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Shade tolerance

Shade tolerance is the minimum light level required for a plant's survival and growth, representing a fundamental ecological trait that enables certain species to persist in low-light environments, such as forest understories shaded by taller vegetation.^[1] This capacity contrasts with shade avoidance strategies, where plants elongate stems to escape shade, and instead involves adaptations that optimize carbon gain and minimize losses under dim conditions.^[2] In plant ecology, shade tolerance plays a pivotal role in structuring communities and driving succession, as tolerant species often dominate late-successional stages while intolerant ones pioneer open areas.^[1] Species are typically classified on a qualitative scale from very tolerant (e.g., sugar maple, Acer saccharum) to very intolerant (e.g., black walnut, Juglans nigra), or quantitatively using metrics like the light compensation point—the irradiance at which net photosynthesis equals zero—which is lower in tolerant plants.^[3] Tolerance rankings reveal trade-offs, such as an inverse relationship with drought or waterlogging resistance, where only a small fraction of temperate woody species (about 10%) tolerate both shade and drought effectively. At the physiological and molecular levels, shade-tolerant plants exhibit traits like lower respiration rates, larger leaf surface areas relative to mass, and phenotypic plasticity in morphology to enhance light capture, alongside genetic regulation by factors such as phytochromes and PIF transcription factors that suppress excessive elongation.^[3]^[2] These adaptations not only influence individual fitness but also ecosystem responses to disturbances and global changes, including altered light regimes from deforestation or climate shifts.^[1]

Definition and Classification

Core Definition

Shade tolerance refers to the capacity of certain plant species to establish, survive, grow, and reproduce under low light conditions, typically ranging from 1% to 10% of full sunlight intensity in dense forest understories or shaded environments.^[5] This trait enables plants to persist in competitive light-limited niches where overstory vegetation filters most incoming solar radiation, contrasting with sun-adapted species that require higher light levels for optimal performance.^[6] Shade tolerance is a multifaceted ecological strategy, often quantified through physiological and demographic responses rather than a single binary measure. Key metrics for assessing shade tolerance include the light compensation point (LCP), defined as the minimum light intensity at which a plant's photosynthetic carbon gain equals its respiratory losses, resulting in net zero growth; shade-tolerant species typically exhibit lower LCPs (e.g., 10-30 µmol m⁻² s⁻¹ photosynthetic photon flux density) compared to shade-intolerant ones, allowing sustained survival in dim conditions.^[5] Relative growth rate (RGR) under shade, calculated as the increase in biomass per unit time relative to initial size, serves as another indicator, with tolerant plants maintaining positive RGR at 1-5% of full sun for extended periods.^[7] Survival thresholds are often expressed as the percentage of full sunlight below which mortality exceeds recruitment, such as below 3% for highly tolerant understory species.^[6] The concept of shade tolerance emerged in early 20th-century forest ecology studies focused on stand dynamics and species replacement in woodlands, with initial quantitative assessments appearing in silvicultural research on tree regeneration under canopies.^[8] For instance, classifications of tree shade tolerance classes (e.g., tolerant, intermediate, intolerant) were formalized in North American forestry literature by the mid-20th century to predict successional patterns.^[9] Representative examples illustrate these thresholds: many ferns, such as the cinnamon fern (Osmundastrum cinnamomeum), are highly shade-tolerant, thriving in deep woodland shade.^[10] In contrast, sunflowers (Helianthus annuus) are shade-intolerant, requiring full sun (at least 6 hours of direct sunlight daily) and exhibiting rapid decline in growth and seed production in shaded conditions.^[11]

