Root Suckers Research Articles

Belowground systems in tropical savanna: Fabaceae morphoanatomical traits and their relation to fire.

Post-fire regeneration characterizes woody vegetation of the Cerrado. Several species (e.g., from the Fabaceae) can resprout after fire due to the presence of storage bud-bearing belowground structures, such as xylopodia, having the capacity to rapidly allocate resources for the formation of new aboveground shoots, an advantage in fire-prone ecosystems. Therefore, we evaluated the morphoanatomical structure of the belowground organs, buds and their storage to elucidate fire-related functional traits in relation to regeneration. Besides the strong capacity of plants with xylopodia to resprout and/or their associated root suckers to propagate laterally, they also provide protection against pathogens, through the presence of defence compounds. We evaluated the morphoanatomy and performed histochemical tests with the belowground organs of eight legume species collected in open savannas in Central Brazil. Two species presented a taproot tuber and the six remaining species had a xylopodium as belowground organ. All xylopodia had buds on their upper portion. These organs were basically composed of lignified tissue, containing defence (phenolic compounds and lipidic substances), and storage (starch) substances. All xylopodia were associated to tuberous roots, and in two species these roots were also root suckers. Thus, the presence of belowground storage organs, in combination with stored defence compounds, likely facilitates the persistence of the investigated legumes in fire-prone ecosystems.

Clonality in black locust (Robinia pseudoacacia L.) and implications for seed production

Key messageThe strong clonal growth of black locust (Robinia pseudoacacia L.) not only influences the stand structure of natural or artificially established stands, but also the genetic composition of seed harvested from such clonal stands. For the commercial production of genetically diverse seeds, the stand structure should be taken into account or, at best, seeds harvested from seed orchards should be used.ContextBlack locust is characterised by intensive asexual reproduction through the formation of root suckers. By this means clonal structures can develop within black locust stands, in which ramets of a single clone can dominate extensive areas.AimsWe want to analyse to what extent clonal structures within black locust stands negatively influence the genetic composition and diversity in seed harvested in such stands. We discuss how a potential reduction in genetic diversity can be reduced by measures taken during harvesting and whether the harvesting of seed orchards may be a better alternative.MethodsWe compare the genetic composition and diversity of parent trees and seed harvested from a clonal black locust stand with a seed orchard in which multiple ramets of selected clones were arranged in a randomised design.ResultsWithin the clonal stand, parent contributions to the seed lot analysed proved to be strongly uneven. Selfing rates were high and large full-sib families dominated within the seed lot. Although the relatively strong pollination from unknown pollen donors, probably located outside of the stand, prevented a massive loss of alleles, high selfing rates and the formation of large full-sib families led to an unequal distribution of alleles within the progeny. Within the seed orchard—even though it had a lower number of clones than expected—the randomised design promoted a more diverse pollination pattern.ConclusionWe conclude that for black locust, seed orchards have the greater potential to ensure a balanced genetic composition of harvested seed lots. If economic considerations make it necessary to harvest seed stands, this should only be done in a considered manner and, if possible, with knowledge of the clonal structures of the stand.

Does genotype affect the ability to form root suckers? A case study in black poplar

Does genotype affect the ability to form root suckers? A case study in black poplar

WITHDRAWN: Multiple resprouting strategies coexist after fire in southeastern Brazil cerrado trees

