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Kevin L. Griffin - One of the best experts on this subject based on the ideXlab platform.
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Light inhibition of foliar respiration in response to soil water availability and seasonal changes in temperature in Mediterranean holm oak (Quercus ilex) forest
Functional Plant Biology, 2017Co-Authors: Matthew H. Turnbull, Roma Ogaya, Adrià Barbeta, Josep Penuelas, Joana Zaragoza-castells, Owen K. Atkin, Fernando Valladares, Teresa Gimeno, Beatriz Pías, Kevin L. GriffinAbstract:In the present study we investigated variations in leaf respiration in darkness (R-D) and light (R-L), and associated traits in response to season, and along a Gradient of soil Moisture, in Mediterranean woodland dominated by holm oak (Quercus ilex L.) in central and north-eastern Spain respectively. On seven occasions during the year in the central Spain site, and along the soil Moisture Gradient in north-eastern Spain, we measured rates of leaf R-D, R-L (using the Kok method), light-saturated photosynthesis (A) and related light response characteristics, leaf mass per unit area (MA) and leaf nitrogen (N) content. At the central Spain site, significant seasonal changes in soil water content and ambient temperature (T) were associated with changes in M-A, foliar N, A and stomatal conductance. R-D measured at the prevailing daily T and in instantaneous R-T responses, displayed signs of partial acclimation and was not significantly affected by time of year. R-L was always less than, and strongly related to, R-D, and R-L/R-D did not vary significantly or systematically with seasonal changes in T or soil water content. Averaged over the year, R-L/R-D was 0.66 +/- 0.05 s.e. (n = 14) at the central Spain site. At the north-eastern Spain site, the soil Moisture Gradient was characterised by increasing M-A and R-D, and reduced foliar N, A, and stomatal conductance as soil water availability decreased. Light inhibition of R occurred across all sites (mean R-L/R-D= 0.69 +/- 0.01 s.e. (n = 18)), resulting in ratios of R-L/A being lower than for R-D/A. Importantly, the degree of light inhibition was largely insensitive to changes in soil water content. Our findings provide evidence for a relatively constrained degree of light inhibition of R (R-L/R-D similar to 0.7, or inhibition of similar to 30%) across Gradients of water availability, although the combined impacts of seasonal changes in both T and soil water content increase the range of values expressed. The findings thus have implications in terms of the assumptions made by predictive models that seek to account for light inhibition of R, and for our understanding of how environmental Gradients impact on leaf trait relationships in Mediterranean plant communities.
Matthew H. Turnbull - One of the best experts on this subject based on the ideXlab platform.
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Light inhibition of foliar respiration in response to soil water availability and seasonal changes in temperature in Mediterranean holm oak (Quercus ilex) forest
Functional Plant Biology, 2017Co-Authors: Matthew H. Turnbull, Roma Ogaya, Adrià Barbeta, Josep Penuelas, Joana Zaragoza-castells, Owen K. Atkin, Fernando Valladares, Teresa Gimeno, Beatriz Pías, Kevin L. GriffinAbstract:In the present study we investigated variations in leaf respiration in darkness (R-D) and light (R-L), and associated traits in response to season, and along a Gradient of soil Moisture, in Mediterranean woodland dominated by holm oak (Quercus ilex L.) in central and north-eastern Spain respectively. On seven occasions during the year in the central Spain site, and along the soil Moisture Gradient in north-eastern Spain, we measured rates of leaf R-D, R-L (using the Kok method), light-saturated photosynthesis (A) and related light response characteristics, leaf mass per unit area (MA) and leaf nitrogen (N) content. At the central Spain site, significant seasonal changes in soil water content and ambient temperature (T) were associated with changes in M-A, foliar N, A and stomatal conductance. R-D measured at the prevailing daily T and in instantaneous R-T responses, displayed signs of partial acclimation and was not significantly affected by time of year. R-L was always less than, and strongly related to, R-D, and R-L/R-D did not vary significantly or systematically with seasonal changes in T or soil water content. Averaged over the year, R-L/R-D was 0.66 +/- 0.05 s.e. (n = 14) at the central Spain site. At the north-eastern Spain site, the soil Moisture Gradient was characterised by increasing M-A and R-D, and reduced foliar N, A, and stomatal conductance as soil water availability decreased. Light inhibition of R occurred across all sites (mean R-L/R-D= 0.69 +/- 0.01 s.e. (n = 18)), resulting in ratios of R-L/A being lower than for R-D/A. Importantly, the degree of light inhibition was largely insensitive to changes in soil water content. Our findings provide evidence for a relatively constrained degree of light inhibition of R (R-L/R-D similar to 0.7, or inhibition of similar to 30%) across Gradients of water availability, although the combined impacts of seasonal changes in both T and soil water content increase the range of values expressed. The findings thus have implications in terms of the assumptions made by predictive models that seek to account for light inhibition of R, and for our understanding of how environmental Gradients impact on leaf trait relationships in Mediterranean plant communities.
T Sampathkumar - One of the best experts on this subject based on the ideXlab platform.
