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Title: Leaf conductance in relation to rate of CO/sub 2/ assimilation. II. Effects of short-term exposures to different photon flux densities. [Zea mays; Phaseolus vulgaris; Eucalyptus pauciflora]

Abstract

When photon flux density incident on attached leaves of Zea mays L. was varied from the equivalent of 0.12 of full sunlight to full sunlight, leaf conductance to CO/sub 2/ transfer, g, changed in proportion to the change in rate of CO/sub 2/, assimilation, A, with the result that intercellular partial pressure of CO/sub 2/ remained almost constant. The proportionality was the same as the previously found in g and A measured at one photon flux density in plants of Zea mays L. grown at different levels of mineral nutrition, light intensities, and ambient partial pressures of CO/sub 2/. In shade-grown Phaseolus vulgaris L., plants, A as photon flux density was increased from about 0.12 up to about 0.5 full sunlight, the proportionality being almost the same in plants grown at low and at high light intensity. When photon flux density incident on the adaxial an abaxial surfaces of the isolateral leaves of Eucalyptus pauciflora Sieb. ex Spreng was varied, g and A also varied proportionally. The leaf conductance in a particular surface was affected by the photon flux density at the opposite surface to a greater extent than was expected on the basis of transmittance. The results indicated thatmore » stomata may, in some way, be sensitive to the photon flux absorbed within the leaf as a whole. 5 references, 4 figures, 1 table.« less

Authors:
; ;
Publication Date:
Research Org.:
Australian National Univ., Canberra City
OSTI Identifier:
7119088
Resource Type:
Journal Article
Resource Relation:
Journal Name: Plant Physiol.; (United States); Journal Volume: 78
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CARBON DIOXIDE; UPTAKE; EUCALYPTUSES; PHOTOSYNTHESIS; MAIZE; PHASEOLUS; EXPERIMENTAL DATA; LEAVES; PARTIAL PRESSURE; PHOTONS; PLANT GROWTH; SOLAR RADIATION; STOMATA; BACTERIA; CARBON COMPOUNDS; CARBON OXIDES; CEREALS; CHALCOGENIDES; CHEMICAL REACTIONS; DATA; ELEMENTARY PARTICLES; GRASS; GROWTH; INFORMATION; LEGUMINOSAE; MASSLESS PARTICLES; MICROORGANISMS; NUMERICAL DATA; OPENINGS; OXIDES; OXYGEN COMPOUNDS; PHOTOCHEMICAL REACTIONS; PLANTS; RADIATIONS; RHIZOBIUM; STELLAR RADIATION; SYNTHESIS; TREES 550500* -- Metabolism

