scholarly journals Biomass allocation of chestnut oak (Quercus castaneifolia C.A. Mey) seedlings: effects of provenance and light gradient

2014 ◽  
Vol 60 (No. 11) ◽  
pp. 443-450 ◽  
Author(s):  
F. Babaei Sustani ◽  
S.G. Jalali ◽  
H. Sohrabi ◽  
A. Shirvani
Keyword(s):  
Biomass Allocation ◽  
Leaf Size ◽  
Growth Conditions ◽  
High Irradiance ◽  
Growth Strategies ◽  
Low Light ◽  
Rainfall Gradient ◽  
Light Levels ◽  
Light Gradient ◽  
Precipitation Regimes

Patterns of biomass allocation were determined for seedlings of five provenances of Quercus castaneifolia from west to east of the Hyrcanian forest along a rainfall gradient. Experimental design was executed under controlled conditions at seven different light levels (10, 20, 30, 40, 50, 60, 70 and 100% full light). We quantified the biomass allocation patterns to leaves, stems and roots. For all provenances total mass increased with irradiance at low light levels, reaching an optimum at an intermediate level but decreasing at a high irradiance level. As results show, in drier provenances and at high light levels, the seedlings invest more biomass into root mass to facilitate water uptake and to alter their leaf size to prevent overheating. In contrast, at wetter provenances and low light levels, towards increased light interception, more biomass is allocated proportionally to leaves and the stems but, accordingly, less to roots. The leaf to root ratio (L/R) was negatively correlated with light, with high correlation at wetter provenances compared to drier ones. In contrast, the relationship between the root to shoot (R/Sh) ratio and light was positively correlated with light, but it was weak at drier provenances and became gradually stronger at wetter ones. Such relationships indicated that chestnut oak seedling growth strategies are different along a rainfall gradient to irradiance levels. Despite similar growth conditions in the greenhouse, different growth strategies may be the result of genetic adaptation to the ecological conditions, especially when precipitation regimes prevail in the native habitat.  

Light Response of Native and IntroducedMiscanthus sinensisSeedlings

2012 ◽  
Vol 5 (3) ◽  
pp. 363-374 ◽  
Author(s):  
David P. Matlaga ◽  
Lauren D. Quinn ◽  
Adam S. Davis ◽  
J. Ryan Stewart
Keyword(s):  
Leaf Area ◽  
Biomass Allocation ◽  
Shade Tolerance ◽  
Light Response ◽  
Leaf Size ◽  
The United States ◽  
Total Leaf Area ◽  
Light Levels ◽  
Light Gradient ◽  
Total Leaf

The Asian grassMiscanthus sinensis(Poaceae) is being considered for use as a bioenergy crop in the U.S. Corn Belt. Originally introduced to the United States for ornamental plantings, it escaped, forming invasive populations. The concern is that naturalizedM. sinensispopulations have evolved shade tolerance. We tested the hypothesis that seedlings from within the invasive U.S. range ofM. sinensiswould display traits associated with shade tolerance, namely increased area for light capture and phenotypic plasticity, compared with seedlings from the native Japanese populations. In a common garden experiment, seedlings of 80 half-sib maternal lines were grown from the native range (Japan) and 60 half-sib maternal lines from the invasive range (U.S.) under four light levels. Seedling leaf area, leaf size, growth, and biomass allocation were measured on the resulting seedlings after 12 wk. Seedlings from both regions responded strongly to the light gradient. High light conditions resulted in seedlings with greater leaf area, larger leaves, and a shift to greater belowground biomass investment, compared with shaded seedlings. Japanese seedlings produced more biomass and total leaf area than U.S. seedlings across all light levels. Generally, U.S. and Japanese seedlings allocated a similar amount of biomass to foliage and equal leaf area per leaf mass. Subtle differences in light response by region were observed for total leaf area, mass, growth, and leaf size. U.S. seedlings had slightly higher plasticity for total mass and leaf area but lower plasticity for measures of biomass allocation and leaf traits compared with Japanese seedlings. Our results do not provide general support for the hypothesis of increasedM. sinensisshade tolerance within its introduced U.S. range compared with native Japanese populations.

