Vol.:(0123456789) 1 3 Community Ecology https://doi.org/10.1007/s42974-020-00020-9 ORIGINAL ARTICLE Improvement of the seedling emergence method in soil seed bank studies using chemical treatments Reza Erfanzadeh 1  · Maryam Daneshgar 1  · Hassan Ghelichnia 2 Received: 8 April 2020 / Accepted: 19 June 2020 © Akadémiai Kiadó Zrt. 2020 Abstract The seedling emergence method (SEM) is the most frequently used method for studying the soil seed bank. The main prob- lem with this method is that it cannot provide a complete assessment of the seed fora present in the soil because its results are infuenced by seed dormancy. In order to break seed dormancy of the soil seed bank, SEM can be combined with some chemical treatments. The objectives of this study were to determine the best chemical treatment which is able to overcome seed dormancy, and to study the efects of diferent chemical treatments on soil seedling emergence of diferent plant func- tional groups. Therefore, twenty soil samples were collected in the early spring in subalpine rangelands in northern Iran. Each soil sample was divided into four equal subsamples, and each subsample was treated by one of the dormancy-breaking treatments including gibberellic acid (GA 3 ), hydrogen peroxide (H 2 O 2 ), potassium nitrate (KNO 3 ) and distilled water as control. The emergent species from the soil samples were categorized into functional groups, i.e., annual forbs, perennial forbs and perennial grasses. The results showed that the highest total seedling emergence was observed in the soil samples treated with GA 3 (5465 seedlings/m 2 ), whereas the lowest seedling emergence was found in the soil samples by KNO 3 appli- cation (586 seedlings/m 2 ). The perennial forbs were the only functional group that responded to all chemical treatments. We concluded that the use of GA 3 for breaking seed dormancy can be useful for providing a more reliable estimation of the soil seed bank characteristics. Keywords Forb · Germination method · Gibberellic acid · Perennial grasses · Seed dormancy Introduction The life cycle of most plant species begins with seeds (Baskin and Baskin 2014). When mature seeds are shed from the parent plant and arrive at the soil surface, germi- nation may happen immediately or may be delayed for a long period (Fenner and Thompson 2005). Thus, a large number of viable seeds may remain dormant in the soil for a long time (Warr et al. 1993). During this time, all the seeds present on or in the soil form a soil seed bank (Fenner and Thompson 2005). According to Bakker (1989), a seed bank is the reservoir of ungerminated seeds in the soil that has the function of replacing adult plants. The soil seed bank is a potential seed source that can play a main role in dynam- ics and regeneration of plant communities (Thompson and Grime, 1979). During the last decades, diferent ways have been used to estimate the soil seed bank. One of the standard meth- ods for detecting the viable seeds in the soil is the seedling emergence method (SEM) (Ishikawa-Goto and Tsuyuzaki 2004; González and Ghermandi 2012). In this method, the soil samples are spread in germination trays in a greenhouse and kept under natural light and temperature conditions and emergent seedlings are then identifed and counted. SEM is widely used to estimate the soil seed bank because it could be a favorable method for large-scale studies and can iden- tify the plant species easily (e.g., Ter Heerdt et al. 1996; Christofoleti and Caetano 1998; Erfanzadeh et al. 2020b). However, a major problem of SEM is that it often under- estimates the number of seeds, especially dormant seeds and seeds of species that require certain germination conditions. In this method, all the viable seeds in the soil samples are * Reza Erfanzadeh Rezaerfanzadeh@modares.ac.ir 1 Rangeland Management Department, Faculty of Natural Resources, Tarbiat Modares University, Tehran, Iran 2 Forest and Rangeland Research Department, Mazandaran Agricultural and Natural Resources Research Centre, AREEO, Sari, Iran