The Chlorophyll Concentration and Photosynthetic Activity of some Parasitic Flowering Plants

Harpe, A. C. De La; Visser, J.H.; Grobbelaar, N.

doi:10.1016/s0044-328x(79)80144-0

Cited by 16 publications

(8 citation statements)

References 14 publications

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“…A similar effect has been observed in response to the related parasite Alectra vogelii (Rambakudzibga et al, 2002). Both Striga and Alectra are parasites that can have very strong negative effects on their hosts, reduce host growth even before emergence from the soil, have low rates of photosynthesis and resemble in many respects holoparasites (de la Harpe et al, 1979;Parker and Riches, 1993;Press et al, 1987;Rambakudzibga et al, 2002).…”

Section: Parasite Effects On Biomass Allocation Of the Hostsmentioning

confidence: 54%

Interactions between a root hemiparasite and 27 different hosts: Growth, biomass allocation and plant architecture

Matthies

2017

Perspectives in Plant Ecology, Evolution and Systematics

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The aim of this study was to investigate the effect of many different host species and their traits on the performance, morphology and architecture of the root hemiparasite Melampyrum arvense L., as well as the effect of the parasite on the growth and biomass allocation of its hosts. M. arvense was grown at two nutrient levels with 27 host species (grasses, legumes, and forbs) from habitats differing in nutrient availability. The biomass of the parasite varied enormously (475-fold) depending on the host species. The mean fraction of parasite biomass allocated to roots (RMF) decreased with increasing quality of a host (measured as total biomass of the parasite) and was only 3% with the best host. An extensive review of published studies showed that access to a host in most cases reduces RMF of root hemiparasites and that the RMF of annual root hemiparasites is low compared to that of autotrophic plants, suggesting that a reduced expenditure on roots is an important advantage of hemiparasitism for annual parasites. In contrast, the RMF of hemiparasitic perennial herbs and woody plants was found to be similar to that of autotrophic plants. Host identity and nutrients also strongly influenced traits of M. arvense other than biomass, e.g. leaf size, seed mass, leaf chlorophyll concentration, nitrogen concentration, height, and the number of vegetative internodes. However, while host plant identity influenced allometric relationships, most of the effects of nutrient level were due to simple changes in overall parasite size. Individual parasite biomass was not correlated with the final shoot or root mass of the host plants growing in the same pot, but increased weakly with host nitrogen concentration. Mean host size at the time of parasite planting, host functional type and the nutrient state of the typical host habitat influenced mean parasite biomass and together explained 64% of its variation. Parasite growth increased with initial host mass, was higher with legumes and forbs than with grasses, and higher with hosts from nutrient-rich habitats. Host damage due to parasitism increased with mean biomass of the parasite, and was lower for fast-growing species and higher for legumes and forbs than for grasses. Differences in damage between similarly good hosts indicated that not only resistance but also tolerance may be important for host responses to parasitism. M. arvense also caused changes in host allometry and increased host RMF, particularly in good host species. However, an extensive literature review found that there is no consistent general pattern of a higher RMF in hosts that are parasitized. Total productivity per pot was reduced by parasite presence suggesting lower resource use efficiency of the parasite, but not for all parasite-host combinations. Patterns of host quality for M. arvense and for its impact on host species differed strongly from those found for the related model hemiparasite Rhinanthus and suggest that hemiparasite-host species interactions may be parasite-specific.

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Section: Parasite Effects On Biomass Allocation Of the Hostsmentioning

confidence: 54%

Interactions between a root hemiparasite and 27 different hosts: Growth, biomass allocation and plant architecture

Matthies

2017

Perspectives in Plant Ecology, Evolution and Systematics

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“…However, the dark reds of the holoparasites C. visseri and M. thomii may not specifically serve for pollinator attraction but may simply result from lack of chlorophyll (De La Harpe et al . ).…”

Section: Discussionmentioning

confidence: 97%

Pollination and breeding system of the enigmatic South African parasitic plant Mystropetalon thomii (Mystropetalaceae): rodents welcome, but not needed

et al. 2017

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Unrelated plants adapted to particular pollinator types tend to exhibit convergent evolution in floral traits. However, inferences about likely pollinators from 'pollination syndromes' can be problematic due to trait overlap among some syndromes and unusual floral architecture in some lineages. An example is the rare South African parasitic plant Mystropetalon thomii (Mystropetalaceae), which has highly unusual brush-like inflorescences that exhibit features of both bird and rodent pollination syndromes. We used camera traps to record flower visitors, quantified floral spectral reflectance and nectar and scent production, experimentally determined self-compatibility and breeding system, and studied pollen dispersal using fluorescent dyes. The dark-red inflorescences are usually monoecious, with female flowers maturing before male flowers, but some inflorescences are purely female (gynoecious). Inflorescences were visited intensively by several rodent species that carried large pollen loads, while visits by birds were extremely rare. Rodents prefer male- over female-phase inflorescences, likely because of the male flowers' higher nectar and scent production. The floral scent contains several compounds known to attract rodents. Despite the obvious pollen transfer by rodents, we found that flowers on both monoecious and gynoecious inflorescences readily set seed in the absence of rodents and even when all flower visitors are excluded. Our findings suggest that seed production occurs at least partially through apomixis and that M. thomii is not ecologically dependent on its rodent pollinators. Our study adds another species and family to the growing list of rodent-pollinated plants, thus contributing to our understanding of the floral traits associated with pollination by non-flying mammals.

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“…However, members of both genera have been reported capable of low rates of 14 CO 2 fixation (MacLeod 1961;De la Harpe et al 1979). This photosynthetic capacity allows the plants to refix some respiratory CO 2 in the light.…”

Section: Discussionmentioning

confidence: 99%

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

2004

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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 (18)O and (13)C compared to their hosts; parasite/host differences were -4.0 per thousand for delta(18)O ( P<0.0001) and -1.9 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 (18)O and (13)C compared to their hosts, but not to the same extent as mistletoes; parasite/host differences were -1.0 per thousand for delta(18)O ( P=0.04) and -1.2 per thousand for delta(13)C ( P=0.0006). In contrast to mistletoes and root hemiparasites, holoparasites were enriched in both (18)O and (13)C compared to their hosts; parasite/host differences were +3.0 per thousand for delta(18)O ( P<0.0001) and +1.5 per thousand for delta(13)C ( P=0.02). The enrichment in (18)O 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 -3.8 per thousand when sampled at midday ( P=0.0003). Enrichment of holoparasites in (13)C 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.

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The Chlorophyll Concentration and Photosynthetic Activity of some Parasitic Flowering Plants

Cited by 16 publications

References 14 publications

Interactions between a root hemiparasite and 27 different hosts: Growth, biomass allocation and plant architecture

Interactions between a root hemiparasite and 27 different hosts: Growth, biomass allocation and plant architecture

Pollination and breeding system of the enigmatic South African parasitic plant Mystropetalon thomii (Mystropetalaceae): rodents welcome, but not needed

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

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