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Phytotoxic effects of (+/-)-catechin in vitro, in soil, and in the field.

- PLoS ONE (2008)

Bottom Line: Experimental application of (+/-)-catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations.Our results demonstrate that (+/-)-catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied at low concentrations in the field.However, there is substantial conditionality in the effects of the allelochemical.

View Article: PubMed Central - PubMed

Affiliation: Centre for Environmental Management of Degraded Ecosystems, University of Delhi, Delhi, India. inderjit@cemde.du.ac.in

ABSTRACT

Background: Exploring the residence time of allelochemicals released by plants into different soils, episodic exposure of plants to allelochemicals, and the effects of allelochemicals in the field has the potential to improve our understanding of interactions among plants.

Methodology/principal findings: We conducted experiments in India and the USA to understand the dynamics of soil concentrations and phytotoxicity of (+/-)-catechin, an allelopathic compound exuded from the roots of Centaurea maculosa, to other plants in vitro and in soil. Experiments with single and pulsed applications into soil were conducted in the field. Experimental application of (+/-)-catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations. Pulses replenished (+/-)-catechin levels in soils, but consistently at concentrations much lower than were applied, and even pulsed concentrations declined rapidly. Different natural soils varied substantially in the retention of (+/-)-catechin after application but consistent rapid decreases in concentrations over time suggested that applied experimental concentrations may overestimate concentrations necessary for phytotoxicity by over an order of magnitude. (+/-)-Catechin was not phytotoxic to Bambusa arundinacea in natural Indian soil in a single pulse, but soil concentrations at the time of planting seeds were either undetectable or very low. However, a single dose of (+/-)-catechin suppressed the growth of bamboo in sand, in soil mixed with organic matter, and Koeleria macrantha in soils from Montana and Romania, and in field applications at 40 microg l(-1). Multiple pulses of (+/-)-catechin were inhibitory at very low concentrations in Indian soil.

Conclusions/significance: Our results demonstrate that (+/-)-catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied at low concentrations in the field. However, there is substantial conditionality in the effects of the allelochemical.

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Related in: MedlinePlus

Measured concentrations of (±)-catechin in soil from India, derived from the application of pulsed deliveries of different concentrations shown in the legend.Values on x-axis denote the days on which sampling was conducted. In detail, “10” and “14” denote sampling prior to the application of (±)-catechin pulses on those days, and “10.2” and “14.2” denote sampling two hours after application. The total (±)-catechin delivered to these soils over all pulses was 0, 340, 680, or 1020 µg g−1. The single error bar shown indicates the largest 1 SE.
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pone-0002536-g002: Measured concentrations of (±)-catechin in soil from India, derived from the application of pulsed deliveries of different concentrations shown in the legend.Values on x-axis denote the days on which sampling was conducted. In detail, “10” and “14” denote sampling prior to the application of (±)-catechin pulses on those days, and “10.2” and “14.2” denote sampling two hours after application. The total (±)-catechin delivered to these soils over all pulses was 0, 340, 680, or 1020 µg g−1. The single error bar shown indicates the largest 1 SE.

Mentions: The detected concentrations of (±)-catechin added in repeated pulses to the sandy loam soils from India were also far lower than the applied amounts of (±)-catechin added to the soil (Fig. 2). No (±)-catechin was observed in control soils, and the treatment calculated to add a total of 340 µg (±)-catechin g−1 of soil also resulted in zero (±)-catechin detected at all times but one, in which we detected 11.4±4.5 µg g−1 immediately after application at day 7. The 680 µg g−1 soil (±)-catechin application resulted in a mean of 14.5±5.8 and a maximum of 47.8±20.2 µg g−1 immediately after application on day 7. The 1020 µg (±)-catechin application g−1 of soil produced a maximum of 77.3±30.9 µg g−1 in the soil immediately after application on day 7 and an average across all measurements of 36.1±10.2 µg g−1 (±)-catechin in the soil. High soil (±)-catechin concentrations were always associated with measurements taken as soon as possible after application; whereas when measured 3–4 days after application of (±)-catechin, the highest concentration detected was 10 µg g−1. Most other measurements at these times were zero. In general, low readings of (±)-catechin corresponded to the development of red-brown coloration of the soil, suggesting that at least a component of the (±)-catechin loss was due to oxidation.


