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Marcescence
Marcescence
Marcescence
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American beech (Fagus grandifolia) in winter
Oak (Quercus) with marcescent foliage
Typical partial marcescence on a mature beech (Fagus sylvatica) tree
Red oak (Quercus rubra) leafing out before dropping marcescent leaves

Marcescence is the withering and persistence of plant organs that normally are shed, and is a term most commonly applied to plant leaves.[1][2] The underlying physiological mechanism is that trees transfer water and sap from the roots to the leaves through their vascular cells, but in some trees as autumn begins, the veins carrying the sap slowly close until a layer of cells called the abscission layer completely closes off the vein allowing the tree to rid itself of the leaf.[3] Leaf marcescence is most often seen on juvenile plants and may disappear as the tree matures. It also may not affect the entire tree; sometimes leaves persist only on scattered branches.[4] Marcescence is most obvious in deciduous trees that retain leaves through the winter. Several trees normally have marcescent leaves such as oak (Quercus),[5] beech (Fagus) and hornbeam (Carpinus), or marcescent stipules as in some but not all species of willows (Salix).[6] All oak trees may display foliage marcescence, even species that are known to fully drop leaves when the tree is mature.[7] Marcescent leaves of pin oak (Quercus palustris) complete development of their abscission layer in the spring.[8] The base of the petiole remains alive over the winter. Many other trees may have marcescent leaves in seasons where an early freeze kills the leaves before the abscission layer develops or completes development. Diseases or pests can also kill leaves before they can develop an abscission layer.

Marcescent leaves may be retained indefinitely and do not break off until mechanical forces (wind for instance) cause the dry and brittle petioles to snap.[9] The evolutionary reasons for marcescence are not clear, theories include: protection of leaf buds from winter desiccation, and as a delayed source of nutrients or moisture-conserving mulch when the leaves finally fall and decompose in spring.[10]

Many palms form a skirt-like or shuttlecock-like crown of marcescent leaves under new growth that may persist for years before being shed.[11][12] In some species only juveniles retain dead leaves[13] and marcescence in palms is considered a primitive trait.[14]

The term marcescent is also used in mycology to describe a mushroom which (unlike most species, described as "putrescent") can dry out, but later revive and continue to disperse spores.[15] Genus Marasmius is well known for this feature, which was considered taxonomically important by Elias Magnus Fries in his 1838 classification of the fungi.[16]

Advantages

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One possible advantage of marcescent leaves is that they may deter feeding of large herbivores, such as deer and moose, which normally eat the twigs and their nutritious buds. Dead, dry leaves make the twigs less nutritious and less palatable.[17] They are also more noisy when browsed, thereby potentially deterring browsers.[18]

Species that display marcescence, such as beech and oak, have adapted to retaining their leaves for prolonged periods to thrive in difficult growing media. When growth is most vulnerable in the early stages of spring, they benefit from the compost provided by the newly dropped and decomposing leaves, allowing them to outcompete species that have already dropped theirs. It is suggested that such variations can significantly impact their success in such conditions. [19]

Some experimentation on plant litter from marcescent trees indicates that keeping the leaves above ground may increase the amount of photodegradation the leaves are exposed to. Because some marcescent species' leaves do not decompose well, the increased photodegradation may allow them to decompose better once they finally fall off the tree.[20]

Others theorize that leaves which remain on a tree due to marcescence allow the tree to trap snow during the winter months. By using their dead leaves to collect additional snow, trees are able to provide themselves more water in spring when the snow begins to melt.[21]

Marcescent leaves may protect some species from water stress or temperature stress. For example, in tropical alpine environments a wide variety of plants in different plant families and different parts of the world have evolved a growth form known as the caulescent rosette, characterized by evergreen rosettes growing above marcescent leaves. Examples of plants for which the marcescent leaves have been confirmed to improve survival, help water balance, or protect the plant from cold injury are Espeletia schultzii and Espeletia timotensis, both from the Andes.[22][23]

The litter-trapping marcescent leaf crowns of Dypsis palms accumulate detritus thereby enhancing their nutrient supply,[24] but in trapping nutrient-rich detritus, palms with marcescent leaf bases are also more likely to allow the germination of epiphytic figs in the marcescent leaves, with the figs possibly subsequently strangling the palms.[25] Palm genera with taxa having marcescent leaf bases and attracting epiphytic fig growth include Attalea, Butia, Caryota, Copernicia, Elaeis, Hyphaene, Livistona, Phoenix, Sabal, and Syagrus.[25]

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Marcescence in various species.

