Effect of Growth Form, Salinity, Nutrient and Sulfide on Photosynthesis, Carbon Isotope Discrimination and Growth of Red Mangrove (Rhizophora mangle L.)

1992 ◽  
Vol 19 (5) ◽  
pp. 509 ◽  
Author(s):  
GH Lin ◽  
LDSL Sternberg
Keyword(s):  
Stomatal Conductance ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
High Salinity ◽  
Co2 Assimilation ◽  
Transpiration Efficiency ◽  
Growth Forms ◽  
Growth Responses ◽  
Isotope Discrimination ◽  
Red Mangrove

The red mangrove (Rhizophora mangle L.), a dominant mangrove species in Florida, frequently occurs in two distinct growth forms, scrub and tall trees. These two growth forms show significant differences in physiology in the field, with lower CO2 assimilation rate, stomatal conductance, and carbon isotope discrimination or higher transpiration efficiency for the scrub form. To elucidate the possible factors responsible for these physiological differences, we studied the physiological and growth responses of scrub and tall red mangrove seedlings grown hydroponically in the greenhouse under 12 different growth conditions combining three salinities (100, 250, 500 mM NaCl), two nutrient levels (10, 100% strength of full nutrient solution), and two sulfide concentrations (0, 2.0 mM Na2S). The two growth forms showed similar physiological and growth responses to these treatments, suggesting no genetic control of physiological and growth differences between the growth forms of this species. High salinity, low nutrient level, and high sulfide concentration all significantly decreased CO2 assimilation, stomatal conductance, and plant growth, but only salinity significantly decreased intercellular CO2 concentration and leaf carbon isotope discrimination, suggesting that the lower carbon isotope discrimination, or higher transpiration efficiency, observed for scrub mangroves in the field is caused only by high salinity during the dry season. Hypersalinity thus seems to be one of the stressful environmental conditions common to all scrub red mangrove forests studied in southern Florida.

scholarly journals An observational constraint on stomatal function in forests: evaluating coupled carbon and water vapor exchange with carbon isotopes in the Community Land Model (CLM4.5)

2016 ◽  
Vol 13 (18) ◽  
pp. 5183-5204 ◽  
Author(s):  
Brett Raczka ◽  
Henrique F. Duarte ◽  
Charles D. Koven ◽  
Daniel Ricciuto ◽  
Peter E. Thornton ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Nitrogen Limitation ◽  
Carbon Isotope Discrimination ◽  
Stable Carbon Isotope ◽  
Atmospheric Co2 ◽  
Stable Carbon ◽  
Isotope Discrimination ◽  
Community Land Model

Abstract. Land surface models are useful tools to quantify contemporary and future climate impact on terrestrial carbon cycle processes, provided they can be appropriately constrained and tested with observations. Stable carbon isotopes of CO2 offer the potential to improve model representation of the coupled carbon and water cycles because they are strongly influenced by stomatal function. Recently, a representation of stable carbon isotope discrimination was incorporated into the Community Land Model component of the Community Earth System Model. Here, we tested the model's capability to simulate whole-forest isotope discrimination in a subalpine conifer forest at Niwot Ridge, Colorado, USA. We distinguished between isotopic behavior in response to a decrease of δ13C within atmospheric CO2 (Suess effect) vs. photosynthetic discrimination (Δcanopy), by creating a site-customized atmospheric CO2 and δ13C of CO2 time series. We implemented a seasonally varying Vcmax model calibration that best matched site observations of net CO2 carbon exchange, latent heat exchange, and biomass. The model accurately simulated observed δ13C of needle and stem tissue, but underestimated the δ13C of bulk soil carbon by 1–2 ‰. The model overestimated the multiyear (2006–2012) average Δcanopy relative to prior data-based estimates by 2–4 ‰. The amplitude of the average seasonal cycle of Δcanopy (i.e., higher in spring/fall as compared to summer) was correctly modeled but only when using a revised, fully coupled An − gs (net assimilation rate, stomatal conductance) version of the model in contrast to the partially coupled An − gs version used in the default model. The model attributed most of the seasonal variation in discrimination to An, whereas interannual variation in simulated Δcanopy during the summer months was driven by stomatal response to vapor pressure deficit (VPD). The model simulated a 10 % increase in both photosynthetic discrimination and water-use efficiency (WUE) since 1850 which is counter to established relationships between discrimination and WUE. The isotope observations used here to constrain CLM suggest (1) the model overestimated stomatal conductance and (2) the default CLM approach to representing nitrogen limitation (partially coupled model) was not capable of reproducing observed trends in discrimination. These findings demonstrate that isotope observations can provide important information related to stomatal function driven by environmental stress from VPD and nitrogen limitation. Future versions of CLM that incorporate carbon isotope discrimination are likely to benefit from explicit inclusion of mesophyll conductance.

