Autumn Colors Research Articles

ArNAC148 induces Acer rubrum leaf senescence by activating the transcription of the ABA receptor gene ArPYR13

Acer rubrum, an ornamental tree known for its stunning autumn colors, has an elusive molecular mechanism that governs its leaf senescence. We performed the genome-wide analysis of NAC transcription factor genes and PYRABACTIN RESISTANCE1-LIKE (PYLs) and found that ArNAC148 and ArPYL13 were significantly upregulated in senescing leaves as compared to mature leaves. Subcellular localization studies confirmed the nuclear localization of ArNAC148 and the cytoplasmic localization of ArPYL13. Electrophoretic mobility shift assay and yeast one-hybrid assay demonstrated that ArNAC148 directly binds to the promoter of ArPYL13. Luciferase reporter assays further showed that ArNAC148 activates the transcription of ArPYL13. The transient expression of ArNAC148 and ArPYL13 in tobacco leaves promoted chlorophyll degradation, increased H2O2 level, MDA contents, and electrolyte leakage in response to abscisic acid (ABA). Moreover, the virus-induced gene silencing of ArNAC148 and ArPYL13 in A. rubrum produced results that were opposite to those observed in transient expression experiments. Our findings suggest that ArNAC148 induces leaf senescence by directly activating the transcription of ArPYL13, providing insights into the ABA-mediated regulatory mechanisms governing leaf senescence in A. rubrum. This study offers new perspectives for researchers to explore the roles of NAC and PYL genes in regulating leaf senescence in woody ornamental plants.

For a Colorful Life: Recent Advances in Anthocyanin Biosynthesis during Leaf Senescence.

Leaf senescence is the last stage of leaf development, and it is accompanied by a leaf color change. In some species, anthocyanins are accumulated during leaf senescence, which are vital indicators for both ornamental and commercial value. Therefore, it is essential to understand the molecular mechanism of anthocyanin accumulation during leaf senescence, which would provide new insight into autumn coloration and molecular breeding for more colorful plants. Anthocyanin accumulation is a surprisingly complex process, and significant advances have been made in the past decades. In this review, we focused on leaf coloration during senescence. We emphatically discussed several networks linked to genetic, hormonal, environmental, and nutritional factors in regulating anthocyanin accumulation during leaf senescence. This paper aims to provide a regulatory model for leaf coloration and to put forward some prospects for future development.

Exploring the impact of autumn color and bare tree landscapes in virtual environments on human well-being and therapeutic effects across different sensory modalities.

The aim of this study is to investigate the impact of different sensory modes on the preferences and therapeutic effects of virtual autumn landscapes on university campuses. In this study, 320 participants, with an average age of 21.11 years (±1.21 years), were exposed to virtual environments featuring autumn color landscapes and bare tree landscapes using visual, auditory, and combined conditions. A control group was included for comparison. Differences in participants' physiological indicators (EEG, heart rate) and psychological measures (POMS, PANAS, SVS, ROS) were analyzed, with the use of the Holm correction (P < 0.05). (1) Autumn virtual landscapes with color had a superior therapeutic effect. (2) There were significant differences in the therapeutic effects of different sensory modes within the same season's landscape categories, suggesting that incorporating additional sensory dimensions may enhance therapeutic outcomes. Based on the study's findings, we recommend that when designing therapeutic environments, attention should be given to seasonal variations and the integration of various sensory modes to optimize therapeutic results.