Marcescent species

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Marcescent species are found in the following (incomplete) list of plant families and genera:

See also

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Marcescence

View on Grokipedia
from Grokipedia
Marcescence is a botanical observed in certain trees and shrubs, characterized by the retention of withered, dead leaves on branches through the winter months rather than their in the fall. This occurs because the zone—the layer of cells at the leaf base that typically facilitates leaf drop—fails to fully develop or activate until spring, allowing the dry, brown leaves to persist and often rattle in the wind. The term derives from the Latin marcescere, meaning "to wither," reflecting the shriveled state of these persistent leaves. This trait is most commonly exhibited by juvenile or young trees of species in the beech (Fagaceae) family, such as American beech (Fagus grandifolia) and various oaks (Quercus spp.), including pin oak (Quercus palustris) and scarlet oak (Quercus coccinea), though it can vary by individual tree, environmental conditions, and age. Marcescence tends to be more pronounced in understory or shaded positions, where it may confer adaptive advantages, and it diminishes as trees mature and develop stronger vascular tissues. The ecological benefits of marcescence include enhanced protection against winter herbivory, as the persistent leaves may deter by deer and other animals through or reduced . Additionally, the retained foliage can provide for buds and young twigs, trapping heat and reducing from cold winds, while potentially allowing for extended nutrient resorption from the leaves before their eventual shedding in spring. These advantages contribute to higher survival rates for saplings in harsh temperate environments, though the exact mechanisms remain an active area of research in .

Definition and Characteristics

Definition

Marcescence is a botanical characterized by the retention and withering of organs that would typically be shed during seasonal changes, most commonly observed in leaves of certain species where the layer fails to fully develop or activate, preventing normal detachment. This results in the organs drying out and persisting on the while remaining attached, rather than falling away as in standard behavior. The term "marcescence" derives from the Latin marcescens, the present participle of marcescere, meaning "to wither" or "to fade," and entered English in the 18th century as a scientific descriptor in botanical literature. Marcescence differs from senescence, which is the general aging and deterioration process in plant tissues leading to death, and from abscission, the programmed physiological mechanism that actively separates senescent organs from the plant body. In marcescence, the organs undergo senescence but experience a delayed or incomplete abscission, distinguishing it as a form of retention rather than timely shedding. This phenomenon occurs primarily in temperate deciduous plants during autumn and winter, where leaves wither but cling to branches until environmental cues in spring trigger their release; however, it can also affect other organs such as floral parts like corollas or bracts in various .

Physical and Morphological Traits

Marcescent leaves exhibit a distinctive appearance, turning brown, dry, and brittle while remaining firmly attached to the stem, often with veins that curl or twist but do not fully detach from the petiole. This retention contrasts with typical autumnal leaf drop, where leaves separate cleanly; instead, marcescent foliage maintains a papery texture and may adopt contorted shapes due to without . Structurally, marcescence involves incomplete weakening of cell walls at the petiole base, resulting in an underdeveloped layer that prevents separation. Petioles in marcescent organs can vary in rigidity, remaining flexible in some cases to withstand or remaining stiff to support prolonged attachment, depending on the plant's morphology. The persistence of these traits typically endures through winter, lasting 3 to 6 months, before shedding occurs in spring, often triggered by mechanical forces such as , , or the physical from emerging new growth. While most commonly observed in leaves, marcescence extends to other organs, including catkins in willows that dry and hang persistently or dead fronds in palms that remain attached along the trunk; non-leaf examples also encompass persistent bracts in certain shrubs, which retain a withered form without detaching.

Causes and Mechanisms

Physiological Processes

Marcescence involves the incomplete development of the layer at the petiole base, where cells normally weaken through enzymatic degradation of the to facilitate separation. In typical species, an imbalance between , which promotes cell wall breakdown via hydrolases like polygalacturonase, and , which inhibits this process, triggers full layer formation and detachment. However, in marcescent plants, the auxin-ethylene balance delays abscission, preventing complete enzymatic dissolution and allowing withered leaves to persist despite . Recent studies indicate that marcescent species, such as oaks in the family, exhibit low abscission zone competency (AZC), with less than 9.13% development by late fall compared to nearly 100% in fully deciduous species, contributing to leaf retention through winter. The structural integrity at the petiole base is maintained during winter , without new tissue production by the dormant . This mimics normal winter but avoids the full vascular isolation seen in abscising leaves, where nutrient withdrawal precedes separation. Hormonal regulation in marcescence centers on altered signaling that delays shedding, with (ABA) involved in stress responses that inhibit premature under autumn conditions. Unlike standard , where rising ABA and accelerate activity, marcescent leaves exhibit relatively lower ABA accumulation, potentially reducing sensitivity to detachment signals and preserving attachment during . Phylogenetic traits in families like contribute to this delay in processes. These processes align with seasonal timing, initiating post-senescence in autumn when shortening days reduce photosynthetic activity and flux, yet without triggering full due to the aforementioned hormonal and genetic delays. Leaves persist through winter , with detachment often occurring in spring upon reactivation of growth hormones like and , coinciding with rising temperatures and renewed cambial activity that finally promotes expression and layer completion.

