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Journal Article

Leaf gas exchange and fluorescence of two teosinte species: Zea mays ssp. parviglumis and Z. diploperennis.

09 Nov 2011-Journal of Tropical Agriculture (Kerala Agricultural University)-Vol. 49, pp 91-94

TL;DR: This study compared the leaf blade characteristics, pigment composition, photosystem II (PSII) photochemistry, and photosynthetic rates (P) of a multi-stemmed annual and a perennial teosinte species growing in a glasshouse under analogous nutritional and environmental conditions to show similar chlorophyll contents and ratios.

AbstractThis study compared the leaf blade characteristics, pigment composition, photosystem II (PSII) photochemistry, and photosynthetic rates (P) of a multi-stemmed annual (Zea mays ssp. parviglumis Iltis & Doebley) and a perennial (Z. diploperennis Iltis, Doebley & Guzman) teosinte species growing in a glasshouse under analogous nutritional and environmental conditions. Similar chlorophyll contents and ratios implied comparable efficiencies of photon energy capture and electron flow through PSII in both species. Maximum photochemical efficiency (Fv/Fm) was about 0.75 at predawn and declined linearly to a minimum at midday of about 0.65, implying down-regulation of photosynthesis. By contrast, maximum P (Pmax) was 11.5% higher in the annual compared to the perennial teosinte, signifying that wild maize germplasm could potentially be used for improving the photosynthetic efficiency of cultivated maize. Future studies, however, should assess a larger number of teosinte species for their differences in leaf area per plant, growth habit, grain yield, and leaf photosynthesis.

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Journal ArticleDOI
TL;DR: It is demonstrated that some perennial cereal species can maintain higher midseason A than their annual crop relatives, and evidence for age-related changes in photosynthetic physiology in a herbaceous perennial plant is found.
Abstract:  Premise of the study: Few previous studies have considered how plant age affects photosynthetic physiology in herbaceous perennials or how photosynthetic capacity in annual cereals compares to perennial relatives. Newly developed perennial cereals offer novel systems for addressing these questions. Our study makes a novel contribution by considering how life history differences affect photosynthetic physiology.  Methods: In two linked fi eld studies, we evaluated effects of life history and plant age on photosynthetic rates ( A ), and related biochemical, morphological, and water-relations traits, comparing 1- and 2-yr-old cohorts of perennial wheat, intermediate wheatgrass, and perennial rye to close annual relatives (wheat and rye).  Key results: Photosynthetic rates ( A ) were 10–50% higher in perennial cereals compared to annuals. In wheatgrass, elevated A was associated with higher carboxylation ( V C ), triose phosphate utilization (TPU) and electron transport rates ( J ), and higher leaf soluble protein and chlorophyll. Younger wheatgrass plants maintained higher A , TPU , J , and V C than older plants did. Perennial wheat and rye differed from annual relatives in some but not all of these parameters. Differences in stomatal limitation were not involved, while differences in stomatal conductance ( g s ) became evident under drier conditions.  Conclusions: This study demonstrates that some perennial cereal species can maintain higher midseason A than their annual crop relatives. These changes are not fully explainable by increased access to soil water and may refl ect trade-offs between allocation to reproduction and to resource acquisition. We also found evidence for age-related changes in photosynthetic physiology in a herbaceous perennial plant.

10 citations


Journal ArticleDOI
TL;DR: This study provides important information on signal transduction pathway changes under drought stress for exploring drought resistance candidate genes in bamboo species.
Abstract: Dendrocalamus minor var. amoenus was analyzed for physiological and proteomic responses under drought stress. The adverse effects of drought on D. minor var. amoenus were primarily affected by gas exchange attributes such as photosynthesis (Pn), stomatal conductance (Gs), and transpiration rate (Tr) decreased as drought intensity increased. Among chlorophyll fluorescence parameters, actual photochemical efficiency of PSII (ΦPSII), electron transport rate (ETR), and non-photochemical quenching (qN) also decreased under increasing drought stress throughout the natural dehydration process (15-30 days). Moreover, superoxide dismutase (SOD) and catalase (CAT) levels increased significantly when subjected to short drought event and then decreased rapidly under severe drought stress. Using twodimensional gel electrophoresis (2-DE), we detected more than 500 protein spots; 41 significant differentially expressed protein spots were uncovered under drought stress. Following matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) identification and BLAST of these 41 proteins spots to an NCBI or Uniprot database, 33 differential protein spots were identified. In addition to determining a suitable protocol for protein extraction from D. minor var. amoenus (or other bamboo species), this study provides important information on signal transduction pathway changes under drought stress for exploring drought resistance candidate genes in bamboo species.

1 citations


Cites methods from "Leaf gas exchange and fluorescence ..."

  • ...Calculations for these parameters were done according to the instrument manufacturer’s instructions (Sobrado, 2011)....