Paclobutrazol Substrate Drenches Control Growth of Nine Black-eyed Susan Cultivars

Our objective was to quantify the efficacy of paclobutrazol substrate drenches on growth of nine black-eyed Susan (Rudbeckia hirta) cultivars. Liners of ‘Autumn Colors’, ‘Cherokee Sunset’, ‘Cherry Brandy’, ‘Denver Daisy’, ‘Glowing’, ‘Happy’, ‘Indian Summer’, ‘Prairie Sun’, and ‘Sunny’ black-eyed Susan were transplanted into 6.5-inch-diameter plastic containers (2 qt) filled with a commercial soilless peat-based substrate. After 16 days, six single-plant replicates received a substrate drench of 5-fl-oz aliquots of solutions containing deionized water [0 mg·L−1 paclobutrazol (control)] or 2.5, 5, 10, or 20 mg·L−1 paclobutrazol (0, 0.375, 0.75, 1.5, and 3.0 mg/pot). Paclobutrazol drenches of 2.5 to 20 mg·L−1 significantly influenced plant height, plant diameter, growth index (GI), and shoot dry weight (SDW) of all black-eyed Susan cultivars, although the magnitude of response to paclobutrazol substrate drench concentration varied with cultivar. For most cultivars, GI, an integrated measurement of height and diameter, was suppressed as paclobutrazol substrate drench concentrations increased from 2.5 to 20 mg·L−1, resulting in plants that were 30% to 43% smaller than untreated plants. Increasing paclobutrazol substrate drench concentrations from 2.5 to 20 mg·L−1 limited SDW of each cultivar differently, although plants were 5% to 59% smaller at 20 mg·L−1 paclobutrazol than untreated plants. Time to flower for ‘Autumn Colors’, ‘Cherry Brandy’, ‘Happy’, ‘Indian Summer’, and ‘Prairie Sunset’ was unaffected by any paclobutrazol substrate drench concentration; however, concentrations of ≤10 mg·L−1 paclobutrazol are suggested for ‘Cherokee Sunset’, ‘Denver Daisy’, ‘Glowing’, and ‘Sunny’, as higher concentrations delay flowering. Our results indicate that growers can attain growth control with substrate drenches containing 5 to 10 mg·L−1 paclobutrazol during greenhouse black-eyed Susan production without delaying flowering.

First report of citrus leaf blotch virus infecting Viburnum lentago in South Korea.

Viburnum lentago (family Adoxaceae) is a perennial plant species native to northeastern United States and southern Canada. Globally, V. lentago is a popular garden plant due to its abundant flowers and beautiful autumnal color. V. lentago is also commercially cultivated for medicinal purposes because its roots and fruits can be used in herbal preparations (Jiao et al. 2021). In June 2022, virus-like symptoms of vein chlorosis and yellowing were observed in the leaves of many V. lentago trees planted in a public park in Wonju, South Korea. Leaf samples were collected from five symptomatic V. lentago trees. To identify the causal agent(s) of the virus-like symptoms, total RNA was isolated from one sample using PureLink® RNA Mini Kit (Invitrogen, USA) and subjected to library construction using Illumina TruSeq RNA Sample Preparation Kit v2 (Illumina, Inc., USA). RNA-Seq was performed using an Illumina NovaSeq 6000 system (Macrogen, Korea). De novo assembly of 118,878,556 quality-filtered reads was performed using the Trinity pipeline (Kwon et al. 2018), yielding 296,109 contigs. BLASTn and BLASTx analyses of the contigs against the GenBank viral reference database identified only one large contig (8,816 nt) containing a 26-nt poly(A) tail of viral origin. This contig had a maximum nucleotide identity of 85.53 % (with 99 % coverage) with isolate HZ (accession No. MH427034) of citrus leaf blotch virus (CLBV; genus Citrivirus, family Betaflexiviridae), suggesting that the collected sample was infected with CLBV. All collected V. lentago samples were tested using RT-PCR with CLBV-specific primers (CLBV-Det-Fw 5'-AACGAGGCCAATTCTGCTAT-3' and CLBV-Det-Rv 5'-GACTGCTTGACTAACAC-CCA-3'). All samples were positive for CLBV. For biological indexing, sap from the symptomatic V. lentago leaves was mechanically inoculated to indicator plants, including Nicotiana benthamiana, N. occidentalis, N. tabacum, Datura stramonium, Chenopodium quinoa, Vigna unguiculata, and V. lentago. Three months later, only V. lentago developed the same vein chlorosis symptoms observed in the collected samples, and no other tested plants exhibited obvious symptoms. Further, only V. lentago sample tested positive for CLBV using RT-PCR analysis. To determine the complete genome sequence of the CLBV V. lentago isolate, the contig sequence was confirmed by de novo sequencing of the RT-PCR products amplified using CLBV-specific primers. The 5' terminal sequence of the contig was determined using the 5' rapid amplification of cDNA ends method (Seo et al. 2015). The full-length sequence of CLBV isolated from V. lentago was 8,795 nt in length (excluding poly(A) tail), and deposited in GenBank under the accession number OP751940. Although numerous isolates of CLBV have been identified in various plant species, including citrus, kiwi, and lemon plants (Cao et al. 2017), the V. lentago isolate is likely a distinct variant because its CP gene has a maximum nucleotide identity of 85.53 % with that of a kiwi isolate (MH339916). With little information available on viral diseases infecting V. lentago, this is the first identified and completely sequenced CLBV infecting V. lentago. Significantly, V. lentago plants infected with CLBV did not flower throughout the summer period, reducing their value as an ornamental plant. Furthermore, V. lentago might have acted as an intermediate host to transfer CLBV to other crops such as citrus. To the best of our knowledge, this is the first report of CLBV infecting V. lentago in South Korea and the world.

