Katja Malovrh

Mrs. Katja Malovrh


Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 April 2024 in Agriculture
Verified
Journal Article
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KMKatja Malovrh
Katja Malovrh
BRBlanka Ravnjak
Blanka Ravnjak
JBJože Bavcon
Jože Bavcon
Mitja KrižmanMitja Križman
Mitja Križman
Floral nectar is mainly a reward in the form of food for pollinators. Its composition plays an important role when pollinators choose their food. Several studies have shown that the popularity of flowers with nectar is influenced by the concentration and ratio of sugars. Here, we present the nectar chemical composition with regard to three main sugars and their concentrations in correlation with abiotic factors for the plant species Salvia pratensis L. and Salvia glutinosa L. through their 2023 flowering season. We sampled nectar using microcapillaries at three different times during the day on sites in nature. Our results show that nectar production in both species is the highest at around 12 a.m. The abiotic factor that affects nectar production in both species is the soil temperature, while UVB radiation does not influence nectar production. Air temperature and air humidity affect the nectar production of S. glutinosa, while soil humidity affects nectar production in S. pratensis. The most represented sugar in S. glutinosa nectar is sucrose, while S. pratensis nectar has more glucose and fructose. Our results show that UVB radiation has an effect on the sucrose level, although it does not have any direct effect on nectar productivity.

3 August 2024 in Diversity
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Journal Article
Open access
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KMKatja Malovrh
Katja Malovrh
JBJože Bavcon
Jože Bavcon
Mitja KrižmanMitja Križman
Mitja Križman
BRBlanka Ravnjak
Blanka Ravnjak
Floral nectar is mainly a reward in the form of food for pollinators. In early spring, when snow can still be present, pollinators have trouble finding food. The composition and productivity of nectar in flowers play an important role in a pollinator’s life. It is known that low temperatures and lower humidity cause lower nectar secretion. Some studies have also shown that the quality of nectar can differ because of lower temperatures. In our research, we analysed whether abiotic factors affect nectar secretion, as well as the nectar composition of the early spring plant species Galanthus nivalis L. and Helleborus niger L. in February 2024. The study was conducted in two locations in nature. Nectar from H. niger was sampled in Tomišelj, Slovenia, whereas nectar from G. nivalis was sampled in Ljubljana, Slovenia. On four different days at three different times of day, we sampled nectar from flowers using microcapillaries. In total, we sampled 48 nectar samples from one species. We analysed soil humidity and temperature, air temperature and humidity, and UVB radiation. Our results show that nectar productivity is highest in the morning for both species. H. niger has sucrose-dominant nectar, while G. nivalis has hexose-dominant nectar. Proline, which is an important amino acid for bees, has the highest level in both species, as does the phenolic compound rutin. Environmental factors do affect nectar secretion. Soil and air temperature affect G. nivalis nectar secretion, while soil humidity affects H. niger nectar secretion. Soil and air temperature also have an effect on higher levels of sugars in both researched nectars. UVB, air humidity, and air and soil temperature seem to have an effect on phenolic compounds, but abiotic factors do not affect amino acids.

1 March 2024 in Land
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Journal Article
Open access
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JBJože Bavcon
Jože Bavcon
KMKatja Malovrh
Katja Malovrh
MTMaja Tomšič
Maja Tomšič
BRBlanka Ravnjak
Blanka Ravnjak
Grassland ecosystems are increasingly vulnerable as they are threatened by both intensive agriculture and abandonment of land use, which leads to overgrowth with scrub vegetation and forest. Given that meadows are habitat types of very high biodiversity, their loss significantly reduces local biodiversity. That is why the University Botanic Gardens Ljubljana has been renting a 2 ha dry meadow at the edge of Ljubljana capital city since 2001, for the purpose of in situ conservation in the urban area. We have been observing the meadow since 1997. In 2023, in addition to the complete inventory of species, we also carried out an inventory and analysis of the community in the meadow using the Braun–Blanquet method in 25 relevés. We recorded 163 plant species in the meadow during the entire growing season, and a total of 82 were recorded in the relevés. Eighteen of the species recorded are on the red list of protected plant species in Slovenia. In the relevés, 15 species types were constant (occurring in 60%) and as many as 21 were unique. The species Peucedanum oreoselinum (L.) Moench was recorded in all relevés (25), followed by the species Bromopsis erecta (Huds.) Fourr. (24), Galium verum L. (24), Briza media L. (23), Brachypodium pinnatum (L.) PB. (22) and Salvia pratensis L. (21).

