Regenerative Succession of Tristaniopsis laurina and Acmena smithii in Riparian Warm Temperate Rain-Forest in Victoria, in Relation to Light and Nutrient Regimes

1990 ◽  
Vol 38 (2) ◽  
pp. 111 ◽  
Author(s):  
DR Melick
Keyword(s):  
Dark Respiration ◽  
Ecological Status ◽  
Photon Flux ◽  
Light Conditions ◽  
Growth Responses ◽  
Low Light ◽  
Light Regimes ◽  
Temperate Rain Forest ◽  
Warm Temperate ◽  
Regenerative Succession

Tristaniopsis laurina and Acmena smithii often form a dominant association in riparian warm temperate rainforest communities in Victoria. The photosynthetic and morphological responses of seedlings of these species to varied light regimes, and the growth responses of seedlings in different nutrient regimes were examined in the laboratory. Acmena smithii was the most shade tolerant, having the lowest light compensation points, dark respiration rates and greater increases in leaf area ratio under low light conditions. Tristaniopsis laurina consistently demonstrated greater maximum rates of leaf photosynthesis at higher photon flux densities. In response to increased nutrients, T. laurina seedlings showed a marked increase in growth and a decrease in root/shoot ratios, while A. smithii demonstrated relatively small growth increases and showed an increase in root/shoot ratios. These results are discussed in relation to the ecological status of these species within the rainforest communities.

Photosynthetic potential of sun and shade Viola species

1984 ◽  
Vol 62 (6) ◽  
pp. 1273-1278 ◽  
Author(s):  
William F. Curtis
Keyword(s):  
Dark Respiration ◽  
Photosynthetic Performance ◽  
Light Conditions ◽  
Low Light ◽  
Light Regimes ◽  
Photosynthetic Plasticity ◽  
Photosynthetic Potential ◽  
Photosynthetic Responses ◽  
Sun And Shade ◽  
Meadow Species

The photosynthetic responses of a forest floor violet (Viola blanda) and a related meadow species (Viola flmbriatula) grown under controlled conditions were measured to test the prediction that these two species were photosynthetically shade and sun adapted, respectively. Based on their low photosynthetic and dark respiration rates, and low light saturation and compensation points, both violets can be classified as shade-tolerant. The forest species was photosynthetically and morphologically inflexible when grown under high light conditions, which led to chlorosis and greatly decreased photosynthetic performance. Conversely, the meadow species was both photosynthetically and morphologically flexible; its photosynthetic performance allowed it to grow well under both high and low light regimes. As a consequence, morphological flexibility may play a greater role than physiological (i.e., photosynthetic) plasticity in regulating the distribution of these two violets under field conditions.

Interactions entre mitochondries et chloroplastes dans la cellule. II. Action du DBMIB, de l'antimycine A et du FCCP sur la spore de Funaria hygrometrica

1977 ◽  
Vol 55 (12) ◽  
pp. 1650-1659 ◽  
Author(s):  
D. Chevallier ◽  
R. Douce ◽  
F. Nurit
Keyword(s):  
Cytochrome Oxidase ◽  
Dark Respiration ◽  
High Light ◽  
Light Conditions ◽  
Oxygen Production ◽  
Low Light ◽  
Funaria Hygrometrica ◽  
Light Intensities

The effect of DBMIB, antimycine A, and FCCP on respiration and photosynthesis of intact chlorophyllic moss (Funaria hygrometrica) spore was investigated.Antimycine A (1 μM) strongly inhibited dark respiration, was without effect on photosynthesis at high light intensities (above the saturation plateau values), and stimulated photosynthesis at low light intensities (below the saturation plateau values).DBMIB (3 μM) inhibited photosynthesis and was without effect, even under light conditions, on the dark respiration. Low amount of FCCP (3 μM) partially inhibited oxygen production at high light intensities. In this case, the inhibition observed was partially relieved by 1 μM antimycine A or 30 μM of KCN; higher concentration of FCCP totally inhibited the oxygen production.It seems likely, therefore, that in the chlorophyllic moss spore the cytochrome oxidase pathway is not functioning under high light intensities and that this inhibition of respiration is attributable to the low cytoplasmic ADP:ATP ratio.

scholarly journals Engineering the phototropin photocycle improves photoreceptor performance and plant biomass production

