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• There were apparent shifts in the phenological events but no changes in the density of buds per tiller. • The relative allocation to either vegetative or sexual reproduction was not affected. • Grass bud banks are adaptable and can modify their regenerative responses according to the timing of climatic events. • Grass species phenology in South African mesic grasslands are sensitive to climate change effects in the short term. Phenological changes can alter grassland community structures by influencing interspecific interactions, population dynamics, individual species migration or extinction, and the fitness of those species on a local scale. In this study, the combined effect of rainfall variation (drought (50 %), ambient rainfall (100 %), and wet (150 %)) and temperature (warmed and ambient) manipulation on the phenology of grass species vis-a-vis their regenerative responses from bud bank s in a mesic grassland was conducted at the Ukulinga Research Farm, University of KwaZulu-Natal, Pietermaritzburg, KwaZulu-Natal. The warming treatment was applied using open-topped warming chambers, and the rainfall treatment was applied using rainout shelters to intercept 50 % of the ambient rainfall. The intercepted rainfall was piped onto the neighbouring plot to increase rainfall by 50 %. This resulted in six treatment combinations, replicated three times and arranged in a split-plot randomized block design. Across the two years of treatment application, the study examined species phenological responses and bud bank density per vegetative and reproductive tiller per tuft. The phenological events were examined to determine the sensitivity of timing and duration of budding and flowering to experimental warming and rainfall manipulation. Generalized linear models were used to analyze whether shifts in these phenological events intensified or stabilized changes in the density of buds per tiller and their relative allocation to either vegetative or sexual reproduction. Drought delayed the timing of budding and flowering and shortened the duration (p < 0.05). There was no effect on the total number of buds per vegetative tiller per tuft compared to the reproductive tillers. Warming advanced the budding timing and extended the budding duration (p < 0.05). Thus, the response of timing and duration of budding and flowering of these studied grass species was sensitive to short-term effects under the ambient and manipulated temperature and moisture regimes in this study. There were apparent shifts in the phenological events but no changes in the density of buds per tiller and their relative allocation to either vegetative or sexual reproduction. These findings show that grass bud banks are adaptable and can modify their regenerative responses according to the timing of climatic events. The study also suggests that some aspects of grass species phenology in South African mesic grasslands are sensitive to climate change effects in the short term. [ABSTRACT FROM AUTHOR]

Asplenium is one of the most species‐rich genera of ferns. While ubiquitous polyploidy and hybridization events, as well as vast distribution ranges, contribute to its remarkable diversity, these facts also lead to extreme classification difficulties. The A. exiguum complex is a natural morphological assemblage of taxa sharing part or all ancestral genomes due to polyploidy and hybridization. Consisting of 4 to 13 taxa mainly distributed in the Sino‐Himalayan region, taxonomic issues of this complex have been debatable for a long time. Here, we collected 49 samples representing the majority of the recognized taxa and reconstructed phylogenetic trees using two plastid loci (rbcL, rpl32‐trnP) and three nuclear loci (pgiC, SQD1, nrDNA). Evidence from ploidy, macro‐ and micromorphology, geographical pattern, and ecological niche was also integrated to illuminate the species boundaries and evolutionary history within the complex. According to our investigation, six taxa, including two diploid species (A. barkamense, A. lushanense), three tetraploid species (A. exiguum, A. glenniei, A. nesii), and one triploid nothospecies (A. ×mickelii), are accepted. Asplenium barkamense, which used to be treated as a synonym of A. nesii in Flora of China, is an independent species and the common diploid progenitor of autotetraploid A. nesii and allotetraploid A. glenniei. Moreover, A. glenniei (= A. yunnanense), widespread in the subtropical and temperate regions of East Asia and occasionally seen in the southwestern United States, Mexico, and northern Guatemala of North America, is an allotetraploid originated from A. barkamense and A. lushanense, whereas A. exiguum, known with a narrow distribution in tropical Asia, is a putative autotetraploid offspring of A. lushanense. Therefore, A. glenniei is restored as an independent species from A. exiguum. Asplenium ×mickelii is supported as a sterile hybrid of A. lushanense and A. glenniei. In addition, our study suggests that the majority of speciation events in the complex probably took place in the Hengduan Mountains, where complicated orogenic activities and climatic oscillations facilitate geographic isolation and polyploid establishment. The two tetraploids, A. nesii and A. glenniei, adapted to distinct climate conditions and colonized wider ranges compared to their parents. [ABSTRACT FROM AUTHOR]