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effect of deficit irrigation on yield relative leaf water content leaf proline accumulation and chlorophyll stability index of cotton maize cropping sequence
Experimental Agriculture, 2014Co-Authors: T Sampathkumar, B J Pandian, P Jeyakumar, P ManickasundaramAbstract:Water stress induces some physiological changes in plants and has cumulative effects on crop growth and yield. Field experiments were conducted to study the effect of deficit irrigation (DI) on yield and some physiological parameters in cotton and maize in a sequential cropping system. Creation of soil Moisture Gradient is indispensable to explore the beneficial effects of partial root zone drying (PRD) irrigation and it could be possible only through alternate deficit irrigation (ADI) practice in paired row system of drip layout that is commonly practiced in India. In the present study, PRD and DI concepts (creation of soil Moisture Gradient) were implemented through ADI at two levels of irrigation using drip system. Maize was sown after cotton under no till condition without disturbing the raised bed and drip layout. Relative leaf water content (RLWC) and chlorophyll stability index (CSI) of cotton and maize were reduced under water stress. A higher level of leaf proline content was observed under severe water-stressed treatments in cotton and maize. RLWC and CSI were highest and leaf proline content was lowest in mild water deficit (ADI at 100% crop evapotranspiration once in three days) irrigation in cotton and maize. The same treatments registered higher values for crop yields, net income and benefit cost ratio for both the crops.
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influence of deficit irrigation on growth yield and yield parameters of cotton maize cropping sequence
Agricultural Water Management, 2013Co-Authors: T Sampathkumar, B J Pandian, P Manickasundaram, M V Rangaswamy, P JeyakumarAbstract:Abstract Field experiments were conducted at Agricultural College and Research Institute, Coimbatore, India during 2007–2009 to study the effect of deficit irrigation practices implemented through drip irrigation system on cotton–maize cropping sequence. Creation of soil Moisture Gradient is essential to explore the beneficial effects of partial root zone drying (PRD) irrigation; and it could be possible through ADI (alternate deficit irrigation) practice in paired row system of drip layout, commonly practiced in India. In the present study, PRD and deficit irrigation (DI) concepts (creation of soil Moisture Gradient) were implemented through ADI at two levels of irrigation using drip irrigation system. Experimental treatments comprised of seven irrigation levels (full and deficit) through drip system with surface irrigation for comparison. Maize was sown after cotton under no till condition without disturbing the raised bed and drip layout. Response of the crops to water stress indicated growth, yield parameters and crop yield were highest in mild water deficit (ADI at 100% ETc once in three days) among different deficit irrigation treatments. Alternate deficit irrigation (ADI100-50 and ADI80-40) resulted in higher values in plant height, LAI (leaf area index) and DMP (dry matter production). Among the deficit irrigation practices, mild deficit (ADI at 100% ETc once in three days) registered higher values for seed cotton yield (3670–3760 kg ha−1), grain yield of maize (7420–7590 kg ha−1). The same treatment registered higher values for net income and benefit cost ratio (BCR) in both the crops. Number of bolls per plant and sympodial branches per plant were the highly correlated parameters to seed cotton yield. In the case of maize, the number of grain per cob and cob weight were the highly correlated parameters to grain yield.
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soil Moisture distribution and root characters as influenced by deficit irrigation through drip system in cotton maize cropping sequence
Agricultural Water Management, 2012Co-Authors: T Sampathkumar, B J Pandian, S MahimairajaAbstract:Abstract Field experiments were conducted during 2007–2009 to study the effect of deficit irrigation practices through drip irrigation system on soil Moisture distribution and root growth in cotton–maize cropping sequence. Creation of soil Moisture Gradient is indispensable to explore the beneficial effects of partial root zone drying (PRD) irrigation and it could be possible only through ADI practice in paired row system of drip layout, that is commonly practiced in India. In the present study, PRD and deficit irrigation (DI) concepts (creation of soil Moisture Gradient) were implemented through alternate deficit irrigation (ADI) at two levels of irrigation using drip system. Experimental treatments comprised of six irrigation levels (full and deficit) through drip system with surface irrigation for comparison. Maize was sown after cotton under no till condition without disturbing the raised bed and drip layout. Roots confined to the shallow depth and recorded the lowest values for both the crops under conventional drip irrigation at 100% ETc. Among the deficit irrigation treatments, mild deficit irrigation produced longer lateral roots from both the sides of the plant. Contrary to rooting depth, severe water stress affected the lateral root spread and recorded lower values than other drip irrigation treatments. Soil Moisture content (SMC) was low nearer to the plant (at 30 cm across the lateral) and far away (at 30 cm along the lateral) from the plant, irrespective of treatments. The reduction in SMC was increased at all locations as applied water level decreased. It is concluded that alternate watering imposed through ADI at 100% ETc produced longer lateral roots with higher values for root dry mass Alternate deficit irrigation (ADI) resulted uneven distribution of soil Moisture content. Among the ADI treatments, ADI at 100% had less uneven distribution than ADI at 80% ETc.