Many trees of the Brazilian savannah have underground organs from which they resprout after a fire, although the relationship between the presence of these organs and the presence of underground resprouts (basal resprouts and root suckers) is unclear. Other relationships may also exist between the height of underground resprouts and the presence of live aerial biomass, multi-stemness and fire impact, tree age and the presence of underground resprouts, and epicormic bud distribution and fire impact. To test all these relationships, data from 367 mature cerrado trees subject to a single prescribed burn in southeastern Brazil were analysed. There was no clear relationship between the presence of underground organs and the presence of underground resprouts, although fire impact strongly influenced the presence of basal resprouts, with 90% of topkilled trees presenting basal resprouts, and this strong influence may have concealed a potential relationship between the presence of underground organs and resprouts. Underground resprouts were 45% taller when trees lacked live aerial biomass because more ground-level sunlight was available for these resprouts to grow. Single-stemmed trees had on average more basal resprouts than multi-stemmed trees, which concerned the translocation of carbohydrate reserves in multi-stemmed trees to maintain the fitness of multiple stems, while single-stemmed trees could store more reserves in their underground organs. However, multi-stemmed trees were more likely than single-stemmed trees to remain unburnt, an effect of less sunlight reaching the ground, suppressing grass cover. Trees >13 years resprouted basally less often since, as the trees were not burnt frequently, they developed deeper roots instead of investing in underground buds. Epicormic bud density was highest in medium fire impacts because a high fire impact led to topkill, while a low fire impact was insufficient to break epicormic bud dormancy. Moreover, the position of the lowest and highest epicormic buds was determined by epicormic bud density, suggesting that, at medium fire impacts, there was greater mobilisation of reserves along the tree stem to activate more epicormic buds.

Genotyping of Autochthonous Rose Populations in the Netherlands for Effective Ex Situ Gene Conservation Management

Most wild rose species in the Netherlands belong to Rosa section Caninae (dogroses), with Rosa arvensis (section Synstylae) and Rosa spinosissima (section Pimpinellifoliae) as other indigenous species. All species are rare, often found in small populations or as scattered individuals, except for Rosa canina and Rosa corymbifera. Conservation strategies have been developed for these roses, with a focus on ex situ methods, including clonal archives and seed orchards, using vegetative propagation from the original shrubs. Efficient collection management aims at preservation of maximum genetic diversity with a minimum of duplicated genotypes. However, dogrose taxonomy is complex because of species hybridization, different ploidy levels, and their matroclinal inheritance due to Canina meiosis. They can also reproduce vegetatively through root suckers. In order to assess the genetic structure and the levels of genetic diversity and clonality within and among the wild rose populations in the Netherlands, we genotyped individuals in wild populations and accessions in the ex situ gene bank with 10 highly polymorphic microsatellite markers. The analysis revealed 337 distinct multilocus genotypes (MLGs) from 511 sampled individuals, with some MLGs shared across different species and sites. The genetic structure analysis showed distinct clusters separating non-dogrose species from the Caninae section. Geographic distribution of MLGs indicated both local and widespread occurrences. Redundancy analysis identified 152 distinct MLGs from 244 gene bank accessions, suggesting a 38% redundancy rate. Core collections were optimized to retain genetic diversity with minimal redundancy, selecting subsets of 20–40 individuals from different species groups. The study highlights the value of genetic characterization in guiding sampling strategies for dogroses. We propose a two-step approach that may be used to reveal clonality and redundancy and to optimize core collections of species that combine sexual and vegetative reproduction, to maximize genetic capture in ex situ gene banks.

Succession as a Natural Tool for Restoration of Oak—Lime Forests on Aspen-Covered Clearcuts

The genus Quercus, including species like pedunculate oak (Quercus robur L.), can play a key role in maintaining climate-resistant mixed forests due to its broad ecological spectrum and drought tolerance. Unfortunately, in some parts of Europe, clearcutting has drastically reduced the oak population. An example of this event is our survey of heritage Oak—Lime forests in European Russia, which were transformed into pure aspen stands. The aim of our study was to provide forecasts and silvicultural recommendations for the passive restoration of these forests. We took a chronosequence approach to assess changes associated with natural succession over 60 years. In our survey of the development of oaks, limes and accompanying tree species (aspen, birches, maples, elms), we used 190 plots ranging across a wide spectrum of forest disturbance due to clearcutting. We demonstrate that aspen reproduce rapidly by root suckers after cutting and occupy more than 60% of the space. But the dominance of aspen decreases continuously from the age of 30, and then the lime trees begin to dominate. Oak does not show successful natural regeneration. Therefore, we recommend planting oak seedlings or sowing acorns, i.e., active restoration, in combination with the natural restoration of lime.

