Absorption and Elimination of the Allelochemical MBOA by Weeds during Seedling Growth

Abstract

6-Methoxy-2-benzoxazolinone (MBOA) is an allelochemical that is found in Poaceae and is generally associated with monocotyledon species. This compound is formed from the glycosylated form of 2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (Gly-DIMBOA) by a two-stage degradation process. The MBOA detoxification capacity of two weed species, namely Echinochloa crus-galli and Lolium rigidum, and a resistant biotype of Lolium rigidum (SLR31) was studied both qualitatively and quantitatively. The product of metabolism is similar for both weed species. This finding indicates that these weeds probably metabolize xenobiotics by an identical route, since the product detected was the same in both cases. Kinetic studies on the absorption and translocation to the shoot showed differences in these processes depending on the species. The analysis of treated plants, which were subsequently transplanted to a growth medium without xenobiotic compound, showed that the weeds studied are capable of transmitting the previously absorbed compound to the medium by root exudation. The results show that this process is another defense mechanism of plants facing external threats.

Mechanisms Underlying Allelopathic Disturbance of Herbicide Imazethapyr on Wheat and Its Neighboring Ryegrass (Lolium perenne)

“…The aim was to quantify the Hx content in both plant tissues and the transmission medium. This approach was informed by prior studies on Hx transportation and absorption, 22 and we hoped to construct a comprehensive picture of the Hx transportation route.…”

“…Notably, while wheat is able to influence weeds by secreting DIMBOA, 21 studies have shown that weeds can transmit the previously absorbed compounds to the medium by root exudation. 22 The investigation of interplant chemical recognition and response characterized by alterations in secondary metabolites holds great significance in expanding our understanding of chemical interactions among plant species. Therefore, for a more comprehensive understanding of the allelopathic disturbance mechanism, it is necessary to study the transformation and transport of secondary metabolites between wheat and neighboring plants.…”

“…Given this characteristic, both DIMBOA and MBOA deserve attention in the study of allelopathy. Notably, while wheat is able to influence weeds by secreting DIMBOA, studies have shown that weeds can transmit the previously absorbed compounds to the medium by root exudation . The investigation of interplant chemical recognition and response characterized by alterations in secondary metabolites holds great significance in expanding our understanding of chemical interactions among plant species.…”