2019 ◽  
Vol 116 (25) ◽  
pp. 12550-12557 ◽  
Author(s):  
Jaynee E. Hart ◽  
Stuart Sullivan ◽  
Paweł Hermanowicz ◽  
Jan Petersen ◽  
L. Aranzazú Diaz-Ramos ◽  
...  
Keyword(s):  
Plant Growth ◽  
Biomass Production ◽  
Plant Biomass ◽  
Targeted Mutagenesis ◽  
Light Conditions ◽  
In Planta ◽  
Low Light ◽  
Light Regimes ◽  
Plant Biomass Production

The ability to enhance photosynthetic capacity remains a recognized bottleneck to improving plant productivity. Phototropin blue light receptors (phot1 and phot2) optimize photosynthetic efficiency in Arabidopsis thaliana by coordinating multiple light-capturing processes. In this study, we explore the potential of using protein engineering to improve photoreceptor performance and thereby plant growth. We demonstrate that targeted mutagenesis can decrease or increase the photocycle lifetime of Arabidopsis phototropins in vitro and show that these variants can be used to reduce or extend the duration of photoreceptor activation in planta. Our findings show that slowing the phototropin photocycle enhanced several light-capturing responses, while accelerating it reduced phototropin’s sensitivity for chloroplast accumulation movement. Moreover, plants engineered to have a slow-photocycling variant of phot1 or phot2 displayed increased biomass production under low-light conditions as a consequence of their improved sensitivity. Together, these findings demonstrate the feasibility of engineering photoreceptors to manipulate plant growth and offer additional opportunities to enhance photosynthetic competence, particularly under suboptimal light regimes.

Flood Resistance of Tristaniopsis laurina and Acmena smithii From Riparian Warm Temperate Rain-Forest in Victoria

1990 ◽  
Vol 38 (4) ◽  
pp. 371 ◽  
Author(s):  
DR Melick
Keyword(s):  
Growth Rate ◽  
Water Stress ◽  
Tree Species ◽  
Rain Forest ◽  
Ecological Status ◽  
Flood Damage ◽  
Temperate Rainforest ◽  
Flood Resistance ◽  
Temperate Rain Forest ◽  
Warm Temperate

The responses of seedlings of Tristaniopsis laurina and Acmena smithii, two important tree species in riparian warm temperate rainforest communities in Victoria, are investigated in relation to flood disturbances. Freshly germinated A. smithii seedlings had died within 5 weeks of complete waterlogging in the greenhouse, and although the young T. laurina seedlings survived waterlogging for 14 weeks, their growth rate was curtailed. Nine-month-old seedlings of both species were found to be relatively tolerant to waterlogging, forming aerenchymatous surface roots after 40 days of flooding. Neither species suffered leaf abscission or demonstrated any other signs of water stress commonly associated with flood intolerant species. In experiments to determine the resilience of these species to physical flood damage, both species also demonstrated a capacity to regenerate vegetatively following the removal of above ground parts in young seedlings. The heartwood of T. laurina was found to be more decay resistant than that of other species in the field including that of A. smithii. The significance of these results are discussed in relation to other factors examined in earlier papers adding to the understanding of the ecological status of these species within the riparian rainforest communities.

scholarly journals Canopy Photosynthesis and Time-of-day Application of Supplemental Light

HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1284-1290 ◽  
Author(s):  
Jakob Markvart ◽  
Eva Rosenqvist ◽  
Helle Sørensen ◽  
Carl-Otto Ottosen ◽  
Jesper M. Aaslyng
Keyword(s):  
Dark Respiration ◽  
High Growth ◽  
Net Photosynthesis ◽  
Time Of Day ◽  
Photon Flux ◽  
Carbon Gain ◽  
Climate Control ◽  
Low Light ◽  
Light Intensities ◽  
Supplemental Lighting

There is increasing use of electricity for supplemental lighting in the northern European greenhouse industry. One reason for this may be to secure a high growth rate during low-light periods by an attempt to increase net photosynthesis. We wanted to clarify which period of the day resulted in the best use of a 5-h supplemental light period for photosynthesis and growth. The periods tested were supplemental light during the night, day, morning, and evening. The experiments were carried out in daylight climate chambers measuring canopy gas exchange. The air temperature was 25 °C and the CO2 level ≈900 ppm. Vegetative chrysanthemum was used, because this species responds quickly to change in light level. The leaf areas of the plant canopies were nondestructively measured each week during the 4-week experimental period. The fact that the quantum yield of photosynthesis is greater at low than at high light intensities favors the use of supplemental light during the dark period, but growth measured as dry weight of the treated plants at the end of the experiments was not significantly different given identical light integrals of the treatments. However, one experiment indicated that increased time with dark hours during day and night (24 h) might decrease net photosynthesis. The assimilation per unit leaf area was approximately the same during times of sunlight through a diffusing screen at 100 μmol·m−2·s−1 of photosynthetic photon flux (PPF) as during times of supplemental (direct) light application at PPF of 200 μmol·m−2·s−1 by high-pressure sodium lamps. We conclude that during the winter and periods of low light intensities, the daily carbon gain does not depend on the time of supplemental light application, but is linked to the total light integral. However, extended time with dark hours during day and night (24 h) might be a disadvantage because of longer periods with dark respiration and subsequent loss of carbon. Our results indicate that during times of low light conditions, it is not necessary to include factors such as the timing of supplemental lighting application to achieve higher net photosynthesis in climate control strategies.

