Leaf acclimation strategies to contrasting light conditions in saplings of different shade tolerance in a tropical cloud forest

2018 ◽  
Vol 45 (9) ◽  
pp. 968 ◽  
Author(s):  
Ana Quevedo-Rojas ◽  
Carlos García-Núñez ◽  
Mauricio Jerez-Rico ◽  
Ramón Jaimez ◽  
Teresa Schwarzkopf
Keyword(s):  
Optical Properties ◽  
Shade Tolerance ◽  
Light Exposure ◽  
Cloud Forest ◽  
Repeated Measurements ◽  
Photon Flux ◽  
Light Conditions ◽  
Light Gradient ◽  
Tolerant Species ◽  
Shade Tolerant Species

To study the acclimation responses of the leaves of saplings of six tree species when changed to low or high levels of irradiance, we carried out a light exposure experiment. Species representative of contrasting shade tolerance groups were identified across a light gradient in the understorey of a Venezuelan Andean cloud forest. Measured traits included gas exchange, chlorophyll fluorescence, and morphoanatomical, biochemical and optical properties. Saplings were grown for 6 months in a shade-house receiving 20% photosynthetic photon flux (PPF) of full sunlight. Plant samples were then moved to shade-houses receiving low PPF (4%) or high PPF (65%). A factorial model (species × PPF), with repeated measurements (0, 15 and 120 days) was designed. Our results showed that morphological and anatomical traits were more plastic to PPF changes than photosynthetic traits. All species were susceptible to photoinhibition (15 days): shade-intolerant species showed dynamic photoinhibition (120 days), whereas shade-tolerant species presented chronic photoinhibition and the consequent inability to increase C assimilation rates under high PPF. The partially shade-tolerant species showed mixed responses; nonetheless, they exhibited larger adjustments in morphoanatomical and optical properties. Thus the acclimation responses of these species when subject to contrasting light conditions could help to explain their distribution along the light gradient in the understorey.

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.

Chlorophyll fluorescence of submerged and floating leaves of the aquatic resurrection plant Chamaegigas intrepidus

2004 ◽  
Vol 31 (1) ◽  
pp. 53 ◽  
Author(s):  
Markus Woitke ◽  
Wolfram Hartung ◽  
Hartmut Gimmler ◽  
Hermann Heilmeier
Keyword(s):  
Chlorophyll Fluorescence ◽  
Shade Tolerance ◽  
Photosynthetic Performance ◽  
Resurrection Plant ◽  
Photon Flux ◽  
Carbon Gain ◽  
Light Conditions ◽  
Total Plant ◽  
Floating Leaves

The role of submerged and floating leaves in plant photosynthetic performance of the aquatic resurrection plant Chamaegigas intrepidus Dinter was investigated by monitoring chlorophyll fluorescence under the fluctuating natural field conditions that characterise the extreme habitat of this species. The performance of the two different leaf types during desiccation–rehydration cycles in the field was examined. PSII quantum efficiency indicates a similar regeneration capacity in both leaf types after water stress. Electron transport rates under controlled light conditions were 3–4 times higher in floating leaves than in submerged leaves. The two leaf types showed specific adaptations to their ambient photosynthetic photon flux densities (PPFD), shade tolerance in the submerged leaves and adaptation to high PPFD in floating leaves. These results imply a significant role of the floating leaves for total plant carbon gain. It is concluded that the combination of high N content of floating leaves and a high availability of CO2 and light at the water surface contributes to the importance of this leaf type for photosynthesis in C. intrepidus.