Chromosome-scale genome assembly and insights into the metabolome and gene regulation of leaf color transition in an important oak species, Quercus dentata.

Quercus dentata Thunb., a dominant forest tree species in northern China, has significant ecological and ornamental value due to its adaptability and beautiful autumn coloration, with color changes from green to yellow into red resulting from the autumnal shifts in leaf pigmentation. However, the key genes and molecular regulatory mechanisms for leaf color transition remain to be investigated. First, we presented a high-quality chromosome-scale assembly for Q. dentata. This 893.54 Mb sized genome (contig N50 = 4.21 Mb, scaffold N50 = 75.55 Mb; 2n = 24) harbors 31 584 protein-coding genes. Second, our metabolome analyses uncovered pelargonidin-3-O-glucoside, cyanidin-3-O-arabinoside, and cyanidin-3-O-glucoside as the main pigments involved in leaf color transition. Third, gene co-expression further identified the MYB-bHLH-WD40 (MBW) transcription activation complex as central to anthocyanin biosynthesis regulation. Notably, transcription factor (TF) QdNAC (QD08G038820) was highly co-expressed with this MBW complex and may regulate anthocyanin accumulation and chlorophyll degradation during leaf senescence through direct interaction with another TF, QdMYB (QD01G020890), as revealed by our further protein-protein and DNA-protein interaction assays. Our high-quality genome assembly, metabolome, and transcriptome resources further enrich Quercus genomics and will facilitate upcoming exploration of ornamental values and environmental adaptability in this important genus.

Red pigments in autumn leaves of Norway maple do not offer significant photoprotection but coincide with stress symptoms.

The reasons behind autumn colors, a striking manifestation of anthocyanin synthesis in plants, are poorly understood. Usually, not all leaves of an anthocyanic plant turn red or only a part of the leaf blade turns red. In the present study, we compared green, red and yellow sections of senescing Norway maple leaves, asking if red pigments offer photoprotection, and if so, whether the protection benefits the senescing tree. Green and senescing maple leaves were illuminated with strong white, green or red light in the absence or presence of lincomycin which blocks photosystem II (PSII) repair. Irrespective of the presence of anthocyanins, senescing leaves showed weaker capacity to repair PSII than green leaves. Furthermore, the rate of photoinhibition of PSII did not significantly differ between red and yellow sections of senescing maple leaves. We also followed pigment contents and photosynthetic reactions in individual leaves, from the end of summer until abscission of the leaf. In maple, red pigments accumulated only during late senescence, but light reactions stayed active until most of the chlorophyll had been degraded. PSII activity was found to be lower and non-photochemical quenching higher in red leaf sections, compared with yellow sections of senescing leaves. Red leaf sections were also thicker. We suggest that the primary function of anthocyanin synthesis is not to protect senescing leaves from excess light but to dispose of carbohydrates. This would relieve photosynthetic control, allowing the light reactions to produce energy for nutrient translocation at the last phase of autumn senescence when carbon skeletons are no longer needed.