Shade Tolerance vs. Shade Avoidance

Shade avoidance syndrome represents a rapid adaptive response in many plants to perceived competition from neighboring vegetation, characterized by exaggerated elongation of stems and petioles, reduced branching, and accelerated vertical growth aimed at escaping shade conditions.^[5] This syndrome is often triggered by a low red-to-far-red (R:FR) light ratio, typically below 0.8, which signals the presence of overhead foliage absorbing red light while transmitting far-red.^[5] Such responses prioritize height gain for better light capture but come at the expense of reproductive output and resource allocation to other functions, like defense, potentially increasing vulnerability to herbivores or pathogens.^[12] In contrast, shade tolerance employs a strategy of endurance rather than escape, enabling plants to maintain compact growth forms and efficiently utilize limited light resources without significant morphological reconfiguration.^[5] Tolerant species focus on optimizing photosynthesis and resource conservation in persistent low-light environments, often exhibiting lower light compensation points that allow survival at irradiance levels as low as 1% of full sunlight.^[5] Avoidance, by reallocating biomass to stem elongation for competitive light foraging, enhances performance in transient shade but imposes evolutionary trade-offs; shade-tolerant plants, adapted to chronic understory conditions, typically show reduced competitive ability and growth rates in open, high-light habitats due to their attenuated escape responses. The detection of shade cues underlying these strategies is mediated by phytochromes, photoreceptor proteins that monitor the R:FR ratio through shifts in their active Pfr (far-red absorbing) to inactive Pr (red absorbing) forms.^[5] A decreased R:FR ratio, favoring Pr accumulation, activates avoidance pathways in sensitive species, whereas tolerant plants dampen this response to conserve energy.^[12] Classic examples illustrate these distinctions: the model plant Arabidopsis thaliana displays strong shade avoidance under laboratory-simulated low R:FR conditions, with pronounced hypocotyl elongation to outgrow competitors.^[5] Conversely, shade-tolerant forest understory herbs like Cardamine hirsuta exhibit minimal elongation and sustained compact architecture in similar shade, prioritizing survival through efficient light use rather than escape.^[12]

Physiological and Morphological Adaptations

Morphological Adaptations

Shade-tolerant plants exhibit a suite of leaf-level morphological adaptations that enhance light capture in dim understories. A key feature is the elevated leaf area ratio (LAR), defined as total leaf area per unit plant mass, which allows these species to allocate biomass efficiently toward expanding photosynthetic surface area relative to overall plant size. This trait is especially pronounced in chronic shade environments, where higher LAR compensates for reduced light intensity by increasing the proportion of plant resources devoted to leaves. Additionally, shade-tolerant leaves are typically thinner, with lower leaf mass per area (LMA) values often below 50 g/m², enabling greater specific leaf area (SLA) for improved photon interception without excessive carbon investment in structural support. Leaf orientation further optimizes this strategy, with blades displaying more horizontal angles to maximize exposure to diffuse, scattered light prevalent in forest canopies, as opposed to the steeper angles in sun-adapted species that prioritize direct beam avoidance. At the stem and overall architectural level, shade-tolerant plants prioritize resource conservation through slender stems that minimize self-shading and support efficient transport in low-energy conditions. Unlike shade-avoidant species, tolerant ones largely avoid etiolation—the excessive internode elongation triggered by far-red light cues—maintaining more compact forms that reduce vulnerability to mechanical stress while sustaining viability under prolonged low light. ^[5] Many also employ clonal growth strategies, such as rhizomatous propagation, to facilitate lateral spread in the understory; for instance, Trillium species produce extensive rhizome networks that generate multiple ramets, allowing persistent colonization of shaded, competitive habitats without reliance on seed dispersal. ^[13] Root-shoot allocation in shade-tolerant plants favors greater belowground investment to compete for nutrients in nutrient-poor, shaded soils, where resource scarcity is common. Shade-tolerant species typically exhibit higher root:shoot ratios than shade-intolerant ones, promoting enhanced foraging and uptake efficiency to support aboveground demands.^[14] Exemplifying these traits, shade-tolerant trees such as sugar maple (Acer saccharum) develop broad, rounded crowns with dense foliage layering to intercept sparse light, differing from the more irregular, open crowns of sun-adapted oaks that favor high-light penetration for rapid juvenile growth. ^[15]

