Carbon isotope composition of latex does not reflect temporal variations of photosynthetic carbon isotope discrimination in rubber trees (Hevea brasiliensis)

Phenolic compounds, hydroquinone and cinnamic acid derivatives have been identified as major allelochemicals with known phytotoxicity from allelopathic plant Acacia melanoxylon R. Br. Several phenolic compounds such as ferulic acid (FA), p-hydroxybenzoic acid (pHBA) and flavonoid (rutin, quercetin) constituents occur in the phyllodes and flowers of A. melanoxylon and have demonstrated inhibitory effects on germination and physiological characteristics of lettuce and perennial grasses. However, to date, little is known about the mechanisms of action of these secondary metabolites in broad-leaved weeds at ecophysiological level. The objective of this study was to determine the response of Rumex acetosa carbon isotope composition and other physiological parameters to the interaction of plant secondary metabolites (PSM) (FA and pHBA) stress and the usefulness of carbon isotope discrimination (Δ13C) as indicative of the functional performance of intrinsic water use efficiency (iWUE) at level of plant leaf. R. acetosa plant were grown under greenhouse condition and subjected to PSM stress (0, 0.1, 0.5, 1.0, and 1.5 mM) for six days. Here, we show that FA and pHBA are potent inhibitors of Δ13C that varied from 21.0‰ to 22.9‰. Higher pHBA and FA supply enhanced/retard the Nleaf and increased the Cleaf while ratio of intercellular CO2 concentration from leaf to air (Ci/Ca) was significantly decreased as compared to control. Leaf water content and leaf osmotic potential were decreased following treatment with both PSM. The Ci/Ca decreased rapidly with higher concentration of FA and pHBA. However, iWUE increased at all allelochemical concentrations. At the whole plant level, both PSM showed pronounced growth-inhibitory effects on PBM and C and N concentration, root fresh/dry weight, leaf fresh/dry weight, and root, shoot length of C3 broad leaf weed R. acetosa. Carbon isotope discrimination (Δ) was correlated with the dry matter to transpiration ratio (transpiration efficiency) in this C3 species, but its heritability and relationship to R. acetosa growth are less clear. Our FA and pHBA compounds are the potent and selective carbon isotope composition (δ13C) inhibitors known to date. These results confirm the phytotoxicity of FA and pHBA on R. acetosa seedlings, the reduction of relative water content and the induction of carbon isotope discrimination (Δ) with lower plant biomass.

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Determination of the Average Partial Pressure of CO2 in Chloroplasts From Leaves of Several C3 Plants

Functional Plant Biology ◽

10.1071/pp9910287 ◽

1991 ◽

Vol 18 (3) ◽

pp. 287 ◽

Cited By ~ 182

Author(s):

SV Caemmerer ◽

JR Evans

Keyword(s):

Partial Pressure ◽

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Isotope Composition ◽

Co2 Assimilation ◽

Carbon Isotope Composition ◽

C3 Plants ◽

Isotope Discrimination ◽

Partial Pressure Of Co2 ◽

Transfer Conductance

Measurements of CO2 and water vapour exchange by leaves were combined with measurements of carbon isotope composition (13C/12C) of CO2 in the air passing over the leaf. Carbon isotope discrimination during CO2 uptake was determined from the difference in carbon isotope composition of the air leaving the leaf chamber with or without a leaf enclosed. Leaves of wheat plants grown with different nitrogen nutrition and leaves of several other species were examined. The measurements, made at different irradiances for a given leaf, showed that carbon isotope discrimination was strongly correlated with the rate of CO2 assimilation as well as the ratio of intercellular to ambient partial pressure of CO2, pI/pa. A function relating carbon isotope discrimination to the rate of CO2 assimilation was used to estimate the CO2 transfer conductance, gw, from the substomatal cavities to the sites of carboxylation for individual leaves. The photosynthetic capacity correlated with the CO2 transfer conductance, gw, and the average ratio of chloroplastic to intercellular partial pressure of CO2, pI/pa, was 0.7. This means that in general under high irradiance, the ratio of chloroplastic to ambient partial pressure of CO2 is about 0.5. In wheat, variation in gw was correlated with the chloroplast surface area appressing intercellular airspaces.