Growth, Morphology, and Physiology of Intsia bijuga Trees Under Varied Light Conditions

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 480c-480
Author(s):  
Robin A. DeMeo ◽  
Thomas E. Marler
Keyword(s):  
Shade Tolerance ◽  
Light Exposure ◽  
Dark Respiration ◽  
Stomatal Density ◽  
Seedling Emergence ◽  
Sunlight Exposure ◽  
Photon Flux ◽  
Light Conditions ◽  
Plant Characteristics ◽  
Growth Differences

Six studies were conducted with Intsia bijuga seedlings to determine the methods and extent of shade tolerance for this species. Growth differences were minimal among plants receiving varied light exposure, although treatments ranged from 19% to 100% sunlight exposure. Light saturated photosynthesis of leaves on plants receiving 24% sunlight was achieved at a photosynthetic photon flux (PPF) of about one-fourth of that for the leaves on plants receiving 100% sunlight exposure. However, photosynthesis under conditions of extremely low PPF was higher for shade-grown plants than for full-sun plants. Shaded plants exhibited lower dark respiration, light compensation point, and light-saturated photosynthesis than full sun plants. Leaflet thickness, palisade layer number, and stomatal density of leaves of shaded plants were reduced compared with full sun plants. At seedling emergence and for several months thereafter, the plants responded to shade primarily with obligate sun plant characteristics. After the plants were established, however, responses to the varied light conditions indicated facultative structural and physiological characteristics.

Growth responses of three contrasting Piper species growing under different light conditions

1990 ◽  
Vol 68 (6) ◽  
pp. 1182-1186 ◽  
Author(s):  
M. Esther Sanchez-Coronado ◽  
Emmanuel Rincòn ◽  
Carlos Vàzquez-Yanes
Keyword(s):  
Growth Chamber ◽  
Los Tuxtlas ◽  
Light Conditions ◽  
Growth Responses ◽  
Low Light ◽  
Light Intensities ◽  
Shade Tolerant Species ◽  
Piper Auritum ◽  
Plastic Responses ◽  
Tropical Station

The growth responses of Piper aequale, Piper auritum, and Piper hispidum under contrasting light conditions at Los Tuxtlas Tropical Station, Mexico, and in growth chamber experiments were investigated. The species showed contrasting growth responses; Piper auritum was the less shade-tolerant species and Piper aequale, on the contrary, showed the ability to exploit conditions of intermediate light intensities, similar to those found in small gaps. Piper hispidum was able to sustain growth in both high and low light conditions; this response appears to be related with morphological plastic responses.

scholarly journals Photosynthetic Responses of Anthurium × ‘Red’ under Different Light Conditions

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 857
Author(s):  
Lingyan Chen ◽  
Muhammad Waqqas Khan Tarin ◽  
Heqiang Huo ◽  
Yushan Zheng ◽  
Jianjun Chen
Keyword(s):  
Photosynthetic Activity ◽  
Chlorophyll Concentration ◽  
Photon Flux ◽  
Total Chlorophyll ◽  
Light Conditions ◽  
Photosynthetic Photon Flux ◽  
Low Light ◽  
Plant Photosynthesis ◽  
Photosynthetic Responses ◽  
Indoor Conditions