Photosynthetic Adaptations

Shade-tolerant plants exhibit distinct photosynthetic adaptations that enhance their ability to capture and utilize limited light energy in understory environments. These modifications primarily involve adjustments in pigment composition and photosystem organization to optimize absorption of the far-red-enriched light spectrum prevalent in shaded conditions. For instance, shade leaves typically display a lower chlorophyll a/b ratio compared to sun leaves, often ranging from 2.5 to 3.0, which increases the proportion of chlorophyll b to better absorb wavelengths in the 640-680 nm range where far-red light predominates.^[16] This shift allows for more efficient light harvesting under diffuse, low-intensity illumination. Additionally, shade-tolerant species enlarge the size of light-harvesting antenna complexes in photosystems I and II, expanding the effective capture area per reaction center and thereby boosting quantum yield at low irradiances. A key feature of photosynthetic efficiency in shade-tolerant plants is their lower light saturation point, typically around 200-400 µmol m⁻² s⁻¹ photosynthetically active radiation (PAR), in contrast to over 1000 µmol m⁻² s⁻¹ for shade-intolerant species. This enables sustained net photosynthesis at intensities where sun-adapted plants would operate below saturation. The relationship between photosynthetic rate (A) and irradiance (I) can be modeled using a rectangular hyperbola derived from Michaelis-Menten kinetics:

A = \frac{\Phi \times I \times A_{\max}}{I + K}

where \Phi is the apparent quantum yield, A_{\max} is the maximum photosynthetic rate, and K is the half-saturation constant (often lower in shade plants, reflecting adaptation to low I). This equation illustrates how shade-tolerant plants maintain higher \Phi values (e.g., 0.05-0.08 mol CO₂ mol⁻¹ photons) under subdued light, prioritizing efficiency over maximum capacity.^[17]^[18] To support survival in light-limited habitats, shade-tolerant plants also reallocate carbon resources, favoring starch storage in roots and stems over immediate growth, which buffers against periods below the light compensation point. This strategy is complemented by reduced dark respiration rates, often 20-50% lower than in shade-intolerant counterparts at equivalent temperatures, minimizing carbon loss and lowering the compensation irradiance to as little as 5-10 µmol m⁻² s⁻¹.^[19] Such adjustments enable prolonged viability in chronic low-light regimes.^[20] Representative examples include ferns of the genus Dryopteris, such as D. intermedia, which thrive under 5% of full sunlight through optimized photosystem II (PSII) efficiency. These species maintain high PSII quantum yields (Fv/Fm ≈ 0.75-0.80) even at low PAR, supported by larger antenna complexes that enhance electron transport under diffuse light without risking photoinhibition.^[21]^[22]

Dynamic Responses to Light Fluctuations

Plants exhibit dynamic responses to fluctuating light conditions, such as intermittent shade or brief sunflecks, through reversible mechanisms that optimize photosynthetic efficiency and minimize damage. These short-term adjustments include leaf reorientation, intracellular chloroplast relocation, and modulation of photosystem configurations, enabling rapid adaptation without structural changes. Such responses are particularly crucial in heterogeneous light environments, like forest understories, where light availability can vary dramatically over minutes or hours.^[23] Leaf movements, including heliotropism and diaheliotropism, allow plants to track or avoid direct sunlight to prevent photoinhibition under stress. In shade conditions, paraheliotropism orients leaves parallel to the sun's rays, reducing intercepted light and thereby protecting photosystem II (PSII) from excess energy that could lead to photodamage. For instance, in common bean (Phaseolus vulgaris), paraheliotropic movements during water stress maintain lower PSII excitation pressure, preserving quantum yield and mitigating photoinhibition in field settings. These movements are mediated by turgor changes in pulvini at the leaf base, responding to light angles and environmental cues.^[24]^[25] Chloroplast movements provide a finer-scale adjustment, repositioning organelles within cells to enhance light capture in low light or avoid it in high light. Blue light, perceived via phototropin receptors (phot1 and phot2), induces accumulation of chloroplasts along cell peripheries perpendicular to weak light rays, increasing light absorption, or avoidance toward anticlinal walls under intense illumination to reduce photodamage. This relocation can boost light capture efficiency by 20-50% in shaded conditions, as seen in species like Arabidopsis thaliana, where phot2 primarily controls avoidance and both phototropins regulate accumulation. The process involves actin-based motility, allowing chloroplasts to optimize photosynthetic output dynamically.^[26] Photosystem modulation occurs through state transitions, which redistribute light-harvesting complexes (LHCII) between PSII and photosystem I (PSI) to balance electron flow. When PSII is overexcited in fluctuating light, the plastoquinone (PQ) pool becomes reduced, activating the kinase STN7 to phosphorylate LHCII, prompting its migration to PSI and increasing its absorption cross-section. This adjustment equalizes electron transport rates between the photosystems, preventing imbalances that could limit overall photosynthesis. The electron transport rate (ETR) can be expressed as:

