Pyrrolizidine alkaloid content in <Emphasis Type="Italic">Senecio</Emphasis>: ontogeny
and developmental constraints |
| |
Authors: | Urs Schaffner Klaas Vrieling Eddy van der Meijden |
| |
Institution: | (1) CABI Bioscience Switzerland Centre, chemin des Grillons 1, CH-2800 Delémont, Switzerland, CH;(2) Institute of Evolutionary and Ecological Sciences, University of Leiden, P.O. Box 9516, NL-2300 RA Leiden, The Netherlands , NL |
| |
Abstract: | Summary. The ontogeny of pyrrolizidine alkaloid (PA) synthesis
and constraints on defence level during the seedling stage were examined
in the annual Senecio vulgaris and the monocarpic perennial
Senecio jacobaea. In both species, PAs were actively
synthesized from the onset of seedling growth so that juvenile stages
did not go through an undefended stage. Roots are known to be the
exclusive sites where PAs are produced. Root biomass was the single most
important biomass parameter explaining variation in total PAs per
seedling. All correlation coefficients between—relative growth
rate and PA concentration were negative, but none was significant.
However, a significant negative—correlation was found between
shoot to root ratio and PA concentration in S. jacobaeaseedlings, suggesting a dilution effect of the PAs. Earlier studies have
shown that the shoot to root ratio is positively correlated with
relative growth—rate of established S. jacobaea plants.
It is therefore suggested that young S. jacobaea plants
with a high shoot to root ratio and hence a high growth capacity
necessarily have lower PA defence levels than plants with a low
shoot to root ratio.
Received 10 July 2002; accepted 16 November 2002. |
| |
Keywords: | , Senecio vulgaris —, S, jacobaea —, pyrrolizidine alkaloids —,ontogeny —, seedling —, chemical defence —, developmental,,,,,constraint |
本文献已被 SpringerLink 等数据库收录! |
|