Effect of bioregulatory agent

The work with DCPTA and other compounds demonstrate the effective use of bioregulatory agents to regulate vegetative plemt growth and development to achieve balanced improvements in agricultural crop quality and yield. 

Bioregulatory agents such as MPTA and DCPTA possess two distinct properties stimulation of the carotenoid biosynthetic pathway and inhibition of the cyclization of the acyclic to the cyclic carotenoids.The stimulation appear to be an indirect effect whereas the inhibitory effect is a direct one. By application of the compounds at lower concentrations at the early stages of its developmental phase, the inhibitory effect can be minmized resulting in the enhancement of desirable color normally associated with the crop. 

The relative effectiveness of a bioregulatory agent on inhibition of cyclizatlon and on stimulation of net carotenoid synthesis leads to variations in the carotenoid response pattern. When fully mature navel oranges are treated postharvest by vacuum infiltration for ten minutes with 2,000 ppm of MPTA, the carotenoid pigment pattern in the flavedo of the peel is quite similar to that observed In the endocarp with the acyclic lycopene as the main pigment as shown in Table I. The control fruits were vacuum infiltrated with water. 

These observations strongly suggest a direct effect of the compound MPTA on Inhibition of the cyclizatlon reaction but an Indirect effect on stimulation of carotenoid synthesis. Similar results were observed with Valencia oranges with another bioregulatory agent 2-diethylaminoethyl-4-ethylphenylether which possess properties similar to MPTA [2]. 

It is quite clear from the above observations that MPTA and DCPTA can enhance food color by increasing the formation of specific carotenoids normally associated with the individual food crop. When the bioregulatory agents are applied at the beginning of developmental phase of the crop at low concentrations, the stimulatory effect on carotenoids is manifested with no cyclase inhibition resulting in enhancement of desirable color quality. 

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