Does carbon storage confer waterlogging tolerance? Evidence from four evergreen species of a temperate rainforest

2018 ◽  
Vol 66 (1) ◽  
pp. 74 ◽  
Author(s):  
M. Delgado ◽  
A. Zúñiga-Feest ◽  
F. I. Piper
Keyword(s):  
Carbon Storage ◽  
Shade Tolerance ◽  
Soluble Sugars ◽  
Carbon Limitation ◽  
Waterlogging Tolerance ◽  
Evergreen Species ◽  
Tolerant Species ◽  
Shade Tolerant Species ◽  
Structural Carbohydrate ◽  
Leaf Chlorophyll Fluorescence

Deep shade and waterlogging are two common stressors affecting seedling performance in the understorey of evergreen rainforests. It has been hypothesised that high levels of carbon storage confer shade- and waterlogging tolerances by preventing carbon limitation under such stresses. Whether the tolerance to both stresses is positively or negatively related remains unclear. To explore the role of carbon storage in the relationships of waterlogging and shade tolerance, we investigated the responses to waterlogging and the levels of carbon storage in two species pairs with contrasting shade tolerance: Embothrium coccineum J.R.Forst.&G.Forst. and Gevuina avellana Mol. (Proteaceae) and Nothofagus dombeyi (Mirb.) Oerst. and Nothofagus nitida (Phil.) Krasser (Nothofagaceae). We subjected seedlings to waterlogging or control conditions for 30 days and evaluated survival, relative growth rate (RGR), biomass distribution, leaf chlorophyll fluorescence (Fv/Fm), and concentrations of total soluble sugars, starch and non-structural carbohydrates in different plant tissues. Waterlogging reduced survival, Fv/Fm and RGR in all species; however, the magnitude of reduction of Fv/Fm and RGR was significantly higher in the shade-intolerant species than in their shade-tolerant counterparts. In general, shade-intolerant species had significantly higher non-structural carbohydrate concentrations in waterlogging than in control conditions. By contrast, shade-tolerant species had similar non-structural carbohydrate concentrations under both conditions. Our results indicate that relatively shade-tolerant species performed better under waterlogging. A reduction in non-structural carbohydrates under waterlogging was not observed in any of studied species; rather, shade-intolerant species exhibited non-structural carbohydrate accumulation suggesting that carbon storage does not confer waterlogging tolerance in these species.

A note on shade tolerance and vegetative propagation of woodland species

1976 ◽  
Vol 192 (1107) ◽  
pp. 257-258 ◽  
Keyword(s):  
Seed Production ◽  
Vegetative Propagation ◽  
Shade Tolerance ◽  
Habitat Conditions ◽  
Tolerant Species ◽  
Shade Tolerant Species

Evidence is provided to show that, for many ‘shade tolerant’ species vegetative modes of increase may compensate for meagre seed-production which may be imposed by the habitat conditions.

Characterizing shade tolerance by the relationship between mortality and growth in tree saplings in a southeastern Texas forest

2001 ◽  
Vol 31 (2) ◽  
pp. 345-349
Author(s):  
Jie Lin ◽  
Paul A Harcombe ◽  
Mark R Fulton
Keyword(s):  
Survival Analysis ◽  
Mortality Risk ◽  
Shade Tolerance ◽  
Mesic Forest ◽  
Tolerant Species ◽  
Shade Tolerant Species ◽  
Zero Growth ◽  
Using Data ◽  
Species Specific ◽  
The Relationship

We investigated the relationship between shade tolerance and sapling mortality using data collected over 15 years in a mesic forest in southeastern Texas. Seven species representing a range of shade-tolerance classes were included in the study. We used survival analysis to estimate species-specific sapling mortality risk (hazard) as a function of recent growth. We found that shade-intolerant species had higher mortality risk at zero growth than shade-tolerant species. The results strongly support the point that shade tolerance can be characterized by the relationship between sapling mortality and growth.

Species variability in growth response to light across climatic regions in northwestern British Columbia

1998 ◽  
Vol 28 (6) ◽  
pp. 871-886 ◽  
Author(s):  
Elaine F Wright ◽  
K Dave Coates ◽  
Charles D Canham ◽  
Paula Bartemucci
Keyword(s):  
British Columbia ◽  
Shade Tolerance ◽  
Growth Response ◽  
High Light ◽  
Low Light ◽  
Climatic Regions ◽  
Light Levels ◽  
Tolerant Species ◽  
Trade Offs ◽  
Shade Tolerant Species