Light is an essential energy source for plant photosynthesis, although it can also be a stress-causing element. Therefore, the current research was aimed to compare photosynthetic responses of Anthurium × ‘Red’ leaves at different positions (bottom old leaf, 1; center mature leaf, 2; top expanded leaf, 3) established under three photosynthetic photon flux densities (PPFDs): 550 μmol·m−2·s−1 as high (H), 350 μmol·m−2·s−1 as medium (M), and 255 μmol·m−2·s−1 as low (L). After six months, all the replicates were relocated to interior rooms with a PPFD of 30 μmol·m−2·s−1. There were no significant differences in chlorophyll concentration of the old leaf among treatments, before (Day 0) and after shifting the plants to interior rooms (Day 30). The total chlorophyll concentrations of the mature and top leaves increased significantly. In greenhouse conditions, H and M treatments did not show any significant change for net photosynthetic rate (Pn) at various leaf positions. However, M2 exhibited an improved Pn in the interior conditions. Plants grown under M treatment were greener and had bigger leaves compared to other treatments. Our study reveals that Anthurium × ‘Red’ photosynthesis responses to different light conditions varied distinctly. However, M treatment can keep the plants looking green by accumulating enough energy for indoor conditions, and middle and lower leaves may be triggered to restore photosynthetic activity under low light or indoor conditions.

scholarly journals Gas Exchange Responses of Papaya Leaves to Light Variation as Influenced by Drought

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 881D-881
Author(s):  
Hiphil S. Clemente ◽  
Thomas E. Marler
Keyword(s):  
Gas Exchange ◽  
High Light ◽  
Photon Flux ◽  
Light Conditions ◽  
Low Light ◽  
Daily Water ◽  
The Mean ◽  
To Receive ◽  
Tracking Response ◽  
Mild Drought

Container-grown papaya plants were subjected to a slow drying cycle by replenishing a portion of the mean daily water loss. When light-saturated net CO2 assimilation (A) of stressed plants was ≈70% of well-watered plants, sun–cloud transitions were simulated by placing shadecloth between a lamp and the leaf cuvette. The cuvette was initially positioned to receive photosynthetic photon flux (PPF) of ≈1600 μmol–m–2–s–1. The shadecloth was placed over the cuvette for a 3-min period (250 μmol–m–2–s–1), then removed. Gas-exchange responses were recorded for another 3 min of high light. Within 20 sec of initiating low light on well-watered plants, A was <50% of the high-light value. Stomatal conductance (gs) of these plants began to decline by 60 sec and slowly declined to <90% of the high-light value. Both A and gs recovered to the original values by ≈2 min following return to the high-light conditions. For stressed plants, the decline of gs under low light began earlier and was of greater magnitude, and gs and A recovery following the return to high light was delayed. These results indicate that papaya has suntracking capabilities, and mild drought stress enhances the tracking response.

scholarly journals Ecophysiological, morphological, and biochemical traits of free-living Diplosphaera chodatii (Trebouxiophyceae) reveal adaptation to harsh environmental conditions

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Cynthia Medwed ◽  
Andreas Holzinger ◽  
Stefanie Hofer ◽  
Anja Hartmann ◽  
Dirk Michalik ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Botanical Garden ◽  
Tree Bark ◽  
Photon Flux ◽  
Low Light ◽  
Transmission Electron ◽  
Light Requirements ◽  
Adaptive Mechanisms ◽  
Terrestrial Habitats ◽  
Excellent Preservation

AbstractSingle-celled green algae within the Trebouxiophyceae (Chlorophyta) are typical components of terrestrial habitats, which often exhibit harsh environmental conditions for these microorganisms. This study provides a detailed overview of the ecophysiological, biochemical, and ultrastructural traits of an alga living on tree bark. The alga was isolated from a cypress tree in the Botanical Garden of Innsbruck (Austria) and identified by morphology and molecular phylogeny as Diplosphaera chodatii. Transmission electron microscopy after high-pressure freezing (HPF) showed an excellent preservation of the ultrastructure. The cell wall was bilayered with a smooth inner layer and an outer layer of polysaccharides with a fuzzy hair-like appearance that could possibly act as cell-cell adhesion mechanism and hence as a structural precursor supporting biofilm formation together with the mucilage observed occasionally. The photosynthetic-irradiance curves of D. chodatii indicated low light requirements without photoinhibition at high photon flux densities (1580 μmol photons m−2 s−1) supported by growth rate measurements. D. chodatii showed a high desiccation tolerance, as 85% of its initial value was recovered after controlled desiccation at a relative humidity of ~10%. The alga contained the low molecular weight carbohydrates sucrose and sorbitol, which probably act as protective compounds against desiccation. In addition, a new but chemically not elucidated mycosporine-like amino acid was detected with a molecular mass of 332 g mol−1 and an absorption maximum of 324 nm. The presented data provide various traits which contribute to a better understanding of the adaptive mechanisms of D. chodatii to terrestrial habitats.

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