Microencapsulated Caraway Essential Oil Affects Initial Growth of Maize Cultivars

• Main Authors: Katarzyna Możdżeń, Agnieszka Krajewska, Jan Bocianowski, Beata Jop, Agnieszka Synowiec
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Molecules
• Subjects: biocidal effect; chlorophyll fluorescence; dose–response test; phytotoxicity; relative chlorophyll content
• Online Access: https://www.mdpi.com/1420-3049/26/16/5059

Caraway (<i>Carum carvi</i> L.) essential oil is a candidate for botanical herbicides. A hypothesis was formulated that the sand-applied maltodextrin-coated caraway oil (MCEO) does not affect the growth of maize (<i>Zea mays</i> L.). In the pot experiment, pre-emergence application of five doses of MCEO was tested on four maize cultivars up to the three-leaf growth stage. The morphological analyses were supported by the measurements of relative chlorophyll content (SPAD), two parameters of chlorophyll <i>a</i> fluorescence, e.g., Fv/Fm and Fv/F0, and fluorescence emission spectra. The analyzed MCEO contained 6.5% caraway EO with carvone and limonene as the main compounds, constituting 95% of the oil. The MCEO caused 7-day delays in maize emergence from the dose of 0.9 g per pot (equal to 96 g m⁻²). Maize development at the three-leaf growth stage, i.e., length of roots, length of leaves, and biomass of shoots and leaves, was significantly impaired already at the lowest dose of MCEO: 0.4 g per pot, equal to 44 g m⁻². A significant drop of both chlorophyll <i>a</i> fluorescence parameters was noted, on average, from the dose of 0.7 g per pot, equal to 69 g m⁻². Among the tested cultivars, cv. Rywal and Pomerania were less susceptible to the MCEO compared to the cv. Kurant and Podole. In summary, maize is susceptible to the pre-emergence, sand-applied MCEO from the dose of 44 g m⁻².