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.

Lignin-Based Phenolic Foam Reinforced by Poplar Fiber and Isocyanate-Terminated Polyurethane Prepolymer

Phenolic foams (PFs) are lightweight (<200 kg/m3), high-quality, and inexpensive thermal insulation materials whose heat and fire resistance are much better than those of foam plastics such as polyurethane and polystyrene. They are especially suitable for use as insulation in chemical, petroleum, construction, and other fields that are prone to fires. However, PFs have poor mechanical properties, poor abrasion resistance, and easy pulverization. In this paper, a polyurethane prepolymer was treated with an isocyanate, and then the isocyanate-terminated polyurethane prepolymer and poplar powder were used to prepare modified lignin-based phenolic foams (PUPFs), which improved the abrasion resistance and decreased the pulverization of the foam. The foam composites were comprehensively evaluated by characterizing their chemical structures, surface morphologies, mechanical properties, thermal conductivities, and flame-retardant properties. The pulverization ratio was reduced by 43.5%, and the thermal insulation performance and flame-retardancy (LOI) were improved. Compared with other methods to obtain lignin-based phenolic foam composites with anti-pulverization and flame-retardant properties, the hybrid reinforcement of foam composites with an isocyanate-terminated polyurethane prepolymer and poplar powder offers a novel strategy for an environmentally friendly alternative to the use of woody fibers.

In vitro co-culture system for Prunus spp. and Armillaria mellea in phenolic foam rooting matric

Armillaria and Desarmillaria spp. are causal agents of a devastating root-borne disease of peach. Breeding resistant rootstock requires a reliable screening tool. An in vitro co-culture screen designed for almond was modified by replacing agar-gelled medium with a more aerated phenolic foam and combining resistant and susceptible rootstocks (i.e., common garden experiment) and minimizes variation in inoculum pressure or rooting substrate among replicate vessels. Eight Prunus rootstocks tested (peach, plum, peach × plum, and choke cherry) were rooted and had no decline in health. Susceptible peach rootstock, ‘GF 305’, was cultured for 15 wk in phenolic foam in the same vessel with a resistant peach × plum hybrid, ‘MP-29’, inoculated with Armillaria mellea at week 5, that led to more severe shoot symptoms in the former after an additional 8 wk. This method accommodated peach genotypes that were difficult to root in agar medium. The difference during a uniform challenge with the A. mellea fungus recapitulates resistant/susceptible reactions. The phenolic foam-based co-culture method will work on many Prunus spp. of potential use in rootstock breeding.