ДИКОПЛОДОВЫЕ ПОРОДЫ НА НАРУШЕННЫХ ЗЕМЛЯХ СЕВЕРНОГО КАВКАЗА

Wild fruit species on disturbed lands grow in degraded areas and have the ability to quickly restore the ecosystem. Restoration of disturbed lands in mountain and piedmont areas plays a big role and is a significant resource in the national economic potential of the region, an important reserve for agricultural production. The article provides an overview of the disturbed lands of the North Caucasus as a result of mining. For the purpose of biological rehabilitation, a classification of technogenic landscapes has been developed. The state of wild fruit and berry plants in disturbed areas has been revealed, which depends on the types of substrate, topography, climate, parts of the slopes and their steepness. Eleven wild fruit species grow naturally in quarries in the study region. Among them, sea buckthorn and dog rose stand out. They tolerate drought well and are resistant to low soil fertility. Cherry plum, common hazel and hawthorn prefer better moisture conditions. The degree of root growth in different parts of the slope has been established, which makes it possible to determine the suitability of soil and hydrological conditions for wild fruit species and to plan appropriate measures. It has been confirmed that the moist parts of the lower slopes are the most favorable for the growth and development of plants. The individuality of the formation of wild fruit and berry plantings according to the exposures at each deposit separately is noted. The prospects of wild fruit breeds capable of producing root shoots are substantiated. It was revealed that the spread of root suckers occurs more intensively on light soils, despite the fact that moisture is better on clay; this is not the main criterion for the spread of suckers. An assortment of wild fruit plants has been developed to create protective plantings in various environmental conditions. Measures are proposed to restore disturbed lands. Key words: WILD FRUIT SPECIES, DISTURBED LANDS, SLOPE, QUARRY, REHABILITATION, ROOT OFFSPRING, ASSORTMENT

Clonal propagation, scale dependent assembly, and nucleation drives natural regeneration in a restinga sandy coastal plain

AbstractOn the sandy coastal plains, environmental filters that limit seedling establishment and survival create a naturally heterogeneous landscape, formed by vegetation patches inserted in a matrix of bare sandy soil. The succession processes in these ecosystems depend on some pioneer species that facilitate the recruitment and survival of other species. Here, we evaluated the spatial pattern and changes of vegetation patches of restinga (i.e., coastal sandy plain vegetation) over one decade (2011–2021). The research was carried out in Alagoas State, Northeast of Brazil. We considered as patches the vegetation islands inserted in a matrix of bare sandy soil and applied methodologies of photointerpretation. Landscape metrics included patch area, edge, shape, and core area. To test the effect of landscape metrics on species occurrence and species richness per patch, we applied generalized linear models (GLM) with binomial and quasi‐Poisson distributions, respectively. We used the “betapart” package to evaluate the importance of turnover and nestedness as drivers of beta diversity among patches. Our data indicate that a key plant (Myrciaria floribunda), which can propagate by root suckers, initiates a succession process, creating regeneration nuclei, which seem to follow a deterministic succession pattern until the patch reaches 10 m2 in area. In the successional sequence, the patches grow and coalesce with neighboring patches. Species richness of patches presented an unimodal response to patch size. Overall, there is a greater contribution of species turnover to among‐patch beta diversity. However, for patches smaller than 10 m2, beta diversity was mostly driven by nestedness, reflecting a process of species addition to the growing patches. The succession pattern found in the study area should be considered for the formulation of nature‐based restoration models, expected to be more efficient and effective for ecosystems with similar environmental filters.

