canceled

Does the heterotrophic C-gain change with the development stages of a hemiparasite? A time series of the isotope abundance in Melampyrum pratense L. and Pedicularis sylvatica L.

Paul Spörlein1, Philipp Giesemann1, Gerhard Gebauer1
1 BayCEER - Laboratory of Isotope Biogeochemistry, University of Bayreuth,

P 9 in Open Poster Session

Introduction

Hemiparasites (partly parasites, partly autotrophic plants) are getting their heterotrophic carbon through the xylem of their hosts. Since the previous work from Giesemann (2016) it is possible to apply a multi-element stable isotope (natural abundance) approach to calculate the proportional heterotrophic carbon gain of a hemiparasite. This approach enables raising the question, whether the hemiparasites change the ratio of carbon gained from their hosts and from photosynthesis during their development.

Material and Methods

At 3 different times leaves of two hemiparasites (Melampyrum pratense L. and Pedicularis sylvatica L.) were collected. The leaf dry weight, plant size and light intensity available to the plant was measured. Next to the hemiparasites three potential host plants were sampled as reference per plot. For the different harvesting times, the isotope ratios of carbon (δ13C), nitrogen(δ15N), oxygen (δ18O) and hydrogen (δ2H), were determined. The stable isotopes abundances were used to estimate the relative percentage of heterotrophically gained carbon. Through total leaf dry biomass carbon from autotrophy and heterotrophy was quantified on an entire pant level. 

Results

Both hemiparasites turned out as depleted in 18O, however, were simultaneously enriched in 2H due to organic carbon gain from their host. Pedicularis was more enriched in 2H than Melampyrum.  Melampyrum (mean heterotrophic C gain: 50%) raised its proportional autotrophic C gain from 44% up to 60%, while Pedicularis (mean heterotrophic C gain: 60%) changed this ratio from 29% to 45% during their ontogenetic development. 

Conclusions

The here investigated hemiparasites gain a significant amount of carbon through heterotrophy. However, the heterotrophically gained carbon plays a more important role in younger plants than in adults. 

 



Keywords: Hemiparasiten, Melampyrum pratense L., Pedicularis sylvatica L., Heterotrophie, Isotope