Drought and Pot Size Effects on Transpiration Efficiency and Carbon Isotope Discrimination of Cowpea Accessions and Hybrids

1994 ◽  
Vol 21 (1) ◽  
pp. 23 ◽  
Author(s):  
AM Ismail ◽  
AE Hall ◽  
EA Bray
Keyword(s):  
Leaf Area ◽  
Carbon Isotope ◽  
Size Effects ◽  
Treatment Effects ◽  
Carbon Isotope Discrimination ◽  
Xylem Sap ◽  
Transpiration Efficiency ◽  
Drought Treatment ◽  
Isotope Discrimination ◽  
Pot Size

Carbon isotope discrimination (Δ) has been proposed as a selection criterion for improving adaptation to water-limited environments because it provides a measure of seasonal transpiration efficiency ( WUE). In cowpea (Vigna unguiculata (L.) Walp.), consistent genotypic and drought-induced differences in Δ and WUE have been observed which were correlated as expected based on theory. Values of Δ and WUE for reciprocal hybrids grown under field conditions indicated nuclear inheritance for both characters. High WUE and low Δ were partially dominant under dry field pot conditions, whereas high Δ was partially dominant under natural wet soil conditions. Studies were conducted to test whether differences in rooting environment and xylem ABA levels are responsible for this change in dominance relations. Cowpea accessions and hybrids were grown in the field and subjected to wet or dry treatments with three different pot sizes. The experiment was conducted twice, giving similar results. The dry treatment resulted in decreases in Δ, and increases in WUE and ABA concentration in the xylem sap. Under drought, genotypes with higher WUE had higher xylem ABA, and the hybrids exhibited greater increases in ABA concentration in response to the dry treatment than either parent. Partial confounding was present in that the hybrids had substantial leaf area and water-use rate, and may have experienced greater soil drought in some conditions than some parents, with interacting effects of pot size. Plants in larger pots produced more biomass and leaf area but with no changes in xylem ABA. Concentration of ABA in the xylem sap was correlated with Δ and WUE for genotypic and drought treatment effects but not for pot size effects. Hybrids tended to have higher Δ and lower WUE in relation to mid-parent means when grown in large wet pots than in small dry ones. Changes in hybrid performance with respect to Δ and WUE were more consistent with changes in xylem ABA for drought treatment effects than for pot size effects. Another chemical signal might be involved in mediating pot size effects.

Correlation between carbon isotope discrimination and transpiration efficiency in lines of the C4 species Sorghum bicolor in the glasshouse and the field

1998 ◽  
Vol 25 (1) ◽  
pp. 111 ◽  
Author(s):  
S. Henderson ◽  
S. von Caemmerer ◽  
G.D. Farquhar ◽  
L. Wade ◽  
G. Hammer
Keyword(s):  
Sorghum Bicolor ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Negative Slope ◽  
Environment Interaction ◽  
Transpiration Efficiency ◽  
Isotope Discrimination ◽  
C4 Species ◽  
C3 Species ◽  
The Mean

Transpiration efficiency, W, the ratio of plant carbon produced to water transpired and carbon isotope discrimination of leaf dry matter, Δd, were measured together on 30 lines of the C4 species, Sorghum bicolor, in the glasshouse and on eight lines grown in the field. In the glasshouse, the mean W observed was 4.9 mmol C mol-1 H2O and the range was 0.8 mmol C mol -1 H2O. The mean Δd was 3.0 and the observed range was 0.4‰. In the field, the mean W was lower at 2.8 mmol C mol-1 H2O and the mean Δd was 4.6‰. Significant positive correlations between W and Δd were observed for plants grown in the glasshouse and in the field. The observed correlations were consistent with theory, opposite to those for C3 species, and showed that variation in Δd was an integrated measure of long-term variation in the ratio of intercellular to ambient CO2 partial pressure, pi/pa. Detailed gas exchange measurements of carbon isotope discrimination during CO2 uptake, ΔA, and pi/pa were made on leaves of eight S. bicolorlines. The observed relationship between ΔA and pi/pa was linear with a negative slope of 3.7‰ in ΔA for a unit change in pi/pa. The slope of this linear relationship between ΔA and pi/pa in C4 species is dependent on the leakiness of the CO2 concentrating mechanism of the C4 pathway. We estimated the leakiness (defined as the fraction of CO2 released in the bundle sheath by C4 acid decarboxylations, which is lost by leakage) to be 0.2. We conclude that, although variation in Δd observed in the 30 lines of S. bicolor is smaller than that commonly observed in C3 species, it also reflects variation in transpiration efficiency, W. Among the eight lines examined in detail and in the environments used, there was considerable genotype × environment interaction.

Carbon Isotope Discrimination and Transpiration Efficiency in Common Bean

Crop Science ◽  
1991 ◽  
Vol 31 (6) ◽  
pp. 1611-1615 ◽  
Author(s):  
James R. Ehleringer ◽  
Stephen Klasen ◽  
Creed Clayton ◽  
Dorothy Sherrill ◽  
Mindy Fuller‐Holbrook ◽  
...  
Keyword(s):  
Common Bean ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Transpiration Efficiency ◽  
Isotope Discrimination

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.

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