Retaining the largest aspen stems during motor-manual release allows to control aspen suckering in young mixedwood stands

Mixedwood stands containing aspens (Populus tremuloides or P. grandidentata) often convert to hardwood-dominated stands after harvesting due to the rapid regeneration of aspen from root suckers, even when sites are promptly replanted with conifer seedlings. Without the use of herbicides, this problem is usually dealt with several passes of motor-manual (“manual”) release of overtopped seedlings. The aim of this study was to test a variation of thinning from below treatment (thinning; only 20% of the largest aspens are retained), and to compare it against two traditional release treatments: broadcast brushing (brushing; 100% removal of aspen) or crop tree release (CTR; removal of competing vegetation 60 to 90 cm around planted spruce) and an un-treated control. The thinning treatment left the 20% larger aspen stems in place, in order that they continue exerting apical dominance on smaller suckers and limit re-suckering of the treated plots. Aspen suckering and growth of planted black spruce seedlings (Picea mariana (Mill.) B.S.P) were measured two- and four-growing seasons following treatments. Results four years after release application showed that the thinning and CTR treatments reduced aspen density by 61% compared to the brushing treatment. In addition, aspen individual stem volume in the thinning treatment was almost 10 times larger than the brushing and twice that of the CTR treatments. Spruce height and ground collar diameter (GCD; 5 cm aboveground line) were both measured, and while height increment was similar in all treatments, diameter increment was greater in the thinning treatment (+42%) compared to the control, brushing and CTR treatments (+17%). Thinning yielded better short-term results than the brushing release in terms of aspen re-suckering and aspen sawlog potential, highlighting the need for adapted silvicultural treatments based on the species’ ecology.

Tissue culture-free transformation of traditional Chinese medicinal plants with root suckering capability.

Tissue culture-free transformation of traditional Chinese medicinal plants with root suckering capability.

Plant vegetative propagation plays a considerable role in the regeneration following slash-and-burn agriculture in Caatinga dry forest

Slash-and-burn agriculture is a common practice in dry forests worldwide. Understanding the relative importance of different regeneration mechanisms following this disturbance provides insights into forest regeneration dynamics and resilience. We assessed differences in structural components, the relative contribution of vegetative and sexual reproduction, and the taxonomic composition of woody assemblages among different habitats in a Brazilian Caatinga dry forest after slash-and-burn agriculture. We assessed vegetation parameters (i.e., basal area, height, species richness, and the frequency of each regeneration mechanism) in recently abandoned fields, regenerating forest stands and old-growth forest stands. Overall, trees originates from root suckers accounted for at least 40% of the individuals, stems, and basal areas across the habitats. The structure of regenerating stands was similar to old-growth stands except for species composition, total number of roots, and number of primary roots. The aboveground basal area varied in total values, but not averages, among habitats, indicating a rapid recovery of aboveground biomass after slash-and-burn agriculture. Conversely, recently abandoned fields had higher belowground basal area and basal area of primary roots, revealing that the trees in these habitats emit more roots even with fewer individuals. There was a high degree of species turnover among the habitats, probably due to both species selection by farmers and environmental effects. Nevertheless, the dominant species presented both regeneration mechanisms across the habitats. Our findings thus show that the Caatinga dry forest regeneration considerably relies on the ability of woody plant species to emit root suckers in addition to sexual reproduction, which should be considered for better management practices as slash-and-burn agriculture is and will continue to be practiced.

Imprint of selective logging on seed regeneration of Brachystegia spiciformis Benth. in dry miombo woodland in Zimbabwe

Woodlands that have been affected by selective logging are ubiquitous in southern Africa but how this harvesting practice impacts seed regeneration of dominant tree species remains unclear. To address this deficiency, the study assessed the effects of different selective logging intensities on post-dispersal seed predation and seedling recruitment of Brachystegia spiciformis Benth. in Ruzawi Forest, Zimbabwe. Data were collected in blocks that were subjected to selective logging intensities of 0 % (00 L, unlogged), 5 % (05 L), 10 % (10 L), and 15 % (15 L). Ten years after logging, three transects (200×30 m) were laid in each block and five main plots (20×20 m) were laid in each transect, making a total of 60 plots. Low-intensity selective logging of 5 % did not cause any significant changes to seed predation levels, densities of true seedlings, seedling sprouts and root suckers, and soil nutrient concentrations. Seed predation was significantly greater in 10 L and 15 L sites than in unlogged and 05 L sites. As logging intensity increased, the relative importance of sexual reproduction decreased and that of vegetative reproduction increased. Canopy cover and seedling density decreased as logging intensity increased but a reverse trend was observed with grass biomass and root sucker density. Grass biomass was negatively correlated with the density of true seedlings and seedling sprouts. Soil organic C, N, P, and K were all significantly reduced in 10 L and 15 L sites than in unlogged and 5 L sites. Our results suggest that unless selective logging is practiced at very low harvest intensities, it can create opportunities for the growth of dense grass swards, potentially promoting rodent seed predation and limiting seedling recruitment. This study recommends effective use of low-impact selective logging practices as well the adoption of woodland management policies that prioritize sustainable utilization practices.

