The Effects of Fig Tree (Ficus carica L.) Leaf Aqueous Extract on Seed Germination and Seedling Growth of Three Medicinal Plants

Abstract

Fig tree cultivation land resources are not fully utilized and introducing them into sustainable medicinal agroforestry systems can effectively achieve resource protection and reuse. Laboratory and pot experiments were applied to study the allelopathic effects of fig tree (Ficus carica L.) leaf aqueous extract at five mass concentrations of 8.3, 10.0, 12.5, 16.7, and 25.0 g/L on the morphological and physiological indexes of mint (Mentha haplocalyx Briq.), dandelion (Taraxacum mongolicum Hand.-Mazz.), and woad (Isatis indigotica Fort.). The results showed that mint had the best seed germination rate. The leaf aqueous extract at lower concentrations had a strong promoting effect on the biomass and photosynthetic parameters of mint, dandelion, and woad. With the increase in leaf aqueous extract concentration, the superoxide dismutase, peroxidase, and catalase activity of mint, dandelion, and woad increased initially and then decreased, but the malondialdehyde content increased. The synthetic allelopathic indexes of the three medicinal plants were in the following order: mint > woad > dandelion. Both the low and medium concentration extracts (8.3 g/L–12.5 g/L) showed an obvious promoting effect, while high concentrations exhibited distinct inhibiting effects. In conclusion, mint is the most suitable medicinal plant to be interplanted with fig trees for introduction into medicinal agroforestry systems.

Response mechanisms of sugarcane seedlings to the allelopathic effects of root aqueous extracts from sugarcane ratoons of different ages

“…The intrinsic factors affecting the photosynthetic efficiency of plants can be divided into two broad categories: stomatal and non-stomatal limitations. The former mainly involve the partial closure of stomata in leaves, whereas the latter mainly exert adverse effects on the quantum efficiency of photosystem II, leading to the degradation of chlorophyll molecules and a reduction in the photosynthetic rate ( Li et al., 2021a ). In the present study, P n and C i exhibited a trend of initially increasing followed by a decrease with increasing extract concentration.…”

The Impact of Aqueous Extracts of Verbesina sphaerocephala and Verbesina fastigiata on Germination and Growth in Solanum lycopersicum and Cucumis sativus Seedlings

“…Mira et al [46] reported the allelopathic effect of Pteridium aquilinum on the germination and growth of economically important weeds. In addition, Li et al [16] studied the effects of aqueous fig leaf (Ficus carica L.) extracts on seed germination and seedling growth in three medicinal species and found that these negatively affected germination, but promoted development.…”

“…Various weeds and wild plants that grow and develop in cultivated fields can contain allelopathic substances that affect seed germination [30]. Various studies, i.e., [15,16,31], have indicated that most allelopathic substances, such as secondary metabolites, are synthesized through the metabolic shikimic acid and isoprene pathways. The known allelopathic substances mainly include phenols, quinones, karinas, flavonoids, terpenes, sugars, glycosides, alkaloids, and non-protein amino acids [32].…”

“…Plant allelopathy is a ubiquitous ecological mechanism in nature and is an important factor that affects seed germination and sometimes harms plant growth; however, as already mentioned, many allelopathic effects will depend on the extract concentration. The higher the concentration of an extract, the more intense its inhibitory effect on seed germination, regardless of the species [16,37,38].…”

“…For example, the aqueous extracts of three wild herbs (Achatherum splendens, Artemisia frigida, and Stellera chamaejasme) were found to allelopathically inhibit lettuce germination, but promote seedling growth when applied in low concentrations [15]. In addition, aqueous extracts of fig leaves (Ficus carica L.) were found to affect germination, but promote growth in three medicinal species (Mint, Dandelion, and Woad) [16].…”