Abstract
The aqueous extract from Carya cathayensis Sarg. exocarp was centrifuged, filtered, and separated into 11 elution fractions by X-5 macroporous resin chromatography. A phenolic compound, 4,8-dihydroxy-1-tetralone (4,8-DHT) was isolated from the fractions with the strongest phytotoxicity by bioassy-guided fractionation, and investigated for phytotoxicity on lettuce (Latuca sativa L.), radish (Raphanus sativus L.), cucumber (Cucumis sativus L.), onion (Allium cepa L.) and wheat (Triticum aestivum L.). The testing results showed that the treatment with 0.6 mM 4,8-DHT could significantly depress the germination vigor of lettuce and wheat, reduce the germination rate of lettuce and cucumber, and also inhibit radicle length, plumule length, and fresh weight of seedlings of lettuce and onion, but could significantly promote plumule length and fresh weight of seedlings of cucumber (p < 0.05). For the tested five plants, the 4,8-DHT was the most active to the seed germination and seedling growth of lettuce, indicating that the phytotoxicity of 4,8-DHT had the selectivity of dosage, action target (plant type) and content (seed germination or seedling growth).
Highlights
The phenomenon of inhibition of one plant’s growth by chemicals released by another plant into environment is generally defined as allelopathy [1]
The overall water extract (8.0 ± 0.1 g) of C. cathayensis exocarp was absorbed on a macroporous resin column, and 11 fractions eluted with ethanol solutions in ascending order of ethanol proportion were evaporated to afford dry residues weighing 5.3708 ± 0.043 g, 0.8605 ± 0.034 g, 0.3805 ± 0.022 g, 0.3158 ± 0.015 g, 0.1807 ± 0.008 g, 0.1325 ± 0.031 g, 0.1051 ± 0.016 g, 0.0981 ± 0.014 g, 0.0966 ± 0.008 g, 0.0997 ± 0.012 g, 0.1618 ± 0.026 g, respectively
Effects of C. cathayensis exocarp extract and eluting fractions on lettuce seed germination were measured by germination rate and germination vigor (Figure 1)
Summary
The phenomenon of inhibition of one plant’s growth by chemicals released by another plant into environment is generally defined as allelopathy [1]. Allelopathic effects are mainly determined by the dose and property of the exuded chemicals, mostly consisting of some secondary metabolites with phytotoxicity, and by various other environment factors [3,4]. Recent advances in our efforts to isolate and identify trace amount of biologically active substances including various allelochemicals have encouraged us to study allelopathy deeper and farther, especially in controlled environments [14]. The present study will describe the process of isolation of 4,8-dihydroxy-1-tetralone (4,8-DHT) and investigate the phytotoxicity activities of this novel compound, to provide a basis for development and utilization of C. cathayensis exocarp and 4,8-DHT as allelochemicals
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