Most canopy-forming macroalgae have disappeared from temperate reefs in southern Japan, one of the ocean warming hotspots, but Sargassum nipponicum is surviving in this region. As this species' annual shoots emerge from holdfasts during summer, both plant components may be highly tolerant to warm and nutrient-poor conditions in this season. The present study examined the effects of temperature and nutrient conditions on holdfast growth, shoot emergence from holdfasts, and shoot growth in S. nipponicum samples collected in Tanegashima Island, southern Japan. The summer temperature in this region (30 °C) allowed holdfast growth and shoot emergence but inhibited shoot growth. Nutrient-poor conditions had limited effects on the first two parameters but suppressed shoot growth. These results suggested that during warm summers and under nutrient-poor conditions in southern Japan, shoots can emerge from S. nipponicum holdfasts but cannot further grow. Additionally, nutrient loading from a nearby river was higher at the only site dominated by S. nipponicum, than at the other sites where this species was absent on Tanegashima Island. This was observed especially between autumn and winter, implying that such a nutrient-rich environment may contribute to shoot growth in S. nipponicum and to the persistence of its population in the area. [ABSTRACT FROM AUTHOR]

During plant development, woody plants progress from a juvenile phase to the reproductive mature phase. This process is marked by morphological, physiological, and biochemical changes, including loss of competence to vegetative reproduction. During in vitro stabilisation, mature tissues undergo rejuvenation, however, the exact degree of juvenility attained is not known and differing regeneration capabilities are observed between genotypes. Markers indicating juvenility state would assist the in vitro rejuvenation process and increase the efficiency of successful micropropagation. Several leaf and stem morphological and anatomical traits were analysed as possible juvenility markers in mature and rejuvenated silver birch in vitro shoots. The results showed that juvenility state of birch in vitro shoots varies between different genotypes and between plants from the same genotype. Mature birch in vitro shoots had approximately two times larger and thicker leaves compared to rejuvenated and juvenile shoots. Stem radius, including cortex, phloem, xylem and pith width as well as phloem width : stem radius and phloem width : xylem width ratio was significantly larger in mature shoots. Periderm development and loss of rooting ability were observed in mature shoots. These anatomical and morphological traits could be used as possible juvenility/maturation markers. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the L.N. Gumilyov Eurasian National University. Bioscience Series is the property of L.N. Gumilyov Eurasian National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Amphicarpic plants produce aerial and subterranean fruits on the same plant. Trifolium polymorphum Poir. is an amphicarpic legume that also reproduces vegetatively by regrowing storage roots. Because of this, resource allocation information for different reproductive strategies is of great interest. In this study, the production of aerial and subterranean seeds and storage roots was evaluated in populations of T. polymorphum. The Pinheiro Machado and Eldorado do Sul populations produced on average the highest (165.50) and lowest (61.87) number of inflorescences per plant, respectively. Total aerial seed production did not differ between populations. Aerial flowers produced more seeds than subterranean flowers. There were positive correlations between number of inflorescences and total aerial seeds (r = 0.73), the number of subterranean legumes and total subterranean seeds (0.94) and between number and weight of storage roots (r = 0.83). Amphicarpy associated with vegetative reproduction is an important strategy for the persistence and increase frequency of T. polymorphum in the natural pastures of the Rio Grande do Sul, where intense grazing and trampling can destroy periodically the aerial part of the plants.

Despite the large popularity of Salix miyabeana for various environmental applications in different parts of the world, most propagation techniques rely mainly on cuttings. However in vitro propagation seems a more reliable solution when selection of new commercial clones and varieties is the goal of propagating willows. The current study is the first attempt to propagate S. miyabeana via in vitro propagation, focusing on two specific aspects: different surface sterilization procedures (i.e. combinations of different sodium hypochlorite concentrations and soaking times) and different types of explants (apical vs. lateral). Our findings show that 3% sodium hypochlorite for 20 min represents the most effective sterilization procedure to ensure healthy plants. Additionally, the material obtained from apical explants showed higher survival rate, budding ability and lower microbiological contamination compared to lateral explants. [ABSTRACT FROM AUTHOR]

This paper uses a Genetic Algorithm (GA) to reduce total tardiness in an identical parallel machine scheduling problem. The proposed GA is a crossover-free (vegetative reproduction) GA but used for four types of mutations (Two Genes Exchange mutation, Number of Jobs mutation, Flip Ends mutation, and Flip Middle mutation) to make the required balance between the exploration and exploitation functions of the crossover and mutation operators. The results showed that use of these strategies positively affects the accuracy and robustness of the proposed GA in minimizing the total tardiness. The results of the proposed GA are compared to the mathematical model in terms of the time required to tackle the proposed problem. The findings illustrate the ability of the propounded GA to acquire the results in a short time compared to the mathematical model. On the other hand, increasing the number of machines degraded the performance of the proposed GA. [ABSTRACT FROM AUTHOR]

Nymphoides peltata (yellow floating-heart), native to Eurasia, is an invasive plant in the USA, where it grows in relatively isolated but widespread populations. The species is capable of sexual reproduction by seed and asexual reproduction through fragmentation. Although N. peltata is recognized as a noxious weed, little is known about its geographic region of origin or its dispersal mechanisms and relative amount of genetic variation in its adventive range. We conducted a genetic analysis of N. peltata by studying 68 localities across the native range and 47 localities in the adventive range, using microsatellite markers to determine genetic variability within and among populations, and to infer regions in the native range from which invasive plants originated. A large number of sites in the USA were genetically identical to one another, and there were two predominant multilocus allele phenotypes that were distributed in the northern and southern latitudes, respectively. Additional USA sites were similar to one of the predominant genetic profiles, with greater genetic diversity in southern populations. The genetically identical sites are consistent with asexual spread, potentially via anthropogenic mechanisms. Plants across the USA range were observed to produce viable seeds, and some genetic variation could be explained by sexual reproduction. All USA plants were more similar to plants in Europe than they were to plants in Asia, indicating that the plants likely were introduced originally from Europe. The existence of two genetic clusters and their similarity to plants in different parts of Europe constitute evidence for at least two N. peltata introductions into the USA. [ABSTRACT FROM AUTHOR]

