Carbon Isotope Discrimination and Photosynthetic Gas Exchange in Coffee Hedgerows During Canopy Development

1994 ◽  
Vol 21 (2) ◽  
pp. 207 ◽  
Author(s):  
MV Gutierrez ◽  
FC Meinzer
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Area Index ◽  
Canopy Development ◽  
Isotope Discrimination ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Sun Leaves

In evergreen species, leaf carbon isotope discrimination (Δ) integrates phenological rhythms in gas exchange as well as seasonal changes in environmental conditions. However, few reports on long term variations in Δ of woody plants are available. We measured Δ, gas exchange, nitrogen content, and photosynthetic nitrogen-use efficiency (PNUE) in coffee hedgerows at different stages of canopy development encompassing a range of leaf area index (LAI) from 0.7 to 7.5. Assimilation was highest in sun leaves, but stomatal conductance was highest in shaded leaves. This resulted in a high correlation between assimilation and stomatal conductance in sun, but not in shaded leaves. Δ was about 20 lower in sun than in shaded leaves, and varied by 2.30 among leaves at different positions along two-year- old branches. These differences in Δ were the result of changes in carbon isotope composition that occurred in mature, fully expanded leaves as they became shaded during subsequent canopy growth. Results from a mass balance model based on leaf gas exchange characteristics and measured foliar Δ values suggested that about 50% of the carbon originally fixed during leaf development in the sun may have subsequently been turned over in the shade. Δ of sun leaves from the upper canopy decreased by about 20 with increasing LAI, indicating that intrinsic water-use efficiency (WUE) of this canopy layer increased during canopy development. In contrast, instantaneous WUE, estimated as assimilation divided by canopy transpiration obtained from sap flow measurements, seemed to decrease with increasing LAI. PNUE of upper canopy sun leaves decreased with increasing LAI, suggesting a physiological compromise between WUE and PNUE mediated by stomatal conductance, which also decreased with increasing LAI. A strong negative correlation obtained between leaf Δ and N content was consistent with a trade-off between intrinsic water- and N-use efficiency.

scholarly journals Association of carbon isotope discrimination with leaf gas exchange and water use efficiency in maize following soil amendment with superabsorbent hydrogel

2018 ◽  
Vol 64 (No. 10) ◽  
pp. 484-490
Author(s):  
Yang Wei ◽  
Li Pin-Fang
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Carbon Isotope ◽  
Water Use ◽  
Carbon Isotope Discrimination ◽  
Photosynthetic Gas Exchange ◽  
Superabsorbent Hydrogel ◽  
Isotope Discrimination ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

The correlation of carbon isotope discrimination (△<sup>13</sup>C) with photosynthetic gas exchange and water use efficiency (WUE) in maize was investigated under low rainfall conditions with or without superabsorbent polymer (SAP). SAP (45 kg/ha) was mixed into the top 10 cm soil layer at sowing in lysimeters. Compared with the control plants not treated with SAP, the application of SAP increased net photosynthesis rate; stomatal conductance (g<sub>s</sub>); transpiration rate; chlorophyll content (Chl) and intrinsic water use efficiency at leaf level (WUE<sub>i</sub>), but decreased intercellular CO<sub>2</sub> concentration (C<sub>i</sub>) and leaf △<sup>13</sup>C. In plants supplied with SAP, leaf △<sup>13</sup>C was positively correlated with C<sub>i</sub> (r = 0.864, P &lt; 0.01) and negatively correlated with g<sub>s</sub> and WUE<sub>i</sub> (r = –0.860 and –0.626, P &lt; 0.01, respectively). Leaf △<sup>13</sup>C was not correlated with Chl with or without SAP. Grain △<sup>13</sup>C significantly decreased by 12.4% and showed a significant negative correlation with grain WUE under SAP treatments (r = –0.670, P &lt; 0.05). These results suggest that in the presence of SAP, maize leaf and grain △<sup>13</sup>C could be good indicators for evaluating maize WUE during periods of low rainfall.

GAS EXCHANGE, GROWTH, YIELD AND BEVERAGE QUALITY OF COFFEA ARABICA CULTIVARS GRAFTED ON TO C. CANEPHORA AND C. CONGENSIS

2001 ◽  
Vol 37 (2) ◽  
pp. 241-252 ◽  
Author(s):  
J. I. FAHL ◽  
M. L. C. CARELLI ◽  
H. C. MENEZES ◽  
P. B. GALLO ◽  
P. C. O. TRIVELIN
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Isotope ◽  
Coffea Arabica ◽  
Carbon Isotope Discrimination ◽  
Growth Yield ◽  
Carbon Gain ◽  
Dry Period ◽  
Isotope Discrimination