Owen K. Atkin - One of the best experts on this subject based on the ideXlab platform.
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Light inhibition of foliar respiration in response to soil water availability and seasonal changes in temperature in Mediterranean holm oak (Quercus ilex) forest
Functional Plant Biology, 2017Co-Authors: Matthew H. Turnbull, Roma Ogaya, Adrià Barbeta, Josep Penuelas, Joana Zaragoza-castells, Owen K. Atkin, Fernando Valladares, Teresa Gimeno, Beatriz Pías, Kevin L. GriffinAbstract:In the present study we investigated variations in leaf respiration in darkness (R-D) and light (R-L), and associated traits in response to season, and along a Gradient of soil Moisture, in Mediterranean woodland dominated by holm oak (Quercus ilex L.) in central and north-eastern Spain respectively. On seven occasions during the year in the central Spain site, and along the soil Moisture Gradient in north-eastern Spain, we measured rates of leaf R-D, R-L (using the Kok method), light-saturated photosynthesis (A) and related light response characteristics, leaf mass per unit area (MA) and leaf nitrogen (N) content. At the central Spain site, significant seasonal changes in soil water content and ambient temperature (T) were associated with changes in M-A, foliar N, A and stomatal conductance. R-D measured at the prevailing daily T and in instantaneous R-T responses, displayed signs of partial acclimation and was not significantly affected by time of year. R-L was always less than, and strongly related to, R-D, and R-L/R-D did not vary significantly or systematically with seasonal changes in T or soil water content. Averaged over the year, R-L/R-D was 0.66 +/- 0.05 s.e. (n = 14) at the central Spain site. At the north-eastern Spain site, the soil Moisture Gradient was characterised by increasing M-A and R-D, and reduced foliar N, A, and stomatal conductance as soil water availability decreased. Light inhibition of R occurred across all sites (mean R-L/R-D= 0.69 +/- 0.01 s.e. (n = 18)), resulting in ratios of R-L/A being lower than for R-D/A. Importantly, the degree of light inhibition was largely insensitive to changes in soil water content. Our findings provide evidence for a relatively constrained degree of light inhibition of R (R-L/R-D similar to 0.7, or inhibition of similar to 30%) across Gradients of water availability, although the combined impacts of seasonal changes in both T and soil water content increase the range of values expressed. The findings thus have implications in terms of the assumptions made by predictive models that seek to account for light inhibition of R, and for our understanding of how environmental Gradients impact on leaf trait relationships in Mediterranean plant communities.
Joana Zaragoza-castells - One of the best experts on this subject based on the ideXlab platform.
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Light inhibition of foliar respiration in response to soil water availability and seasonal changes in temperature in Mediterranean holm oak (Quercus ilex) forest
Functional Plant Biology, 2017Co-Authors: Matthew H. Turnbull, Roma Ogaya, Adrià Barbeta, Josep Penuelas, Joana Zaragoza-castells, Owen K. Atkin, Fernando Valladares, Teresa Gimeno, Beatriz Pías, Kevin L. GriffinAbstract:In the present study we investigated variations in leaf respiration in darkness (R-D) and light (R-L), and associated traits in response to season, and along a Gradient of soil Moisture, in Mediterranean woodland dominated by holm oak (Quercus ilex L.) in central and north-eastern Spain respectively. On seven occasions during the year in the central Spain site, and along the soil Moisture Gradient in north-eastern Spain, we measured rates of leaf R-D, R-L (using the Kok method), light-saturated photosynthesis (A) and related light response characteristics, leaf mass per unit area (MA) and leaf nitrogen (N) content. At the central Spain site, significant seasonal changes in soil water content and ambient temperature (T) were associated with changes in M-A, foliar N, A and stomatal conductance. R-D measured at the prevailing daily T and in instantaneous R-T responses, displayed signs of partial acclimation and was not significantly affected by time of year. R-L was always less than, and strongly related to, R-D, and R-L/R-D did not vary significantly or systematically with seasonal changes in T or soil water content. Averaged over the year, R-L/R-D was 0.66 +/- 0.05 s.e. (n = 14) at the central Spain site. At the north-eastern Spain site, the soil Moisture Gradient was characterised by increasing M-A and R-D, and reduced foliar N, A, and stomatal conductance as soil water availability decreased. Light inhibition of R occurred across all sites (mean R-L/R-D= 0.69 +/- 0.01 s.e. (n = 18)), resulting in ratios of R-L/A being lower than for R-D/A. Importantly, the degree of light inhibition was largely insensitive to changes in soil water content. Our findings provide evidence for a relatively constrained degree of light inhibition of R (R-L/R-D similar to 0.7, or inhibition of similar to 30%) across Gradients of water availability, although the combined impacts of seasonal changes in both T and soil water content increase the range of values expressed. The findings thus have implications in terms of the assumptions made by predictive models that seek to account for light inhibition of R, and for our understanding of how environmental Gradients impact on leaf trait relationships in Mediterranean plant communities.