Photoregulation and photodamage in Schefflera arboricola leaves adapted to different light environments

1999 ◽  
Vol 26 (5) ◽  
pp. 485 ◽  
Author(s):  
U. Schiefthaler ◽  
A. W. Russell ◽  
H. R. Bolhàr-Nordenkampf ◽  
C. Critchley
Keyword(s):  
Xanthophyll Cycle ◽  
De Novo ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Synthesis Rate ◽  
Long Term Effects ◽  
Photosynthetic Rates ◽  
Full Sunlight ◽  
Schefflera Arboricola ◽  
Sun Leaves

Leaves of the subtropical understorey shrub Schefflera arboricola Hayata growing in full sunlight had higher specific leaf weight, higher chlorophyll a/b ratios, lower total chlorophyll content and a threefold higher xanthophyll cycle pigment content than leaves growing in a naturally shaded, but sunfleck-punctuated, environment. A number of measurements, all made in situ and during natural day/night cycles, were taken as follows: current photochemical capacity (F√F m after 10 min dark-adaptation), size and epoxidation state of the xanthophyll cycle, CO 2 gas exchange and determination of the D1 synthesis rate. In sun leaves the lowest daily F√F m was found to be approximately 0.6, the change from maximum correlating with an increase in zeaxanthin. Daily changes in zeaxanthin were partly due to de novo synthesis and turnover. We suggest that sun leaves can dissipate most of the excess light energy absorbed safely via the photoprotective xanthophyll cycle. D1 synthesis rates did not correlate with photosynthetic photon flux density or F√F m . The shade leaves had high F√F m values and constant photosynthetic rates throughout the day except during sunflecks, when photosynthetic rates increased and D1 synthesis accelerated, all without a substantial decrease in F√F m . It seems that leaves of S. arboricola adapted to natural shade conditions can use sunflecks to contribute significantly to their pro-ductivity. The third leaf type investigated was from greenhouse-grown plants of S. arboricola after exposure to full sunlight. These leaves showed a rapid and large reduction in F√F m (to 0.3), which neither correlated with zeaxanthin formation nor recovered within the same day. From long-term effects following full sunlight exposure of greenhouse-grown plants we suggest that this F√F m reduction actually reflects photodestruction.

Capacity for Energy Dissipation in the Pigment Bed in Leaves With Different Xanthophyll Cycle Pools

1994 ◽  
Vol 21 (5) ◽  
pp. 575 ◽  
Author(s):  
B Demmig-Adams ◽  
WW Iii Adams
Keyword(s):  
Energy Dissipation ◽  
Xanthophyll Cycle ◽  
High Growth ◽  
Full Sunlight ◽  
Growth Irradiance ◽  
Shade Tolerant Species ◽  
Monstera Deliciosa ◽  
Schefflera Arboricola ◽  
Sun Leaves ◽  
Photosynthetic Capacities

Photosynthetic capacities, xanthophyll cycle components, and the capacity for photoprotective dissipation of excess excitation in the chlorophyll pigment bed were compared in two groups of species acclimated to different growth irradiance. These were sun leaves of three species with moderately high maximal photosynthetic capacities, tulip, rose, and periwinkle (Vinca minor), and leaves which had developed under very low irradiance from three shade-tolerant species, Monstera deliciosa, Philodendron caudatum and Schefflera arboricola. All sun leaves possessed larger xanthophyll cycle pools and greater maximal zeaxanthin (and antheraxanthin) contents and also displayed a greater maximal capacity for photo-protective energy dissipation in the pigment bed than the leaves acclimated to very low irradiance. The sun leaves also maintained a considerably lower reduction state of photosystem II at full sunlight than the leaves acclimated to very low irradiance. Thus, during exposure to full sunlight, these sun leaves were able to dissipate a major portion of the absorbed light through the combination of photosynthesis and energy dissipation in the pigment bed. Under the same conditions, these two processes combined were able to dissipate only a small fraction of the absorbed light in the leaves acclimated to very low irradiance. Most of the above differences between sun-acclimated leaves and leaves acclimated to very low irradiance existed not only between species but also within a species. Acclimation of Monstera deliciosa to a high growth irradiance resulted in leaves with a larger xanthophyll cycle pool, a greater maximal zeaxanthin (and antheraxanthin) content, and a greater capacity for energy dissipation in the pigment bed.

