The Effect of Phosphorus and Potassium on Transpiration, Leaf Diffusive Resistance and Water-Use Efficiency in Sitka Spruce (Picea sitchensis) Seedlings

Bradbury, Ian K.; Malcolm, D. C.

doi:10.2307/2402573

Cited by 52 publications

(30 citation statements)

References 9 publications

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“…Similarly, Lindhauer (1985) using a steady state porometer reported reduced leaf conductances when potted Helianthus annuus plants growing in a climatized chamber were supplied with higher levels of K fertilizer, and comparable reports from studies with conifers can be found in the literature (e.g. Bradbury and Malcolm, 1977).…”

Section: Introductionsupporting

confidence: 70%

Diurnal courses and factorial dependencies of leaf conductance and transpiration of differently potassium fertilized and watered field grown barley plants

Lösch

Jensen²,

Andersen³

1992

Plant Soil

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During the grain filling period we followed diurnal courses in leaf water potential (~), leaf osmotic potential (~0), transpiration (E), leaf conductance to water vapour transfer (g) and microclimatic parameters in field-grown spring barley (Hordeum distichum L. cv. Gunnar). The barley crop was grown on a coarse textured sandy soil at low (50 kg ha -~) or high (200 kg ha -1) levels of potassium applied as KCI. The investigation was undertaken at full irrigation or under drought. Drought was imposed at the beginning of the grain filling period.Leaf conductance and rate of transpiration were higher in the flag leaf than in the leaves of lower insertion. The rate of transpiration of the awns on a dry weight basis was of similar magnitude to that of the flag leaves. On clear days the rate of transpiration of fully watered barley plants was at a high level during most part of the day. The transpiration only decreased at low light intensities. The rate of transpiration was high despite leaf water potentials falling to rather low values due to high evaporative demands. In water stressed plants transpiration decreased and midday depression of transpiration occurred. Normally, daily accumulated transpirational water loss was lower in high K leaves than in low K leaves and generally the bulk water relations of the leaves were more favourable in high K plants than in low K plants.The factorial dependency of the flag leaf conductances on leaf water potential, light intensity, leaf temperature, and leaf-to-air water vapour concentration difference (AW) was analysed from a set of field data. From these data, similar sets of microclimatic conditions were classified, and dependencies of leaf conductance on the various environmental parameters were ascertained. The resulting mathematical functions were combined in an empirical simulation model. The results of the model were tested against other sets of measured data. Deviations between measured and predicted leaf conductance occurred at low light intensities. In the flag leaf, water potentials below -1.6 MPa reduced the stomatal apertures and determined the upper limit of leaf conductance. In leaves of lower insertion level conductances were reduced already at higher leaf water potentials. Leaf conductance was increased hyperbolically as photosynthetic active radiation (PAR) increased from darkness to full light. Leaf conductance as a function of leaf temperature followed an optimum curve which in the model was replaced by two linear regression lines intersecting at the optimum temperature of 23.4°C. Increasing 206 L6sch et al. leaf-to-air water vapour concentration difference caused a linear decrease in leaf conductance. Leaf conductances became slightly more reduced by lowered water potentials in the low K plants. Stomatal closure in response to a temperature change away from the optimum was more sensitive in high K plants, and also the decrease in leaf conductance under the influence of lowered ambient humidity proceeded with a higher sensitivity in high K plants. Thus, und...

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Section: Introductionsupporting

confidence: 70%

Diurnal courses and factorial dependencies of leaf conductance and transpiration of differently potassium fertilized and watered field grown barley plants

Lösch

Jensen²,

Andersen³

1992

Plant Soil

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“…However, nurse shrubs effectively modified one soil property, available K, being in all cases higher under shrubs than in open interspaces. Potassium seems to increase plant resistance to drought, mainly due to osmotic adjustments and a reduction in transpiration rates, which in turn involves a higher water-use efficiency (Bradbury & Malcom 1977;van den Driessche 1991;Egilla et al 2001). Despite its potential benefit, this nutrient has never been highlighted when analysing facilitation mechanisms by nurse plants, with most studies focusing on the modification of soil nitrogen as the main nutrient-related facilitation mechanism (Pugnaire et al 1996;Moro et al 1997;Carrillo-García et al 2000).…”

Section: Relative Importance Of Soil Vs Canopy Effectsmentioning

confidence: 99%

Canopy vs. soil effects of shrubs facilitating tree seedlings in Mediterranean montane ecosystems