\text{ETR} = \Phi_\text{PSII} \times \text{PAR} \times 0.84 \times 0.5

where \Phi_\text{PSII} is the quantum yield of PSII, PAR is photosynthetically active radiation, 0.84 accounts for chlorophyll absorbance, and 0.5 assumes equal distribution between photosystems; state transitions modulate \Phi_\text{PSII} by altering effective cross-sections.^[27]^[28]^[29] In understory plants, these dynamic responses are essential for exploiting sunflecks—brief high-light patches comprising only 1-10% of daily light integral but contributing up to 50% of total carbon gain. For example, in temperate forest seedlings like those of Acer saccharum, rapid chloroplast repositioning and state transitions during sunflecks enhance CO₂ fixation, allowing survival in deeply shaded habitats where steady diffuse light alone is insufficient. Such adaptations underscore the role of transient mechanisms in bridging light gaps for net positive photosynthesis.^[23]^[30]

Ecological and Evolutionary Aspects

Role in Plant Succession and Communities

Shade tolerance plays a pivotal role in forest succession, particularly within the Clementsian model of community development, where species replace one another in predictable zonation patterns driven by light availability and competitive interactions. In this framework, shade-intolerant pioneer species, such as trembling aspen (Populus tremuloides), initially colonize disturbed sites like gaps created by fire or logging, rapidly exploiting high-light conditions to establish dominance in early successional stages.^[31] As canopy closure reduces light penetration, these pioneers are gradually supplanted by more shade-tolerant species that persist and regenerate beneath the maturing overstory, leading to late-successional climax communities. For instance, in eastern North American temperate forests, highly shade-tolerant trees like American beech (Fagus grandifolia) and sugar maple (Acer saccharum) characterize stable, old-growth beech-maple forests, where their ability to reproduce and grow in under 10% of full sunlight sustains long-term dominance.^[32]^[33] In plant communities, shade tolerance facilitates understory persistence and alters competition dynamics by enabling subordinate species to survive prolonged low-light suppression, thereby minimizing intense light-based rivalry among canopy layers. Shade-tolerant individuals maintain viability in dim environments, allowing gradual upward recruitment into gaps without immediate displacement by faster-growing intolerant competitors. A classic example is eastern hemlock (Tsuga canadensis), the most shade-tolerant North American tree species, which seedlings can endure in as little as 5% of full sunlight, outcompeting less tolerant hardwoods in deeply shaded understories and contributing to hemlock-dominated stands on mesic sites.^[34]^[35] This persistence reduces the overall competitive pressure for light, promoting a stratified community structure where tolerant species occupy lower strata, fostering coexistence rather than exclusion.^[8] Shade tolerance gradients further enhance biodiversity by structuring vertical forest layers and supporting diverse understory assemblages in shaded habitats. In temperate forests, these gradients allow a continuum of species with varying light requirements to partition niches, from highly tolerant herbs and shrubs in the darkest subcanopy to moderately tolerant midstory plants, thereby increasing overall species richness. For example, understories in old-growth temperate deciduous forests often harbor 30–60 herbaceous and woody species per hectare, with shade tolerance enabling the maintenance of this diversity through reduced light competition and niche differentiation.^[36]^[37] Such layering contributes to ecosystem resilience by buffering against disturbances and supporting pollinators, decomposers, and wildlife.^[8] Interactions between shade tolerance and climate further influence community dynamics, particularly under changing environmental conditions. Enhanced shade tolerance supports species migration into altered canopies during climate shifts, as tolerant trees can establish in partially shaded transitional zones, facilitating range expansions in response to warming or shifting disturbance regimes.^[38] However, shade-tolerant species often exhibit heightened vulnerability to combined drought and shade stress, where low light exacerbates water limitations by slowing photosynthetic recovery and increasing mortality risk in understories during prolonged dry periods.^[39] This interaction may hinder persistence in increasingly variable climates, potentially disrupting succession and reducing biodiversity in mesic forests.^[40]

