LI Yan-Bin, ZHANG Qin, WAN Chuan-Xing, GONG Ming-Fu, ZHANG Li-Li
Cotton Science. 2009, 21(6): 497-502.
Cotton stalks were inoculated with some rhizospheric soil and decomposed under the temperature of 35 ℃. After decomposing 60 hours,the decomposing products were extracted by mixture of acetone and ethyl acetate in 5 days. The extract was concentrated and then subjected to bio-assay and chemical constituents analysis by GC-MS technique. The results indicated that cotton stalk decomposing products showed allelopathy on seed germination and seedling growth. It was observed that under concentration of 0.5g·L-1,1.0 g·L-1,1.5g·L-1 extract,the seed germination was constrained under higher concentration but promoted under lower concentration. The cotton stalk decomposing products showed significant inhibition on seedling growth（P < 0.01）even under the concentration of 0.5g·L-1. And weakened root vigor,reduced chlorophyll contents and declined fresh weight and plant height were found when the extract added into hydroponic culture. A lethal effect on tested cotton seedling was observed when the concentration of extract in nutrition solution reached to 1.5g·L-1. Activities of SOD and POD were induced at lower concentration but inhibited by higher concentrations of the extract. Higher contents of MDA were also found in higher concentration extract treatments. Total of 24 main constituents were detected in cotton stalk decomposing products by GC-MS analysis,the predominant constituents including 4-hydroxy-4-methyl-2-pentanone (27.31%),dibutyl phthalate (7.87%),hexadecanoic acid (6.69%),butanedioic acid,methyl-,bis (1-methylpropyl) ester (6.40%),9,12-octadecadienoic acid (Z,Z)-(5.43%),etc. Several of them have been identified as allelochemicals which were frequently reported.
