Mineral nutrition and heterotrophy in the water conservative holoparasite Hydnora Thunb. (Hydnoraceae)

Stable carbon and nitrogen isotope signatures of root-holoparasiticCynomorium songaricumand its hosts at the Tibetan plateau and the surrounding Gobi desert in China

“…Our results are not consistent with previous studies that have found that a less negative holoparasite δ 13 C value and a decreased δ 15 N value are always observed relative to their hosts [6,21,25,27,35]. Despite an underlying assumption that complete heterotrophy will result in identical parasite/host δ 13 C signatures, we found significant differences in δ 13 C values between the holoparasite C. songaricum and its host N. tangutorum roots at the Tibetan plateau at high elevations (Figure 3), which supports the previous observations that δ 13 C values of parasites are depleted compared to hosts regardless of parasitic types (holoparasite, hemiparasite or mistletoe) [5,21,25,27,36,37]. This inconsistency can be attributed to δ 13 C partitioning within the tissue types and organs of hosts [5,24,38] (Table 2).…”

“…Although δ 15 N values are higher in N. tangutorum than in N. sibirica, the relationships between δ 13 C and δ 15 N values of both the holoparasites and hosts are significantly and negatively correlated, mirroring the nutritional relationship between the holoparasites and hosts. Our study indicates that tissue samples with more negative δ 13 C values tended to have more positive δ 15 N values, as shown by Bolin et al [5]. However, when differences between the holoparasite and host δ 13 C values were plotted against the differences between the holoparasite and host δ 15 N values, no significant correlation was observed, reflecting a segregation of δ 13 C and δ 15 N enrichment within the holoparasite tissues.…”

“…Holoparasite C. songaricum holoparasites and their hosts in differing environments [2,5], there still exists little knowledge on the ecological interactions of the root holoparasites and hosts in arid areas [6,7]. The root holoparasite Cynomorium songaricum (Cynomoriaceae, Saxifragales), known in Chinese herbal medicine as 'suoyang', is widely distributed at the Tibetan plateau and the surrounding Gobi desert.…”

“…Stable carbon isotopes have been studied extensively to address various research questions and have provided valuable information about water use efficiency and carbon gain of parasitic plants [6,20,21,27]. However, identifying sources of nitrogen used by parasites needs further investigation [5]. Because holoparasites cannot produce reduced carbon through photosynthesis and other reduction processes, it has been suggested that identical or similar δ 13 C values should be observed in the hosts and parasites [19,20].…”

Ecophysiology of the holoparasitic angiosperm Cistanche phelypaea (Orobancaceae) in a coastal salt marsh

“…In their study of the holoparasite Hydnora (3 species) and 3 other hemiparasites, Bolin et al (2010) found that the stable isotope ratios (δ 13 C and δ 15 N for holoparasites and δ 15 N for hemiparasites) were significantly correlated with hosts. They explained that these relationships indicate complete dependence on the hosts for nitrogen.…”