Genetic and Molecular Mechanisms

Shade tolerance in plants is governed by a complex network of genetic and molecular pathways that differentiate it from shade avoidance responses. Central to these mechanisms are phytochrome interacting factors (PIFs), a family of bHLH transcription factors that typically promote hypocotyl elongation and other avoidance traits in response to low red-to-far-red (R:FR) light ratios. In shade-tolerant species, such as Cardamine hirsuta, PIF activity is attenuated through enhanced expression and stability of negative regulators like HFR1 (long hypocotyl in far-red 1), which inhibits PIF function and represses shade-induced growth promotion.^[5] This repression allows tolerant plants to maintain compact growth and optimize resource allocation under persistent low-light conditions rather than investing in rapid elongation.^[5] Quantitative trait locus (QTL) studies have identified multiple genomic regions associated with shade tolerance, such as those influencing grain yield under low-light conditions in rice (Oryza sativa), where 20 novel QTLs were mapped, explaining variations in traits like plant height and biomass.^[41] Heritability estimates for shade tolerance traits in rice under shaded conditions range from 58% for yield maintenance, indicating a moderate genetic basis amenable to breeding.^[42] Hormonal signaling pathways integrate with these genetic controls to fine-tune shade responses. Auxin (indole-3-acetic acid, IAA) and brassinosteroids (BRs) primarily drive shade avoidance by promoting cell elongation; for instance, PIFs induce auxin biosynthesis genes like YUC9 in shade-avoiding species such as Arabidopsis thaliana.^[5] In contrast, abscisic acid (ABA) enhances shade tolerance through stress signaling pathways that prioritize survival over growth, modulating hyponasty and resource conservation in low light.^[43] Gibberellins (GAs) are inhibited in tolerant responses, as evidenced by down-regulation of GA biosynthesis genes in shade-tolerant mutants, which limits elongation and supports compact architecture under canopy shade.^[44] This hormonal antagonism, where ABA opposes GA and auxin effects, underlies the molecular distinction between tolerance and avoidance strategies.^[45] Evolutionarily, shade tolerance represents a polygenic trait shaped by trade-offs between growth potential in high light and survival in shaded understories. The growth-survival trade-off hypothesis posits that tolerant species allocate resources away from rapid biomass accumulation toward defense and efficient light harvesting, a pattern observed across angiosperms and gymnosperms. Recent studies as of 2025 highlight increasing phenotypic plasticity in shade tolerance as an evolutionary response to climate-induced changes in forest light regimes, potentially aiding adaptation but also introducing trade-offs with other stresses.^[46] Fossil evidence from the Devonian period highlights early adaptations, with lycophytes like those in the Asteroxylales exhibiting prostrate habits and root systems suited to shaded forest floors, as seen in mid-Devonian assemblages where arborescent forms created understory niches.^[47]^[48] Genome-wide association studies (GWAS) in forest trees, such as European beech (Fagus sylvatica), reveal multiple genes contributing to adaptive traits like drought resistance in shaded canopy conditions, illustrating the polygenic nature that may overlap with light tolerance mechanisms.^[49] Specific examples illustrate these mechanisms in action. In tomato (Solanum lycopersicum), mutations in the DET1 (de-etiolated 1) gene, such as the hp-2 allele, result in constitutive photomorphogenesis with elevated chlorophyll and carotenoid levels, enhancing light capture efficiency and conferring improved performance in low-light environments akin to shade tolerance.^[50] These genetic insights provide a foundation for understanding how shade tolerance evolves and is expressed, influencing plant fitness in dense vegetation.