Tree attribute assessment in urban greenwood using ground-based LiDAR and multiseasonal aerial photography data

Advances in LiDAR and unmanned aerial vehicle technology have made high-resolution data available, which can be used for individual tree detection and assessing tree attributes. The accuracy of these assessments is still not clear for stands with high tree species diversity as well as leaf-off and leaf-on conditions. The aim of this study was to assess the quality of tree top detection and individual tree heights extracted from photogrammetric point clouds and canopy height models as well as ground-based LiDAR clouds in mixed and coniferous forest stands depending on the phenological stage. The study has been carried out in the Botanical Garden of the Petrozavodsk State University (Republic of Karelia, Russia). Four flight missions (in 2019–2021) using Phantom 4 Pro quadcopter were conducted in the arboretum (&gt; 200 tree species) during periods of leafless, leaf biomass growth, full foliage and autumn leaf colouration. A single ground-based laser scanning was performed using a Leica BLK 360. Multiseasonal ultra-high resolution orthophoto mosaics (1.1–2.8 cm/pixel), photogrammetric point clouds (average density is 4200 points/m2), as well as LiDAR clouds (11 600 points/m2) were obtained. Further analysis was performed on three sites differing in tree species composition, tree density and site area. Tree tops were automatically detected from photogrammetric point clouds and their heights were estimated using R environment software. We found that most of the trees (78.9%) were correctly detected by algorithms based on photogrammetric data collected in periods of full foliage and autumn colouration. We also found that the number of false positive (FP) and false negative (FN) cases increased with decreasing in green biomass on deciduous trees. Compared with an average value, tree detection quality increased by 9.4% for coniferous trees with cone-shaped crowns (Abies sibirica, A. balsamea, A. fraseri, Picea abies, P. pungens, P. omorika, Pseudotsuga menziesii, Larix sibirica) regardless of the tree density, and tree detection quality decreased by 10% for coniferous trees with an ellipsoidal-shaped crowns (e.g. Thuja occidentalis, genus Pinus) or in cases for broad-leaved trees with high tree density. The lowest value of tree detection quality (F = 0.49) was found for the leafless period. High values (F = 0.84) obtained for periods of full foliage and autumn colouration indicates that tree detection quality was well in general. For the biomass growth period, this value (F = 0.69) also indicates a high quality of tree detection results. We also found that tree heights estimated using photogrammetric data well matched with tree heights measured on LiDAR clouds (R2 = 0.99). The highest accuracy was obtained for coniferous trees with cone-shaped crowns. We also estimated the height increments of different tree species between 2019 and 2021 based on photogrammetric point clouds. The highest annual height increment was obtained for Pinus sibirica (52 cm), and the lowest for Pseudotsuga menziesii (32 cm). Overall, our results have shown the potential to use photogrammetric and LiDAR data for tree mapping and estimating tree attributes in multi-species forest stands of arboretums or urban parks, as well as in natural forests.

First Report of Smoketree Rust Caused by Pileolaria cotini-coggygriae in the Midwestern United States

Smoketrees (or smoke bush, Cotinus spp.) are large deciduous trees or bushes in the Anacardiaceae. European smoketrees ( Cotinus coggygria Scop.) are valued as an ornamental for their unusual flowers and striking autumn color. In June 2020, leaves of C. coggygria from a single tree in a home landscape in Franklin, Indiana, were found to be infected. Leaves with evidence of rust disease—plant tissue distortion with visible fungal growth—were submitted to the Purdue Plant and Pest Diagnostic Laboratory. Morphological identification was supported by extracting DNA from the specimen, sequencing the 28S region of the nuclear ribosomal DNA repeat, and comparing this to another accessioned P. cotini-coggygriae specimen (PUR018082; GenBank accession #MZ188974) from the Arthur Fungarium (PUR), resulting in 100% identity shared. This is the first vouchered record of P. cotini-coggygriae in the Midwestern United States.

