HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (15) Citing Articles via Google Scholar Google Scholar Articles by Zeng, R. S. Articles by Tu, C. Y. Search for Related Content PubMed Articles by Zeng, R. S. Articles by Tu, C. Y. Agricola Articles by Zeng, R. S. Articles by Tu, C. Y. Related Collections Weed Management Crop Physiology & Metabolism Allelopathy

ALLELOPATHY SYMPOSIUM

Physiological and Biochemical Mechanism of Allelopathy of Secalonic Acid F on Higher Plants

Inst. of Tropical & Subtropical Ecology, S. China Agric. Univ., Wushan, Guangzhou, 510642, People's Republic of China

Corresponding author (rszeng{at}scau.edu.cn)

Our previous work indicated that secalonic acid F (SAF) was the major allelochemical produced by Aspergillus japonicus. Studies showed that SAF markedly inhibited the seedling growth of sorghum (Sorghum vulgare Pers.), hairy beggarticks (Bidens pilosa L.), and barnyardgrass (Echinochloa crus-galli (L.) Beauv.). It significantly reduced the activities of superoxide dismutase (SOD) and peroxidase (POD) at a concentration of 0.3 mM. Secalonic acid F enhanced malondialdehyde (MDA) contents, but it lowered the content of chlorophyll (CHL) a and b as well as the photosynthetic rates of tested plants. Respiration, membrane permeability, and abscisic acid (ABA) content increased after treatment with SAF, but the reduction activity of the root system was lowered. There is no remarkable change in the soluble proteins of plants that are treated with SAF. Transmission electron microscope (TEM) observations showed that treated plants exhibited amorphous mitochondria without integral membranes and swelling chloroplasts without membranes in a disorderly arrangement. The SAF treatment also damaged the stratiform structure of the chloroplasts and the membranes and structure of the nuclei. These results suggest that SAF may weaken the protective ability of plant tissues against membrane lipid peroxidation and damage the whole membrane system of plants, resulting in the ultrastructure destruction of chloroplasts, mitochondria, and nuclei. Cell ultrastructure destruction causes a reduction of photosynthesis and root activities and an increase in respiration. These abnormal physiological processes contribute to the inhibition of plant growth.

Abbreviations: ABA, abscisic acid • DMF, dimethyl formamide • EC, electric conductivity • ELISA, enzyme-linked immunosorbent assay • MDA, malondialdehyde • POD, peroxidase • SAF, secalonic acid F • SOD, superoxide dismutase • TEM, transmission electron microscope