Citation Formats

Wong, S.C., Cowan, I.R., and Farquhar, G.D. Leaf conductance in relation to rate of CO/sub 2/ assimilation. II. Effects of short-term exposures to different photon flux densities. [Zea mays; Phaseolus vulgaris; Eucalyptus pauciflora]. United States: N. p., 1985. Web.
Wong, S.C., Cowan, I.R., & Farquhar, G.D. Leaf conductance in relation to rate of CO/sub 2/ assimilation. II. Effects of short-term exposures to different photon flux densities. [Zea mays; Phaseolus vulgaris; Eucalyptus pauciflora]. United States.
Wong, S.C., Cowan, I.R., and Farquhar, G.D. 1985. "Leaf conductance in relation to rate of CO/sub 2/ assimilation. II. Effects of short-term exposures to different photon flux densities. [Zea mays; Phaseolus vulgaris; Eucalyptus pauciflora]". United States. doi:.
@article{osti_7119088,
title = {Leaf conductance in relation to rate of CO/sub 2/ assimilation. II. Effects of short-term exposures to different photon flux densities. [Zea mays; Phaseolus vulgaris; Eucalyptus pauciflora]},
author = {Wong, S.C. and Cowan, I.R. and Farquhar, G.D.},
abstractNote = {When photon flux density incident on attached leaves of Zea mays L. was varied from the equivalent of 0.12 of full sunlight to full sunlight, leaf conductance to CO/sub 2/ transfer, g, changed in proportion to the change in rate of CO/sub 2/, assimilation, A, with the result that intercellular partial pressure of CO/sub 2/ remained almost constant. The proportionality was the same as the previously found in g and A measured at one photon flux density in plants of Zea mays L. grown at different levels of mineral nutrition, light intensities, and ambient partial pressures of CO/sub 2/. In shade-grown Phaseolus vulgaris L., plants, A as photon flux density was increased from about 0.12 up to about 0.5 full sunlight, the proportionality being almost the same in plants grown at low and at high light intensity. When photon flux density incident on the adaxial an abaxial surfaces of the isolateral leaves of Eucalyptus pauciflora Sieb. ex Spreng was varied, g and A also varied proportionally. The leaf conductance in a particular surface was affected by the photon flux density at the opposite surface to a greater extent than was expected on the basis of transmittance. The results indicated that stomata may, in some way, be sensitive to the photon flux absorbed within the leaf as a whole. 5 references, 4 figures, 1 table.},
doi = {},
journal = {Plant Physiol.; (United States)},
number = ,
volume = 78,
place = {United States},
year = 1985,
month = 1
}
  • Plants of Zea mays were grown with different concentrations of nitrate (0.6, 4, 12, and 24 millimolar) and phosphate (0.04, 0.13, 0.53, and 1.33 millimolar) supplied to the roots, photon flux densities (0.04, 0.13, 0.53, and 1.33 millimolar) supplied to the roots, photon flux densities (0.12, 0.5, and 2 millimoles per square meter per second), and ambient partial pressures of CO/sub 2/ (305 and 610 microbars). Differences in mineral nutrition and irradiance led to a large variation in rate of CO/sub 2/ assimilation per unit leaf area (A, 11 to 58 micromoles per square meter per second) when measured undermore » standard conditions. The variation was shown, with the plants that had received different amounts of nitrate, to be related to variations in the nitrogen and chlorophyll contents, and phosphoenolpyruvate and ribulose-1,5-bisphosphate carboxylase activities per unit leaf area. Irrespective of growth treatment, A and leaf conductance to CO/sub 2/ transfer (g), measured under standard conditions were in almost constant proportion, implying that intercellular partial pressure of CO/sub 2/ (p/sub i/), was almost constant at 95 microbars. The same proportionality was maintained as A and g increased in an initially nitrogen-deficient plant that had been supplied with abundant nitrate. It was shown that p/sub i/ measured at a given ambient partial pressure was not affected by the ambient partial pressure at which the plants had been grown, although it was different when measured at different ambient partial pressures. This suggests that the close coupling between A and g in these experiments is not associated with sensitivity of stomata to change in p/sub i/. Similar, though less comprehensive, experiments were done with Gosypium hirsutum, and yielded similar conclusions, except that the proportionality between A and g at normal ambient partial pressure of CO/sub 2/ implied p/sub i/ approx. = 200 microbars. 11 references, 6 figures, 1 table.« less
  • Rates of CO/sub 2/ assimilation and leaf conductances to CO/sub 2/ transfer were measured in plants of Zea mays during a period of 14 days in which the plants were not rewatered, and leaf water potential decreased from -0.5 to -0.8 bar. At any given ambient partial pressure of CO/sub 2/, water stress reduced rate of assimilation and leaf conductance similarly, so that intercellular partial pressure of CO/sub 2/ remained almost constant. At normal ambient partial pressure of CO/sub 2/, the intercellular partial pressure of CO/sub 2/ was estimated to be 95 microbars. This is the same as had beenmore » estimated in plants of Zea mays grown with various levels of nitrogen supply, phosphate supply and irradiance, and in plants of Zea mays examined at different irradiances. After leaves of Phaseolus vulgaris L. and Eucalyptus pauciflora Sieb. ex Spreng had been exposed to high irradiance in an atmosphere of CO/sub 2/-free N/sub 2/ with 10 millibars O/sub 2/, rates of assimilation and leaf conductances measured in standard conditions had decreased in similar proportions, so that intercellular partial pressure of CO/sub 2/ remained almost unchanged. As the conductance of each epidermis that had not been directly irradiated had declined as much as that in the opposite, irradiated surface it was hypothesized that conductance may have been influenced by photoinhibition within the mesophyll tissue. 16 references, 4 figures, 3 tables.« less