Invasions of alien species have become a global problem worldwide. Our paper presents the results of the study of the chorology of the invasive species Ambrosia artemisiifolia L. within the Right-Bank Forest-Steppe of Ukraine (RBFSU). We identified 13 new growth areas in the study area. These studies cover the observation and recording of the phenological behaviour of this species during 2020-2021. Although phenological observations are mainly carried out on cultivated plants, the data obtained as a result of the study is an important resource for preparing an invasive species control plan. Based on the indicators of temperature fluctuations, drought tolerance, light tolerance, relation to soil fertility, reproduction and shoot regeneration of A. artemisiifolia, a scoring method was proposed using the coefficient of complex adaptive potential (CCAP). However, our work is a pioneering study aimed at counteracting the spread of alien plants.

Most canopy-forming macroalgae have disappeared from temperate reefs in southern Japan, one of the ocean warming hotspots, but Sargassum nipponicum is surviving in this region. As this species’ annual shoots emerge from holdfasts during summer, both plant components may be highly tolerant to warm and nutrient-poor conditions in this season. The present study examined the effects of temperature and nutrient conditions on holdfast growth, shoot emergence from holdfasts, and shoot growth in S. nipponicum samples collected in Tanegashima Island, southern Japan. The summer temperature in this region (30 °C) allowed holdfast growth and shoot emergence but inhibited shoot growth. Nutrient-poor conditions had limited effects on the first two parameters but suppressed shoot growth. These results suggested that during warm summers and under nutrient-poor conditions in southern Japan, shoots can emerge from S. nipponicum holdfasts but cannot further grow. Additionally, nutrient loading from a nearby river was higher at the only site dominated by S. nipponicum, than at the other sites where this species was absent on Tanegashima Island. This was observed especially between autumn and winter, implying that such a nutrient-rich environment may contribute to shoot growth in S. nipponicum and to the persistence of its population in the area.

Bud banks are considered a crucial factor in regulating the species composition of grassland communities and maintaining the ecological function of alpine grasslands. However, few studies have paid attention to the dynamic changes of bud banks from undisturbed to severely degraded alpine meadows. Therefore, this study examined the correlations between plant diversity and bud bank traits at different stages of alpine meadows degradation. Grass biomasses and plant diversity were found to be highest in moderately degraded meadows, and sedge biomasses were highest in lightly degraded meadows. Lack of disturbance and moderate disturbance by herbivores increased the bud bank density of alpine meadows. Consistent with the changes in bud bank density, bud bank diversity was highest in undisturbed meadows. The structural equation model indicated that the densities of rhizome and the densities and diversities of tiller buds play crucial roles in facilitating the greater diversity of the plant community. Our findings suggest that the diversities and densities of rhizome and tiller buds in the degradation stages are synchronized with changes in plant diversity, and in the regenerative ability of bud banks, which largely determine the outcome of restoration in degraded meadows. These findings could provide a frame of reference for effectively restoring degraded alpine regions by regenerating bud banks. The potential driving force and renewal capacity of bud banks should be taken into account in restoring the Qinghai-Tibet Plateau’s degraded meadow. [ABSTRACT FROM AUTHOR]

Invasions of alien species have become a global problem worldwide. Our paper presents the results of the study of the chorology of the invasive species Ambrosia artemisiifolia L. within the Right-Bank Forest-Steppe of Ukraine (RBFSU). We identified 13 new growth areas in the study area. These studies cover the observation and recording of the phenological behaviour of this species during 2020-2021. Although phenological observations are mainly carried out on cultivated plants, the data obtained as a result of the study is an important resource for preparing an invasive species control plan. Based on the indicators of temperature fluctuations, drought tolerance, light tolerance, relation to soil fertility, reproduction and shoot regeneration of A. artemisiifolia, a scoring method was proposed using the coefficient of complex adaptive potential (CCAP). However, our work is a pioneering study aimed at counteracting the spread of alien plants. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flower‐smut fungal infection has been widely observed in many plant species. As plants infected with flower‐smut fungi exhibit visible changes in floral morphology and flower sterility, researchers have intensively studied the effects of the disease on sexual reproduction in host plants. Although most host plants are clonal perennials, the effects of flower‐smut disease on clonal reproduction remain unclear. Here, we investigated the detrimental effects of flower‐smut disease on clonal reproduction of a perennial host plant, Barnardia japonica. Barnardia japonica is a bulbous perennial and host of the flower‐smut fungus Antherospora vaillantii. Diseased and healthy bulbs collected from fields at the end of the growing season were individually grown in pots for 1 year in a greenhouse, and their annual growth was analyzed, including offspring production. Survival, flowering probability, and the total bulb mass (i.e., the sum of a parent and its living offspring masses) at the end of the 1‐year growth period and annual growth of the total bulb mass were comparable between diseased and healthy plants. We found a marked difference between diseased and healthy plants in the probability of clonal reproduction, which was 50% lower in diseased plants. Additionally, the number and mass of living offspring bulbs per parent were lower in diseased plants than in healthy plants. Our results indicate the detrimental effects of flower‐smut disease on clonal reproduction in B. japonica, providing new insights into the effects of flower‐smut disease on the reproduction of perennial host plants. [ABSTRACT FROM AUTHOR]

