Evidence for “gibberellin-like” activity of coumarin

Abstract

The existing body of information defines some regulatory functions to secondary metabolites like coumarin (COU). Experience and some experimental results in our laboratory tempted us to test a GA-like activity of COU. Experiments were conducted with endospermic (de-embryonated) and embryonic wheat half grains treated with different concentrations of COU, for different time courses, alone or in combination with the GAbiosynthesis inhibitor paclobutrazol (P). Results showed that treatment with COU caused stimulation of amylase synthesis and secretion from aleurone layer cells. P did not affect synthesis but slightly reduced excretion of amylase. However, germination percentage of intact wheat grains and seedling growth were inhibited by COU in a concentration-dependent manner. This indicates that COU has some GA-like effect, and also affects other aspects of germination and seedling establishment. This GA-like effect was also confirmed by the observed increase in elongation of wheat seedlings second leaf sheath and pea stem when treated with COU. These potential regulatory roles of COU may indicate that secondary metabolites have more important roles during different plant developmental processes.

Phytotoxic Potential and Biological Activity of Three Synthetic Coumarin Derivatives as New Natural-Like Herbicides

“…Similarly, Prabodh et al [43] and Khanh et al [44] observed that higher concentrations of template coumarin (above of 350 µM) were needed to reach 50% inhibition of Lactuca sativa , Lolium perenne and E. crus-galli germination process. Comparable results were also observed by Saleh and Abu El-Soud [45] on wheat germination. Also, other natural coumarins isolated from Meliaceae and Rutaceae, such as psoralen, showed lowest phytotoxic activity on germination process causing the complete inhibition at 1mM concentrations [46].…”

“…All the synthetic molecules strongly affected the root system more than the natural coumarins [45,46] inducing modifications on root morphology and anatomy, such as unaligned cells, gravitropism loss and root hair inhibition. Similar results were observed by several authors in treated roots with oryzalin, taxol and colchicines, affecting microtubule organization [63,64,65], which could also justify root hair loss [66,67].…”

Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging of Metabolites during Sorghum Germination

“…The production of hydrolytic enzymes excreted by the aleurone and scutellum layers is triggered by gibberellins, hormones produced in the scutellum and transported to the aleurone cells (reviewed by Yamaguchi, 2008;Sponsel, 2016). In wheat for example, the phenolic specialized metabolite coumarin has been shown to induce production of hydrolytic enzymes in aleurone cells (Saleh and Abu El-Soud, 2015). Tissue-wise localization of compounds during early germination and seedling development may, therefore, lend clues to their significance and biological activity.…”

Coumarin-Mediated Growth Regulations, Antioxidant Enzyme Activities, and Photosynthetic Efficiency of Sorghum bicolor Under Saline Conditions

“…COU has a strong antioxidant nature, which may regulate plant growth by showing effective antioxidant capacity ( Parvin et al, 2021 ). COU also possess gibberellin-like activity and can stimulate amylase biosynthesis in germinating seeds (of wheat) and increase stem length in pea seedlings by inhibiting paclobutrazol (a GA inhibitor) activity ( Saleh et al, 2015 ; Saleh and El-Soud, 2015 ).…”