Growth ofPseudotsuga menziesiiandTsuga heterophyllaseedlings along a light gradient: resource allocation and morphological acclimation

1997 ◽  
Vol 75 (9) ◽  
pp. 1424-1435 ◽  
Author(s):  
D. Mailly ◽  
J. P. Kimmins
Keyword(s):  
Leaf Morphology ◽  
Biomass Accumulation ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Low Light ◽  
Growing Seasons ◽  
Light Levels ◽  
Light Gradient ◽  
Relative Light Intensity

Silvicultural alternatives that differ in the degree of overstory removal may create shady environments that will be problematic for the regeneration of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Gradients of light in the field were used to compare mortality, growth, and leaf morphological acclimation of two conifer species of contrasting shade tolerances: Douglas-fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.). Results after two growing seasons indicated that Douglas-fir mortality occurred mainly at relative light intensity (RLI) below 20%, while western hemlock mortality was evenly distributed along the light gradient. Height, diameter, and biomass of the planted seedlings increased with increasing light for both species but at different rates, and maximum biomass accumulation always occurred in the open. Douglas-fir allocated more resources to stem biomass than western hemlock, which accumulated more foliage biomass. Increases in specific leaf area for Douglas-fir seedlings occurred at RLI ≤ 0.4 and red/far red (R/FR) ratio ≤ 0.6, which appear to be the minimal optimum light levels for growth. Conversely, western hemlock seedlings adjusted their leaf morphology in a more regular pattern, and changes were less pronounced at low light levels. These results, along with early mortality results for Douglas-fir, suggest that the most successful way to artificially regenerate this species may be by allowing at least 20% of RLI for ensuring survival and at least 40% RLI for optimum growth. Key words: light, light quality, leaf morphology, acclimation.

scholarly journals Variability in leaf and crown morphology correlated with light availability in five natural populations of Quercus castaneifolia C.A. Mey

2017 ◽  
Vol 63 (No. 6) ◽  
pp. 275-281 ◽  
Author(s):  
Babaei Fariba ◽  
Jalali Seyed Gholamali ◽  
Sohrabi Hormoz ◽  
Shirvany Anoshirvan
Keyword(s):  
Leaf Area ◽  
Light Availability ◽  
Natural Populations ◽  
High Irradiance ◽  
Morphological Variations ◽  
Proportional Allocation ◽  
Light Levels ◽  
Light Gradient ◽  
Controlled Conditions ◽  
Crown Morphology

In this study, we investigate seedlings of Quercus castaneifolia C.A. Mey, from five different provenances for the research on leaf and crown morphological variations in relation to a light gradient under controlled conditions in a greenhouse. The results show that significant variations occurred in many parameters due to the effects of light availability. The seedling responses to low light include the proportional allocation of more biomass to leaves, leading to higher leaf mass, leaf area, crown area, specific leaf area and leaf area ratio, in contrast, the seedlings grown in high irradiance faced a high temperature resulting in higher transpiration. At this period, seedlings alter their leaf and crown size to prevent overheating. In this experiment, in spite of the same treatments in controlled conditions in a greenhouse, the seedlings from different provenances indicate different responses to light levels. It seems that the seedlings try to maximize their surface area for the intake of light as the most limiting resource in wet provenances. Such responses under the same treatment are adaptive strategies which allow oak seedlings to have the best function under stressed conditions. For Q. castaneifolia as a species with broad fundamental niches in Hyrcanian forests, these variations may be achieved by a combination of genotypic differentiation and phenotypic plasticity.

scholarly journals Morphological and Photosynthetic Response to High and Low Irradiance ofAeschynanthus longicaulis

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qiansheng Li ◽  
Min Deng ◽  
Yanshi Xiong ◽  
Allen Coombes ◽  
Wei Zhao
Keyword(s):  
Light Stress ◽  
High Irradiance ◽  
Anthocyanin Content ◽  
Light Conditions ◽  
Leaf Color ◽  
Low Light ◽  
Light Levels ◽  
Chlorophyll Fluorescence Parameter ◽  
Fluorescence Parameter ◽  
Length Width

Aeschynanthus longicaulisplants are understory plants in the forest, adapting to low light conditions in their native habitats. To observe the effects of the high irradiance on growth and physiology, plants were grown under two different light levels, PPFD 650 μmol·m–2·s–1and 150 μmol·m–2·s–1for 6 months. Plants under high irradiance had significantly thicker leaves with smaller leaf area, length, width, and perimeter compared to the plants grown under low irradiance. Under high irradiance, the leaf color turned yellowish and the total chlorophyll decreased from 5.081 mg·dm−2to 3.367 mg·dm−2. The anthocyanin content of high irradiance leaves was double that of those under low irradiance. The plants under high irradiance had significantly lower Amax(5.69 μmol·m–2·s–1) and LSP (367 μmol·m–2·s–1) and higher LCP (21.9 μmol·m–2·s–1). The chlorophyll fluorescence parameterFv/Fmwas significantly lower and NPQ was significantly higher in high irradiance plants. RLCs showed significantly lowerETRmax⁡andEkin plants under high irradiance. It can be concluded that the maximum PPFD of 650 μmol·m–2·s–1led to significant light stress and photoinhibition ofA. longicaulis.