We characterize variation in radial and height growth of saplings of 11 tree species across a range of light levels in boreal, sub-boreal, subalpine, and temperate forests of northwestern British Columbia. Shade-tolerant species had the greatest response to an increase in light at low-light levels but had low asymptotic growth at high light. Shade-intolerant species had weaker responses to increases at low light but had the highest growth rates at high light. The effects of climate on intraspecific variation in sapling response to light were also related to shade tolerance: across different climatic regions, the most shade-tolerant species varied in their response to low-light but not high light, while shade-intolerant species varied only in their high-light growth. Species with intermediate shade tolerance varied both their amplitude of growth at high light and the slope of the growth response at low light. Despite the interspecific trade-offs between high- and low-light growth, there was a striking degree of overlap in the light response curves for the component species in virtually all of the climatic regions. Successional dynamics in these forests appear to be more strongly governed by interspecific variation in sapling survival than growth.

scholarly journals Traits controlling shade tolerance in tropical montane trees

2019 ◽  
Vol 40 (2) ◽  
pp. 183-197 ◽  
Author(s):  
Elisée Bahati Ntawuhiganayo ◽  
Félicien K Uwizeye ◽  
Etienne Zibera ◽  
Mirindi E Dusenge ◽  
Camille Ziegler ◽  
...  
Keyword(s):  
Tree Species ◽  
Shade Tolerance ◽  
Plant Traits ◽  
Plant Biomass ◽  
Leaf Traits ◽  
Interspecific Variation ◽  
Clear Understanding ◽  
Tolerant Species ◽  
Whole Plant ◽  
Shade Tolerant Species

Abstract Tropical canopies are complex, with multiple canopy layers and pronounced gap dynamics contributing to their high species diversity and productivity. An important reason for this complexity is the large variation in shade tolerance among different tree species. At present, we lack a clear understanding of which plant traits control this variation, e.g., regarding the relative contributions of whole-plant versus leaf traits or structural versus physiological traits. We investigated a broad range of traits in six tropical montane rainforest tree species with different degrees of shade tolerance, grown under three different radiation regimes (under the open sky or beneath sparse or dense canopies). The two distinct shade-tolerant species had higher fractional biomass in leaves and branches while shade-intolerant species invested more into stems, and these differences were greater under low radiation. Leaf respiration and photosynthetic light compensation point did not vary with species shade tolerance, regardless of radiation regime. Leaf temperatures in open plots were markedly higher in shade-tolerant species due to their low transpiration rates and large leaf sizes. Our results suggest that interspecific variation in shade tolerance of tropical montane trees is controlled by species differences in whole-plant biomass allocation strategy rather than by difference in physiological leaf traits determining leaf carbon balance at low radiation.

scholarly journals Leaf optical properties as affected by shade in saplings of six tropical tree species differing in successional status

2003 ◽  
Vol 15 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Rogéria Pereira Souza ◽  
Ivany F. M. Válio
Keyword(s):  
Optical Properties ◽  
Chlorophyll Content ◽  
Tree Species ◽  
Tropical Tree ◽  
Successional Status ◽  
Tropical Tree Species ◽  
Leaf Chlorophyll ◽  
Tolerant Species ◽  
Leaf Optical Properties ◽  
Shade Tolerant Species

Tree species differing in successional status may present different responses to shade. Adjustments at leaf level may affect their optical properties, leading to changes in PAR (photosynthetically active radiation) absorbance. The aim of this study was to evaluate leaf optical properties as affected by understory shade in saplings of six tropical tree species differing in successional status and degree of shade tolerance. Chlorophyll content and specific leaf area (SLA) were also evaluated. The effects of shade on leaf optical properties and chlorophyll content differed among the studied species, whereas increased SLA was a common response for all species, reflecting the occurrence of thinner leaves under shade. The three studied shade-tolerant species - Esenbeckia leiocarpa, Myroxylon peruiferum and Hymenaea courbaril - presented a greater PAR absorbance under shade. The response of the shade-intolerant species was varied. While Schizolobium parahyba also showed a greater PAR absorbance under shade, Chorisia speciosa did not alter its spectral properties and Cecropia pachystachya presented an opposite pattern, with smaller absorbance under shade. Increases in leaf chlorophyll content were significant in the shade-tolerant species, whereas they were absent or of small magnitude in the shade-intolerant ones. Although the shade-induced decrease of leaf reflectance was the only response that safely discriminated tolerant from intolerant species, the adjustments in leaf chlorophyll content and optical properties were more consistent for the tolerant species.