Synopsis

The 2021 Media Education Conference (MEC 2021 [ulapland.fi]) took place on top of Ounasvaara Hill in Rovaniemi from September 28–October 1, 2021. MEC (formerly NBE) is an informal and friendly conference that participants attend to exchange ideas and information dealing with media education, educational use of ICTs, and learning environments. MEC 2021 was organized by the Media Education Hub at the University of Lapland. The theme of MEC 2021 was “Media Education in Autumn Colors.” MEC 2021 also celebrated the 20th birthday of the Media Education Hub. MEC 2021 participants were invited to submit paper proposals to be published in this special issue of seminar.net.&#x0D; The themes and topics of the ninth MEC conference dealt with a) media, digital, and information literacies; b) digital media in teaching and learning; c) playful learning; and d) media education, participation, and well-being.

Winter dormancy in trees

Plants growing in temperate and boreal regions of the world have to face strikingly different environmental conditions during summer and winter. Being sessile organisms, plants have had to develop various strategies to adapt to these changes in light, temperature, and water availability, thereby optimizing their 'economy of growth'. While annual plants can endure unfavorable winter conditions in the form of a seed, or under a protective cover of thick snow, perennial plants such as trees adapt by going into a stage of deep sleep called winter dormancy. To enter dormancy, vegetative growth is stopped in the late summer or early autumn and the shoots are converted into buds, where the shoot apical meristems are protected by tightly closed and hardened bud scales (Figures 1 and 2). At the same time, cold hardiness develops and the need for water and nutrient uptake is drastically reduced. Deciduous trees also go through leaf senescence whereby the leaves develop their autumn colors and are shed (Figure 1A). The trees then spend the beginning of the winter in a state of deep sleep in which they are completely unreceptive to any environmental signals telling them to wake up. However, as winter progresses, the trees are gradually released from this slumber and will eventually flush their buds in the spring. Vegetative growth then resumes with the formation of new leaves and shoots during summer until the trees again go into growth cessation and the cycle is closed (Figures 1 and 2). This cycle of growth and dormancy is central for the ability of trees to adapt to growth at different latitudes and elevations. The further north, or the higher the elevation at which the trees grow, the earlier in the season the trees enter growth cessation and the later they flush their buds in the spring. This is because meteorological winter arrives earlier in the season and lasts longer into the spring. The trees therefore have to stop growth earlier in the season to ensure that they have enough time to complete bud formation and to develop cold hardiness and dormancy. They also have to be sure that winter is really over before flushing their buds. Winter dormancy is therefore a clear case of a trade-off between the length of the growing season and the protection against winter damage - a nice example of 'economy in biology', the theme of this special issue. This primer will briefly summarize what we know about the environmental signals that influence the annual growth cycle in trees, as well as our current understanding of the genetic pathways and molecular mechanisms regulated by these signals.

