Distribution of phosphorus and calcium from nodal roots of <i>Trifolium repens</i>: the relative importance of transport via xylem or phloem

Lötscher, M.; Hay, M. J. M.

doi:10.1111/j.1469-8137.1996.tb01911.x

Cited by 18 publications

(9 citation statements)

References 21 publications

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“…The latter would be expected to decline gradually as plants repair themselves. The P in pasture‐plants is usually very mobile (Lötscher and Hay 1996), and also largely in orthophosphate form (>60%, J. Scott, personal communication, 2007). Studies of decomposing residues and hayed‐off pasture‐plants (harding grass–subterraneum clover mix; Phalaris tuberose – Trifolium subterraneum L.) have shown from 68 to 90% of total P leached is water soluble molybdate‐reactive (inorganic) P (Sharpley and Smith 1981, Bromfield and Jones 1972).…”

Section: Resultsmentioning

confidence: 99%

Sources of Phosphorus Lost from a Grazed Pasture Receiving Simulated Rainfall

2007

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Nutrients exported from grazing systems contribute to eutrophication of surface waters. In this study the contributions of soil, pasture-plants, and dung to P exports in overland flow were compared using simulated rainfall. The treatments were (i) grazed pasture-plants (isolated from soil by application of petrolatum to the soil surface), (ii) grazed pasture-plants and supporting soil, (iii) grazed pasture-plants and soil and treading, and (iv) grazed pasture-plants and soil and treading and dung. In general, dissolved reactive P (DRP) accounted for the majority of the P exported and P losses decreased in the order: treading and dung treatment>treading>pasture-plants and soil>pasture-plants. Very little dissolved organic P was lost in overland flow and the effects of treading diminished with time. Over a normal grazing cycle (30 d), the portion of P lost from pasture-plants was approximately half that lost from pasture-plants and soil, one-third that lost from treaded pasture-plants and soil, and one-quarter that lost from treaded pasture-plants, soil, and dung. The DRP in the pasture-plants treatment was approximately half that in the pasture-plants and soil treatment and suggests that a significant portion of the P exported from these systems is derived directly from pasture-plants. Due to higher proportions of particulate P (PP) in the treaded and dung treatments, DRP accounted for less of total P than in the pasture-plants and pasture-plants and soil treatments. Lower infiltration capacities probably caused by mechanical disaggregation at the soil surface are consistent with the higher proportions of PP in the treading treatments. These results were used to estimate P exports from a field trial site in Southland, New Zealand. The results suggested that P export attributable to fertilizer, dung, pasture-plants, and soil components were approximately 10, 30, 20, and 40%, respectively. These results suggest that since 90% of the P exports are derived from the soil-plant system and dung returns, managements to lessen P exports should continue to focus on maintaining soil P within the optimal range for pasture-plant production and maintaining soil surface properties that maximize infiltration and minimize overland flow.

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Section: Resultsmentioning

confidence: 99%

Sources of Phosphorus Lost from a Grazed Pasture Receiving Simulated Rainfall

2007

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“…The 5% soil moisture in the present experiment appeared to reduce the uptake and transport of Rb in C. disticha , whereas increased Rb transport was found in C. arenaria . Reduced transpiration has been demonstrated to reduce nitrogen transport (de Kroon et al ., 1998), and phosphorus and calcium transport (Lötscher & Hay, 1996), while a higher percentage of phosphorus was found in unwatered than in watered ramets in Agrostis stolonifera (Marshall, 1990). Therefore, the different patterns at low water availability might reflect physiological differences between C. arenaria (from dry habitats) and C. disticha (from moist habitats) in the uptake of mineral nutrients from relatively dry soil.…”

Section: Discussionmentioning

confidence: 99%

Extensive physiological integration in Carex arenaria and Carex disticha in relation to potassium and water availability

D’Hertefeldt

Falkengren‐Grerup

2002

New Phytologist

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Summary• Physiological integration between ramets is beneficial when acquiring heterogeneously distributed resources, and is hypothesized to occur when the benefits of resource sharing outweigh the costs. Our aim was to investigate if resource availability affected physiological integration in Carex arenaria and Carex disticha .• Ramet systems were grown in high potassium and high water (K+ W+), high K and low water (K+ W-), or low K and high water (K-W+) for 1 month. Thereafter, water and K transport were traced with erythrosin and rubidium, respectively.• Carex arenaria and C. disticha transported erythrosin over seven ramet generations and rubidium throughout the whole ramet system, but C. arenaria exported 20% more rubidium from the labelled shoot than C. disticha . A detailed analysis of a subset of plants suggested that C. disticha in low K abundance shared more rubidium than in high K abundance, and that C. arenaria ramets in both K+ W-and K-W+ shared more resources than K+ W+ ramets.• We demonstrated long-distance resource transport for K and water in C. arenaria and C. disticha . The distance of integration was not affected by resource availability in C. arenaria or C. disticha , but local concentrations of K showed marked and contrasting responses to nutrient and water treatment in both species.

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“…Clones of Trifolium repens also show a high degree of physiological integration, including both acropetal and basipetal translocation of resources between ramets along a stolon (Chapman et al, 1992;Lotscher and Hay, 1996;Yu et al, 2009). On the other hand, this legume species has shown sensitivity to ambient southern hemisphere UV-B levels in the field, and the sensitivity to enhanced UV-B varied among populations, and cultivars bred for agricultural performance were sensitive to UV-B (Hofmann et al, , 2003aLindroth et al, 2000).…”

Section: Introductionmentioning

confidence: 94%