Effect of shade treatment on the growth and vitality of cloudberry Rubus chamaemorus

L. Āboliņa¹²*, A. Karlsons¹ and A. Osvalde¹

¹Latvia University of Life Sciences and Technologies, Faculty of Agriculture and Food technology, Lielā street 2, LV-3001 Jelgava, Latvia
²University of Latvia, Institute of Biology, O. Vaciesa street 4, LV-1004 Riga, Latvia
*Correspondence: laura.abolina@lu.lv

Abstract:

Cloudberry Rubus chamaemorus is a promising new berry species for cultivation in Latvia. This study aimed to assess how different shade levels influence cloudberry growth and vitality in semi-controlled conditions. Cloudberries (variety ‘Nyby’) were planted in enclosed planting area and grown under four shading treatments, using shading nets: control (no shade), 30%, 50%, and 80% shade for two years. Non-destructive SPAD measurements were taken weekly during the growing season (from May to August) in both years. Leaf size was measured at the end of August in both years, while leaf density and leaf nutrient concentrations were determined at the end of August in 2024. The results revealed significant differences between treatments for all of the measurements, with the highest values observed in plants under the 80% shade in both years. In the second year, the 50% an 80% shade treatments had similar results. Overall, the highest plant vitality was observed under 50% and 80% shade, demonstrating that netting effectively protects cloudberries from excessive sunlight. While larger leaves might improve light capture, they also require additional energy, potentially reducing resources available for fruit production. Thus, we suggest the 50% shade to be the most effective for cloudberries in the Latvian climate, as it balances protection with optimal energy conservation. Additionally, optimal fertilizing in the field could improve plant health and yield, therefore further studies regarding the combined effects of shade and fertilization on cloudberry production are required.

Key words:

Morpho-physiological effects of Stymjod foliar application on Dactylis glomerata L.

J. Sosnowski¹*, K. Jankowski¹, M. Truba¹, J. Novák², E. Zdun¹ and J. Skrzyczyńska¹

¹Siedlce University of Natural Sciences and Humanities, Prusa street 14, PL-08110 Siedlce, Poland
²Slovak University of Agriculture in Nitra, Tr. A. Hlinku street 2, SK94976 Nitra, Slovakia
*Correspondence: jacek.sosnowski@uph.edu.pl

Abstract:

The aim of the experiment was to study the effects of foliar application of a growth regulator containing iodine nanoparticles, with the trade name of Stymjod, on morphometrics, photosynthetic activity and chlorophyll content of Dactylis glomerate L. The following parameters were determined: the weight of fresh and dry matter of plants, leaves and roots, the number of shoots and leaves, potential (FV/Fm) and effective (ΔF/F_m’) quantum efficiency of photosystem, photochemical (qP) and non-photochemical (qN) quenching, as well as chlorophyll a and chlorophyll b content in leaf blades. The pot experiment was carried out in a breeding room. Stymjod was applied at 1.5%, 3% and 4.5% concentrations in the spray solution. It is a nanotechnology-based growth regulator, with easily assimilable forms of mineral and organic ingredients, favorably affecting plant ontogenesis. Plants were treated twice with a single dose of 50 mL of spray per pot. They were sprayed till they were completely covered with the liquid. Distilled water was used to spray control plants. The results were statistically processed using analysis of variance, while the significance of the differences between means was determined with Tukey’s test with P = 0.05. In the experiment it was found that different concentrations of Stymjod in the spray resulted in different response of plants. The best morphological effects were obtained using the concentration of the product exceeding 3%. In the test conditions Stymjod applied to D. glomerata increased the efficiency of the photosynthetic apparatus and the content of chlorophyll pigments.

Key words:

chlorophyll content, Iodine, photosynthetic activity, plant morphology