  • Electron microscopic examination of leaves from bean (Phaseolus vulgaris L.) tobacco (Nicotiana tabacum L.) and cotton (Gossipyum hirsutum L.) fumigated for .5 to 2 hours with 0.3 - 1 ppm of the individual oxidants revealed that changes in the ultrastructure of the cells occurred in a sequential fashion with time following the fumigation period. Although occasional cells showed severe damage immediately after fumigation, the most obvious change was an enhanced clarity of the cell membranes. Subsequently, and often prior to the appearance of any visual symptoms of damage, changes in the chloroplasts and mitochondria are observed. In bean and cottonmore » the chloroplast stroma becomes denser and ordered arrays of granules and fibrils develop in the stroma. In tobacco the ordered arrays of granules did not occur but the stroma increased in density and grana frequently had a curvilinear appearance. However, determination of chloroplast axial ratios indicated a general decrease in volume of the tobacco chloroplasts in the fumigated plants as compared to control non-treated plants. The increase density of the stroma, formation of fibrils, and general decrease in volume is probably the result of an increase dehydration of the chloroplasts brought on by permeability changes induced by the pollutants.« less
  • Corn (Zea mays L. 'N6A4C2') and dwarf horticultural beans (Phaseolus vulgaris L. 'common') were grown in the growth chamber in a Typic Eutrochrept A horizon soil amended with Cr(OH)/sub 3/, tannery effluent, and tannery sewage sludge each at two levels, with and without citric acid added. Water-soluble Cr(VI) and Cr(III) were measured in unplanted soils periodically during the growth period and in bulk and rhizosphere soils of the planted treatments at harvest. Plant tops and roots were analyzed for dry weight and Cr. Soil separated from bean roots after 46 d of growth in a 10-mmol Cr(OH)/sub 3/ kg/sup -1/more » soil treatment contained less soluble Cr(VI) and more soluble Cr(III) than unplanted soil receiving the same Cr(III) treatment. The bean roots and tops in this treatment had higher levels of Cr than did plants grown in unamended soil. The level of Cr in bean roots after 46 d was highly correlated with Cr(VI) levels in unplanted soils 1 to 3 d after seeding. Adding citric acid to the soil significantly increased Cr levels in bean shoots and roots grown in the Cr(OH)/sub 3/ treatment. Compared with controls, levels of Cr in bean tops were not increased in treatments with tannery effluent (0.5 and 1.0 mmol Cr(III) kg/sup -1/) nor with tannery sewage sludge (1.0 and 10 mmol Cr(III) kg/sup -1/), but root levels were increased in these treatments. Dry matter yields of corn roots and shoots were lowered in the 10-mmolCr(OH)/sub 3/ treatments more than were yields of beans. Chromium levels in the roots and tops were increased in these treatments, especially if citric acid was added.« less
  • The main objective of this study was to ascertain effects of some edaphic factors on the uptake and influence of Ni on plant growth since Ni is a common trace element contaminant as well as an important component of serpentine soils. Corn (Zea mays L. inbred Ys/sub 1//Ys/sub 1/) was grown in Yolo loam soil amended to give soil pH values of 4.2, 5.6, 7.5, and 8.2. A level of 100 ..mu..g Ni/g soil was not toxic to the corn. Shoot concentrations of Ni increased as soil pH decreased for both application rates of Ni. A level of 250 ..mu..gmore » Ni/g soil decreased yields more at soil pH below 7. Iron, Zn, and Mn levels in shoots did not appear to be directly related to the Ni applications although Fe levels tended to increase as a result of smaller plant size. PI54619-5-1 soybeans (Glycine max L.) were grown in soil at two different pH values (with and without CaCO/sub 3/) and with and without a level of 1000 ..mu..g Ni/g added as the sulfate and thoroughly mixed with the soil and equilibrated for 1 month prior to transplanting the soybeans with and without application of a chelating agent, DTPA (diethylene triamine pentaacetic acid), commonly used to correct Fe deficiency in plants. Plants were killed in the soil of pH 6.2 when the 1000 ..mu..g Ni/g soil was added. The pH 7.2 soil decreased the toxicity of Ni. The DTPA had little effect on yields, but increased the amount of Ni in plants. Nickel decreased the Fe, Zn, Cu, and Mn concentrations of the plants. Stems contained less Ni than did leaves. In another experiment, EDTA (ethylenediamine tetraacetate) greatly increased Ni concentrations in bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen) and in barley (Hordeum vulgare L. C.V. Atlas 57) grown in Yolo loam soil, and simultaneously increased Fe concentrations. Lime (CaCO/sub 3/ or MgCO/sub 3/) decreased toxicity of Ni in bush beans. DTPA increased Ni transport in bush beans and increased the ratio of Ni in leaves to that in stems at soil pH 7.5 and 8.2, but not at pH 4.0 and 5.8.« less