Sweet Pepper Seed Germination and Seedling Growth After Treatment with Slug Mucus

Abstract

The development of new methods of crop production is the most promising field of research in agriculture. There are numerous chemical techniques of seed treatment before sowing; however, mollusc mucus has not been considered as a natural alternative of seed treatment yet. In this study, we treated sweet pepper seeds with Spanish slug mucus before sowing. Seed germination success, germination time, as well as the performance of seedling growth were compared between experimental and control groups. The main result showed that seeds treated with slug mucus required significantly fewer days to germinate than seeds without treatment. Although treated seeds exhibited faster germination, seedlings showed slower growth than in the control group. No significant difference of seed germination success between the control and experimental group was found.

Herbivore kairomones affect germination speed, seedling growth, and herbivory

“…Treated seeds germinated 14% faster than control seeds, a result that they attributed to mucus acting like a sponge to store and hold water around the seed coat. The authors were unable to explain, however, why seedlings emerging from treated seeds were (despite a 1.5-day germination advantage) 24% smaller than control seedlings after three weeks (Zolovs et al 2022). We believe that a risk-mediated tradeoff in resource allocation-discussed belowmay explain both their results and ours.…”

“…Much less is known about the effect of herbivore risk cues on seed germination. The only work similar to ours appears to be a recent study evaluating the potential use of naturally occurring substances in agriculture that dipped pepper (Capsicum annuum) seeds in Arion vulgaris mucus as a pre-sowing seed treatment to promote faster germination and decreased plant growth (Zolovs et al 2022). Treated seeds germinated 14% faster than control seeds, a result that they attributed to mucus acting like a sponge to store and hold water around the seed coat.…”

“…Other studies have shown that terrestrial slug mucus incudes defense in Arabidopsis thaliana (Falk et al 2014). Both snails and slugs are important herbivores of seeds (Meldau et al 2014;Miczajka et al 2019) and seedlings (Buschmann et al 2006;Fenner et al 2002;Hanley et al 2011;Moshgani et al 2014), and exposure to their locomotion mucus has been shown to affect growth and subsequent herbivore damage in several plant species (Orrock et al 2018;Zolovs et al 2022). Although these studies suggest an important and unappreciated role of mollusk kairomones in shaping plant defense and tness, it is unclear whether it is a widespread phenomenon.…”