Physiological Aspects of Parasitism in Mistletoes (<i>Arceuthobium</i> and <i>Phoradendron</i>). I. The Carbohydrate Nutrition of Mistletoe

Hull, Richard T.; Leonard, O. A.

doi:10.1104/pp.39.6.996

Cited by 111 publications

(48 citation statements)

References 10 publications

(15 reference statements)

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“…All are characterized by some form of physiological bridge or interface, the haustorium, with the host vascular system. Most of the mistletoes tap only water and mineral nutrients from the host system, but a few, including Arceuthobium (Hull and Leonard 1964) and Tristerix (Mauseth, Montanegro, and Walckowiak 1984) have been shown to obtain photosynthetic product through this absorptive organ as well. (Barlow 1983).…”

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confidence: 99%

Morphological aspects of seedling establishment in four temperate region Phorandendron spp.

Ruhland¹

2000

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~ Four species of Phoradendron were examined for seedling morphology:P. bolleanum subsp. densum (on Junius), ~· californicum (on Prosopis), ~· juniperinum subsp. juniperinum (on Junip erus , ~· villosum subsp. Cotyledons of all species in the study were found to be persistent and possess a distinctive tip probably resulting from the site of attachment to the endosperm. These distinctive, persistent cotyledons and other clearly identified morphological features, allow to readily distinguish between plumular and adventitious shoots.

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Morphological aspects of seedling establishment in four temperate region Phorandendron spp.

Ruhland¹

2000

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“…Following the early work of Hull and Leonard (7,8), Ehleringer, Schulze and co-workers (5,18) have shed light on the principles underlying diversion of host resources to xylem-tapping mistletoes. A common feature is that mistletoe leaves have a Tn' in excess of that of their host, thus favoring the flux of resources to the parasite.…”

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Gas Exchange Characteristics of the Sorghum-Striga Host-Parasite Association

Press¹,

Tuohy²,

Stewart³

1987

Plant Physiol.

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Gas exchange characteristics are reported for both members of the sorghum-Striga host-parasite association. Both Striga hermonthica (Del.) Benth and Striga asiatica (L.) Kuntze had transpiration rates considerably in excess of those of sorghum (Sorghum bicolor (L.) Moench, cv CSH1). Stomatal conductance in both Striga spp. showed little response to periods of darkness and moderate water stress. Low rtes of net CO2 fixation and high rates of dark respiration led to no net daily (24 hours) C gan, and Striga would appear to be reliant on its host for photosynthate. Infection of sorghum plants with either S. hermoxthica or S. asiatica reduced host photosynthetic capacity. Infected sorghum plants were also more prone to water stress, but reduced rates of CO2 fixation could not be accounted for in terms of lower stomatal conductance. Lower stomatal conductances were associated with an increase in water use efficiency (WUE) in uninfected sorghum; however, Strigainfected sorghum plants had lower WUE than those of uninfected plants.We suggest that Striga exerts a specific effect on processes affecting C acquisition in sorghum leaves. The water relations of S. hennonthica and S. asiatica are not characteristic of plants growing in semiarid environments and are more likely to reflect the nature of the parasitic life-style. Despite transfer of water and solutes from host to parasite, the reduction in C fixation observed in infected sorghum plants appears to be the major determinant of growth reductions observed in sorghum supportng Striga Parasitic angiosperms rely on one or more neighboring plants (the host) either partially or totally for the acquisition of water, inorganic and organic solutes. Transfer is achieved via the haustorium, which may be located either above ground (e.g. green leafy mistletoes) or below ground (e.g. Striga) and links the Striga hermonthica and Striga asiatica (Scrophulariaceae) are parasitic on members of the Gramineae. They are the most serious cause of yield reduction in sorghum in the rainfed semiarid tropics (3). Their low photosynthetic activity compared to autotrophic Scrophulariaceae (12,19) coupled with the reduction in productivity of host plants (1), suggests a dependence on host photosynthate. In addition, Striga has only a vestigial root system, making independent uptake of water and inorganic solutes unlikely.In comparison with autotrophic Scrophulariaceae, Striga has a high Tn and poor stomatal control (19) and may have mechanisms in common with the mistletoes for the withdrawal of host transport fluids.In this paper we compare the C and H20 relations of sorghum and Striga, and consider: (a) the extent to which Striga is reliant on host photosynthate, (b) the effects of parasitism on host C acquisition, (c) the extent to which Striga employs a high Tn for the diversion of host water and solutes, and (d) the consequences of an additional water sink on the water status of the host. MATERIALS AND METHODSPlant Material and Growth Conditions. Sorghum (Sorghum bicolor (L.) M...