The formation of bulbils, which are storage organs, is an important agronomic trait and a unique morphological feature in the vegetative reproduction of yam. We found a landrace of water yam (Dioscorea alata L.), which rarely forms bulbils, that produces bulbils during periods of high rainfall. We investigated the physiological mechanism of bulbil formation in response to over-moist soil and relevant factors at the single plant level. Waterlogging (WL) treatment markedly increased the number of bulbils initiated, predominantly toward the upper nodes. This formed-bulbil was an accessory bud developed as a storage organ in leaf axils. Photosynthetic capacity decreased under WL, attributed to stress-induced stomatal closure. WL stress also reduced dry matter partitioning to the belowground organs. During tuber enlargement in WL plants, photosynthetic products accumulated in the aboveground organs and were transported to the bulbils as a result of reduced translocation to belowground organs. We investigated the effect of abscisic acid (ABA) on bulbil formation on the basis of changes in the sink–source balance in response to WL stress. ABA treatment of leaf axils enhanced bulbil formation in unstressed plants, suggesting that increased ABA is one of the factors that initiate bulbils. Our study shows that bulbil initiation occurs as a result of changes in physiological conditions in response to WL stress. This finding may provide fundamental information for the control of bulbil production. This response of bulbil formation, as an environmentally adaptive trait of the tropical water yam, may underlie the survival strategy of vegetatively propagated plants. [ABSTRACT FROM AUTHOR]

Both seed and bud banks play important roles in the recruitment and maintenance of macrophyte communities; however, few studies have investigated them simultaneously. We investigated the abundance, species composition, and seasonal patterns of seed and bud banks in two dominant macrophyte communities, Carex and Miscanthus, in the Dongting Lake wetlands. The seed densities of both communities were lower from November (after flooding) to March and increased dramatically before flooding (in May). The bud densities of the two dominant communities peaked in the coldest month of the year (January), decreased markedly in March, and were the lowest before flooding. The seed banks of the two macrophyte communities were mainly composed of annual species and a few perennial species, whereas the bud banks were composed of only dominant perennials. Furthermore, the perennial species present in bud banks did not occur in seed banks. Among the soil variables, the bud densities of both plant communities were negatively associated with soil bulk density, whereas the seed density of the Miscanthus community was positively associated with soil bulk density. Our results suggest that seed and bud banks are complementary in the potential recruitment of macrophyte communities; that is, bud banks regulate the demography of dominant perennials, and seed banks contribute to the recruitment and dispersal of annual species. Given the high abundance of annuals and near absence of the most dominant perennials in the seed bank, the bud banks of dominant perennial species should be more widely used in wetland restoration and management. [ABSTRACT FROM AUTHOR]

Few studies have explored changes in the sizes of diatom cells which can be due to sexual reproduction in lakes, as observations of natural populations have been limited. We measured seasonal changes in the cell sizes and densities of the diatom Fragilaria crotonensis Kitton in Lake Biwa from February 2012 to January 2017 and examined possible causal variables on sexual reproduction and cell density of F. crotonensis. Cell size tended to decrease with increase in cell density in spring and summer to autumn, though the pattern was not so clear in 2012 and 2013. The highest cell density (1.6 × 104 cells L-1) was recorded in May 2014, with the average cell size being 73.5 μm; the lowest density (7.1 cells L-1) was recorded in December 2016 (average cell size 86.5 μm), reflecting biannual cell size reduction and restoration which can be due to sexual reproduction. We used time series analysis to delineate the seasonality of cell size changes of the target diatom and Convergent Cross-Mapping (CCM) to explore the effects of possible causal variables on sexual reproduction and cell density of F. crotonensis and to evaluate the influences of environmental factors. We found that water temperature may influence the cell density (vegetative reproduction) of F. crotonensis, though we could not identify any possible causal variables for the algal sexual reproduction. In addition, time series decomposition analysis, together with the seasonal changes in cell size mentioned above, proved that the target diatom followed reduction in cell size twice a year. [ABSTRACT FROM AUTHOR]