Gas exchange, leaf carbon isotope discrimination, growth, yield and beverage quality were evaluated for two Coffea arabica cultivars (Catuai and Mundo Novo), grafted on to C. canephora and C. congensis progenies growing in open fields. During the years 1994 to 1997, grafting resulted in an average increase in bean yield of 151 and 89% for Catuai and Mundo Novo respectively. As analysed by sensory analyses and by the ratio between the mono-isomers and di-isomers of caffeoylquinic acid, beverage quality of the C. arabica was not altered by grafting. Shoot growth was significantly greater in grafted plants, showing an increase of 52% in total leaf area compared with the non-grafted plants. Under conditions of water excess in the soil there was little difference in the transpiration and stomatal conductance rates between the grafted and non-grafted plants, but the net photosynthesis was higher in grafted plants. With an accentuated water deficit in the soil in the dry period, the grafted plants showed significantly higher transpiration and stomatal conductance rates than the non-grafted plants, and similar values to those of C. canephora. Carbon isotope discrimination was greater in the grafted plants, suggesting greater root hydraulic conductance. The results suggest that the better performance of the grafted plants during the dry period was due to the greater capacity of the root system of C. canephora to provide water to the shoot thereby maintaining greater gas exchange in the leaves and consequently a greater carbon gain.

scholarly journals Carbon Isotope Discrimination, Gas Exchange, and Growth of Container-grown Conifers Under Cyclic Irrigation

HortScience ◽  
2013 ◽  
Vol 48 (7) ◽  
pp. 848-854 ◽  
Author(s):  
Amanda J. Taylor ◽  
R. Thomas Fernandez ◽  
Pascal Nzokou ◽  
Bert Cregg
Keyword(s):  
Gas Exchange ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Pinus Strobus ◽  
High Rate ◽  
Conifer Species ◽  
Isotope Discrimination ◽  
Irrigation Rate ◽  
Picea Pungens ◽  
Intrinsic Water Use Efficiency

The objective of this study was to quantify the effects of cyclic irrigation on growth and physiology of container-grown conifer species in pot-in-pot (PIP) production in the upper Midwest. Trees of four conifer species (Picea glauca var. densata, Picea pungens, Abies fraseri, and Pinus strobus) were grown in 25-L containers and assigned to one of four combinations of irrigation rate (low or high) and daily irrigation cycle frequency (one or four). Irrigation rates were based on common nursery practice in the region (2 cm rainfall equivalent/day) and one-half the standard rate (1 cm rainfall equivalent/day). Cyclic irrigation increased relative height growth and relative caliper growth of Pinus strobus by over 80% and 35%, respectively, compared with once-daily irrigation. The high-rate irrigation increased relative caliper growth of Picea pungens by 40% compared with the low rate. The effects of irrigation regime on needle- or shoot-level gas exchange varied by species and date of measurement. Carbon isotope discrimination (Δ13C) of needle and wood tissue was positively correlated (r ≥ 0.64, P < 0.001) with needle conductance to water vapor (gwv) and negatively correlated (r ≤ −0.60, P< 0.001) with intrinsic water use efficiency (WUEi). Carbon isotope discrimination of wood and needle tissue decreased with the low irrigation rate, indicating increased WUEi associated with reduced gwv. Cyclic irrigation had relatively little effect on Δ13C except for Pinus strobus. Our findings suggest that carbon isotope composition of wood and needle tissue provides a sensitive and accurate representation of plant response to varying moisture availability. From a water management perspective, identifying optimal irrigation rates appears to be more important than number of daily cycles for these crops grown in the midwestern United States.

scholarly journals 121 TREE GROWTH, LEAF NITROGEN, NET GAS EXCHANGE, AND CARBON ISOTOPE DISCRIMINATION IN CITRUS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 445f-445
Author(s):  
Jim Syvertsen ◽  
J. Lloyd ◽  
G. D. Farquhar
Keyword(s):  
Gas Exchange ◽  
Carbon Isotope ◽  
Tree Growth ◽  
Carbon Isotope Discrimination ◽  
Root Bark ◽  
Canopy Development ◽  
Isotope Discrimination ◽  
Volkamer Lemon ◽  
Gas Exchange System ◽  
Leaf N

Four to six-yr-old `Red Ruby' grapefruit trees on either `Volkamer' lemon (VL) or sour orange (SO) rootstocks were fertilized with 3 rates of nitrogen (N) over a 3 year period. We studied the effects of leaf N concentration on stomatal conductance (gs), net assimilation (A) of CO2 (Li-Cor portable gas exchange system), carbon isotope discrimination (δ 13C) of tree tissues, root growth, canopy development and fruit yield. Using springtime measurements of net gas exchange during the fifth year, gs, A and leaf tissue δ 13C were positively correlated with leaf N. The faster growing trees on VL had larger canopy volumes and fruit yields but lower leaf N, A and δ 13C than those on SO. Thus δ 13C was positively correlated with A but negatively related to tree size and yield. By the sixth year, δ 13C was still related to N but tree growth had apparently obscured any rootstock effects on leaf N, water use efficiency, A and δ 13C. Leaf and trunk bark tissue δ 13C did not differ but root bark had lowest δ 13C regardless of rootstock species.

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