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Journal ArticleDOI
TL;DR: This study aims to investigate the agronomic and physiological performance of selected perennial wheat genotypes derived from crosses between Triticum aestivum L. and Thinopyrum spp to evaluate if they could give a contribute both to face climate changes and to restore soil health.
Abstract: Perennial crops are emerging as an effective strategy for adapting to climate change, but also for mitigating net greenhouse gas emissions from agriculture. This study aims to investigate the agronomic and physiological performance of selected perennial wheat genotypes derived from crosses between Triticum aestivum L. and Thinopyrum spp to evaluate if they could give a contribute both to face climate changes and to restore soil health. Four perennial wheat genotypes were grown in Central Italy and compared in terms of agronomic traits, root development (biomass and length) and ecophysiological parameters with an annual common wheat cultivar. Plants were, on average, taller in perennial wheat genotypes than in annual wheat as well as the number of tillers per plant (+ 49%), root length (+ 43%) and root biomass (+ 31%) in both years, whereas, perennial wheat kernels were smaller (− 15%). Post harvest regrowth occurred in different amounts in all perennial wheat genotypes. In terms of the ecophysiological response, perennial wheat lines revealed higher soil respiration and lower stomatal conductance than annual wheat. On the contrary, transpiration rate, water use efficiency and photosynthesis were higher in annual genotype than in perennial ones. The environmental benefits of adopting perennial grains are discussed together with suggestions on optimal field management and future breeding strategies.

References
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Journal ArticleDOI
Abstract: Various equations for the determinations of total chlorophyll and individual amounts of chlorophylls a and b in extracts from plant tissues exist (see Holden, 1976) and some of them (e.g. Arnon, 1949) are widely used. Additional modifications to the equations have also been developed so as to permit an estimate of total carotenoids to be made from the spectrum of the same mixture in diethyl ether (Ziegler & Egle, 1965; Gaudillire, 1974). During the course of studies that involved the use of various solvents we noted large discrepancies (>40%) between estimations made using the different published equations for particular solvents, all of which were known to contain the same amount of pigments. Taking advantage of a t.1.c. method (Lichtenthaler 8t Pfister, 1978) that permits a distinct separation of the two chlorophylls and also the major carotenoids using light petroleum (b.p. 40-6O0C)/dioxane/propan-2-ol (7 :3 : 1, by vol.) as developing solvent, fresh samples of chlorophyll a and b uncontaminated with each other were readily available for re-evaluation of the published specific absorption coefficients. Those values published by Smith & Benitez (1955), using diethyl ether, were found to be still the most acceptable, and relative specific absorption coefficients to these values were established (Table 1) for various other solvents. The red peak maxima of the chlorophylls were shifted to longer wavelengths with increasing polarity of the solvents; in our case diethyl ether, acetone, 80% (v/v) acetone, 96% (v/v) ethanol and methanol. The red absorption peaks of the chlorophylls were also broadened in the same sequence and the values for the specific absorption coefficients decreased. At the same time suitable values for total carotenoids at 470nm were also determined. On the basis of these coefficients the following equations were derived to determine the individual levels of both chlorophyll a (C,) and chlorophyll b (C,) and the total amounts of carotenoids (Cx+c) and chlorophylls (C,+ C,) [in pg.(ml of plant extract)-'] the measured absorbance values (A) at different wavelengths:

4,407 citations


Journal ArticleDOI
01 Jan 1992
Abstract: PHOTO PROTECTION 604 Prevention oj Excessive Light Absorption... 604 Removal of Excess Excitation Energy Directly within the Light-Capturing System ......... ...... . . ..... ..... . .... . ..... ...... .... . .. . .. . . ..... . . . ... ... . 604 Removal oj Active Oxygen Formed in the Photochemical Apparatus ........ . . .. . . . . . . 605 INACTIV A TIONiTURNOVER OF PS II 606 THE XANTHOPHYLL CYCLE AND THERMAL ENERGY DISSIPATION: A PHOTOPROTECTIVE RESPONSE 608 Characteristics oj the Xanthophyll Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 608 Association Among the De-epoxidized State oj the Xanthophyll Cycle, Thermal Energy Dissipation. and Photoprotection .. .. . . . .. . . ...... .. .. ... ... 609 Operation of the Xanthophyll Cycle in the Field . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .... . . . .. . . . . 611 CONCLUSIONS 618