scholarly journals Insights into the Light Response of Skeletonema marinoi: Involvement of Ovothiol

Marine Drugs ◽  
2020 ◽  
Vol 18 (9) ◽  
pp. 477
Author(s):  
Alfonsina Milito ◽  
Ida Orefice ◽  
Arianna Smerilli ◽  
Immacolata Castellano ◽  
Alessandra Napolitano ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Biological Activities ◽  
Model Systems ◽  
Human Model ◽  
Photon Flux ◽  
Intensity Increase ◽  
Light Conditions ◽  
Great Ability ◽  
Square Wave ◽  
Skeletonema Marinoi

Diatoms are one of the most widespread groups of microalgae on Earth. They possess extraordinary metabolic capabilities, including a great ability to adapt to different light conditions. Recently, we have discovered that the diatom Skeletonema marinoi produces the natural antioxidant ovothiol B, until then identified only in clams. In this study, we investigated the light-dependent modulation of ovothiol biosynthesis in S. marinoi. Diatoms were exposed to different light conditions, ranging from prolonged darkness to low or high light, also differing in the velocity of intensity increase (sinusoidal versus square-wave distribution). The expression of the gene encoding the key ovothiol biosynthetic enzyme, ovoA, was upregulated by high sinusoidal light mimicking natural conditions. Under this situation higher levels of reactive oxygen species and nitric oxide as well as ovothiol and glutathione increase were detected. No ovoA modulation was observed under prolonged darkness nor low sinusoidal light. Unnatural conditions such as continuous square-wave light induced a very high oxidative stress leading to a drop in cell growth, without enhancing ovoA gene expression. Only one of the inducible forms of nitric oxide synthase, nos2, was upregulated by light with consequent production of NO under sinusoidal light and darkness conditions. Our data suggest that ovothiol biosynthesis is triggered by a combined light stress caused by natural distribution and increased photon flux density, with no influence from the daily light dose. These results open new perspectives for the biotechnological production of ovothiols, which are receiving a great interest for their biological activities in human model systems.

Managing for Mature Habitat in Production Forests of Western Oregon and Washington

1996 ◽  
Vol 10 (2) ◽  
pp. 422-428 ◽  
Author(s):  
Elizabeth C. Cole
Keyword(s):  
Pacific Northwest ◽  
Coarse Woody Debris ◽  
Management Practices ◽  
Woody Debris ◽  
Wildlife Habitat ◽  
Low Grade ◽  
Habitat Features ◽  
Canopy Opening ◽  
Tolerant Species ◽  
Shade Tolerant Species

Standard timber management practices in the Pacific Northwest result in stands which often vary from unmanaged stands in structure and composition. Forest and wildlife managers have identified a deficit of stands in the mature (> 100-yr-old) age class that contain certain desirable wildlife habitat features. Techniques are being developed that would increase the likelihood that managed stands can produce these characteristics. The key desirable components in these stands include large (> 75 cm diam breast height) conifer trees, snags, coarse woody debris, and understory structure, including regeneration. Vegetation management techniques can facilitate development of these components within stands. Thinning the overstory, underplanting shade-tolerant species, and creating snags and coarse woody debris can be accomplished within a production forest. Maintaining shade-intolerant species requires a higher level of disturbance and canopy opening than needed for shade-tolerant species. Treatments which remove competition from shrubs and herbaceous plants may be necessary to insure growth and survival of understory regeneration. Injection of different herbicides into low-grade conifers may yield different types of snags in comparison to girdling or topping. Although much of the understory may be eliminated during future thinnings and final harvest, some of the structure will remain and could be carried over into the next rotation along with snags and large coarse woody debris. These treatments are expected to enhance mature habitats in present and future cycles with minimum impact on yield.

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