Environmental and Genetic Factors

Marcescence is more prevalent in temperate regions characterized by harsh winters, where cold temperatures and low humidity contribute to delayed . In these environments, late spring frosts can postpone autumn , allowing leaves to remain attached longer and potentially enhancing retention through winter. Similarly, winter frosts and summer droughts in transitional temperate-Mediterranean ecotones promote marcescence by protecting leaf buds from and extreme cold, as observed in southern European forests. Soil and site conditions also influence the extent of marcescence, particularly in nutrient-poor or exposed habitats where face limitations. In drought-prone areas, such as submediterranean belts, marcescence increases as a response to stress, helping to maintain hydration in vulnerable tissues. Exposed sites with low further favor this trait, as standing can facilitate recycling back to the upon eventual shedding, supporting growth in challenging conditions. Genetically, marcescence exhibits a strong heritable component, predominantly within the family and the broader order, where it appears as an evolutionary trait in certain lineages. This predisposition is polygenic, with expression varying based on individual tree health and environmental cues, leading to inconsistent retention across populations. For instance, marcescent oaks in the Quercus section show taxonomic clustering, underscoring genetic control over processes.

Ecological Significance

Adaptive Advantages to Plants

Marcescence confers several adaptive benefits to individual , particularly in temperate and high-altitude environments where winter conditions pose significant survival challenges. By retaining withered leaves through , enhance their resilience against environmental stresses and biotic pressures, thereby improving overall fitness and resource efficiency. One primary advantage is protection against herbivory, as marcescent leaves deter browsing by large herbivores such as deer and moose. The dry, low-nutritional-value foliage, combined with its rustling noise when disturbed, makes it unappealing and acts as a physical barrier to access tender twigs and buds. Studies on deciduous trees demonstrate that retention of dead leaves significantly reduces grazing preference and consumption; for instance, experimental trials showed that branches with marcescent leaves were browsed less by deer than those with leaves removed, with reduced twig damage observed in species like European beech (Fagus sylvatica) and hornbeam (Carpinus betulus). Marcescent leaves also safeguard emerging buds and meristems during winter by providing a protective barrier against frost, , and mechanical injury. The retained foliage creates a that buffers against desiccating winds and extreme cold, preventing of dormant tissues and reducing the risk of freeze damage to sensitive growth points. This insulation is particularly vital for juvenile trees and lower branches, where temperatures are lower, helping to maintain bud viability until spring growth resumes. This role is hypothesized for temperate trees, with limited empirical support; however, experimental evidence from high-altitude tropical rosette species like confirms that marcescent layers mitigate freeze-thaw damage to stems and . In regions with seasonal snowfall, marcescence may aid water retention by trapping and among the leaves, which melts in spring to provide accessible moisture for absorption. This mechanism ensures a reliable during early growth phases when may be limited, enhancing hydration in water-stressed habitats. Additionally, marcescence facilitates nutrient recycling by allowing dead leaves to decompose on-site during spring, releasing stored like and directly to the plant's at the onset of active growth. This delayed breakdown prevents leaching over winter and synchronizes release with peak demand, providing a competitive edge in nutrient-poor soils. In temperate ecosystems, this process alters litter chemistry through , accelerating microbial and immobilization for later uptake. In high-altitude tropical species like , marcescent leaves offer specialized protection by insulating the stem and against freeze-thaw cycles. The layered dead foliage minimizes temperature fluctuations, keeping internal tissues above freezing thresholds to avoid embolisms in and injury to water-storage , thereby maintaining hydraulic function in freezing-prone paramo environments.

