaxial part of the leaf had greater sensitivity and that the Multiplex? sensor showed higher sensitivityfor detection of indices. No changes were found in plant photosynthesis. However, greater stress was detected in the treatmentwith tannery sludge.