Autotoxicity effect of water extracts from rhizosphere soil of Elymus sibiricus in different planting years on seed germination, physiological characteristics and phytohormones of seedlings

• Published in: PeerJ (San Francisco, CA) CA), 2022-07, Vol.10, p.e13768-e13768, Article e13768
• Main Authors: Yang, Hang, Su, Jinglong, Qi, Juan
• Format: Article
• Language: English
• Subjects: Abscisic acid; Acetic acid; Acidic soils; Agricultural Science; Antioxidants; Autotoxicity; Decomposition; E. sibiricus; Elymus - physiology; Elymus sibiricus; Germination; Gibberellins; Grasslands; Indoleacetic acid; Life span; Organic acids; Physiological aspects; Physiology; Phytohormones; Plant growth; Plant Growth Regulators - pharmacology; Plant Science; Planting; Planting years; Rhizosphere; Rhizosphere soil extracts; Seed germination; Seedlings; Seeds; Soil; Soil Science; Water; Water - pharmacology
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.13768

is a highly valuable perennial forage that is widely planted in the Qinghai-Tibet Plateau (QTP) region. However, artificial grasslands have a short utilization lifespan, and reach the highest yield in the 2nd and 3rd year of plantation, then rapidly drop its productivity. We hypothesized that autotoxicity is one of the mechanisms for the reduction of the productivity. To test this hypothesis, we prepared the water extract from rhizosphere soils of planted for 3, 4, 5, and 8 years and examined the effects of the extract concentrations at 0.05, 0.1, 0.2, and 0.5 g/mL on seed germination, seedling growth, physiological characteristics and phytohormones in the aboveground and roots of . The results showed that the soil extract concentration, planting years, and their interaction had significant influences on the most of these indices. The soil extract inhibited the seed germination and growth of seedlings, and the inhibitory effects appeared to be stronger at the 0.5 g/mL rhizosphere soil extract for 5 and 8 years. The superoxide dismultase and peroxide activities, the free proline concentration, soluble sugar concentration were altered. The malondialdehyde concentration was, in general, increased, especially in 8 years soil extract. The indole acetic acid and gibberellic acids concentrations were lowered, while the abscisic acid concentration varied. These changes were depending on the extract concentration and the years of planting, without clear patterns in some of them in response to the extract concentration and planting years. In summary, autotoxicity can be a contributor to the retardation of the growth and development of artificial grasslands. The inhibitory effects could be attribute to impaired antioxidant capacity and disturbance of osmortic-regulatory substances and plant hormones, and are more profound on the root than on the aboveground part of the seedlings.