Roles in Ecosystems

Marcescence contributes to nutrient cycling in ecosystems by altering the decomposition dynamics of persistent leaves, which undergo from (UV) radiation exposure while still attached to the plant. This process breaks down complex compounds like , enhancing the litter's decomposability once it falls to the and accelerating the release of nutrients such as and into the . Such effects are particularly pronounced in nutrient-poor environments, where delayed shedding minimizes leaching losses during wet seasons. Beyond nutrient dynamics, marcescent leaves provide critical and resources for , fostering community-level interactions in winter landscapes. Retained foliage offers shelter for overwintering , birds, and bats, creating microhabitats that support during periods of scarcity. For instance, these leaves can host decomposer communities, including fungi, which initiate breakdown processes and indirectly contribute to nutrient inputs via animal frass deposition from species. This sheltering role enhances trophic connections, as sheltered in marcescent canopies serve as prey for birds, thereby sustaining food webs in woodlands. Marcescence also influences microclimatic conditions at the scale through accumulation and shading effects. The eventual shedding of persistent leaves forms thicker layers that insulate forest soils, reducing temperature fluctuations and conserving moisture, which benefits and microbial activity. Additionally, standing dead phytomass creates shading that limits light penetration to the , moderating competitive interactions among smaller and promoting stratified community structures. In high-elevation or arid settings, such as Himalayan alpine zones, this insulation can trap and protect against , aiding overall understory survival. While largely beneficial, marcescence may pose drawbacks in certain contexts, such as increased risk from accumulated dry during droughts, potentially altering . In resource-limited environments, retained dead material can temporarily limit nutrient access for neighboring and decomposers, though this is offset by eventual photodegradative enhancements. Research gaps persist, particularly on post-2020 impacts and tropical dynamics, where interactions like potential facilitation remain underexplored.

Examples of Marcescent Species

Temperate Deciduous Trees

In temperate forests of eastern and , marcescence is prominently observed in several tree species adapted to regions with relatively mild winters that allow for leaf retention without excessive mechanical damage. These areas, including the Eastern Forest and central European woodlands, provide conditions where persistent can offer protective benefits, such as shielding buds from and herbivores. Oaks in the genus Quercus are among the most common marcescent species, with red oak (Quercus rubra) and pin oak (Quercus palustris) frequently retaining a portion of their senesced leaves through winter, often on lower branches of younger or stressed s. This partial retention varies by environmental conditions and tree age, with leaves eventually dislodging in spring due to new expansion or wind. Beech trees exhibit particularly high persistence of marcescent leaves. The European beech (), native to temperate from the to southern , commonly holds onto most of its dead foliage over winter, creating a distinctive rustling canopy. Similarly, the American beech (Fagus grandifolia), widespread in eastern North American forests, shows strong retention, with one study on medium-sized saplings documenting approximately 50% of leaves persisting into early before shedding. Hornbeams also display characteristic marcescence, with leaves curling and remaining attached well into winter. The European hornbeam (Carpinus betulus), a shade-tolerant species in European mixed forests, retains its withered leaves until spring bud break, enhancing winter silhouette visibility. In North America, the American hophornbeam (Ostrya virginiana) mirrors this trait, holding curled, dry leaves on lower branches throughout the cold season in eastern woodlands. Certain willow species in the genus Salix demonstrate marcescence, particularly in leaves or reproductive structures like catkins, though less consistently than in family trees. This trait appears in riparian and moist temperate habitats across eastern and , where milder winters facilitate prolonged retention without severe tissue damage.

