Phosphorus deficiency alters scaling relationships between leaf gas exchange and associated traits in a wide range of contrasting Eucalyptus species

2018 ◽  
Vol 45 (8) ◽  
pp. 813 ◽  
Author(s):  
Nur H. A. Bahar ◽  
Paul P. G. Gauthier ◽  
Odhran S. O'Sullivan ◽  
Thomas Brereton ◽  
John R. Evans ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Phosphorus Deficiency ◽  
Leaf Traits ◽  
Leaf Mass Per Area ◽  
Eucalyptus Species ◽  
P Deficiency ◽  
Scaling Relationships ◽  
Wide Range ◽  
Leaf Metabolism

Phosphorus (P) limitation is known to have substantial impacts on leaf metabolism. However, uncertainty remains around whether P deficiency alters scaling functions linking leaf metabolism to associated traits. We investigated the effect of P deficiency on leaf gas exchange and related leaf traits in 17 contrasting Eucalyptus species that exhibit inherent differences in leaf traits. Saplings were grown under controlled-environment conditions in a glasshouse, where they were subjected to minus and plus P treatments for 15 weeks. P deficiency decreased P concentrations and increased leaf mass per area (LMA) of newly-developed leaves. Rates of photosynthesis (A) and respiration (R) were also reduced in P-deficient plants compared with P-fertilised plants. By contrast, P deficiency had little effect on the temperature sensitivity of R. Irrespective of P treatment, on a log-log basis A and R scaled positively with increasing leaf nitrogen concentration [N] and negatively with increasing LMA. Although P deficiency had limited impact on A-R-LMA relationships, rates of CO2 exchange per unit N were consistently lower in P-deficient plants. Our results highlight the importance of P supply for leaf carbon metabolism and show how P deficiencies (i.e. when excluding confounding genotypic and environmental effects) can have a direct effect on commonly used leaf trait scaling relationships.

scholarly journals Leaf Photosynthetic Capacity of Sunlit and Shaded Mature Leaves in a Deciduous Forest

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 318
Author(s):  
Guangman Song ◽  
Quan Wang ◽  
Jia Jin
Keyword(s):  
Close Relationships ◽  
Deciduous Forest ◽  
Photosynthetic Capacity ◽  
Leaf Gas Exchange ◽  
Nitrogen Concentration ◽  
Leaf Traits ◽  
Leaf Nitrogen ◽  
Leaf Mass Per Area ◽  
Clear Understanding ◽  
Equivalent Water Thickness

A clear understanding of the dynamics of photosynthetic capacity is crucial for accurate modeling of ecosystem carbon uptake. However, such dynamical information is hardly available and has dramatically impeded our understanding of carbon cycles. Although tremendous efforts have been made in coupling the dynamic information of photosynthetic capacity into models, using “proxies” rooted from the close relationships between photosynthetic capacity and other available leaf parameters remains the popular selection. Unfortunately, no consensus has yet been reached on such “proxies”, leading them only applicable to limited cases. In this study, we aim to identify if there are close relationships between the photosynthetic capacity (represented by the maximum carboxylation rate, Vcmax) and leaf traits for mature broadleaves within a cold temperature deciduous forest. This is based on a long-term in situ dataset including leaf chlorophyll content (Chl), leaf nitrogen concentration (Narea, Nmass), leaf carbon concentration (Carea, Cmass), equivalent water thickness (EWT), leaf mass per area (LMA), and leaf gas exchange measurements from which Vcmax was derived, for both sunlit and shaded leaves during leaf mature periods from 2014 to 2019. The results show that the Vcmax values of sunlit and shaded leaves were relatively stable during these periods, and no statistically significant interannual variations occurred (p > 0.05). However, this is not applicable to specific species. Path analysis revealed that Narea was the major contributor to Vcmax for sunlit leaves (0.502), while LMA had the greatest direct relationship with Vcmax for shaded leaves (0.625). The LMA has further been confirmed as a primary proxy if no leaf type information is available. These findings provide a promising way to better understand photosynthesis and to predict carbon and water cycles in temperate deciduous forests.

scholarly journals Phosphorus deficiency changes carbon isotope fractionation and triggers exudate reacquisition in tomato plants

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Raphael Tiziani ◽  
Youry Pii ◽  
Silvia Celletti ◽  
Stefano Cesco ◽  
Tanja Mimmo
Keyword(s):  
Root Exudates ◽  
Isotope Fractionation ◽  
Phosphorus Deficiency ◽  
Plant Roots ◽  
P Deficiency ◽  
Tomato Plants ◽  
Tomato Roots ◽  
Wide Range ◽  
Hydroponically Grown ◽  
Over Time

