Agrobiological and morfobiochemical aspects of studying plum scion/stock combinations

Abstract

In 2018-2020, the study was carried out in the Leninsky municipality of Moscow region to explore garden plum in terms of its growth, productivity and morphobiochemical processes depending on the stock. Planting was in 5×2.5 m plots. The subjects of the study include trees of 2 plum varieties (Yaichnaya Sinyaya and Utro) with 5 stocks: plum seedling stock (control), Novinka, OP-23-23, OPA-15-2 and 140-1. The trees were 18 years of age. The influence of the stock on the leaf morphology, biochemical indicators, growth and productivity of grafted plum trees was established. An increase in the linear and radial growth of trees in comparison with the control was noted on clonal stocks OPA-15-2 and OP-23-23, a decrease in height by 15-20% – on 140-1 and Novinka stocks. The minimal average length of shoots was identified for trees grafted on the 140-1 and Novinka (9-12 cm) stocks. When grafted on OPA-15-2 and OP-23-23 stocks, the total shoot growth was 1.7 times greater than on the seedling stock. The leaf area ranged from 21.4 (Yaichnaya Sinyaya/seedling stock) to 36.2 m2/tree. (Utro/OPA-15-2). Th e low-growing tree stock 140-1 produced a smaller assimilation apparatus than in the control. The leaf area index ranged from 4.3 to 7.2. The OPA-15-2 and OP-23-23 clonal stocks provided the optimal values of the leaf biometric indicators. The study of leaf microsculpture revealed the morphological differences depending on the stock for total number of stomata and their size. The stomatal index ranged from 1.7 to 2.0. The influence of stock on the content of photosynthetic pigments and their ratio was established by means of spectrophotometry. An increase in the content of the sum of chlorophylls (a + b) to 8.3 mg/ml and their highest ratio was observed in the leaves of the Utro/OPA- 15-2 and Yaichnaya Sinyaya/OP-23-23 combinations. The maximum values of antioxidant activity (over 90%) and content of phenolic compounds in leaves were recorded with OP-23-23 stock. Gas chromatography-mass spectrometry revealed quantitative differences in the composition of low-molecular metabolites (glycerol, myo-inositol, fumaric-, quinic- and lactic acids) depending on the stock. The productivity of garden plum varieties was 1.4-1.9 times higher when grafted with OPA-15-2, Novinka and OP-23-23 in comparison with seedling stock. Cultivation of the Yaichnaya Sinyaya variety with these stocks resulted in an increase in yield from 8 to 15 tonnes/ha, and cultivation of the Utro variety – from 12 to 18 tonnes/ha.