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“…The upper parts of the plants exposed to "4C0 or treated with '4C-fructosyl-sucrose, after removing the spike, were freeze-dried, pressed, and autoradiographed (6). The x-ray films were then developed according to the procedure of Hull and Leonard (10). In a separate experiment, the spikes, harvested from "4C02 and "4C-fructosyl-sucrose treated plants, were used for autoradiography.…”

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“…The flag eaves were inserted between two sponge plastic gaskets. B: The complete apparatus used for the simultaneous 14C02 treatment of flag leaves'from 10 wheat plants.…”

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Movement of ¹⁴C-labeled Sugars into Kernels of Wheat (Triticum aestivum L.)

Sakri

Shannon

1975

Plant Physiol.

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An anatomical study of wheat (Triticum aestivunt L.) kernels 14 days after anthesis revealed that the tracheary elements of the pericarp vascular bundle are not in direct continuity with those of the rachilla. The phloem was continuous from the rachilla into the crease of the pericarp.Shortly after exposure of the flag leaf to '4CO2, relatively high proportion of the "C extracted from the pericarp and endosperm was found in glucose and fructose. With additional time, the percentage of 14C in the monosaccharides declined and that in sucrose increased to a maximum 3 hours after "CO2 exposure. The monosaccharides comprised about onehalf of the soluble sugars extracted from the pericarp. Based on these observations, it appeared that sucrose hydrolysis might be prerequisite to sugar movement from the terminal phloem elements in the pericarp and into the endosperm. However, when "4C-fructosyl-sucrose was injected into the peduncle, there was little additional randomization of the 14C between the glucose and fructose moieties of sucrose extracted from the pericarp and endosperm compared to the rachis sucrose. If we assume that injected sucose was transported to the kernels via the phloem, then either sucrose moves out of the terminal phloem elements in the pericarp and into the endosperm unaltered, or if hydrolysis and resynthesis are a prerequisite to transport into the endosperm, the products of hydrolysis are not freely available for isomerization.Phloem elements responsible for the transport of sugars from leaves to developing maize (Zea mays L.) kernels terminate in the pedicel (upper rachilla) (14). Sugars in transit to a developing kernel move out of the phloem elements in the pedicel through the placento-chalazal tissue and into the endosperm ' (7) concluded that nutrients entering a wheat kernel through the vascular bundle at the base of the crease move across the chalaza and out into the endosperm through the nucellar projection.We showed previously that sucrose is cleaved to glucose and fructose prior to or during movement into the starchy endosperm of maize (27) both edges of the assimilate chamber to form a gas-tight seal around the flag leaves. Four 300-w General Electric4 cool lamps positioned above the photosynthetic chamber (Fig. 1B) supplied approximately 3100 ft-c of light intensity at the level of the flag leaves. The flag leaves of 10 plants, growing in separate pots, were enclosed in the assimilation chamber. A vacuum pump was attached to the air inlet and greenhouse air was pulled through the chamber for 30 min. Following the 30-min equilibration period, the vacuum pump was removed and the '4CO2 generator was inserted between the air inlet and outlet forming a closed system. To generate "4CO2, 0.5 ml of 80% lactic acid was added to a vial containing 1 mg of Ba'4CO3 (129 uCi). The released '4CO2 was swept into the chamber by 'Mention of a trademark name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the United States Department of Agriculture ...

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Physiological Aspects of Parasitism in Mistletoes (Arceuthobium and Phoradendron). I. The Carbohydrate Nutrition of Mistletoe

Cited by 111 publications

References 10 publications

Morphological aspects of seedling establishment in four temperate region Phorandendron spp.

Morphological aspects of seedling establishment in four temperate region Phorandendron spp.

Gas Exchange Characteristics of the Sorghum-Striga Host-Parasite Association

Movement of ¹⁴C-labeled Sugars into Kernels of Wheat (Triticum aestivum L.)

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Physiological Aspects of Parasitism in Mistletoes (Arceuthobium and Phoradendron). I. The Carbohydrate Nutrition of Mistletoe

Cited by 111 publications

References 10 publications

Morphological aspects of seedling establishment in four temperate region Phorandendron spp.

Morphological aspects of seedling establishment in four temperate region Phorandendron spp.

Gas Exchange Characteristics of the Sorghum-Striga Host-Parasite Association

Movement of 14C-labeled Sugars into Kernels of Wheat (Triticum aestivum L.)

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Movement of ¹⁴C-labeled Sugars into Kernels of Wheat (Triticum aestivum L.)