et al. 2005

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Question: Is the facilitative effect of nurse shrubs on early recruitment of trees mediated by a 'canopy effect' (microclimate amelioration and protection from herbivores), a 'soil effect' (modification of soil properties), or both? Location: Two successional montane shrublands at the Sierra Nevada Protected Area, SE Spain. Method: Seedlings of Quercus and Pinus species were planted in four experimental treatments: (1) under shrubs; (2) in open interspaces without vegetation; (3) under shrubs where the canopies were removed; (4) in open interspaces but covering seedlings with branches, mimicking a shrub canopy. Results: Both effects benefited seedling performance. However, microclimatic amelioration due to canopy shading had the strongest effect, which was particularly pronounced in the drier site. Below-ground, shrubs did not modify soil physical characteristics, organic matter, total N and P, or water content, but significantly increased available K, which has been shown to improve seedling water-use efficiency under drought conditions. Conclusions: We propose that in Mediterranean montane ecosystems, characterised by a severe summer drought, pioneer shrubs represent a major safe site for tree early recruitment during secondary succession, improving seedling survival during summer by the modification of both the aboveand below-ground environment.Keywords: Nurse shrub; Positive interaction; Potassium; Removal experiment; Shade.Nomenclature: Castroviejo et al. (1986Castroviejo et al. ( -2001 for Quercus and Pinus species, and Molero-Mesa et al. (1992) for shrub species.

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“…Hence, one means by which K deficiency reduces photosynthesis is by decreasing stomatal conductance [40,50]. More generally, transpiration increases (and WUE decreases) if K is in poor supply [7,29]. In these cases, changes in stomatal conductance are not responsible for the decline in photosynthesis; instead the large K requirement for protein synthesis [27] is probably responsible for strong correlations between concentrations of K and proteins such as Rubisco [20].…”

Section: Introductionmentioning

confidence: 99%

Differential effects of N, P and K on photosynthesis and partitioning of N in Pinus pinaster needles

Warren

McGrath²,

Adams

2005

Ann. For. Sci.

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-We investigated the response of one-year-old Pinus pinaster Ait. growing on a sandy, nutrient-poor soil to the factorial addition of N, P and K. We tested two hypotheses: (1) fertiliser application increases rates of light-saturated photosynthesis (A max ) and leaf-level wateruse efficiency (WUE, as indicated by carbon isotope composition), and (2) greater concentrations of N and Rubisco explain fertiliser-promoted increases in A max and WUE. Two years after fertiliser application, the height of P. pinaster was significantly greater in plots to which P was added (127 ± 7 cm; mean ± SE of three replicate plots) compared to those without added P (70 ± 10 cm), but was unaffected by addition of N or K. The fraction of N present as Rubisco varied between 4 and 18% and was unrelated to N concentrations, but positively related to P and K concentrations. A max and δ 13 C did not vary significantly among treatments and were unrelated to concentrations of Rubisco, N, P or K. We conclude that fertiliser application two years previously has little effect on current A max and δ 13 C of P. pinaster, and thus the previously reported effects of fertiliser on gas exchange are likely ephemeral. nitrogen / phosphorus / potassium / photosynthesis / rubiscoRésumé -Effets différentiels de N, P et K sur la photosynthèse et le fractionnement de N dans les aiguilles de Pinus pinaster. La réponse de plant de Pinus pinaster Ait., poussant sur un sol sableux et pauvre, a été étudiée en fonction de l'addition de N, P et K. Deux hypothèses ont été testées : (1) la fertilisation accroît le taux de saturation lumineuse de la photosynthèse (A max ) et le niveau d'efficience de l'eau (WUE, évalué par la composition isotropique du carbone), (2) une plus grande concentration de N et de rubisco explique que la fertilisation accroît A max et WUE. Deux années après l'application de la fertilisation, la hauteur de P. pinaster était significativement plus grande dans les placeaux où P avait été ajouté (127 ± 7 cm, moyenne ± SE de 3 répétitions), comparativement à ceux sans addition de P (70 ± 10 cm) mais n'était pas affectée par l'addition de N et K. La fraction de N présente sous la forme de rubisco variait entre 4 et 18 % et n'était pas expliquée par les concentrations en N, mais était positivement expliqué par les concentrations en P et K. A max et δ 13 ne variaient pas significativement avec le traitement et n'était pas reliés aux concentrations en rubisco, N, P ou K. On conclue que l'application d'un fertilisant deux ans auparavant a peu d'effet sur les valeurs actuelles de A max et δ 13 C de P. pinaster et alors les effets rapportés auparavant des fertilisants sur les échanges gazeux sont probablement éphémères. azote / phosphore / potassium / photosynthèse / rubisco Abbreviations: A max , maximum rate of light-saturated photosynthesis at ambient CO 2 ; CE, capillary electrophoresis; C i , intercellular CO 2 concentration; Chl, chlorophyll; g s , stomatal conductance; LAI, leaf area index; PPFD, photosynthetic photon flux density; Rubis...

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The Effect of Phosphorus and Potassium on Transpiration, Leaf Diffusive Resistance and Water-Use Efficiency in Sitka Spruce (Picea sitchensis) Seedlings

Cited by 52 publications

References 9 publications

Diurnal courses and factorial dependencies of leaf conductance and transpiration of differently potassium fertilized and watered field grown barley plants

Diurnal courses and factorial dependencies of leaf conductance and transpiration of differently potassium fertilized and watered field grown barley plants

Canopy vs. soil effects of shrubs facilitating tree seedlings in Mediterranean montane ecosystems

Differential effects of N, P and K on photosynthesis and partitioning of N in Pinus pinaster needles

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