Practical Applications

In Horticulture and Landscaping

In horticulture and landscaping, shade tolerance is a key consideration for selecting plants that thrive in low-light environments, such as under tree canopies, north-facing gardens, or urban settings with building shadows. Full shade, defined as less than three hours of direct sunlight per day, suits species like hostas (Hosta spp.), which feature broad leaves that capture diffuse light effectively, and impatiens (Impatiens walleriana), valued for their colorful blooms in moist, shaded beds. Partial shade, offering three to six hours of sun, accommodates plants such as astilbe (Astilbe spp.), with feathery plumes that add texture and height to borders. Integrating USDA hardiness zones ensures suitability; for instance, hostas perform well in zones 3-9, while impatiens favor zones 10-11 or as annuals in cooler climates. Effective garden design leverages shade tolerance through vertical layering, placing groundcovers like ferns (e.g., Dryopteris filix-mas) at the base, mid-level perennials such as bleeding hearts (Dicentra spectabilis) in the middle, and taller shrubs like rhododendrons (Rhododendron spp.) as canopy elements to create multi-tiered, low-maintenance compositions. Soil amendments, including organic matter like compost, enhance moisture retention in shaded areas where evaporation is reduced, promoting root health without fostering root rot. Landscapers advise against overwatering in these conditions, recommending well-drained soils amended with perlite to maintain balance. Shaded gardens often face challenges like increased humidity leading to pest issues, such as slugs targeting ferns, which can be mitigated through cultural practices including mulching with coarse materials to deter moisture-loving invertebrates and improve air circulation. Recent trends in the 2020s emphasize native shade-tolerant plants for sustainable landscaping, with species like wild ginger (Asarum canadense) and foamflower (Tiarella cordifolia) reducing maintenance needs through lower fertilizer and irrigation demands, as demonstrated in urban greening projects.

In Forestry and Agriculture

In silviculture, shade tolerance is a key criterion for species selection in forest management to promote sustainable regeneration and stand diversity. Tree species are classified into tolerance categories—very tolerant (e.g., eastern hemlock, American beech, balsam fir), tolerant (e.g., red maple), intermediate (e.g., eastern white pine), and intolerant (e.g., black cherry, quaking aspen)—based on their ability to survive and grow under reduced light conditions in the understory.^[51]^[52] These rankings guide practices such as uneven-aged management, where shade-tolerant species are favored for maintaining continuous cover, while intermediate and intolerant species are planted in canopy gaps to accelerate succession. Gap-phase regeneration models, which mimic natural disturbances by creating small openings in mixed stands, leverage these tolerances to enhance biodiversity and resilience; for instance, larger gaps favor intermediate species for rapid height growth, while smaller gaps support tolerant species for long-term stability.^[53] In agriculture, shade tolerance enables effective intercropping in agroforestry systems, where understory crops thrive beneath taller trees, optimizing land use and resource efficiency. Coffee (Coffea arabica), a moderately shade-tolerant crop, is commonly grown under native shade trees like Inga spp., which reduce irradiance by 25-75% while transmitting approximately one-third of full sunlight to the understory, maintaining photosynthetic rates and improving bean quality through moderated temperatures and reduced water stress.^[54]^[55] These systems enhance overall productivity by diversifying income from timber or fruits alongside coffee, with studies showing shade-adapted F1 hybrids yielding up to 37% more green beans than traditional varieties, alongside 50% higher light-use efficiency despite reduced irradiance.^[54] Such practices mitigate climate risks, as shade trees buffer extreme conditions, supporting sustainable yields in tropical regions. Amid climate change, breeding programs in European forestry target enhanced shade tolerance to address canopy shifts and increased droughts since the 2000s, which have altered light regimes and regeneration patterns. For example, in drought-prone areas, selective breeding of shade-tolerant species like European beech (Fagus sylvatica) has identified polygenic traits for improved drought resistance, enabling better survival under denser canopies.^[49] Similarly, programs for Scots pine (Pinus sylvestris) have inadvertently boosted drought tolerance through growth-focused selection, aiding adaptation to post-2018 drought events that caused widespread mortality in Central Europe.^[56]^[57] These efforts prioritize resilient genotypes to counteract warming-induced canopy closure, ensuring viable regeneration in mixed forests. Economically, incorporating shade-tolerant species in forestry can reduce replanting costs by promoting natural regeneration over intensive artificial planting, as these species establish successfully in partially shaded sites. This approach not only cuts establishment expenses but also boosts ecosystem services like carbon sequestration, yielding broader financial returns in sustainable management.

