Development of seedlings of Quercus robur L. in the early stages of ontogenesis

The collection of woody plants of the Botanical Garden-Institute of the Far Eastern Branch of the Russian Academy of Sciences Q. robur was not represented. There have been no previous successful attempts to introduce this species in the Far East. Therefore, we have started a study on the possibility of introducing Q. robur in Primorsky Krai. Acorns for sowing were collected in the green areas of Yerevan, Armenia (Poplavok ark). The acorns were harvested 2 months after their mass fall on November 29, 2023. The sample size is more than 100 pieces. The oak species has been identified as Q. robur f. praecox. The sowing qualities of acorns have been studied. The mass of 1,000 acorns in our study was 8370 g. Their diameter ranged from 16 to 23 mm (on average 21 mm), height 39.4 (36-43) mm. The indicator germination of acorns was determined at different terms of storage from 60 to 90%. The germination of acorns after storage at low plus temperature increased (up to 90%), which indicates the high quality of acorns. The results of the study of the development of seedlings at the early stage of ontogenesis are presented. The root begins to grow immediately after planting, reaching 250 mm in length by 2 months (by the time of emergence of seedlings) with lateral roots 10-30 mm long each. 2.5 months after sowing, the epicotyle height average 60-70 mm. Transplanting seedlings delayed shoot growth and/or stimulated the formation of additional shoots, the second shoot formed in 30%, the third in 10% of acorns. The shoot height of one-year-old seedlings, when grown indoors, was 20.8 (11-35) cm, in those planted in open ground 15 (6-25) cm. Leaf fall in plants planted in the ground occurred in the last decade of October, with a steady decrease in the average daily air temperature to +12 °C. In indoor conditions, the leafless period lasted 20 days in January. The data were obtained over a period 1.5 years. Phenological observations were conducted from November 2023 to the present. A portion of the oak seedlings were planted in the open ground in the first year to determine the possibility of their overwintering in the region. The photographs presented in the article were taken by the authors.