Allelopathic Effects of Water Extracts of Maize Leaf on Three Chinese Herbal Medicinal Plants

Xiaobang Peng

doi:10.15835/nbha47111226

Abstract

Plants generate various secondary metabolites named as allelochemicals that can be release into the environment and influence the growth and development of other plants or the same plant. The potential allelopathic effect of maize (Zea mays L.) on seed germination, seedling growth and physiology was investigated with three medicinal plants (Platycodon grandiflorum A.DC, Scutellaria baicalensis Georgi and Salvia miltiorrhiza Bge) with different concentrations (0, 0.5%, 1.0%, 2.5%, 5.0%, 10.0%). Low concentrations (0.5%, 1.0%) of maize leaf aqueous extract stimulated the germination and seedling growth (root length, shoot height, fresh weight) of all receptor plants significantly. With the concentration of the aqueous extract increased, the stimulating effects gradually decreased, and even changed into inhibited. The aqueous leachate of maize leaves exerted different allelopathic effects on physiology of different test medicinal plants. For Platycodon grandiflorum A.DC, there was no significant difference in photosynthesis rate at all the tested concentration compared with control. In Scutellaria baicalensis Georgi the lower concentration (0.5%, 1.0%, 2.5%) of leachates stimulated the net photosynthesis rate, yet the higher concentration (5.0%, 10.0%) decreased the net photosynthesis rate, and all the tested concentration have inhibited effects on Salvia miltiorrhiza Bge and decreased its net photosynthesis rate. However, the content of soluble sugar and soluble protein of all receptor plants were stimulated by low concentrations (0.5%, 1.0%, 2.5%) of maize leaf aqueous extract. Allelopathy can affect the seed germination, early seedling growth and physiology of three medicinal plants.

Highlights

Allelopathy is defined as the direct or indirect harmful or beneficial effects of one plant on another through the production and release of secondary metabolites into the environment (Machado, 2007; Baziar et al, 2014)
The highest germination rate of Scutellaria baicalensis Georgi was appeared at the concentrations of 5.0% (Table 1)
The results showed that low concentrations of maize leaf aqueous extract stimulated the rate of seed germination of the three medicinal plants, and high concentration of the aqueous extract could have an inhibitory effect on seed germination of the three medical plants

Summary

Introduction

Allelopathy is defined as the direct or indirect harmful or beneficial effects of one plant on another through the production and release of secondary metabolites into the environment (Machado, 2007; Baziar et al, 2014). The secondary metabolites exhibiting allelopathic potential are called as allelochemicals, which can be produced by plants that interact with the surrounding environment by influencing the growth and development of neighboring plants (Liu et al, 2016; Sitthinoi et al, 2017). For the past several years, many researchers have done much work of allelopathy using plants leaf aqueous extract (Jefferson and Pennacchio, 2003; Dorning and Cipollini, 2006; Hou et al., 2016; Gulzar et al, 2017), and the results showed that this method was still the most efficiency approach for allelopathic effects research.

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