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Identification and analysis of low light tolerant rice genotypes in field ...
As per the analysis of variance, genotypic variance explained 39% of the total yield-variation under shade with 58% heritability. Overall, the maintenance of ...Missing: QTL | Show results with:QTL
[42]
Abscisic acid modulates shade avoidance by inducing hyponasty ...
Abscisic acid (ABA) plays a crucial role in mediating LRFR-induced hyponasty. They demonstrate that exposure to LRFR rapidly increases the biosynthesis of ABA.
[43]
Transcriptome Analysis Reveals Differential Gene Expression and a ...
We examined the expression of gibberellin (GA) biosynthesis genes and found that they were down-regulated in shadow-1 plants compared to wild type, notably ...
[44]
Abscisic Acid and Gibberellins Antagonistically Mediate Plant ... - PMC
Mar 27, 2018 · Shade stress up-regulates ABA level in tomato and sunflower. Solanum lycopersicum Helianthus annuus, Kurepin et al., 2007; Cagnola et al., 2012.<|separator|>
[45]
Lycophyta: Fossil Record
The oldest lycophytes, the Asteroxylales, sometimes called the Drepanophycales, appear in the fossil record in the early Devonian.
[46]
A Middle Devonian vernal pool ecosystem provides a snapshot of ...
This study aims to test the hypothesis of the environmental partition at the local scale by reconstructing the fossilized forest-floor landscape.<|separator|>
[47]
Genomic basis for drought resistance in European beech forests ...
Jun 16, 2021 · Drought resistance in European beech is a moderately polygenic trait that should respond well to natural selection, selective management, and breeding.Sampling, Climate... · Associated Genes And Gene... · Materials And Methods
[48]
Manipulation of DET1 expression in tomato results in ... - NIH
The tomato HIGH PIGMENT-2 gene encodes an orthologue of the Arabidopsis nuclear protein DE-ETIOLATED 1 (DET1). From genetic analyses it has been proposed ...
[49]
[PDF] Tolerance of Tree Species - Forest and Wildlife Ecology
Tree species that compete well under full shade are called very tolerant species; those that require full sunlight and limited competition are called very.
[50]
[PDF] Table 1. Shake tolerance ratings of some Ohio tree species. - Ohioline
Harvesting and Reproduction Methods for Ohio Forests. Table 1. Shade tolerance ratings of some Ohio tree species. Intolerant. Intermediate. Tolerant.
[51]
Gap Structure and Regeneration in the Mixed Old-Growth Forests of ...
Jan 9, 2020 · Forest management mimicking natural processes represents an approach to maintain mixed, uneven-aged stands at small spatial scales.
[52]
Shaded-Coffee: A Nature-Based Strategy for Coffee Production ...
Despite a 60% reduction in irradiance below the canopy of the shade trees, coffee plants grown under shade increased their light-use efficiency by 50% and the ...
[53]
Ecosystem services in coffee agroforestry: their potential to improve ...
Oct 27, 2023 · In summary, shade trees that reduce light intensity to coffee by approximately one-third can provide the following regulation and ...Missing: transmission | Show results with:transmission
[54]
Implications of Breeding for Growth on Drought Tolerance in Scots ...
Jun 23, 2025 · Families from breeding stands have higher drought resistance but lower genetic variation than the ones from natural forests, especially in the case of canopy ...
[55]
Impacts on and damage to European forests from the 2018–2022 ...
Jan 6, 2025 · This study consolidates data on drought and heat damage in European forests from 2018 to 2022, using Europe-wide datasets.
[56]
Reforestation success can be enhanced by improving tree planting ...
Jun 15, 2023 · Successful cost-effective reforestation plantings depend substantially on maximising sapling survival from the time of planting, ...