Cyperus aromaticus (Navua sedge) is a problematic perennial weed in pastures and crops including sugarcane, banana, rice, and fruits and vegetables in tropical climates. It reproduces both via rhizomes and seeds. As a regenerative and storage organ, these rhizomes play an important part in the invasion, establishment, and persistence of this weed. To eliminate their regenerative ability, it is important to understand the regrowth potential with respect to rhizome fragment size and burial depth. This study evaluated the emergence of C. aromaticus from rhizomes in a controlled condition. Three different sizes of rhizome fragments were buried at seven depths of up to 20 cm in two soil types. The experimental measurements included (i) the time for tillers to emerge, (ii) the cumulative emergence of tillers, recorded weekly, and (iii) the number of underground emerging tillers. The cumulative shoot emergence and the number of underground tillers produced were found to be positively correlated with the initial length of the rhizome fragments and negatively correlated with the burial depth. The time for the emergence of the tillers was negatively correlated with the burial depth, and soil type had no significant effect on any of the parameters recorded. There was no emergence recorded from rhizomes buried at 15 cm depth and deeper, irrespective of their size. Our results indicate that the combination of the fragmentation of rhizomes into small pieces and a deep burial, below 15 cm, is an important aspect to control the regeneration of C. aromaticus from rhizomes, if tillage is carried out, and can therefore form a part of an integrated weed management strategy for this troublesome weed. [ABSTRACT FROM AUTHOR]

Exploring the diversity and formation mechanism of under-ground bud banks is essential for understanding the renewal of plant populations and community succession. However, there are few studies on the response of bud bank size and composition to different degradation gradients in alpine meadows. In view of this, we investigated the size and composition of bud bank under four degradation gradients (non-degraded:ND, lightly degraded:LD, moderately degraded:MD, and heavily degraded:HD) caused by overgrazing in a typical alpine meadow in Tibet, China, using a unit area excavation sampling method, and analyzed the correlation between above-ground plant community composition and bud bank density. Our results showed that: (i) in the ND alpine meadow, rhizome buds were dominant, in the LD, tiller buds were dominant, and in the MD, root-sprouting buds were dominant; (ii) total bud bank and cyperaceae bud density decreased with increasing degradation gradient, the density of leguminosae was insignificant in each degradation gradient, and the density of gramineae and forb were dominant in LD and MD meadows, respectively; (iii) total bud bank density was significantly and positively correlated with total above-ground biomass in the LD gradient, tiller bud density was significantly positively correlated with the species diversity index of above-ground vegetation under the ND gradient, rhizome bud density was significantly and positively correlated with total above-ground biomass in the LD gradient, and root-sprouting density was significantly negatively correlated with total above-ground biomass in ND meadows, but was significantly positively correlated with the species diversity index of the LD gradient. Therefore, our research shows that rhizome buds are more important in ND meadow habitats, tiller buds are more important in LD meadow habitats, and root-sprouting buds are more important in MD meadows. The response of bud banks to degradation gradient varies with different types of bud banks and different functional groups of plants, and the survival strategy of bud banks is of great value for community restoration and regeneration, which should be paid more attention to in subsequent alpine meadow research. [ABSTRACT FROM AUTHOR]

Elymus repens (L.) Gould), Cirsium arvense (L.) Scop. and Sonchus arvensis L. are important arable creeping perennial weeds in Europe. These are clonal plants with subterranean reproductive organs (E. repens, rhizomes, the two dicots, horizontal creeping roots) sprouting from ramets. We tested the sprouting ability and early growth of ramet sprouts at temperatures typical for Nordic autumn climate and with different preconditions of the mother plant (time in autumn, mother plant age, climate change experiences of the mother plants (two experiments)). The species reacted differently, with S. arvensis not sprouting at all, and C. arvense ramets sprouting at higher temperatures than those of E. repens, which sprouted at all tested temperatures. Plant age affected only the ramet sprout biomass of E. repens. Climate change during mother plant growth only affected C. arvense, with the highest above-ground biomass of the sprouted ramets at an elevated temperature and ambient CO2. Testing earlier in autumn showed more sprouting and biomass for C. arvense and E. repens than testing later in the season. The observed temperature responses confirmed more and bigger sprouts with higher autumn temperatures. Controlling the sprouted ramets in autumn is easier for E. repens than for C. arvensis. Due to their low/no sprouting ability in autumn, the ramets of S. arvensis cannot be controlled in autumn. [ABSTRACT FROM AUTHOR]

Calafate (Berberis microphylla) is a native and widely distributed Patagonian shrub, which produces edible fruits with excellent antioxidant and nutraceutical properties. This study evaluates its multiplication by the rooting of stem cuttings, a widely used method in fruit species with little success so far in B. microphylla. This work was carried out using stakes prepared in late winter from the basal, middle and apical portions of the most recently developed semi-hardwood shoots. Three plant communities corresponding to contrasting environments were included (rainforest, shrubland and steppe), and four auxin (indole-butyric acid, IBA) concentrations were applied: 0 ppm (0 %), 2000 ppm (0.2 %), 5,000 ppm (0.5 %) and 8,000 ppm (0.8 %). After ninety days on a bottom-heated rooting-bed in a greenhouse, adventitious root formation was higher in cuttings derived from rainforest material. This difference was, on average, 40 % greater for the basal portions than for the middle and apical portions. The IBA treatments did not improve rooting, although the increase in root weight and length was recorded at the highest concentration as compared to the intermediate concentrations. It is concluded that the multiplication of B. microphylla by stem cuttings is possible, and that the geographical and topological stake origin are important factors for adventitious root development. [ABSTRACT FROM AUTHOR]