Abstract Plant roots are able to exude vast amounts of metabolites into the rhizosphere in response to phosphorus (P) deficiency. Causing noteworthy costs in terms of energy and carbon (C) for the plants. Therefore, it is suggested that exudates reacquisition by roots could represent an energy saving strategy of plants. This study aimed at investigating the effect of P deficiency on the ability of hydroponically grown tomato plants to re-acquire specific compounds generally present in root exudates by using 13C-labelled molecules. Results showed that P deficient tomato plants were able to take up citrate (+ 37%) and malate (+ 37%), particularly when compared to controls. While glycine (+ 42%) and fructose (+ 49%) uptake was enhanced in P shortage, glucose acquisition was not affected by the nutritional status. Unexpectedly, results also showed that P deficiency leads to a 13C enrichment in both tomato roots and shoots over time (shoots—+ 2.66‰, roots—+ 2.64‰, compared to control plants), probably due to stomata closure triggered by P deficiency. These findings highlight that tomato plants are able to take up a wide range of metabolites belonging to root exudates, thus maximizing C trade off. This trait is particularly evident when plants grew in P deficiency.

Tomato plants reuptake root exudates and alter carbon isotope fractionation under phosphorus deficiency

2021 ◽  
Author(s):  
Raphael Tiziani ◽  
Fabio Trevisan ◽  
Youry Pii ◽  
Silvia Celletti ◽  
Stefano Cesco ◽  
...  
Keyword(s):  
Root Exudates ◽  
Isotope Ratio ◽  
Isotope Fractionation ◽  
Phosphorus Deficiency ◽  
P Deficiency ◽  
Tomato Plants ◽  
Tomato Roots ◽  
Wide Range ◽  
Isotope Ratio Mass Spectrometer ◽  
Hydroponically Grown

<p>Plant roots are able to exude vast amounts of metabolites into the rhizosphere especially when subjected to phosphorus (P) deficiency to increase P solubility and thus its´ uptake. This causes noteworthy costs in terms of energy and carbon (C) for the plants. For this reason, we suggested that exudates reacquisition by roots could represent an energy saving strategy of plants. This study aimed at investigating the effect of P deficiency on the ability of hydroponically grown tomato plants to re-uptake specific metabolites generally present in root exudates by using <sup>13</sup>C-labelled molecules. Hence, tomato plants have been grown for 21 days in full and P deficient nutrient solution. Exudates reuptake has been assessed by immersion of roots in a solution containing <sup>13</sup>C labeled glycine, glucose, fructose, citrate, and malate. δ<sup>13</sup>C analysis was performed using a Continuous Flow Isotope Ratio Mass Spectrometer (CFIRMS). Results revealed that P deficient tomato plants were able to take up significantly more citrate (+37%) and malate (+37%), when compared to controls. While also glycine (+42%) and fructose (+49%) uptake was enhanced in P shortage, glucose acquisition was not affected by plants nutritional status. Unexpectedly, results also highlighted that P deficiency leads to a <sup>13</sup>C enrichment in both tomato roots and shoots over time (shoots +2.66 ‰, roots +2.64 ‰, compared to control plants). This could be explained by stomata closure triggered by P deficiency resulting in an increased use of <sup>13</sup>CO<sub>2</sub> in respect to <sup>12</sup>CO<sub>2</sub>, normally preferred by RuBisCO. Our findings highlight that tomato plants are able to take up a wide range of metabolites belonging to root exudates, thus optimizing C trade off. This trait is particularly evident when plants grew in P deficiency.</p>

Effects of prolonged elevated temperature on leaf gas exchange and other leaf traits in young olive trees

2020 ◽  
Author(s):  
Andrea Miserere ◽  
M Cecilia Rousseaux ◽  
Edmundo L Ploschuk ◽  
M Magdalena Brizuela ◽  
Matías H Curcio ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Elevated Temperature ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Leaf Traits ◽  
Moderate Increase ◽  
Temperature Level ◽  
Stomatal Size ◽  
Olive Trees ◽  
Temperature Levels

