The effect of a novel compound on yield and fruit quality in hydroponically grown tomatoes

[摘要] English: A company, Elementol (Pty) Ltd, requested the evaluation of their novel product, Pheroids.Pheroids is apparently a micro-emulsion that has the ability to act as a vehicle transportingphytologically beneficial substances over membranes. They further claim that Pheroidsalone, has plant growth promoting qualities. However, little information on Pheroids wasprovided, as its patent registration is still pending.Lycopersicon esculentum (cv. Floridade) was used for this study as it is prone todeveloping a nutritional disorder, Blossom-end rot (BER), under circumstances thatpromote a calcium deficiency in fruits. It can reduce potential yield with up to 70%.The plants were cultivated in a controlled greenhouse environment in a drip hydroponicset-up using complete- and calcium deficient nutrient media. The plants cultivated in thecalcium deficient nutrient medium markedly developed BER. In an effort to reduce theoccurrence of BER, these plants were treated with additional calcium using 1% and2% CaCl2 solutions, singly and mixed with Pheroids, as foliage sprays. The purpose ofthese treatments was to test the ability of Pheroids to act as a vehicle for the transport ofadditional calcium into the plants. Control plants cultivated in a complete nutrient mediumwere also treated foliarly with pure Pheroids to determine the possible stimulatory effect ofPheroids on plant growth.Reduced yield, and the subsequent high incidence of BER, as a result of the calciumdeficiency, was prevented by supplying calcium stressed plants with additional calcium inthe form of the 1% and 2% CaCl2 foliage sprays. These treatments improved yield abovethat of the calcium stressed plants, but failed to completely prevent the occurrence of BER.Mixing Pheroids with these CaCl2 solutions addresses its potential to transport additionalcalcium into the plants to improve cellular calcium concentrations. The 2% CaCl2 Pheroidsmixture specifically proved to be a very efficient treatment in reducing the effect of acalcium deficiency on yield and the development of BER. Although BER was not completely prevented, the yield and income generated with this mixture comparedfavourably to that of control plants.The efficiency of this 2% CaCl2 Pheroids mixture as a preventative foliage spray forreducing the occurrence of BER, were also compared to a treatment where only the fruitsof calcium stressed plants were treated with this mixture. Treating only the fruits reducedthe occurrence of BER effectively, but yield and profit were markedly decreased, making itineffective, unpractical and uneconomical.A further aim of this study was to investigate the ability of Pheroids to act as a growthpromoting substance by spraying control plants with Pheroids. The data obtained suggestedthat Pheroids stimulated plant growth in general as it stimulated yield. However, itspotential stimulatory response also promoted the development of BER, and subsequently areduction in net yield and profit. Since general plant growth was stimulated by Pheroidsunder control conditions, it is recommended that Pheroids should be extensively tested on avariety of crops to evaluate its growth stimulating potential.In summary, it appeared that Pheroids has the potential to act as a growth promotingsubstance, but needs further detailed investigation. However, it did indeed act as a vehiclefor the transportation of phytologically beneficial substances over membranes, especiallyin tomatoes grown under calcium stress conditions. Taking into consideration that mostcrops are grown in sub-optimal conditions, Pheroids might have numerous potentialapplications for the agricultural industry.

[发布机构] University of the Free State