Genetic diversity can influence resilience and adaptative capacity of organisms to environmental change. Genetic diversity within populations is largely structured by reproduction, with the prevalence of asexual versus sexual reproduction often underpinning important diversity metrics that determine selection efficacy. Asexual or clonal reproduction is expected to reduce genotypic diversity and slow down adaptation through reduced selection efficacy, yet the evolutionary consequences of clonal reproduction remain unclear for many natural populations. Here, we examine the genomic consequences of sympatric sexual (haplodiplontic) and clonal morphs of the kelp Ecklonia radiata that occur interspersed on reefs in Hamelin Bay, Western Australia. Using genome-wide single nucleotide polymorphisms, we confirm significant asexual reproduction for the clonal populations, indicated by a significantly lower number of multi-locus lineages and higher intra-individual diversity patterns (individual multi-locus heterozygosity, MLH). Nevertheless, co-ancestry analysis and breeding experiments confirmed that sexual reproduction by the clonal morph and interbreeding between the two morphs is still possible, but varies among populations. One clonal population with long-term asexuality showed trends of decreased selection efficacy (increased ratio non- vs. synonymous gene diversities). Yet, all clonal populations showed distinct patterns of putative local adaptation relative to the sexual morph, possibly indicating maladaptation to local environmental conditions and high vulnerability of this unique clonal morph to environmental stress.

In the experimental plantings of the alien species Bethlehem lungwort Pulmonaria saccharata, the transport of phytotoxic phenols with leaf leachates into the soil of the subcronal area was detected. At a concentration from 0 to 15.7 µg/mL in the leachates, the phenol content in the soil reached 13.9 µg/g. The biomass of vegetation growing from the seed bank depended significantly on the accumulation of phenolic substances by the soil, the intensity of vegetative reproduction of P. saccharate, and the solar illumination. The effect of density-dependent allelopathy caused a lag-phase in the accumulation of phenols by the soil. A model of the phenologically ordered interaction of competitive traits of a species, including an allelopathic factor, is proposed. It is noted that the proposed approach can help clarify the specificity of the influence of alien species on native species and communities. [ABSTRACT FROM AUTHOR]

The stem branch trait of the stolon enables the common wild rice to produce new individuals through vegetative reproduction habit. In order to understand the genetic mechanism of stem branch character, we developed introgression lines (ILs) with the irrigated rice variety Yundao1 (YD1, Oryza sativa) as the recipient parent and Yuanjiang common wild rice (YJCWR, O. rufipogon) as the donor parent for subsequent identification of the relevant genes. An IL named IL-J85 was selected, which can originate new individuals from stem branches on stem nodes. Furthermore, the newly formed individuals can survive cutting to bear normally and produce the same yield per plant as IL-J85, which saved the growth time and production cost. Two QTLs (quantitative traits loci) related to the stem branch trait, qSBR1 and qSBR5, were first mapped on chromosomes 1 and 5. The near isogenic lines NIL-Y37 and NIL-D1 in the background of Yunjing 37 and Dianjingyou 1 were cultivated, showing the same characteristics as IL-J85. Our results provide new insights into the underlying genetic mechanism of the stem branch trait in the common wild rice and have the value of breeding utilization using vegetative reproduction to fix heterosis and breed new rice varieties with the cutting characteristic. [ABSTRACT FROM AUTHOR]

Plant phenotypic and reproductive plasticity is strongly influenced by long-term grazing activities. It is important to understand the life history of dominant plant species, such as Kobresia humilis of alpine meadow, for the stability and sustainable grazing administration meadow on the Qinghai-Tibetan Plateau (QTP). We compared the effects of different grazing treatments (grazing yak, Y; grazing Tibetan sheep, S; and grazing Tibetan sheep and yak, S+Y) on the reproductive and phenotypic plasticity of K. humilis in an alpine meadows on the northeastern margin of the Qilian Mountains in China. The results showed that different grazing treatments had significantly effects on the K. humilis phenotype and reproductive plasticity. The Y treatment significantly reduced the plant height, crown width and K. humilis biomass, but increased the density, which was 1.27 and 1.53 times higher than that in the S+Y and S treatments, respectively. Further, the S+Y treatment significantly increased the crown width, biomass, and future life expectancy of K. humilis. Whereas the S treatment increased the height of K. humilis significantly, which was 1.57 and 1.10 times higher than that in the Y and S+Y treatments, respectively. Both Y and S treatments significantly increased the sexual reproduction efficacy of K. humilis but reduced the storage efficacy. The storage efficacy at S+Y treatment was highest among these treatments. Further, grazing treatments did not change the resource allocation strategy of K. humilis, while the sexual reproductive efficacy was significantly higher than the vegetative reproduction efficacy. The storage efficacy was significantly higher than the growth efficacy among the different grazing treatments. The increase of Cyperaceae indicates the degradation of Cyperaceae—Poaceae meadows. This study showed that grazing Tibetan sheep is a more sustainable grazing method in cold season pastures of alpine meadows on the QTP.

