Oxygen and carbon isotope composition of parasitic plants and their hosts in southwestern Australia

被引：55

作者：

Cernusak, LA

Pate, JS

Farquhar, GD

机构：

[1] Australian Natl Univ, Res Sch Biol Sci, Environm Biol Grp, Canberra, ACT 2601, Australia

[2] Australian Natl Univ, Res Sch Biol Sci, Cooperat Res Ctr Greenhouse Accounting, Canberra, ACT 2601, Australia

[3] Univ Western Australia, Fac Nat & Agr Sci, Sch Plant Biol, Nedlands, WA 6907, Australia

来源：

OECOLOGIA | 2004年 / 139卷 / 02期

关键词：

holoparasite; mistletoe; resource acquisition; root hemiparasite;

D O I：

10.1007/s00442-004-1506-6

中图分类号：

Q14 [生态学（生物生态学）];

学科分类号：

071012 ; 0713 ;

摘要：

We measured leaf dry matter delta(18)O and delta(13)C in parasitic plants and their hosts growing in southwestern Australia. Parasite/host pairs included two mistletoe species, three species of holoparasites, and five species of root hemiparasites. Among these parasite functional types, significant variation was observed in parasite/host isotopic differences for both delta(18)O (P<0.0001, n=65) and delta(13)C (P<0.0001, n=64). Mistletoes were depleted in both O-18 and C-13 compared to their hosts; parasite/host differences were -4.0parts per thousand for delta(18)O (P<0.0001) and -1.9parts per thousand for delta(13)C (P<0.0001). The lower delta(18)O in mistletoe leaf dry matter compared to their hosts is consistent with the frequently observed high transpiration rates of these parasites. Root hemiparasites were also depleted in O-18 and C-13 compared to their hosts, but not to the same extent as mistletoes; parasite/host differences were -1.0parts per thousand for delta(18)O (P=0.04) and -1.2parts per thousand for delta(13)C (P=0.0006). In contrast to mistletoes and root hemiparasites, holoparasites were enriched in both O-18 and C-13 compared to their hosts; parasite/host differences were +3.0parts per thousand for delta(18)O (P<0.0001) and +1.5parts per thousand for delta(13)C (P=0.02). The enrichment in O-18 for holoparasite dry matter did not result from more enriched tissue water; holoparasite tissue water delta(18)O was less than host leaf water delta(18)O by a difference of -3.8parts per thousand when sampled at midday (P=0.0003). Enrichment of holoparasites in C-13 compared to their hosts is consistent with a generally observed pattern of enrichment in heterotrophic plant tissues. Results provide insights into the ecology of parasitic plants in southwestern Australia; additionally, they provide a context for the formulation of specific hypotheses aimed at elucidating mechanisms underlying isotopic variations among plants.

引用

页码：199 / 213

页数：15

共 84 条

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