Tombul Fındık Çeşidinin Köklenme Kabiliyeti Üzerine Çelik Alma Zamanı ve Bitki Büyüme Düzenleyicilerinin Etkisi

The study was carried out to determine the effect of cutting time, IBA and putrescine treatments on the rooting of the cuttings of Tombul hazelnut cultivar. The plant material of study consisted of cuttings prepared from one-year-old root sucker of Tombul hazelnut cultivar. The cuttings collected on three different dates (15 June, 10 July and 4 August) were performed three treatments (control, 2000 ppm IBA and 2000 ppm IBA+1600 ppm putrescine). Depending on the interaction of cutting time and treatment, the highest rooting was determined in the cuttings treated IBA collected in June (16.7%), while the lowest in the control cuttings (0%) in all periods. Except for the cuttings treated IBA+putrescine collected in August, callus did not occur in other treatments. The number of roots per cutting was determined between 0.0 (control in all applications) and 15.5 (taken in July and IBA applied). Root length was measured from 0.0 (control in all applications) to 8.0 cm (received in June and IBA applied). The best results in rooting level were recorded in cuttings treated IBA collected in July (4.0). The best results in terms of rooting and root properties of cuttings of Tombul hazelnut cultivar were generally determined in cuttings treated IBA collected in June.

The Effect of Collection Time, IBA and Putrescine Treatments on the Rooting Potential of Foşa Hazelnut Cultivar

Objective: The aim of the research was to determine how collection time, IBA, and putrescine treatments affected the rooting potential of the Foşa hazelnut cultivar (Corylus avellana L.).
 Material and Methods: Cuttings were taken from 1-year-old root suckers of Foşa hazelnut cultivar on 4 different dates (June 15, July 10, August 4 and August 28; in 2021 year). 3 different treatments [Control, IBA (2000 ppm) and IBA+putrescine (2000 ppm+1600 ppm)] were performed to the prepared cuttings. Rooting, callusing, survived cutting ratio, dead cutting ratio, root number, root length, rooting level, number of cutting with buds, number of cutting with shoot, and number of cutting with leaves properties were investigated in cuttings removed from the rooting medium.
 Results: The collection time and treatments had a significant effect on the rooting ability of Foşa hazelnut cuttings. Depending on the collection time and treatments interaction, the callusing ranged from 1.7 (in IBA+putrescine treatment in the June 15) to 96.7% (in IBA treatment in the July 10). Rooting was determined between 0 (in control in the August 3, in control and IBA+putrescine treatments in the August 28) and 26.7% (in IBA treatment in the July 10). The root number was determined from 0 (in control in the August 3, in control and IBA+putrescine treatments in the August 28) to 13.1 (in IBA treatment in the July 10). Root length was measured between 0 (in control in the August 3, in control and IBA+putrescine treatments in the August 28) and 7.4 cm (in IBA treatment in the July 10). The best rooting scale was determined in (2.5) cuttings collected in July 10 and treated with IBA. It was followed by (2.3) cuttings treated IBA collected in June 15.
 Conclusion: It was determined that the rooting ability of IBA-treated semi-hardwood cuttings collected in the early period from Foşa hazelnut cultivar was higher.