Pinus pinea is an interesting species for its valued pine nuts. Despite the high demand for this nut, the species is mostly harvested from natural forests, because the time elapsed until the trees come into production hinders advances toward a more intensive cultivation. The grafting technique has been used to favor an earlier production in native Mediterranean habitats. In Chile, stone pine has been recently included in orchards. The objective of this study was to assess the initial performance in terms of growth, entry into production and cone yield of three grafting trials of the species established in Chile; two of the trials included nursery-grafted plants and the other, in situ grafting of P. pinea on a 3-year-old P. radiata plantation. An earlier entry into production and a higher number of female strobili and 1-year-old conelets (up to 2.9 times) were found in nursery-grafted plants compared with control seedlings. Growth was higher in trees in situ grafted onto radiata pine than in seedlings; eight years after grafting, the trees had achieved reproductive maturity, 67% had on average three cones per tree, and the presence of female strobili and 1-year-old conelets was 6.6 and 15.6 times higher than in seedlings, respectively. Radiata pine could be a feasible rootstock for either in-nursery or in situ stone pine grafting. Grafting accelerated stone pine entry into production, showing to be an effective tool for stone pine propagation and cropping. [ABSTRACT FROM AUTHOR]

Mutation rate estimates for vegetatively reproducing organisms are rare, despite their frequent occurrence across the tree of life. Here we report mutation rate estimates in two vegetatively reproducing duckweed species, Lemna minor and Spirodela polyrhiza. We use a modified approach to estimating mutation rates by taking into account the reduction in mutation detection power that occurs when new individuals are produced from multiple cell lineages. We estimate an extremely low per generation mutation rate in both species of duckweed and note that allelic coverage at de novo mutation sites is very skewed. We also find no substantial difference in mutation rate between mutation accumulation lines propagated under benign conditions and those grown under salt stress. Finally, we discuss the implications of interpreting mutation rate estimates in vegetatively propagating organisms.

The formation of bulbils, which are storage organs, is an important agronomic trait and a unique morphological feature in the vegetative reproduction of yam. We found a landrace of water yam (Dioscorea alata L.), which rarely forms bulbils, that produces bulbils during periods of high rainfall. We investigated the physiological mechanism of bulbil formation in response to over-moist soil and relevant factors at the single plant level. Waterlogging (WL) treatment markedly increased the number of bulbils initiated, predominantly toward the upper nodes. This formed-bulbil was an accessory bud developed as a storage organ in leaf axils. Photosynthetic capacity decreased under WL, attributed to stress-induced stomatal closure. WL stress also reduced dry matter partitioning to the belowground organs. During tuber enlargement in WL plants, photosynthetic products accumulated in the aboveground organs and were transported to the bulbils as a result of reduced translocation to belowground organs. We investigated the effect of abscisic acid (ABA) on bulbil formation on the basis of changes in the sink–source balance in response to WL stress. ABA treatment of leaf axils enhanced bulbil formation in unstressed plants, suggesting that increased ABA is one of the factors that initiate bulbils. Our study shows that bulbil initiation occurs as a result of changes in physiological conditions in response to WL stress. This finding may provide fundamental information for the control of bulbil production. This response of bulbil formation, as an environmentally adaptive trait of the tropical water yam, may underlie the survival strategy of vegetatively propagated plants.

An experimental farm has been installed in the Kiel Fjord, western Baltic Sea, aiming at the development of a sustainable production process for Fucus species (Fucus vesiculosus, Fucus serratus). The envisaged cultivation method includes the unattached rearing of thalli in baskets deployed in the sea and their vegetative reproduction. Fertility (i.e., receptacle formation) is expected to be problematic for this approach, because receptacles are terminated in growth and degrade after gamete release. In culture experiments, natural fertility led to only minimal overall growth in F. vesiculosus and even weight loss in F. serratus. Therefore, we tested if long-term unattached cultivation of formerly attached thalli leads to a lowering of fertility by an acclimatization process. However, fertility after 1 and 2 years of unattached cultivation was statistically equal and still comparable to the high fertility of attached populations. Furthermore, we tested if the only known naturally unattached population in the western Baltic Sea near Glücksburg, which remains largely infertile in the wild, keeps its low fertility if put under culture conditions. During an experimental 1-year cultivation, thalli from this population remained almost entirely vegetative (2.0 ± 3.1% fertile apices). Hence, the Glücksburg population is a promising source of aquacultural seedling biomass. Yet, further tests are necessary to check, if the fertility remains low over several years of cultivation. If unattached populations are used as source for commercial cultures, the collection of seedling material should always be accompanied by strong measures to ensure the continued integrity of these valuable habitats. [ABSTRACT FROM AUTHOR]