scholarly journals Carbon gain optimization in five broadleaf deciduous trees in response to light variation within the crown: correlations among morphological, anatomical and physiological leaf traits

2015 ◽  
Vol 74 (1) ◽  
pp. 71-94 ◽  
Author(s):  
Rosangela Catoni ◽  
Loretta Gratani ◽  
Francesco Sartori ◽  
Laura Varone ◽  
Mirko U. Granata
Keyword(s):  
Phenotypic Plasticity ◽  
Deciduous Forest ◽  
Light Variation ◽  
Stress Factors ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Deciduous Species ◽  
Shade Leaves ◽  
Sun Leaves

AbstractLeaf trait variations in five deciduous species (Quercus robur, Corylus avellana, Populus alba, Acer campestre, Robinia pseudoacacia) growing in an old broadleaf deciduous forest in response to light variation within the tree crown was analyzed. Net photosynthetic rate (PN), leaf respiration rate (R) and the photosynthetic nitrogen use efficiency were, on average, more than 100% higher in sun than in shade leaves. A. campestre and C. avellana sun leaves had the highest specific leaf area (SLA, 156.0 ± 17.9 cm2 g-1) and the lowest total leaf thickness (L, 101.9 ± 8.8 μm) underlining their shade-tolerance. Among the shade-intolerant species (Q. robur, P. alba and R. pseudoacacia), Q. robur had the lowest SLA and the highest L in sun leaves (130.6 ± 10.0 cm2 g-1 and 160.8 ± 9.6 μm, respectively) since shade-intolerant species typically have thicker leaves. The higher PN decrease in respect to R decrease from sun to shade leaves attested the higher sensitivity of PN than R to light variations within the crown. This determined a 69% lower R/PN in sun than in shade leaves. This result is further attested by the significant correlation between PN and the relative photosynthetic photon flux density. The shade-tolerant species have a 76% higher R/PN ratio than the shade-intolerant ones. The measured leaf phenotypic plasticity (PI = 0.35) was in the range of broadleaf deciduous species. Plasticity is a key trait useful to quantify plant response to environmental stimuli. It is defined as the ability of a genotype to produce different phenotypes depending on the environment. Among the considered species, Q. robur showed the highest PI (0.39) and P. alba the lowest (0.29). Knowledge on phenotypic plasticity is important in making hypotheses about the dynamics of the studied forest in consideration of environmental stress factors, including invasive species competition and global climate change.

Seasonal photosynthetic performance of Nereocystis luetkeana

1984 ◽  
Vol 62 (4) ◽  
pp. 664-670 ◽  
Author(s):  
W. N. Wheeler ◽  
R. G. Smith ◽  
L. M. Srivastava
Keyword(s):  
Flux Density ◽  
Late Summer ◽  
Photosynthetic Performance ◽  
Initial Slope ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Rates ◽  
Chl A ◽  
Light Intensities ◽  
Nereocystis Luetkeana

Pigment levels, photosynthetic performance, and tissue nitrogen levels of three age-class blade disks of Nereocystis luetkeana were followed over one complete and two partial growth seasons. Chlorophyll (chl) a, fucoxanthin, and chlorophyll c all showed high levels in fall–winter and low levels in late summer. The molar ratios also varied with much higher fucoxanthin: chl a and chl c: chl a ratios in early spring than in late summer–fall. Plots of maximum photosynthetic rates (Pmax) at saturating light intensities and initial slopes (α) derived from photosynthetic rates at subsaturating light intensities also showed seasonal variations, with maxima in August and September and minima in April. The saturating light irradiance, IR, also showed a maximum in late summer and a minimum in winter. Tissue nitrate levels were high in winter, declined to near zero levels in May–August, and increased again in fall–winter. Amino acids and total N followed a similar pattern. The older tissues farthest from the bulb had higher Pmax and pigment levels as well as internal nitrate levels than young proximal tissues. Environmental data on sea-water nitrate, photon flux density, and temperature and data on mannitol and total C are presented. It appears that there is a significant negative correlation between photon flux density and initial slope of photosynthesis and between Pmax and temperature below 15 °C. At temperatures above 15 °C, internal N concentrations, which in turn are governed by the ambient nitrate concentration, appear to become limiting. Pigment levels, especially chlorophyll a, showed a direct correlation with ambient nitrate. These data are discussed in relation to the possible biennial nature and growth strategy of Nereocystis.

