Piotr Czuchaj

The study aimed to determine the content of phenolic compounds (phenolic acids and flavonoids) and organic acids in dried flowers and water infusions of non-oxidised and oxidised flowers from four lilac cultivars. The diversity in the total phenolic and flavonoid content was in the flowers (18.35–67.14 and 2.03–2.65 mg g⁻¹ DW, respectively) and infusions (14.72–47.78 and 0.20–1.84 mg per 100 mL infusion, respectively) depending the flower colour and form (oxidised and non-oxidised). Phenolic compounds and organic acids were susceptible to oxidation. Compared to infusions, flowers had more phenolic compounds and organic acids. The highest content of most phenolic compounds was confirmed for non-oxidised purple flowers (up to 7825.9 µg g⁻¹ DW for chlorogenic acid) while in infusions for non-oxidised white flowers (up to 667.1 µg per 100 mL infusions for vanillic acid). The phenolic profile of the infusions was less diverse than that of flowers. The scavenging ability ranged from 52 to 87%. The highest organic acid content in flowers was for oxidised blue and purple flowers (2528.1 and 2479.0 µg g⁻¹ DW, respectively) while in infusions the highest organic acid content was for oxidised purple flowers (550.1 µg per 100 mL infusions).

The influence of selected fertilizer within a 6-month period of operation was assessed: Basacote Plus ^6M, Osmocote Plus ^6M, Plantacote Plus ^6M. Plants grown in the substrate without slow-release fertilizer, which were supplied with nutrients only for top dressing, were the control. Two cultivars of the Maxi type of cyclamen were grown in greenhouse in pots during the period from the 25th to the 50th week of the year. While planting the seedlings, 2 g of slow-release fertilizer were added to the substrate directly under the roots. From the third week of cultivation, the plants of each combination were fertilized with top dressing every week. Plant height and diameter, number of leaves, weight of the above-ground part, tuber diameter, earliness of flowering, number of flowers and buds, as well as the content of macro and micronutrients were assessed. The addition of Osmocote ^6M or Plantacote ^6M into the substrate resulted in plants with a larger fresh weight and larger diameter and earlier flowering with more flowers and buds at the end of the experiment than with Basacote ^6M or with only top dressing. The applied slow-release fertilizers had an effect on the content of K, Ca, and Fe in the leaves of Persian cyclamen. The cultivar ‘Rainier White F1’ had significantly more leaves, buds, and flowers and a higher content of P, K, Cu, Zn, and Mn than the cultivar ‘Halios Pure White Compact F1’.

Two cultivars of Heuchera L. - ‘Mysteria’ and ‘Peppermint Spice’ were grown in a collection at a sunny site and a slightly shaded one. The access of sunlight was limited by shade nets, which were stretched on wooden scaffolding over the plants. The dynamics of growth of the plants in the sunny and half-shaded sites was assessed in the growth periods, in two consecutive years. After the second year, the content of anthocyanins in the leaves of different physiological maturity (young, mature and fully mature) was measured. Apart from August, during the whole growth period both cultivars formed more leaves during the first year of cultivation. Both the ‘Mysteria’ and ‘Peppermint Spice’ cultivars formed more leaves at the sunny site. The research showed that the highest content of anthocyanins in the Heuchera ‘Mysteria’ and ‘Peppermint Spice’ cultivars growing at the sunny and half-shaded sites was found in young leaves, whereas the lowest content was noted in fully mature leaves. The highest content of anthocyanins in both Heuchera cultivars was found at the initial growth period, i.e. between May and July, when the light intensity was the greatest, regardless of the place of cultivation. At the end of the growth period, the biosynthesis of anthocyanins decreased significantly. Anthocyanins accumulated in the vacuole are able to play a role as the screening pigments under intensive PAR and UV-B radiation. ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********