6 July 2025 in Plants
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Journal Article
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KMKatja Malovrh
Katja Malovrh
BRBlanka Ravnjak
Blanka Ravnjak
Mitja KrižmanMitja Križman
Mitja Križman
JBJože Bavcon
Jože Bavcon
Crataegus monogyna Jacq. and Prunus spinosa L. are common spring-flowering species in Slovenia. They occur in large stands and sometimes overgrow in unmanaged meadows. They are known as an excellent source of nectar for bees and other pollinators. Phenolic compounds are known as antioxidant for both pollinators and plants. We were interested in comparing plant species in terms of their phenolic compound content: rutin, quercetin, (iso)quercitrin, chlorogenic acid, and hyperoside. Their nectar was obtained from both plant species in 2024 in Ljubljana and the area surrounding Ljubljana. We took 96 samples of each species. The nectar was sampled with microcapillary tubes and analysed by HPLC. When studying the influence of abiotic factors on the concentration of phenolic compounds, the correlations were weak, so we cannot say with certainty which environmental factors affect which phenolic compounds and in what way. Rutin is predominant in the nectar of P. spinosa and chlorogenic acid is predominant in the nectar of C. monogyna. Hyperoside is found in the lowest concentration in both plant species. We found that although C. monogyna secreted much less nectar at midday, it was more concentrated in phenolic compounds at this time than in the morning. In P. spinosa, nectar secretion was highest in the morning, and the concentration of phenolic compounds was also highest in the morning.

22 September 2025 in Plants
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Journal Article
Open access
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KMKatja Malovrh
Katja Malovrh
JBJože Bavcon
Jože Bavcon
Mitja KrižmanMitja Križman
Mitja Križman
BRBlanka Ravnjak
Blanka Ravnjak
Fragaria vesca L. is a common plant species in Slovenia. It flowers from May to July. Our study was conducted throughout the 2024 season in two locations at which we sampled nectar in F. vesca flowers. To take the nectar samples, we used microcapillaries. We studied Fragaria vesca nectar production and its composition (sugars, amino acids, and phenolic compounds) throughout the day. We had some problems with sampling nectar in the afternoon, which affected our research, since there were times during which we could not obtain any samples. F. vesca on average secreted 0.02 μL nectar per one flower sample. Our data show that nectar production is highest in the morning, nectar is hexose-dominant, and the time of day affects the sugar concentration, which reaches a maximum at noon. The most common amino acid in F. vesca nectar is proline, and the amino acid concentration is highest in the morning. Quercetin and rutin are common phenolic compounds in the nectar of F. vesca, and the concentration of phenolic acids is highest at noon, as bees are the most active in the spring when mornings are colder.

Verified
Journal Article
Open access
PDF file
JBJože Bavcon
Jože Bavcon
KMKatja Malovrh
Katja Malovrh
MTMaja Tomšič
Maja Tomšič
BRBlanka Ravnjak
Blanka Ravnjak
Botanic gardens have an important role in educating people about plants. Direct contact with plants has a positive effect on the perception and understanding of plants and prevents plant blindness. In botanic gardens, pupils can learn about plants through practical work. At the Ljubljana University Botanic Gardens, educational programmes for schools have existed since 1986. Every year the Ljubljana University Botanic Gardens is visited by many different groups, from the youngest to oldest (kindergarten, primary school, graduate and professional school students, and faculties). We run around 350 guided tours for groups per year. Groups can choose either a guided tour with work sheets and workshops or they can visit the botanic gardens on their own. Most of groups are children from primary school. Ljubljana University Botanic Gardens offers programmes related to the valid school curriculum in Slovenia. Our programmes include guided tours based on level of pupils and/or practical work. The most popular time to visit is spring. But, we still have visitors in winter due to our tropical greenhouse. The most popular programme at our botanic gardens is the general tour. With our pedagogical programmes we contribute to plant knowledge, since we teach our pupils about nature.