Effects of photon flux density on photosynthesis, growth, flowering, and oil content in Boronia

1998 ◽  
Vol 49 (5) ◽  
pp. 791 ◽  
Author(s):  
J. M. Wann ◽  
R. Orifici ◽  
Z. E. Spadek ◽  
J. A. Plummer
Keyword(s):  
Light Intensity ◽  
Flux Density ◽  
Oil Content ◽  
Natural Habitat ◽  
Volatile Oil ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Cut Flowers ◽  
Eucalyptus Marginata ◽  
Full Sunlight

Boronia heterophylla is cultivated for cut flowers and B. megastigma for volatile oil production. Both species are endemic to south-western Western Australia and their natural habitat is often shaded by a canopy of Melaleuca parviflora or Eucalyptus marginata. Shade tents were used to examine the influence of reduced photon flux density (PFD) on photosynthesis, growth, and flower production in B. heterophylla and B. megastigma. Volatile oil content was also examined in B. megastigma. Photosynthesis in field-grown B. heterophylla was saturated at 16·2 µmol CO2/m 2·s under a PFD of 1022 µmol/m 2·s (75% full sunlight). Flower number was highest under 75% full sunlight but the number of harvestable stems was the same under 75% and full sunlight. More flowers were produced by B. megastigma plants grown under 75% full sunlight. Content of α-pinene and limonene decreased with decreasing light intensity, whereas β-ionone and docecyl acetate increased with decreasing light intensity

Growth, yield and plant-water relations of four cowpea (Vigna unguiculata) cultivars in the Sahel

1996 ◽  
Vol 126 (2) ◽  
pp. 183-190 ◽  
Author(s):  
M. V. K. Sivakumar ◽  
B. R. Ntare ◽  
J. M. Roberts
Keyword(s):  
Stomatal Conductance ◽  
Water Use ◽  
Vigna Unguiculata ◽  
Growth Yield ◽  
Net Photosynthesis ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Dual Purpose ◽  
Area Index ◽  
Photosynthetic Rates

SUMMARYThe response of four cowpea (Vigna unguiculata(L.) Walp.) cultivars to the warm, semi-arid tropical environment at the ICRISAT Sahelian Center at Sadore, Niger was studied during 1985 and 1986 interms of leaf area index (LAI), dry matter (DM) accumulation, net photosynthesis, stomatal conductance, total water use and yield. Among the three improved cultivars, IT82D–716 is early and erect, cv. IT83S–947 is early and spreading and cv. TVX4659–03E is a medium-duration, highyielding, dual-purpose type. The local cv. Sadore Local is a long-duration, photosensitive, spreading type used mainly for fodder. In both years, Sadore Local recorded the highest LAI. IT82D–716 and IT83S–947 produced < 1·3 t/ha of DM in both years, whereas TVX 4659–03E produced > 2 t/ha of DM and proved superior to Sadore Local in partitioning DM into pods. The four cultivars did not differ significantly either in stomatal conductance or in net phytosynthetic rates. Observed maximum photosynthetic rates of c. 20 μmol/m2/s lie at the bottom of the range 21–38 μmol/m2/s reported for 31 cowpea genotypes in an earlier study. Photosynthetic rates increased with increasing photon flux density. TVX4659–03E had an advantage in total seed plus fodder yields while the local cultivar gave significantly greater fodder yields in both years. Seed and fodder yields, as well as water-use efficiency, confirmed the advantages offered by the dual-purpose cultivar TVX4659–03E. Future breeding efforts in the Sahel should focus on dual-purpose (grain/fodder) cowpea types.