Dynamics of seasonal changes in introduced plants in Eastern Transbaikalia

The article presents a comparative analysis of the seasonal development of introduced plants in the weather conditions of Eastern Transbaikalia for the growing periods from 2014 to 2019. The results presented are taken from 6-year phenological observations conducted in the arboretum of the Institute of Natural Resources, Ecology and Cryology SB RAS. We constructed the phenological spectra of the studied objects by year. We studied the main phenological indicators of vegetation the East Asian forest-steppe and Manchurian-Daurian preboreal species. We analyzed the meteorological data: the mean daily air temperatures and precipitation for the months of the growing season (2014–2019), and the sum of active temperatures and precipitation for this period. The data on the dynamics of the development of shrubby plant species in conditions of Eastern Transbaikalia for 2014–2019 indicate that plants respond adaptively to changes in weather conditions. Hereditary and physiological characteristics showed that the introduced plants are characterized as cold-resistant and drought-resistant. Corylus heterophylla and Armeniaca sibirica are most sensitive to temperature extremes in spring, in contrast to Euonymus maackii, which were stable. Low above-zero air temperatures in spring and a large amount of precipitation encourage plants to pass the development stages (phenophases) faster than in dry and warm weather (Corylus heterophylla, Armeniaca sibirica). At the same time, low temperatures (frosts) in spring with a wet period at the time of flowering negatively affect the further fruit formation in Corylus heterophylla individuals. Rainy or cloudy days reduce the color intensity of the autumn leaves, and cool, dry, and sunny weather contributes to the autumn color scheme. Armeniaca sibirica and Corylus heterophylla are variable in terms of the onset of the main phenophases; individuals of the Euonymus maackii species have minimal individual variability. The longest growing seasons on the phenological spectrum were registered in 2014 and 2018–2019 (in Corylus heterophylla individuals – 190 days), which contributes to the accumulation of more phytomass. The shortest growing season was registered in 2015 (Armeniaca sibirica – 150 days).

Evaluation of late‐season nitrogen source application on autumn color and winter injury of ‘Riviera’ bermudagrass in the upper transition zone of the United States

AbstractLate summer and autumn application of nitrogen (N) to bermudagrass (Cynodon spp.) in the transition zone has been associated with enhanced turfgrass color but has been thought to increase the potential for winter injury. Eleven N sources were applied in late summer and early autumn to provide a total annual N level of 98 kg ha−1 in Olathe, KS to evaluate fall color and spring green coverage of ‘Riviera’ bermudagrass [Cynodon dactylon (L.) Pers.]. Treatments included experimental coated urea fertilizers, N sources containing urease inhibitors, urea, and nontreated turfgrass. Significant winter injury occurred throughout the experimental area. Turfgrass color in late October was positively correlated with green coverage evaluated in May (r = .55; P &lt; .001). For example, bermudagrass treated with AND3.0EX (Poly/Humic Coated Urea) had a color rating of 3.5 (1 to 9 scale; 9 = dark green) in late October, and green coverage in May was 44%. Nontreated turfgrass had a color rating of 1.5 in late October, and green coverage in May was 8%. Enhanced winter survival of bermudagrass following late‐season N application may require that turfgrass managers rethink traditional N programs limiting application to only late spring and midsummer dates in the transition zone.

Implementation of the visual aesthetic quality of slope forest autumn color change into the configuration of tree species

Urban expansion leads to changes in the visual aesthetic quality and ecological degradation of the surrounding slope forest landscapes. Color is a crucial visual element to examine when viewing this large-scale slope forest landscape from a long distance. This is particularly true for the autumn color of slope forest, which is very attractive to the public. An exploration of the relationship between the change in color of a natural slope forest and its visual aesthetic quality enables the implementation of the configuration of superior aesthetic tree species. Therefore, it can provide aesthetic rules and a reference to configure local tree species to support their visual aesthetic quality, ecological sustainability and native biodiversity restoration in a local urban slope forest. However, such research is critically lacking. This study investigated the visual aesthetic quality of the color dynamics of a natural slope forest in Jiaozi Mountain, China in the autumn. We analyzed both the composition of tree species and the changes in color for each species of tree in nine forest sites that exhibited superior visual aesthetic quality. The results showed that the forests with superior visual aesthetic quality were more green, red, and yellow, had moderately higher saturation and value, more obvious color contrast, and diverse colors with primary and secondary contrast. Diverse and balanced color patches or a dominant color patch contrasted by many small patches with interspersed color components also highlighted the superior visual aesthetic quality of slope forest features. Different combinations of color features can result in high visual aesthetic quality. The 84 tree species in the superior visual aesthetic quality forests primarily displayed 10 types of color changes that varied as green, yellow, blue, red, withered yellow, withered red and gray.

Implications of nitrogen translocation efficiency for hypotheses on the evolution of autumn colours-: A response to Joly 2021 (https://doi.org/10.1111/jeb.13961) and to Renner and Zohner 2021 (https://doi.org/10.1111/jeb.13957).