2,293 citations


Journal ArticleDOI
TL;DR: FO and FV are the same type of fluorescence, both emanating from the bulk chlorophyll of Photosystem II, according to simple theory, which predicts that the ratio FV/FM should equal phipo.
Abstract: The quenching action of dibromothymoquinone on fluorescence and on primary photochemistry was examined in chloroplasts at −196 °C. Both the initial (F0) and final (FM) levels of fluorescence as well as the fluorescence of variable yield (Fv = FM − F0) were quenched at −196 °C to a degree which depended on the concentration of dibromothymoquinone added prior to freezing. The initial rate of photoreduction of C-550 at — 196 °C, which was assumed to be proportional to maximum yield for primary photochemistry, ϕPo, was also decreased in the presence of dibromothymoquinone. Simple theory predicts that the ratio FVFM should equal ϕPo. Excellent agreement was found in a comparison of relative values of ϕPo with relative values of FVFM at various degrees of quenching by dibromothymoquinone. These results are taken to indicate that F0 and FV are the same type of fluorescence, both emanating from the bulk chlorophyll of Photosystem II. Dibromothymoquinone appears to create quenching centers in the bulk chlorophyll of Photosystem II which compete with the reaction centers for excitation energy. The rate constant for the quenching of excitation energy by dibromothymoquinone is directly proportional to the concentration of the quencher. Rate constants for the de-excitation of excited chlorophyll molecules by fluorescence, kF, by nonradiative decay processes, kD, by photochemistry, kP, and by the specific quenching of dibromothymoquinone, kQ, were calculated assuming the absolute yield of fluorescence at F0 to be either 0.02 or 0.05.

842 citations


"Leaf gas exchange and fluorescence ..." refers background in this paper

  • ...Midday reduction of Fv/Fm as a consequence of changes in Fm and Fv without significant changes in Fo indicates reduction of photochemical efficiency due to photoprotective mechanisms (Kitajima and Butler, 1975)....

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Journal ArticleDOI
Abstract: Chlorophyll fluorescence parameters (Chl FPs) derived from the slow (long-term) induction kinetics of modulated Chl a fluorescence are reviewed and analysed with respect to their application in photosynthesis research. Only four mutually independent Chl FPs, calculated from values of five essential Chl fluorescence (ChlF) yields, are distinguished as the basic ones. These are: the maximum quantum yield of PS2 photochemistry (ΦPO), the photochemical quenching of variable ChlF (qP), the non-photochemical quenching of variable ChlF (qN), and the relative change of minimum ChlF (qO). ΦPO refers to the dark-adapted state of a thylakoid membrane, qP, qN and qO characterise the light-adapted state. It is demonstrated that all other Chl FPs can be determined using this quartet of parameters. Moreover, three FPs related to the non-radiative energy dissipation within thylakoid membranes are evaluated, namely: the non-photochemical ChlF quenching (NPQ), the complete non-photochemical quenching of ChlF (qCN), and the effective quantum yield of non-photochemical processes in PS2 (ΦN). New FPs, the total quenching of variable ChlF (qTV) and the absolute quenching of ChlF (qA) which allow to quantify co-action of the photochemical and non-photochemical processes during a light period are defined and analysed. The interpretation of Chl FPs and recommendations for their application in the photosynthesis research are also given. Some alternative FPs used in the laboratory practice have only an approximate character and can lead to incorrect conclusions if applied to stressed plants. They are reviewed and compared with the standard ones. All formulae and conclusions discussed herein are verified using experimental values obtained on young seedlings of the Norway spruce (Picea abies [L.] Karst.).

573 citations


Journal ArticleDOI
TL;DR: Molecular analyses identified one form of teosinte (Zea mays ssp. parviglumis) as the progenitor of maize and a few loci of large effect that appear to represent key innovations during maize domestication.
Abstract: ▪ Abstract Maize and its closest wild relatives, the teosintes, differ strikingly in the morphology of their female inflorescences or ears. Despite their divergent morphologies, several studies indicate that some varieties of teosinte are cytologically indistinguishable from maize and capable of forming fully fertile hybrids with maize. Molecular analyses identified one form of teosinte (Zea mays ssp. parviglumis) as the progenitor of maize. Analyses of the inheritance of the morphological traits that distinguish maize and teosinte indicates that they are under the control of multiple genes and exhibit quantitative inheritance. Nevertheless, these analyses have also identified a few loci of large effect that appear to represent key innovations during maize domestication. Remaining challenges are to identify additional major and minor effect genes, the polymorphisms within these genes that control the phenotypes, and how the combination of the individual and epistatic effects of these genes transformed teo...

500 citations


"Leaf gas exchange and fluorescence ..." refers background in this paper

  • ...), native to Mexico and Central America (Buckler and Holtsford, 1966; Doebley, 2004)....

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  • ...This selection process seems enormously complex and involves a multiplicity of genes that control tillering, kernel size, composition, palatability, and leaf size (Doebley, 2004)....

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  • ...Future studies should, therefore, focus on a larger number of the reported teosinte races (Buckler and Holtsford, 1966; Doebley, 2004), and its differential leaf area, growth duration and habit, grain yield, and photosynthentic potential....

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