The effect of growth promotors and retardants on the morphogenesis, photosynthesis and productivity of tomatoes (Lycopersicon esculentum Mill.)

Abstract

There were studied the peculiarities of growth processes, the formation of the leaf apparatus, its mesostructure and photosynthetic activity, as well as the biological productivity of the Bobcat hybrid tomato plants under the influence of synthetic analogues of growth promoting hormones — 1-naphthaleneacetic acid (1-NAA), gibberellic acid (GA3), 6-benzylaminopurine (6-BAP), and retardants — chloromequate chloride (ССС-750), tebuconazole (EW-250), ethephon (2-chloroethylphosphonic acid, 2-CEPA), which differ in the action mechanism. It was revealed that growth promotors increased, and retardants reduced the tomato plants height. It was established that 1-NAA, GA3, and CCC-750 increased the leaf number on the plant, while under 2-CEPA treatment, the index was less than the control, and under the EW-250 action it remained practically unchanged. All growth regulators, except 2-CEPA, increased the leaf blades number, the fresh weight, and leaf area. All growth promotors increased the whole plant dry weight, while the retardants EW-250 and CCC-750 did not affect this index, and 2-CEPA significantly reduced it. All retardants and 6-BAP significantly increased the total chlorophyll content in tomato leaves, while under the action of GA3 this index decreased. The retardants EW-250 and CCC-750, and the growth promotor 6-BAP contributed to the thickening of the tomato leaf chlorenchyma, and the ethylene producer 2-CEPA reduced it. Under the influence of all growth regulators, except 2-CEPA, the volume of columnar parenchyma cells increased. It was established that at the stage of fruit formation onset, all growth regulators, except 1-NAA, increased the rate of CO2 assimilation, photorespiration, dark respiration and transpiration. All growth regulators, except 2-CEPA, contributed to the increase in tomatoes yield, while the use of the growth promotor 6-BAP and the retardant EW-250 proved to be the most effective.