Implications of nitrogen translocation efficiency for hypotheses on the evolution of autumn colours-: A response to Joly 2021 (https://doi.org/10.1111/jeb.13961) and to Renner and Zohner 2021 (https://doi.org/10.1111/jeb.13957).

Coloration and phenology manifest nutrient variability in senesced leaves of 46 temperate deciduous woody species

Abstract Senesced-leaf nutrient concentrations vary significantly among coexisting plant species reflecting different leaf nutrient use strategies. However, interspecific variation in senesced-leaf nutrients and its driving factors are not well understood. Here, we aimed to determine interspecific variation and its driving factors in senesced-leaf nutrients. We explored interspecific variation in carbon (C), nitrogen (N) and phosphorus (P) concentrations in newly fallen leaves of 46 coexisting temperate deciduous woody species across the Maoershan Forest Ecosystem Research Station, Northeast China. The relative importance of 10 biotic factors (i.e. mycorrhiza type, N-fixing type, growth form, shade tolerance, laminar texture, coloring degree, coloring type, peak leaf-coloration date, peak leaf-fall date and end leaf-fall date) was quantified with the random forest model. N and P concentrations varied 4- and 9-fold among species, respectively. The high mean N (15.38 mg g−1) and P (1.24 mg g−1) concentrations suggested a weak N and P limitation in the studied forest. Functional groups had only significant effects on specific nutrients and their ratios. P concentration and N:P were negatively correlated with peak and end leaf-fall dates for the ectomycorrhiza species group. Brighter-colored leaves (red &amp;gt; brown &amp;gt; yellow &amp;gt; yellow-green &amp;gt; green) tended to have lower N and P concentrations and higher C:N and C:P than darker-colored leaves. The random forest model showed that autumn coloration and leaf-fall phenology contributed 80% to the total explanation of nutrient variability among species. The results increase our understanding of the variability in senesced-leaf nutrients as a strategy of woody plant nutrition in temperate forests.

Effect of hydroponic and peat-free media in transplant production of Rudbeckia hirta varieties under different photoperiodic lighting and their photosynthetic parameters

The purpose of this research was to determine the effects of varieties, different light conditions (short day, long day, natural short day with light pollution), and different growing media (perlite, peat-free, peat-based, aeroponics system) on Rudbeckia hirta plant production under controlled conditions (greenhouse). The morphological effects of each treatment (photoperiodic lightings and media) on different Rudbeckia varieties determined at 11 weeks-old ’Napfény’, ’Toto Gold’, ’Autumn Colors’, ’Prairie Sun’ and 16 weeks-old ’Napfény’. Plantlets received 12 hours daylight did not initiate flowers, remained stage of the leaf rosette in case of all varieties. The 14 hours light treatment in the aeroponics system and the same treatment in perlite and control (natural short day with 14 hours light pollution) plantlets had developed inflorescences or flower buds. The inflorescence axis of ‘Napfény’ was appeared at 13 weeks under long-day conditions, with 1.7 (perlite) - 2.7 (aeroponics) flower buds in 16 weeks. ’Toto Gold’, ’Autumn Colors’, ’Prairie Sun’ varieties developed inflorescences at 8 weeks, 14 hours aeroponics system resulted in the most of flower buds (’Toto Gold’: 6.5, ’Autumn Colors’: 3.25,’Prairie Sun’: 4.8 flower buds) at 11 weeks. Long daylight manipulation could be minimized crop times and achieved flowering potted plants at 11 weeks. The peat-based and peat-free media effect was observed on ‘Autumn Colors’. The number of leaves of peat-free ‘Autumn Colors’ transplants (16.8-20.3) was significantly higher than peat-based media (13.5-15.5). Other morphological parameters were not affected by the media treatments.

A test of the photoprotection hypothesis for the evolution of autumn colours: Chlorophyll resorption, not anthocyanin production, is correlated with nitrogen translocation.

