Nitrogen signals and their ecological significance for seed germination of ten psammophilous plant species from European dry acidic grasslands

Abstract

The presented study evaluated effects of potassium nitrate (KNO3), ammonium nitrate (NH4 NO3) and ammonium chloride (NH4Cl) on the germination-related characteristics of 10 species from European dry acidic grasslands. Germination was studied under controlled laboratory conditions. The seeds were subjected to KNO3, NH4 NO3 and NH4Cl in four doses (1, 10, 50 and 100 mM) and to distilled water. Final germination percentage, index of germination velocity and index of germination synchrony were determined. Content of nitrogen in the soil probed from the site of seeds collection was also analyzed. Significant effects of type of the nitrogen compounds and their concentrations were observed. High concentrations of nitrogen-containing salts inhibited completion of germination in almost all species. Helichrysum arenarium and Hypericum perforatum showed preference for NH4+ over NO3‒, whereas Arnoseris minima, Alyssum montanum, Jasione montana and Spergula morisonii showed preference for NO3‒ over NH4+. Centaurea scabiosa, C. stoebe and Hypochaeris radicata had no preference and wide tolerance to the type of nitrogen-containing compound. Echium vulgare showed differential response hard for interpretation. A. montanum and J. montana showed stenotopic behavior in terms of nitrogen-related conditions. It is proposed that nitrogen-rich soil gaps favor establishment of more nitro-tolerant plant species (e.g. C. scabiosa, C. stoebe and H. radicata) as compared to nitrogen-poor ones.

Acidity and availability of aluminum, iron and manganese as factors affecting germination in European acidic dry and alkaline xerothermic grasslands

“…Overall, it is worth noting that both alkaline xerothermic and acidic dry grasslands are composed of (1) species with pH requirements for completion of germination exactly matching the pH of the substratum on which they can be found, (2) pH-undifferentiated species (wide theoretical regeneration niche) and (3) species characterized with marked pH preferences however having also partial ability to complete germination under non-optimal conditions. It is known that there is diversity of germination strategies within the flora of alkaline and acidic grasslands, including such adaptations as reaction to nitrogen ( Wala, Kołodziejek & Patykowski, 2021 ), ability to withstand thermal aging ( Tausch et al, 2019 ) and complete germination under a given thermoperiod ( Tudela-Isanta et al, 2017 ). Although previous studies suggested that alpine calcicoles and calcifuges possessed group-specific adaptations allowing completion of germination under acidity matching their centers of abundance ( Tudela-Isanta et al, 2018 ), a homogeneous reaction within a group is probably not as plausible in lowland temperate grasslands ( Margreiter et al, 2020 ).…”

Factors Affecting Seed Germination of the Invasive Species Symphyotrichum lanceolatum and Their Implication for Invasion Success

“…The seed is sensitive to changes in environmental conditions such as temperature, light, moisture, and nitrate content [ 22 ]. Nitrate can regulate germination both alone or in combination with other abiotic factors, such as alternating temperature or light [ 22 , 23 ]. Increased nitrogen availability in soil could help break seed dormancy and stimulate germination [ 24 ].…”

Functional Identification of 9-Cis-Epoxycarotenoid Dioxygenase Genes in Double Dormant Plant-Herbaceous Peony

“…and endogenous factors (such as phytohormones, sugars and nitrogen compounds, etc.) (Chen, et Wala, et al 2021). Phytohormones are important growth regulators in this process.…”