Modified hydroponics and phenolic foam as technological innovations in the production of coffee seedlings from cuttings

Brazilian coffee production represents an important activity in the country’s agricultural sector and, for this reason, it requires innovative technologies for the production of seedlings, which is one of the most important inputs in crop implantation. Thus, plant cloning by cutting, mineral nutrition via modified hydroponics and the use of alternative substrates appear as technological innovations for seedling production. This study evaluated the production of clonal coffee seedlings in a modified hydroponic system in comparison to the conventional climate-controlled greenhouse system, using vermiculite and phenolic foam as alternative substrates. At the end of the experiment, the seedlings were analyzed for growth (height, stem diameter, number of total leaves, leaf area, root area, shoot and root dry matter) and physiological (chlorophyll content and stomatal conductance) characteristics. For the statistical analysis, a completely randomized design was used in a factorial scheme 2 (types of substrate) x 2 (cultivation systems) with six replications and ten plants per plot. The innovative modified hydroponic system leads to a greater growth of coffee seedlings produced by cuttings in tubes with vermiculite compared to those produced in conventional systems. The substrate phenolic foam can be used alternatively in the air-conditioned greenhouse system. However, in the modified hydroponic system, it is not indicated, as it causes total seedling mortality.

Towards Functional Insect Feeds: Agri-Food By-Products Enriched with Post-Distillation Residues of Medicinal Aromatic Plants in Tenebrio molitor (Coleoptera: Tenebrionidae) Breeding

Sustainability, circular economy and alternative production systems are urgent imperatives for humanity and animal husbandry. Unless wasted, agri-food by-products can offer a promising source of high value. We evaluated the effect of rice bran (RB), corncob (CC), potato peels (PP), solid biogas residues (BR), and olive-oil processing residuals (OR), as alternative substrates to wheat bran (WB as control), on the growth and nutritional value of Tenebrio molitor during its breeding for animal feeds and/or human consumption. Innovation-wise, we further investigated the substrate supplementation (0, 10, 20%) with post-distillation residues of Mediterranean aromatic-medicinal plants (MAPs: lavender, Greek oregano, rosemary, olive; 1:1:1:1 ratio). Tenebrio molitor larvae (TML) were reared in all the studied substrates, and TML and diets’ proximate and fatty acid compositions as well as total phenol and flavonoid content and antioxidant potential were assessed using standard procedures. After statistical analysis of correlations, we observed that CC promoted oviposition and progeny survival; larval weight and dry matter were positively affected mainly by dietary energy and fat content; number of TML and/or larval weight increased using 10% MAPs inclusion in WB, RB and OR or RB, OR, BR and PP, respectively, which did not affect protein content; TML fatty acid composition decreased the content of saturated ones and increased that of mono-unsaturated ones; MAPs residues had an apparent favorable impact on total phenolic content and antioxidant activity of each substrate, with RB displaying the highest capacity and content. These findings indicate that alternative substrates can be exploited and their enrichment with natural phenolics is able to influence T. molitor growth, offering highly beneficial and nutritional value.

Influence of alternative substrates on biomass and quality of cedar seedlings

The production of native species seedlings is essential for the establishment of planted forests or for the recovery of degraded areas. In the nursery stage, the quality of the substrate is crucial for plant growth and development. The objective of this work was to evaluate the influence of alternative substrates, produced from agroforestry residues and decomposed forage grasses, on the biomass input and quality of cedar (Cedrela odorata) seedlings. The experiment was carried out in a greenhouse, located in Rio Branco, Acre, in a completely randomized design, with three treatments, consisting of substrates: brachiaria organic compost (1:1); organic compost combined with crushed brazil nut husk (2:1) and commercial substrate, with ten repetitions. At 90 days after sowing, total, shoot and root dry matter and Dickson's quality index were evaluated. The organic compost from Brachiaria grass favors the accumulation of biomass, improves the quality of cedar seedlings and can replace the commercial substrate in a viable way.

The effect of different substrates on oyster mushroom (Pleurotus ostreatus) spawn growth

The study aimed to find alternative substrates for growing spawn of oyster mushroom (Pleurotus ostreatus). The experiment was laid out in a completely randomized design with three compositions of substrates. The substrate compositions were: (1) Substrate A (corn 100%), (2) Substrate B (corn and sawdust mix in a ratio of (1:1, v/v)), and (3) Substrate C (corn and sawdust mix in a ratio of (3:1, v/v)). All compositions were replicated 18 times. The complete colonization (days) and mycelium growth rate (cm day−1) were recorded. Means were analyzed by Analysis of Variance (ANOVA) and duncan test was performed if there were significant between the substrate compositions. The results showed that substrate C was the best substrate indicated with the fastest complete colonization of 14.17±0.92 and the highest growth rate of 0.85±0.06 cm day−1.

Production of eucalyptus seedlings using alternative substrates

The efficiency of forest species production is associated with the seedlings quality. Hence, the substrate used is a determining factor in crop productivity, such as eucalyptus. Thus, the physical and chemical parameters of alternative and sustainable substrates were evaluated using coconut fiber and vermicompost in the production of Corymbia citriodora seedlings. Plants performance and quality were also evaluated by determining plant biomass and Dickson’s quality index, with or without mineral supplementation during cultivation. Results revealed that the proposed substrates obtained good physical and chemical characteristics when compared to a commercial substrate. The fertilization of seedlings showed to be essential in the production of more vigorous and better quality plants. The best quality C. citriodora seedlings was produced in the commercial substrate. However, it is worth highlighting the seedlings performance using alternative substrates such as coconut fiber and vermicompost, which represent a great potential for improvement, mainly due to its low cost and the observed result regarding the possible availability of nutrients in a gradual and constant way during the plants development.

Optimization of Spectrophotometric and Fluorometric Assays Using Alternative Substrates for the High-Throughput Screening of Lipase Activity

The effects of reaction conditions on the spectrophotometric and fluorometric assays using alternative substrates (p-nitrophenyl palmitate and 4-methylumbelliferyl oleate) were investigated to optimize them for the high-throughput screening of lipase activity from agricultural products. Four model lipases from Chromobacterium viscosum, Pseudomonas fluorescens, Sus scrofa pancreas, and wheat germ (Triticum aestivum) were allowed to hydrolyze the alternative substrates at different substrate concentrations (1–5 mM), operating pH (5.0–8.0), and operating temperatures (25–55°C). The results show that both the spectrophotometric and fluorometric assays worked well at the standard reaction conditions (pH 7.0 and 30°C) for finding a typical lipase, although pH conditions should be considered to detect the catalytic activity of lipases, which are applicable to more acidic or alkaline pH circumstances. To validate the optimized conditions, the high-throughput screening of lipase activity was conducted using 17 domestic agricultural products. A pileus of Pleurotus eryngii showed the highest activity in both the spectrophotometric (633.42 μU/mg) and fluorometric (101.77 μU/mg) assays. The results of this research provide practical information for the high-throughput screening of lipases using alternative substrates on microplates.