COMPARATIVE RESPONSES OF PHOTOSYNTHESIS TO GROWTH TEMPERATURE IN SOYBEAN (Glycine max [L.] Merrill) CULTIVARS

1988 ◽  
Vol 68 (2) ◽  
pp. 419-425 ◽  
Author(s):  
F. CAULFIELD ◽  
J. A. BUNCE
Keyword(s):  
Glycine Max ◽  
Photosynthetic Photon Flux Density ◽  
Temperature Acclimation ◽  
Effect Of Temperature ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Maturity Group ◽  
Photosynthetic Rates ◽  
Glycine Max L ◽  
Maturity Groups

The effect of temperature during growth on the photosynthetic characteristics of soybean (Glycine max [L.] Merrill) was studied using cultivars from Maturity Group 00 (Altona, Fiskeby V, Flambeau, Maple Presto, McCall) and MG VIII (Hampton 266–A, Hardee, Johnston, Kirby). In one experiment plants were grown with 950 μmol m−2s−1 photosynthetic photon flux density (PPFD) at 18, 20, 25 and 30 °C. When grown at 20 °C, MG 00 cultivars averaged significantly higher rates of photosynthesis measured at 25 °C and saturating PPFD than did MG VIII cultivars. Cultivars were also grown with a PPFD of 540 μmol m−1 at 17.5, 20.0, 22.5 and 25.0 °C. Maturity Group 00 cultivars averaged higher photosynthetic rates than MG VIII cultivars at the 20.0 and 22.5 °C growth temperatures. The other growth environments produced no significant differences between maturity groups. Photosynthetic rates differed between cultivars, but not maturity groups, after exposure to a single night with a gradual temperature decline to 8 °C. Photosynthetic rates recovered in 28 h. Two cultivars, Altona and Johnston, were grown outdoors at three times during one growing season at Beltsville, and their maximum photosynthetic rates changed depending on the temperatures during leaf development, in agreement with the data from the controlled environment studies.Key words: Soybean, Glycine max [L.] Merrill, photosynthesis, temperature, acclimation

scholarly journals The effects of sooty mold on photosynthesis and mesophyll structure of mahogany (Swietenia macrophylla King., Meliaceae)

Bragantia ◽  
2006 ◽  
Vol 65 (1) ◽  
pp. 11-17 ◽  
Author(s):  
José Pires de Lemos Filho ◽  
Élder Antônio Sousa Paiva
Keyword(s):  
Incident Light ◽  
Light Availability ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Effective Quantum Yield ◽  
Swietenia Macrophylla ◽  
Sooty Mold ◽  
Fluorescence Measurements ◽  
Shade Leaves ◽  
Sun Leaves

The aim of present study was to evaluate the effects of the sooty mold on anatomy and photochemical activity of mahogany (Swietenia macrophylla) leaves. The photochemical features of shade-developed leaves with or without sooty mold were compared to those of sun leaves using chlorophyll a fluorescence measurements. Leaf anatomy was also evaluated using conventional techniques. The degree of blockage of the photosynthetic active photon flux density (PPFD) by sooty mold and its effect on photochemistry were evaluated. Sun leaves showed thick mesophyll with palisade parenchyma disposed in a uniseriate layer, whereas shade leaves showed narrow mesophyll, independently of sooty mold presence. The effective quantum yield (deltaF/Fm') and the apparent electron transport rate (ETR) of sun leaves were higher than those of shade leaves. The values of ETR suggested that photochemistry saturation occurred at lower PPFD in shade-grown plants. Lower values of the deltaF/Fm' and, consequently, lower values of ETR were observed in leaves with sooty mold. A reduction of 40% of the incident light was seen due to physical blockage by sooty mold which is presumably responsible for an additional decrease of ETR values. Our data indicated that sooty mold did not directly damage the leaf, but reduce leaf photochemistry capacity, by decreasing light availability.