Phytotoxic effects of (+/-)-catechin in vitro, in soil, and in the field.

- PLoS ONE (2008)

Measured concentrations of (±)-catechin in soil from India, derived from the application of pulsed deliveries of different concentrations shown in the legend.Values on x-axis denote the days on which sampling was conducted. In detail, “10” and “14” denote sampling prior to the application of (±)-catechin pulses on those days, and “10.2” and “14.2” denote sampling two hours after application. The total (±)-catechin delivered to these soils over all pulses was 0, 340, 680, or 1020 µg g−1. The single error bar shown indicates the largest 1 SE.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2481294&req=5

pone-0002536-g002: Measured concentrations of (±)-catechin in soil from India, derived from the application of pulsed deliveries of different concentrations shown in the legend.Values on x-axis denote the days on which sampling was conducted. In detail, “10” and “14” denote sampling prior to the application of (±)-catechin pulses on those days, and “10.2” and “14.2” denote sampling two hours after application. The total (±)-catechin delivered to these soils over all pulses was 0, 340, 680, or 1020 µg g−1. The single error bar shown indicates the largest 1 SE.
Mentions: The detected concentrations of (±)-catechin added in repeated pulses to the sandy loam soils from India were also far lower than the applied amounts of (±)-catechin added to the soil (Fig. 2). No (±)-catechin was observed in control soils, and the treatment calculated to add a total of 340 µg (±)-catechin g−1 of soil also resulted in zero (±)-catechin detected at all times but one, in which we detected 11.4±4.5 µg g−1 immediately after application at day 7. The 680 µg g−1 soil (±)-catechin application resulted in a mean of 14.5±5.8 and a maximum of 47.8±20.2 µg g−1 immediately after application on day 7. The 1020 µg (±)-catechin application g−1 of soil produced a maximum of 77.3±30.9 µg g−1 in the soil immediately after application on day 7 and an average across all measurements of 36.1±10.2 µg g−1 (±)-catechin in the soil. High soil (±)-catechin concentrations were always associated with measurements taken as soon as possible after application; whereas when measured 3–4 days after application of (±)-catechin, the highest concentration detected was 10 µg g−1. Most other measurements at these times were zero. In general, low readings of (±)-catechin corresponded to the development of red-brown coloration of the soil, suggesting that at least a component of the (±)-catechin loss was due to oxidation.

Bottom Line: Experimental application of (+/-)-catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations.Our results demonstrate that (+/-)-catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied at low concentrations in the field.However, there is substantial conditionality in the effects of the allelochemical.

View Article: PubMed Central - PubMed

Affiliation: Centre for Environmental Management of Degraded Ecosystems, University of Delhi, Delhi, India. inderjit@cemde.du.ac.in

ABSTRACT

Background: Exploring the residence time of allelochemicals released by plants into different soils, episodic exposure of plants to allelochemicals, and the effects of allelochemicals in the field has the potential to improve our understanding of interactions among plants.

Methodology/principal findings: We conducted experiments in India and the USA to understand the dynamics of soil concentrations and phytotoxicity of (+/-)-catechin, an allelopathic compound exuded from the roots of Centaurea maculosa, to other plants in vitro and in soil. Experiments with single and pulsed applications into soil were conducted in the field. Experimental application of (+/-)-catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations. Pulses replenished (+/-)-catechin levels in soils, but consistently at concentrations much lower than were applied, and even pulsed concentrations declined rapidly. Different natural soils varied substantially in the retention of (+/-)-catechin after application but consistent rapid decreases in concentrations over time suggested that applied experimental concentrations may overestimate concentrations necessary for phytotoxicity by over an order of magnitude. (+/-)-Catechin was not phytotoxic to Bambusa arundinacea in natural Indian soil in a single pulse, but soil concentrations at the time of planting seeds were either undetectable or very low. However, a single dose of (+/-)-catechin suppressed the growth of bamboo in sand, in soil mixed with organic matter, and Koeleria macrantha in soils from Montana and Romania, and in field applications at 40 microg l(-1). Multiple pulses of (+/-)-catechin were inhibitory at very low concentrations in Indian soil.

Conclusions/significance: Our results demonstrate that (+/-)-catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied at low concentrations in the field. However, there is substantial conditionality in the effects of the allelochemical.

Show MeSH
Related in: MedlinePlus