Variations in growth and biochemical parameters in annual cherry plants under the infl uence of growth regulators

Abstract

This study addresses the influence of the Applin drug on the growth and biochemical parameters of the leaves in three annual cultivars of cherries (Tyutchevka, Podarok Ryazani and Chermashnaya) grafted onto the Izmailovsky rootstock. The research was carried out in 2021-2022 both in field and laboratory conditions at the Federal Horticultural Centre for Breeding, Agrotechnology and Nursery. It was established that following treatment with Applin, the biometric indicators improved, with the yield of branched annual cherry seedlings increasing to 100 %. The treatment and removal of apical leaves stimulated the formation and growth of lateral branches in annual plants. The number of lateral shoots in experimental plants of the Chermashnaya cultivars increased by 6 times, while in the Tyutchevka and Podarok Ryazani cultivars, it increased by 3-4 times relative to the control. Growth regulators induced an increase in the average length of lateral shoots to 30-50 cm in all cultivars. The total length of the branches in the experimental Chermashnaya cultivar was 118.5 cm, which is 6.7 times higher than in the control. The other two cultivars exhibited a 4–4.5 times increase in total growth in treated plants compared with the control. Biochemical studies revealed an increase in photosynthetic pigment content in leaves following Applin treatment. The total content of phenolic compounds and antioxidant activity exhibited significant changes. A positive correlation (r = 0.709) was observed between the antioxidant activity of the aqueous extract and the amount of phenolic compounds. The content of chlorophylls (a+b) in the leaves of treated plants increased by 5-10%. Depending on the cultivar, the content of carotenoids varied from 1.1 to 1.8 mg/g, remaining practically constant following treatment. All cultivars showed an increase in the “chlorophyll (a+b)/carotenoids” ratio. Applin treatment also influenced the synthesis of primary and secondary metabolites, stimulating an increase in the content of carbohydrates (fructose, sucrose, turanose, and trehalose) and phenolic compounds (quinic and chlorogenic acids) in cherry plant leaves