Comparative carbon dioxide exchange for two Populus clones grown in growth room, greenhouse, and field environments

1984 ◽  
Vol 14 (6) ◽  
pp. 924-932 ◽  
Author(s):  
Neil D. Nelson ◽  
Paul Ehlers
Keyword(s):  
Net Photosynthetic Rate ◽  
Leaf Area ◽  
Photosynthetic Rate ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Growth Environment ◽  
Photosynthetic Rates ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Growth Room

Light-saturated net photosynthetic rates per unit leaf area were 1.6–2.1 times greater for the photosynthetically mature leaves of plants of two hybrid Populus clones (NC-5260, 'Tristis No.1' (Populustristis Fisch. × P. balsamifera L.); NC-5326, 'eugenei' (P. deltoides Bartr. ex Marsh. × P. nigra L.)) grown in pots in the field than in comparable plants from a controlled environment growth room and a winter greenhouse. Stomatal resistances to CO2 in the field trees were only 0.4–0.6 of those in growth room and greenhouse trees. Mesophyll (residual) resistances to CO2 in field trees were 0.4–0.8 of those in growth room and greenhouse trees. Field plants had specific leaf weights 1.5–1.8 times higher than growth room and greenhouse plants, likely primarily owing to the greater average photosynthetic photon flux density in the field (835, 225, and 142 μE m−2 s−1 for field, growth room, and greenhouse conditions, respectively). When net photosynthetic rates (Ps) were corrected for the differences in specific leaf weights to derive net photosynthetic rate per unit leaf dry weight, the values were similar for plants from the three environments (Ps in field trees was 0.9–1.2 times Ps in growth room and greenhouse trees); gross photosynthetic rates per unit leaf weight were even more similar. Internal leaf CO2 concentrations, and photorespiration and dark respiration rates per unit leaf area were not related to growth environment. However, photorespiration rate as a percentage of net photosynthetic rate was lower in the field trees (12–16% in field trees, 19–24% in growth room trees, and 23–39% in greenhouse trees). Net photosynthetic rate was shown to be under strong genetic control in these clones. The effects of growth environment on variables of carbon exchange are sensitive to the basis of expression of those variables.

scholarly journals ‘L-93’ Creeping Bentgrass Putting Green Responses to Various Winter Light Intensities in the Southern Transition Zone

HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1751-1756 ◽  
Author(s):  
Christian M. Baldwin ◽  
Haibo Liu ◽  
Lambert B. McCarty ◽  
Hong Luo ◽  
Joe E. Toler
Keyword(s):  
Transition Zone ◽  
Chlorophyll Concentration ◽  
Acid Ethyl Ester ◽  
Creeping Bentgrass ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Full Sunlight ◽  
Putting Green ◽  
Soil Temperatures ◽  
The Impact

Seasonal variations in temperature and solar radiation in the warm climatic region of the transition zone increase difficulty of creeping bentgrass [Agrostis stolonifera var. palustris (Huds.)] management throughout the year. The impact of winter shade on bentgrass quality and subsequent residual effects of winter shade in spring and summer months has not been investigated. Therefore, a 2-year field study investigated trinexapac-ethyl (TE) [4-(cyclopropyl-α-hydroxy-methylene)-3,5-dioxy-cyclohexanecarboxylic acid ethyl ester] as a winter management strategy to alleviate winter shade stress and determined the winter shade tolerance of ‘L-93’ creeping bentgrass under various reduced light environments. Treatments included a full-sunlight control; 58% and 96% morning, afternoon, and full-day shade artificial; and TE (0.02 kg a.i./ha) applied every 2 weeks from December to July. Data collection included daily light measurements (photosynthetic photon flux density), monthly canopy and soil temperatures, visual turfgrass quality (TQ), chlorophyll concentration, clipping yield, total root biomass, and total root nonstructural carbohydrates. Under 96% shade, canopy temperatures were reduced ≈57% from December to February, whereas soil temperatures were reduced 39% in February compared with full sunlight. Afternoon shade (58%) maintained acceptable TQ throughout winter for both years. Applying TE every 2 weeks in the winter negatively impacted bentgrass quality; however, TE enhanced spring and summer quality. Morning or afternoon shade minimally impacted parameters measured. Overall, moderate winter shade may not limit ‘L-93’ creeping bentgrass performance as a putting green in the transition zone. Results suggest winter shade does not contribute to creeping bentgrass summer decline because all shade-treated plots fully recovered from shade damage in spring months.

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