The effects of plant growth regulators on growth, yield, and phenolic profile of lentil plants

The effects of plant growth regulators (PGRs) such as gibberellic acid (GA3), indole-3-acetic acid (IAA), kinetin, Prohexadione-Calcium (Prohex-Ca), and Topflor on lentil plants were investigated employing physiological and biochemical methods. GA3 increased lentil plants growth by 43%, while growth retardants (Prohex-Ca and Topflor) inhibited it by 34% as expected. Lentil 1000-seeds weight was decreased by 26% in plots supplemented with GA3. In contrast to Prohex-Ca and Topflor increased lentil 1000-seeds weight by 16% and 30%, respectively. In seeds, the total phenolic content (TPC) was significantly correlated (r2 = 0.99) to their total antioxidant capacity (TAC). HPLC–MS detection showed that specific phenolic compounds (catechin, epicatechin, rutin, p-coumaric acid, quercetin, kaempferol, gallic acid and resveratrol) appear to be the compounds with the greatest influence on the TAC values. Catechin is the most abundant phenolic compound in lentil seeds (up to 74 μg g−1 of fresh weight). Kinetin significantly increased rutin, epicatechin and gallic acid content in lentil seeds compared to control (93%, 79% and 49%, respectively). The variability in phenolic content among different PGRs treatments can be used as a benchmark for the selection of specific PGR to obtain lentil seeds with high phenolic content and high antioxidant properties as food ingredients.