Effects of 13C isotope-labeled allelochemicals on the growth of the invasive plant Alternanthera philoxeroides

Abstract

The secondary metabolites of indigenous plants have significant allelopathic inhibitory effects on the growth and development of invasive alien plants. Methyl palmitate (MP) and methyl linolenate (ML) were used as exogenous allelopathic substances. The research investigated the differences of inhibitory effects of MP and ML on the growth of seedlings of Alternantheraphiloxeroides, and calculated their morphological characteristics, biomass, physiological indicators and the response index (RI). The synthetical allelopathic index (SE) of 1 mmol/L MP was the smallest (− 0.26) and the allelopathic inhibition was the strongest; therefore, it was selected as a 13C-labeled allelochemical. The distribution of 1 mmol/L MP in different parts of A.philoxeroides and the correlation between the biomass ratios of roots, stems and leaves and the 13C content were studied by 13C stable isotope tracing experiments. Atom percent excess (APE) between roots, stems and leaves of A.philoxeroides treated with 1 mmol/L MP were significantly different in terms of magnitude, with leaves (0.17%) > roots (0.12%) > stems (0.07%). The root, stem and leaf biomass ratios of invasive weeds had great significant positive correlation with 13C content (p < 0.01, R2 between 0.96 and 0.99). This current research provides a new idea and method for the control of A.philoxeroides, but large-scale popularization remains to be studied.

Allelopathic effects of Thuidium kanedae on four urban spontaneous plants

“…Allelopathy primarily influences seed germination and seedling growth, as documented in the literature 21 , 22 . It is widely reported that allelopathic interactions can result in "low promotion and high inhibition" effects on seed germination of recipient plants 23 , 24 , although some studies have reported exclusively inhibitory outcomes 25 – 28 . In our study, the aqueous extract of T. kanedae markedly suppressed the germination of O. japonicus , T. mongolicum , and V. philippica seeds, with the degree of inhibition intensifying at higher concentrations.…”