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Advances in measurements and models of photosynthetic carbon isotope discrimination in C3plants

Plant Cell & Environment ◽

10.1111/pce.12346 ◽

2014 ◽

Vol 37 (7) ◽

pp. 1494-1498 ◽

Cited By ~ 27

Author(s):

NEREA UBIERNA ◽

GRAHAM D. FARQUHAR

Keyword(s):

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Isotope Discrimination ◽

Photosynthetic Carbon

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Genetic variation in carbon isotope discrimination and its relationship to growth under field conditions in full-sib families of Piceamariana

Canadian Journal of Forest Research ◽

10.1139/x95-005 ◽

1995 ◽

Vol 25 (1) ◽

pp. 39-47 ◽

Cited By ~ 53

Author(s):

Lawrence B. Flanagan ◽

Kurt H. Johnsen

Keyword(s):

Genetic Variation ◽

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Isotope Composition ◽

Stable Carbon Isotope ◽

Leaf Tissue ◽

Tree Height ◽

Strong Negative Correlation ◽

Isotope Discrimination ◽

Sib Families

Measurements of the stable carbon isotope composition of leaf tissue were made on Piceamariana (Mill.) B.S.P trees from four full-sib families grown on three different field sites at the Petawawa National Forestry Institute, Ontario, Canada. The four families chosen exhibited genetic variation for growth characteristics. Genetic variation was also observed for carbon isotopic discrimination (Δ) among the families of P. mariana. In addition, a strong correlation occurred between Δ values measured on trees in 1991 and 1992, two years that had very different precipitation and temperature conditions during the growing season, indicating that the ranking of individual trees remained almost constant between years. A strong, negative correlation was observed between average carbon isotope discrimination and average tree height for the four families on the driest, least productive site, as was expected based on leaf photosynthetic characteristics. There was no significant correlation, however, between Δ values and growth on the other two study sites, where productivity was higher.

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Short-Term Measurements of Carbon Isotope Discrimination in Several C4 Species

Functional Plant Biology ◽

10.1071/pp9920263 ◽

1992 ◽

Vol 19 (3) ◽

pp. 263 ◽

Cited By ~ 121

Author(s):

SA Henderson ◽

SV Caemmerer ◽

GD Farquhar

Keyword(s):

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Isotope Composition ◽

Leaf Gas Exchange ◽

Short Term ◽

Isotope Discrimination ◽

C4 Species ◽

Linear Relationships ◽

Partial Pressures ◽

Wide Range

Carbon isotope discrimination (Δ) and leaf gas-exchange were measured simultaneously for a number of C4 species. Linear relationships were found between A and the ratio of intercellular to ambient partial pressures of CO2, pI/pa. These data were used to estimate the fraction of CO2 released by C4-acid decarboxylation in the bundle sheath, which subsequently leaks out to the mesophyll. We define this fraction as the leakiness of the system and it is also a measure of the extent to which phosphoenolpyruvate (PEP) carboxylations exceed ribulose 1,5-bisphosphate (RuBP) carboxylations. For Sorghum bicolor and Amaranthus edulis, leakiness was estimated at 0.2 and was constant over a wide range of irradiances (between 480 and 1600 μmol quanta m-2 s-1), intercellular CO2 pressures (between 30 and 350 μbar) and leaf temperatures (from 21�C to 34�C). At irradiances less than 240 μmol quanta m-2 s-1, leakiness appeared to increase. For a number of dicotyledonous and monocotyledonous species, of the various C4-decarboxylation types, leakiness was also estimated at 0.2. Contrary to expectation, amongst the 11 species examined, those with suberised lamellae did not show lower values of leakiness than those without suberised lamellae. For one NAD-ME and one PCK monocot, the estimates of leakiness were significantly higher at 0.30 and 0.25, respectively. Long-term discrimination (assessed from carbon isotope composition of leaf dry matter) did not correlate well with these short- term measures of discrimination. We suggest that this may be due to differences between species in fractionations occurring after photosynthesis.

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LEAF MORPHOLOGY AND CARBON ISOTOPE DISCRIMINATION VALUES IN PURPLE SPURGE (EUPHORBIA PEPLIS L.)

Israel Journal of Plant Sciences ◽

10.1080/07929978.1996.10676628 ◽

1996 ◽

Vol 44 (1) ◽

pp. 11-18 ◽

Cited By ~ 1

Author(s):

G. Patrignani ◽

L. Carraro ◽

P. Iacumin ◽

M. Orsenigo

Keyword(s):

Carbon Isotope ◽

Carbon Fixation ◽

Carbon Isotope Discrimination ◽

Mediterranean Coast ◽

Isotope Discrimination ◽

Photosynthetic Carbon Fixation ◽

The Family ◽

Photosynthetic Carbon ◽

Photosynthetic Type ◽

Anatomy And Ultrastructure

Among the numerous species of the family Euphorbiaceae the photosynthetic carbon fixation follows three pathways: C3, C4, CAM. The object of the present research was Euphorbia peplis L., grown and collected on a Mediterranean coast. Leaf anatomy and ultrastructure together with carbon isotope discrimination measurements indicated that E. peplis is ascribable to the NADP-malic enzyme C4 photosynthetic type.

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