Photosynthesis in Pineapple (Ananas comosus comosus [L.] Merr) Measured Using PAM (Pulse Amplitude Modulation) Fluorometry

Tropical Plant Biology (Impact Factor: 1.52). 12/2010; 3(4):193-203. DOI: 10.1007/s12042-010-9057-y


PAM (Pulse Amplitude Modulation) fluorometer techniques directly measure the light reactions of photosynthesis that are otherwise difficult to estimate in CAM (Crassulacean Acid metabolism) plants such as pineapple (Ananas comosus comosus cv. Phuket). PAM machines calculate photosynthesis as the Electron Transport Rate (ETR) through PSII (4 electrons per O2 produced) as mol m-2 s-1. P vs. E curves fitted the waiting-in-line function (an equation of the form ETR = (ETRmax × E/Eopt.e1-E/Eopt) allowing half-saturating and optimal irradiances (Eopt) to be estimated. Effective Quantum Yield (Ymax), Electron Transport Rate (ETRmax) and the Non-Photochemical Quenching parameter, NPQmax all vary on a diurnal cycle but the parameter qNmax does not show a systematic variation over a diurnal period. Phuket pineapple is a "sun plant" with Optimum Irradiance (Eopt) from 755 to 1,130 μmol m-2 s-1 (400-700 nm) PAR but photosynthetic capacity is very low in the late afternoon even though light conditions are favourable for rapid photosynthesis. Total CO2 fixed nocturnally as C4-dicarboxylic acids by leaves of the Phuket pineapple was only ≈0.14 gC m-2 d-1 (0.012 mol C m-2 d-1). Titratable acid of leaves was depleted about 3 pm (15:00) and shows a classical CAM diurnal cycle. The Phuket pineapple variety only stored enough CO2 as C4 acids to account for only about 2.5% of photosynthesis (Pg) estimated using the PAM machine (≈5.6 gC m-2 d-1). Phuket pineapples are classifiable as CAM-Cycling plants but nocturnal fixation of CO2 is so low compared to the more familiar Smooth Cayenne variety that it probably recycles only a small proportion of the respiratory CO2 produced in leaves at night and so even CAM-cycling is only of minor importance to the carbon economy of the plant. Unlike the Smooth Cayenne pineapple variety, which fixes large amounts of CO2 nocturnally, the Phuket pineapple is for practical purposes a C3 plant.

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    • "This accumulation is small compared to that in classical CAM plants (Lü ttge 2007). There is no evidence for mobilization and depletion of organic acids during the day, as would be found in CAM plants (Clusia: Lü ttge 2007, 2008; Kalanchoë: Griffiths et al. 2008; Dendrobium: Ritchie and Bunthawin 2010b; pineapples: Chen et al. 2002; Ritchie and Bunthawin 2010a) or is found in aquatic plants with SAM/CAM physiology (Isoetes: Keeley 1983; Littorella: Aulio 1985). "
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    ABSTRACT: Water lilies, such as the blue Egyptian water lily (Nymphaea caerulea Savigny), are ubiquitous aquatic plants. Leaves of mature plants normally unfold at the surface and are floating or emergent. Some aquatic vascular plants have a form of CAM (crassulacean acid metabolism) known as submerged aquatic metabolism (SAM). The presence of aerenchyma in water lily leaves and petioles makes it very difficult to measure photosynthesis in water lily plants by gas exchange. Pulse amplitude modulation (PAM) fluorometer techniques provide direct information on the light reactions of plants. PAM technology calculates photosynthesis as the electron transport rate (ETR) through PSII (4 electrons per O2 produced) in mol m−2 s−1. Here, relative ETR (rETR) was based on an assumed leaf absorptance factor of 0.84. Photosynthesis-versus-irradiance (P vs. E) curves were fitted with the waiting-in-line function ( ). Maximum effective quantum yield, maximum relative ETR (rETRmax), and quantum efficiency all vary on a diurnal cycle. The nonphotochemical quenching parameters qNmax and NPQmax are highly correlated with each other ( , ) but do not show a systematic variation over a diurnal cycle. Nymphaea is a “sun plant” with optimum irradiance (Eopt) of 1000 μmol m−2 s−1 PPFD or higher. Titratable acid of leaves varied from ∼50 to 70 mol H+ m−3 (leaf water basis) and was depleted at ∼0600 and 1800 hours each day, a diel pattern inconsistent with SAM/CAM physiology. The N. caerulea C4 acid pool is too small to support substantial SAM-type metabolism. Gross photosynthesis of Nymphaea leaves had a high value of ∼5.3 g C m−2 d−1. For a daily irradiance of 56 mol m−2 PPFD, this works out to a 3.3% conversion efficiency in terms of moles of carbon.
    International Journal of Plant Sciences 02/2012; 173(2):124-136. DOI:10.1086/663168 · 1.53 Impact Factor
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    ABSTRACT: The effect of vanillin on Agrobacterium-mediated transformation of pineapple v N36 was examined. Vanillin in concentrations ranging from 0-500 μM was included in the medium during co-cultivation of the longitudinalsection pineapple plantlets with Agrobacterium tumefacients strains LBA4404 that harboured the hygromycin phosphotransferase gene (hpt). The transformants were selected in 20 μg/ml hygromycin, and confirmed by GUS histochemical assay and polymerase chain reaction. The highest GUS assay, 50% positive blue colour, was observed in 500 μM vanillin. Findings suggested that vanillin might substituted for ecetosyringone for Agrobacterium-mediated transformation of pineapple plantlets
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