scholarly journals Effects of mycorrhizal fungi on tree seedling growth: quantifying the parasitism–mutualism transition along a light gradient

2016 ◽  
Vol 46 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Inés Ibáñez ◽  
Sarah McCarthy-Neumann
Keyword(s):  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
High Light ◽  
Competitive Interactions ◽  
Tree Seedlings ◽  
Tree Seedling ◽  
Low Light ◽  
Light Levels ◽  
Light Gradient ◽  
Tree Seedling Growth

Mycorrhizal fungi colonize tree seedlings shortly after germination, and the nature of this relationship (mutualistic to parasitic) has been reported to vary as a function of resources; however, this transition has rarely been quantified. Using a light gradient, we grew seedlings of eight tree species in soils that were cultivated by several co-existing species of trees. We used data on root mycorrhizal fungi to quantify colonization along the gradient of light. We then analyzed plant growth as a function of both the light gradient and the extent of mycorrhizal colonization. Mycorrhizal fungi colonization varied among species but was not correlated with the species’ seed sizes or shade tolerances. Within a species, colonization varied among soil sources, but those differences followed neither the conspecific–heterospecific dichotomy, nor the soil host’s arbuscular–ectomycorrhizal associations commonly reported. At high light levels, seedlings growth increased with increasing levels of colonization for seven species, and at low light levels, the effect of colonization was negative for five species. We also quantified the light threshold at which the plant – mycorrhizal fungi relationship shifted from neutral to positive (four species), from negative to neutral (one species), and from neutral to negative (one species), documenting differences among species that could exacerbate competitive interactions during recruitment.

scholarly journals Effects of Light, N and Defoliation on Biomass Allocation in Poa annua

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1783
Author(s):  
Louis John Irving ◽  
Sayuki Mori
Keyword(s):  
Biomass Allocation ◽  
Light Level ◽  
Poa Annua ◽  
Root Mass ◽  
Light Conditions ◽  
Low Light ◽  
Light Levels ◽  
Below Ground ◽  
Shoot Mass

Plants allocate biomass to above- and below-ground organs in response to environmental conditions. While the broad patterns are well-understood, the mechanisms by which plants allocate new growth remain unclear. Modeling approaches to biomass allocation broadly split into functional equilibrium type models and more mechanistically based transport resistance type models. We grew Poa annua plants in split root boxes under high and low light levels, high and low N supplies, with N supplied equally or unequally. Our data suggest that light level had the strongest effect on root mass, with N level being more important in controlling shoot mass. Allocation of growth within the root system was compatible with phloem partitioning models. The root mass fraction was affected by both light and N levels, although within light levels the changes were primarily due to changes in shoot growth, with root mass remaining relatively invariant. Under low light conditions, plants exhibited increased specific leaf area, presumably to compensate for low light levels. In a follow-up experiment, we showed that differential root growth could be suppressed by defoliation under low light conditions. Our data were more compatible with transport resistance type models.

Photoinhibition of DCMU-Enhanced Fluorescence in Lake Ontario Phytoplankton

1987 ◽  
Vol 44 (12) ◽  
pp. 2144-2154 ◽  
Author(s):  
M. Putt ◽  
G. P. Harris ◽  
R. L. Cuhel
Keyword(s):  
Vertical Mixing ◽  
Natural Populations ◽  
Bright Light ◽  
Euphotic Zone ◽  
Lake Ontario ◽  
Enhanced Fluorescence ◽  
Low Light ◽  
Light Levels ◽  
Phosphorus Status

Measurement of 1-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) enhanced fluorescence (FDCMU) suggested that photoinhibition of photosynthesis was frequently an artifact of in situ bottle incubations in Lake Ontario phytoplankton. In a seasonal study, FDCMU of all populations was depressed by bright light in an incubator. However, when the euphotic zone did not exceed the depth of the mixed layer, vertical transport of phytoplankton into either low-light or dark regions apparently allowed reversal of photoinhibition of FDCMU. Advantages of FDCMU as a bioassay of vertical mixing include rapidity of response time, ease of measurement in the field, and insensitivity of this parameter to changes in phosphorus status of the population. Because of seasonal changes in the photoadaptive response of natural populations, the rate constants and threshold light levels required to cause the response must be determined at each use if the method is to be quantitative.

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