Tropical and Other Species

In tropical environments, marcescence manifests prominently in various palm species of the family, where dead fronds persist attached to the trunk, often forming a dense skirt beneath living foliage. This trait contrasts with temperate adaptations by addressing year-round challenges like humidity fluctuations and biotic pressures rather than seasonal cold. For instance, the coco-de-mer palm (Lodoicea maldivica), endemic to the islands, exhibits pronounced marcescence, with dead leaves remaining on the trunk for extended periods—sometimes years—before detaching. This retention slows leaf litter turnover in its monodominant forests, delaying nutrient release to the soil and potentially conserving resources in nutrient-poor insular ecosystems. Several genera within display this characteristic, including Dypsis and Attalea. In Dypsis scandens, a climbing palm native to , stems bear multiple dead marcescent leaves alongside living ones, contributing to the plant's overall architecture in humid forest understories. Similarly, species of Attalea, such as those found in Central and South American rainforests, feature massive pinnate leaves that become marcescent after , persisting until mechanical forces dislodge them. The (Phoenix dactylifera), widely cultivated in arid tropical and subtropical regions, can also retain dead fronds if unpruned, though this varies by management practices. Research on African and Asian species, such as those in the genus (e.g., the doum palm), highlights gaps in understanding, with limited documentation of their marcescent tendencies despite their prevalence in habitats. Beyond lowland palms, marcescence appears in high-altitude tropical settings, such as the Andean páramos, where it helps plants endure chronic environmental stresses like intense solar radiation, , and temperature extremes. The giant rosette plant Espeletia schultzii, native to Venezuela's high elevations above 3,000 m, loosely retains dead leaves around the stem with minimal mechanical attachment, potentially insulating the living core and reducing water loss. An experimental removal of dead leaves from 50 adult plants at 3,600 m revealed their role in maintaining plant vigor under these conditions, as treated individuals showed higher susceptibility to stress compared to controls. Closely related Espeletia timotensis displays analogous retention, adapting to the páramo's perpetual harshness without distinct seasons. In tropical contexts, marcescence often facilitates unique adaptations, such as deterring colonization and climber attachment, differing from temperate frost-related benefits. The persistent skirt of dead s in palms and similar structures in tropical tree-ferns physically blocks seeds and vines from reaching the trunk, preserving access to light and resources for the host plant. Additionally, retained dead material enables nutrient hoarding; in L. maldivica, prolonged persistence traps organic , enhancing local nutrient availability through gradual . While less studied in shrubs, some tropical species exhibit similar persistence, and fungal analogs exist in genera like Marasmius, where fruiting bodies remain marcescent—drying out but reviving with moisture to resume spore production—mirroring plant-like durability in humid environments.

References

  1. https://arboretum.harvard.edu/stories/the-essence-of-marcescence/
  2. https://extension.illinois.edu/blogs/good-growing/2024-12-06-stubborn-beauty-oak-leaves-marcescence-explained
  3. https://blog.richmond.edu/writing/2023/01/09/word-of-the-week-marcescence/
  4. https://landscapeplants.oregonstate.edu/plants/quercus-coccinea
  5. https://sites.psu.edu/ecologistsnotebook/2020/06/25/signs-of-summer-4-natural-history-of-the-american-beech-part-2/
  6. https://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=1265&context=cate
  7. https://www.umass.edu/agriculture-food-environment/landscape/newsletters/hort-notes/hort-notes-2023-vol-3410
  8. https://pmc.ncbi.nlm.nih.gov/articles/PMC12555018/
  9. https://mdc.mo.gov/discover-nature/field-guide/oaks
  10. https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.4410
  11. https://www.biologydiscussion.com/plants/senescence-and-abscission-of-leaves-botany/20618
  12. https://vtecostudies.org/blog/abscission-and-marcescence-in-the-woods/
  13. https://pmc.ncbi.nlm.nih.gov/articles/PMC2944983/
  14. https://www.researchgate.net/publication/393729475_Making_a_clean_break_contrasting_leaf_abscission_dynamics_across_temperate_leaf_habits
  15. https://nph.onlinelibrary.wiley.com/doi/full/10.1046/j.0028-646x.2001.00194.x
  16. https://www.jstor.org/stable/2471297
  17. https://www.researchgate.net/publication/267288838_The_eco-physiology_of_marcescence_in_dominant_oak_species_in_Missouri
  18. https://pmc.ncbi.nlm.nih.gov/articles/PMC6447859/
  19. https://www.researchgate.net/publication/369221887_Not_all_temperate_deciduous_trees_are_leafless_in_winter_The_curious_case_of_marcescence
  20. https://www.nature.com/articles/s41598-020-78576-9
  21. https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.4410
  22. https://alcesjournal.org/index.php/alces/article/view/607
  23. https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-3040.ep11589230
  24. https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.14513
  25. https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.14174
  26. https://www.wunderground.com/cat6/Marcescence-Why-Some-Trees-Keep-Their-Leaves-Winter
  27. https://fpdcc.com/oak-trees-leaves-winter-marcescence/
  28. https://bgflora.net/families/betulaceae/carpinus/carpinus_betulus/carpinus_betulus_en.html
  29. https://tnstateparks.com/blog/the-mystery-of-marcescence
  30. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=129059
  31. https://pubmed.ncbi.nlm.nih.gov/39954104/
  32. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:985384-1/general-information
  33. https://www.palmweb.org/cdm_dataportal/taxon/ed0de1fc-9c0b-490a-a80f-f59de94439d9
  34. https://www.jstor.org/stable/2388171
  35. https://www.jstor.org/stable/2260398
  36. https://www.mykoweb.com/CAF/genera/Marasmius.html
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