Drivers of post‐fire resprouting success in restored Banksia woodlands

AbstractDisturbances can alter persistence trajectories of restored ecosystems. Resprouting is a common response of plants to disturbances such as fire or herbivory. Therefore, understanding a plant's resprouting response can inform successful restoration. We investigated patterns and drivers of resprouting following fire in fire‐prone Banksia woodlands restored after sand mining in the Mediterranean‐climate region of Western Australia. We applied experimental fire to samples of nine species with different resprouting types (rhizome, root crown, root sucker and lignotuber) across a 4‐ to 27‐year‐old restoration chronosequence. We investigated the influence of pre‐fire plant size, restoration age and soil conditions on resprouting success, defined by: (i) the probability of resprouting (measured ~5 months after fire), (ii) the probability of surviving the first summer and, (iii) vigour (both measured ~12 months post‐fire). We found that the probability of initial resprouting was high across most species, but summer survival was lower but comparable to that in other post‐mining restored ecosystems following fire. Generally, pre‐fire plant size did not influence probability of resprouting, while size and soil conditions were important for two species survival. Pre‐fire plant size was a significant predictor of vigour for all species with soil conditions influencing four species. Restoration age significantly influenced survival of three species. However, as our models explained low amounts of variation in probabilities of resprouting and survival (R2 = <0.11), other factors influencing resprouting success remain unidentified. Resprouting response to fire disturbance in restored Banksia woodlands are species and resprouter type specific, with plant size and soil conditions potentially more informative for understanding responses to disturbances than restoration age alone.

Growth response and survival of American beech, yellow birch, and sugar maple regeneration to partial harvest

In northern hardwood stands, silvicultural treatments aimed at regenerating sugar maple and yellow birch, such as site preparation and mechanical control of American beech saplings, often results in the formation of dense thickets of beech regeneration. The objective of this study was to compare the growth and survival of beech regeneration originating from stump sprouts, root suckers and seedlings, with yellow birch and sugar maple regeneration in partially harvested stands under cervid browsing pressure. Over an eight-year period, 997 individuals of the three species were monitored in three northern hardwood stands dominated by sugar maple, yellow birch, and American beech in Quebec, Canada. Each stand included replicates of four partial harvesting treatments and a control, providing a gradient of light and competition conditions. Beech stump sprouts and root suckers had higher growth and survival probabilities than seedlings of all three species under all light and competition conditions. Results suggest that treatments triggering beech sprouts should be applied with caution and under conditions that ensure sufficient survival and development of desired species. This study also provides evidence that selective browsing by cervids could be an important overriding factor exacerbating the effect of beech competition on yellow birch regeneration.

Considering both sexual and clonal reproduction could help loosen the conflict of use over Robinia pseudoacacia

Black locust (Robinia pseudocacacia) is a widely planted tree for wood production; however, it is a very problematic invasive species through Europe. At local scale, this tree is able to invades adjacent ecosystems owing to its strong ability of asexual reproduction through root suckers. Due to this phenomenon, the role of sexual reproduction has been quite neglected at local scale. Here, we propose a double approach (i) to evaluate the ability of the species to develop under forest cover using French national forest inventory data (ii) to quantify the role of sexual and asexual reproduction at local scale using a simple visual assessment method. We evidenced that juvenile black locust regenerates in broadleaved forests where R. pseudoacacia did not contribute to the adult canopy; moreover, a significant higher presence in riparian forests relatively to non-riparian ones was demonstrated using national forest inventory data. Regeneration from sexual reproduction mode significantly contributes to local scale invasion (38% of the up-rooted juvenile plants) with a significantly higher ratio of sexual reproduction within oak dominated forests compared to pine dominated ones. We conclude that black locust forestry should consider that both reproduction modes contribute to the species natural regeneration and that both modes can occur under both coniferous and broadleaved forest cover. Thus, we propose to set up safety buffers around sensitive ecosystems such as natural reserves or riparian areas, to maintain black locust cultivation while minimising undesired invasions in natural areas.