A prominent hypothesis for the adaptive value of anthocyanin production in the autumn leaves of trees and shrubs is that anthocyanins protect leaves from photooxidative stress at low temperatures, allowing a better resorption of nutrients-in particular, nitrogen-before leaf fall. While there is evidence that anthocyanins enable photoprotection, it is not clear whether this translates to improved nitrogen translocation and how this can explain inter-specific variation in autumn colours. A recent comparative analysis showed no correlation between temperature and anthocyanin production across species but did not analyse nitrogen content and nitrogen resorption efficiency. Here, we provide this comparison by analysing the nitrogen content of mature and senescent leaves and their autumn colours in 55 species of trees. We find no correlation between the presence of anthocyanins and the efficiency of nitrogen resorption. We find, instead, that nitrogen resorption is more efficient in species with yellow autumn colours, pointing to chlorophyll resorption, rather than anthocyanin synthesis, as the main determinant of nitrogen translocation efficiency. Hence, our results do not corroborate the photoprotection hypothesis for the evolution of autumn colours.

Vermont’s Forests Provide Many Ecosystem Services Including Carbon Sequestration and Climate Change Mitigation

Photo 1: Vista from the top of the gondola in Smugglers Notch, Mt Mansfield State Forest, Vermont. This photograph captures just how vast Vermont’s forests are. Forests account for approximately 76% of Vermont’s land area, making it the fourth most heavily forested state in the United States. Given this, policymakers in the state have identified forests as an important tool in the fight against climate change. The goal of this research was to evaluate the mitigation potential of a range of forest management scenarios applied across the state. Photo credit: Emily Stephens. Photo 2: Overlooking Nichols Pond, in Woodbury, Vermont. In addition to carbon sequestration, Vermont’s forests provide many ecosystem services including aesthetic and economic values. Vermont is one of the ultimate fall foliage destinations in the United States, with over one million visitors traveling to Vermont in October alone to take in the picturesque landscapes ablaze with autumn colors. When considering implementation of forest management practices and policies to enhance carbon sequestration, it is critical to also consider the impacts on the other benefits these forests provide. Photo credit: Emily Stephens. Photo 3: Kayaking on Groton Lake first thing in the morning, Groton State Forest, Vermont. In this study, we evaluate practical ways to sustainably manage forests and their products to reduce greenhouse gas emissions. This report can serve to inform policymakers on potential biophysical responses of Vermont's forests to various management scenarios. If a goal is to integrate carbon sequestration into broader forest management objectives, it will be important to minimize trade-offs with other ecosystem services, such as the recreational opportunities, water quality, and wildlife habitat that the state’s forests provide. Photo credit: Emily Stephens. These photographs illustrate the article “Opportunities for Forest Sector Emissions Reductions: A state-level analysis” by Alexa J. Dugan, Jeremy W. Lichstein, Al Steele, Juha M. Metsaranta, Steven Bick, David Y. Hollinger published in Ecological Applications. https://doi.org/10.1002/eap.2327

Bitki Tercihleri ve Bitkisel Tasarım Kriterleri Açısından Otopark Alanlarının Değerlendirilmesi: Akdeniz Üniversitesi Yerleşkesi Örneği

The aim of this study is to evaluate the parking lots in Akdeniz University campus within the scope of plant material diversity, planting design elements and criteria. 97 parking areas have determined in the campus and a total of 75 plant species have been identified in these areas, including 43 trees, 7 shrubs, 22 shrubs and 3 twining plants. The most preferred species are Platanus orientalis, Pinus brutia and Washingtonia robusta. Plants often meet the functions of shading and creating space. The most common shrub species are Nerium oleander, Lantana camara, Pittosporum tobira and these species have determined to have restriction and direction functions. According to planting design elements colour and texture are dominant with their dendrological features such as different flower structures and autumn color change, different leaf and branching characteristics. It was determined the rhythm-repeat planting design principle is dominant where the alle afforestation technique is dominant.