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

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 transporting phytologically beneficial substances over membranes. They further claim that Pheroids alone, has plant growth promoting qualities. However, little information on Pheroids was provided, as its patent registration is still pending. Lycopersicon esculentum (cv. Floridade) was used for this study as it is prone to developing a nutritional disorder, Blossom-end rot (BER), under circumstances that promote 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 hydroponic set-up using complete- and calcium deficient nutrient media. The plants cultivated in the calcium deficient nutrient medium markedly developed BER. In an effort to reduce the occurrence of BER, these plants were treated with additional calcium using 1% and 2% CaCl2 solutions, singly and mixed with Pheroids, as foliage sprays. The purpose of these treatments was to test the ability of Pheroids to act as a vehicle for the transport of additional calcium into the plants. Control plants cultivated in a complete nutrient medium were also treated foliarly with pure Pheroids to determine the possible stimulatory effect of Pheroids on plant growth. Reduced yield, and the subsequent high incidence of BER, as a result of the calcium deficiency, was prevented by supplying calcium stressed plants with additional calcium in the form of the 1% and 2% CaCl2 foliage sprays. These treatments improved yield above that 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 additional calcium into the plants to improve cellular calcium concentrations. The 2% CaCl2 Pheroids mixture specifically proved to be a very efficient treatment in reducing the effect of a calcium deficiency on yield and the development of BER. Although BER was not completely prevented, the yield and income generated with this mixture compared favourably to that of control plants. The efficiency of this 2% CaCl2 Pheroids mixture as a preventative foliage spray for reducing the occurrence of BER, were also compared to a treatment where only the fruits of calcium stressed plants were treated with this mixture. Treating only the fruits reduced the occurrence of BER effectively, but yield and profit were markedly decreased, making it ineffective, unpractical and uneconomical. A further aim of this study was to investigate the ability of Pheroids to act as a growth promoting substance by spraying control plants with Pheroids. The data obtained suggested that Pheroids stimulated plant growth in general as it stimulated yield. However, its potential stimulatory response also promoted the development of BER, and subsequently a reduction in net yield and profit. Since general plant growth was stimulated by Pheroids under control conditions, it is recommended that Pheroids should be extensively tested on a variety of crops to evaluate its growth stimulating potential. In summary, it appeared that Pheroids has the potential to act as a growth promoting substance, but needs further detailed investigation. However, it did indeed act as a vehicle for the transportation of phytologically beneficial substances over membranes, especially in tomatoes grown under calcium stress conditions. Taking into consideration that most crops are grown in sub-optimal conditions, Pheroids might have numerous potential applications for the agricultural industry.