Autotoxicity in Panax notoginseng of root exudatesand their allelochemicals

Abstract

The growth of Panax notoginseng (Burk.) F. H. Chen is frequently hindered due to replanting failure. In the present study, the objective is to determine whether root exudates from P. notoginseng have autotoxicity and identification of allelochemicals from root exudates or rhizosphere soil. We investigated autotoxicity in P. notoginseng using seedling emergence bioassays and hydroponic culture. The allelochemicals in the soils and root exudates were identified with GC-MS, and the autotoxicity of the identified key allelochemicals was investigated by bioassay. The results showed that the root exudates, and extracts from consecutively cultivated soils also showed significant autotoxicity against seedling emergence and growth. In the non-renewed culture solution without activated charcoal (AC), the fresh and dry mass of P. notoginseng tubers of roots was reduced by about half compared to the addition with AC. A total of 44 different components from all samples were defined by GC-MS analyses. Furthermore, the results of multiple statistical analysis showed a t the difference among cultivated soil, uncultivated soil and root exudates. Bioassay of the identified allelochemicals revealed that benzoic acid, phthalic acid, palmitic acid, and stearic acid significantly affected the root growth of P. notoginseng. These substances at 100 μM more significantly decreased the number of lateral roots. Our results demonstrated that autotoxicity results in replant failure of P. notoginseng.

Vanillin, a Newly Discovered Autotoxic Substance in Long-Term Potato Continuous Cropping Soil, Inhibits Plant Growth by Decreasing the Root Auxin Content and Reducing Adventitious Root Numbers

“…This result has not been previously reported in potatoes but was commonly observed in other plants, such as tobacco, hemlock, and P. ginseng . Furthermore, vanillin highly decreased the potato yield at 70 μg g –1 , whereas ferulic acid and p -hydroxybenzoic acid had a lesser effect.…”

“…This result has not been previously reported in potatoes but was commonly observed in other plants, such as tobacco, 33 hemlock, 44 and P. ginseng. 23 Furthermore, vanillin highly decreased the potato yield at 70 μg g −1 , whereas ferulic acid and p-hydroxybenzoic acid had a lesser effect. p-Hydroxybenzoic acid showed an inhibitory effect at 110 μg g −1 , and ferulic acid may be higher as a result of differences in the chemical structure of various phenolic acids.…”

“…Identifying the types of autotoxic substances that cause plant autotoxicity allows for the development of effective management measures to maintain plant productivity. Phenolic acids are the most widely studied autotoxic substances as a result of their significant effects. , However, different species of plants are often by different phenolic acids as a result of their species specificity; e.g., benzoic acid, phthalic acid, palmitic acid, and stearic acid are the main autotoxic substances in Panax ginseng, and cinnamic acid and clove acid are the main autotoxic substances in cucumber, , while in potato, ferulic acid and p -hydroxybenzoic acid are generally considered to be the main autotoxic substances causing a potato continuous cropping obstacle. , However, the methods used for determination typically rely on pot tests or periodic sampling over a period of several years, mainly emphasizing variations in root secretion during a specific growth phase, which may not accurately reflect actual continuous cropping soil conditions. Therefore, it is necessary to improve the sampling method of autotoxic substances in potatoes.…”

Research on soil‐borne diseases of ginseng due to root exudates

“…Furthermore, replanting a crop in old soil increases the incidence of soil-borne diseases (Dong et al, 2018). However, soil-borne diseases are different from plant to plant and the detailed mechanisms involved are not fully investigated (Xiang et al, 2022). American ginseng (Panax quinquefolius L.) is a perennial herb native to hardwood forests in eastern North America that is a relative of Asian ginseng (Panax ginseng C. A. Meyer) in the genus Panax of the Araliaceae family occurring in North America (Liu et al, 2020).…”

“…Furthermore, replanting a crop in old soil increases the incidence of soil‐borne diseases (Dong et al., 2018). However, soil‐borne diseases are different from plant to plant and the detailed mechanisms involved are not fully investigated (Xiang et al., 2022).…”