Abstract Despite the economic importance of long-lived crop species in the Mediterranean Basin and their expansion to new warmer regions, their potential responses to prolonged temperature increases have not been adequately addressed. The objectives of this study were to: (i) assess leaf gas exchange responses to prolonged elevated temperature in young olive trees; (ii) evaluate some additional leaf traits such as stomatal density and size under these same conditions; and (iii) determine whether photosynthetic acclimation to temperature was apparent. A field experiment with two temperature levels was conducted using well-irrigated, potted olive trees (cvs. Arbequina, Coratina) grown in open-top chambers during the summer and early fall in two growing seasons. The temperature levels were a near-ambient control (T0) and a heated (T+) treatment (+4 °C). Maximum photosynthetic rate (Amax), stomatal conductance (gs), transpiration (E) and chlorophyll fluorescence were measured. Stomatal size and density and trichome density were also determined. The Amax, gs and chlorophyll fluorescence were little affected by heating. However, leaf E was higher at T+ than T0 in the summer in both seasons due in large part to the moderate increase in vapor pressure deficit that accompanied heating, and consequently water-use efficiency was reduced in heated leaves. When reciprocal temperature measurements were conducted in mid-summer of the second season, Amax values of T0 and T+ leaves were higher under the temperature level at which they grew than when measured at the other temperature level, which suggests some thermal acclimation. Stomatal size and density were greater in T+ than in T0 grown leaves in some cases, which was consistent with a greater E in T+ leaves when measured at both temperature levels. These results suggest that acclimation to long-term changes in temperature must be carefully considered to help determine how olive trees will be influenced by global warming.

scholarly journals Leaf 13C and 15N composition shedding light on easing drought stress through partial K substitution by Na in eucalyptus species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nikolas Souza Mateus ◽  
Antonio Leite Florentino ◽  
Jessica Bezerra Oliveira ◽  
Elcio Ferreira Santos ◽  
Salete Aparecida Gaziola ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Chlorophyll Concentration ◽  
Dry Mass ◽  
Eucalyptus Species ◽  
Gas Exchange Parameters ◽  
Lower Growth ◽  
Mda Content ◽  
Exchange Parameters

AbstractThis work aimed to investigate the partial K-replacement by Na supply to alleviate drought-induced stress in Eucalyptus species. Plant growth, leaf gas exchange parameters, water relations, oxidative stress (H2O2 and MDA content), chlorophyll concentration, carbon (C) and nitrogen (N) isotopic leaf composition (δ13C and δ15N) were analyzed. Drought tolerant E. urophylla and E. camaldulensis showed positive responses to the partial K substitution by Na, with similar dry mass yields, stomatal density and total stomatal pore area relative to the well K-supplied plants under both water conditions, suggesting that 50% of the K requirements is pressing for physiological functions that is poorly substituted by Na. Furthermore, E. urophylla and E. camaldulensis up-regulated leaf gas exchanges, leading to enhanced long-term water use efficiency (WUEL). Moreover, the partial K substitution by Na had no effects on plants H2O2, MDA, δ13C and δ15N, confirming that Na, to a certain extent, can effectively replace K in plants metabolism. Otherwise, the drought-sensitive E. saligna species was negatively affected by partial K replacement by Na, decreasing plants dry mass, even with up-regulated leaf gas exchange parameters. The exclusive Na-supplied plants showed K-deficient symptoms and lower growth, WUEL, and δ13C, besides higher Na accumulation, δ15N, H2O2 and MDA content.

Corrigendum to: Leaf water use efficiency differs between Eucalyptus seedlings from contrasting rainfall environments

2004 ◽  
Vol 31 (7) ◽  
pp. 757 ◽  
Author(s):  
Dane S. Thomas ◽  
Matthew J. Searson ◽  
Jann P. Conway ◽  
Kelvin D. Montagu
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Leaf Gas Exchange ◽  
Eucalyptus Grandis ◽  
Eucalyptus Species ◽  
Use Efficiency ◽  
Leaf N Content

This study investigates the putative role of thicker leaves in enhancing photosynthetic capacity and water-use efficiency (WUE) of Eucalyptus species native to xeric environments. Three Eucalyptus species, Eucalyptus grandis Hill. (ex Maiden), E. sideroxylon Cunn. (ex Woolls) and E. occidentalis (Endl.), were grown under well-watered or water-limited conditions in a single compartment of a temperature-controlled glasshouse. Eucalyptus grandis is native to a mesic environment while E. sideroxylon and E. occidentalis are native to xeric environments. Leaves of E. sideroxylon and E. occidentalis were thicker and contained more nitrogen (N) on a leaf-area basis than E. grandis. Leaf gas-exchange measurements indicated that the photosynthetic capacity of E. sideroxylon and E.�occidentalis was greater than E. grandis and that stomatal conductance and WUE were negatively correlated. Whole-plant, gas-exchange and carbon-isotope measurements showed that E. sideroxylon and E. occidentalis had lower WUE than E. grandis under both well-watered and water-limited conditions. However, there was no difference in N-use efficiency between species. We suggest that stomatal conductance and leaf N content are functionally linked in these seedlings and conclude that thick leaves can, in some conditions, result in low WUE.

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