First Report on The Naturalized <i>Alocasia cucullata</i> (Araceae) in Java, Indonesia

The presence of naturalized Alocasia cucullata (Lour.) G.Don (Araceae) in Java is reported for the first time in this paper. The species is an introduced ornamental plant native to India, Sri Lanka, and Indo-China and was only known in cultivation. In this study we collected samples from its naturalized populations in Sukabumi Regency (Cibadak Subdistrict), Sumedang Regency (Jatinangor and Tanjungsari Subdistrict). The observed population grows along the roadside, coastal, ITB Jatinangor green space area, and palm oil plantation. In nature, A. cucullata may spread vegetatively either through root suckers, corms, and stem fragments. The description, distribution map, photographs, and a brief discussion are provided here.

Wildfire promotes the invasion of Robinia pseudoacacia in the unmanaged Mediterranean Castanea sativa coppice forests

In the Mediterranean region of southern Europe, Castanea sativa Mill. (Castanea) coppice stands are being invaded by non-native pioneer tree species due to recurrent coppicing and wildfire disturbances. There is a need to control the spread of non-native tree species in Castanea coppices due to their pivotal socio-economic role, however, to facilitate this, further research into invasive strategies and their interactions with disturbances is required. The non-native Robinia pseudoacacia L. (Robinia) has widely colonized the overaged and unmanaged Castanea coppice forests in Vesuvius National Park, which were disturbed by the low-severity fires in the summer of 2017. Here, we aimed to assess the functional traits conferring a competitive advantage to the Robinia over Castanea and the changes in spatial stand patterns driven by wildfire disturbance. To achieve this we assessed the spatial stem patterns, regeneration strategies, and conducted field-assessments and remote sensing of the spring leaf phenology of both Castanea and Robinia in five 300–600 m2 plots. After the 2017 wildfire, root suckers constituted 72% (±12) of the Robinia vegetative living sprouts and occurred up to a distance of 10 m from the adult parent trees under the canopy of the Castanea trees. NDVI-based estimates at the start of the growing season (sos) in Castanea occurred over a 7 day period, from DOY 118–124, increasing at a rate (rsp) of 0.10–0.16, in agreement with the field-based assessment of spring leaf phenology. In Robinia, the sos estimated at DOY 109 from the NDVI seasonal trajectory disagreed with the field-based observations, which started later than Castanea, after approximately DOY 133. Here, the high percentage cover (∼90%) of the understory species influenced NDVI-based estimates of Robinia leaf spring phenology. The results suggest that low-severity wildfires increased the invasiveness of Robinia, and that vegetative regeneration strategies, rather than earlier spring phenology, conferred a competitive advantage in the fire-disturbed Castanea coppice stands. The results thus suggest that appropriate management of invasive Robinia trees to conserve the continuous canopy cover of Castanea stands should guide nature-based solutions to control the spread of non-native tree species.

Comparison of shoot and root regeneration of miniature potted rose (Rosa x hybrida L.) and Damask rose (R. damascena Mill.) in microculture system

Miniature potted rose and Damask rose are important commercial plant cultivars in ornamental horticulture. Root suckers are common rose propagation method, but it is slow and seasonally dependent. In this survey, the propagation of nodal explants of these two species was studied through in vitro regeneration system. 16 and 24 different media were used for study of shoot and root regeneration respectively. The axillary buds were sprouted earlier in miniature rose than R. damascena. Shoot induction and proliferation (shoot ramification and growth) were observed 5 and 17 days after planting in miniature rose and 16 and 38 days in R. damascena respectively. The highest shoot proliferation obtained in media 3 and 7 in miniature rose, and medium 16 for R. damascena. These three media were recorded as optimal media with 100 % shoot proliferation. In these media, root initiation and growth of miniature rose (respectively after 78 and 92 days) was earlier than Damask rose (respectively 125 and 138 days). The successful rooting occurred in three and two media for miniature and Damask rose respectively. Rooting frequency was higher in the half strength MS liquid media than the others. Thus, cultivar potted rose as a modern species is propagated easier than old rose (R. damascena).