Egeria najas is a submerged aquatic macrophyte native to South America, with high propagation in reservoirs and natural lakes, whose reproductive strategy is little known. Understanding the genetic diversity of macrophyte populations can provide important information about this species' dispersion and colonization strategies, and support management actions. We aimed to genetically characterize populations of E. najas that colonize reservoirs and natural aquatic habitats (in a floodplain) in the Upper Paraná River basin, using the molecular markers ITS and trnL-trnF. The results showed the absence of genetic variation for the nuclear marker ITS and 13 distinct haplotypes for trnL-trnF. One of these haplotypes occurred in all habitats and 11 are unique haplotypes, of which 5 occurred in the Itaipu Reservoir and 6 in the floodplain. The null genetic diversity for the nuclear marker and the genetic homogeneity of the studied populations indicates that the reproduction of E. najas is mostly vegetative. The source of chloroplast marker haplotype variability may be somatic mutations. The connectivity among aquatic environments associated with river flow favors the transport of aquatic macrophyte propagules to different habitats. In the case of E. najas , whose vegetative propagules regenerate easily, the frequency of migrations supports the low genetic variability observed in populations of the Upper Paraná. In addition, the ability to occupy new habitats and recolonize disturbed ones strongly indicates that E. najas populations follow the metapopulation dynamics. • The results showed variation for the chloroplastidial DNA (trnL-trnF) , with 13 distinct haplotypes for Egeria populations. • ITS's null genetic diversity and the genetic homogeneity indicates that the reproduction of E. najas is mostly vegetative. • The spatial dynamic of Egeria subpopulations follows the metapopulation dynamics. [ABSTRACT FROM AUTHOR]

Tropical Flora of the Earth contains inexhaustible stock of genetic resources. Review of the main fruit trees and woody plants of this region has been carried out. Their characteristics, biological features, data on their places of origin and regions of cultivation are given. Information on the results of karyological studies of these species, use of molecular cytogenetics methods, comparative genomics and transcriptomics for some of them are presented. In tropical countries the trees, such as Indian mango, one of the most delicious and popular fruits, are grown. Widely used for food the fruits such as bread fruit tree, jackfruit, papaya, cheese fruit tree, tomato tree, bilimbi tree are also common. Information on such interesting fruit trees and woody plants as durian, mangosteen, pitahaya, longan, litchi, rambutan, pulasan, kanistel, ackee and others are given. A review of fruit plant species of the genera Annona, Psidium, Syzygium, Averrhoa, Ziziphus, Passiflora has been presented. Different species of Citrus and banana cultivars are of great importance in fruit production in the tropics and subtropics. It was established that among tropical fruit trees and woody plants there are diploids, tripolids, tetraploids, while in karyotypes of some species B­chromosomes may occur. Many tropical fruit woody plants are polyploid (mango, bread fruit tree, jackfruit, species of the genera Psidium, Syzygium and Ziziphus). The results of the genomes sequencing indicate that some species possibly are ancient polyploids. A number of tropical fruit trees exhibit the phenomena of caulifloria and ramifloria (jackfruit, chempedak, papaya, durian) when flowers and then fruits are formed on the trunk and large branches. Some species reproduce vegetatively. Among fruit woody plants, as well as in many other plants, hybridization is widely spread (mangosteen, species of genera Citrus, Annona, Hylocereus, Musa) and polyembryony may be found.

The stem branch trait of the stolon enables the common wild rice to produce new individuals through vegetative reproduction habit. In order to understand the genetic mechanism of stem branch character, we developed introgression lines (ILs) with the irrigated rice variety Yundao1 (YD1, Oryza sativa) as the recipient parent and Yuanjiang common wild rice (YJCWR, O. rufipogon) as the donor parent for subsequent identification of the relevant genes. An IL named IL-J85 was selected, which can originate new individuals from stem branches on stem nodes. Furthermore, the newly formed individuals can survive cutting to bear normally and produce the same yield per plant as IL-J85, which saved the growth time and production cost. Two QTLs (quantitative traits loci) related to the stem branch trait, qSBR1 and qSBR5, were first mapped on chromosomes 1 and 5. The near isogenic lines NIL-Y37 and NIL-D1 in the background of Yunjing 37 and Dianjingyou 1 were cultivated, showing the same characteristics as IL-J85. Our results provide new insights into the underlying genetic mechanism of the stem branch trait in the common wild rice and have the value of breeding utilization using vegetative reproduction to fix heterosis and breed new rice varieties with the cutting characteristic.

Gyrinops versteegii is one of protected species because of the rare existence. One of the efforts to keep the preserved is by cultivation. Cultivation techniques using generative basis has already done a lot. However, this technique has several limitations, due to the recalcitrant character of the seeds and the inequality of the characteristics of the progeny with their parent. Meanwhile, vegetative techniques will produce a new individual that have the same characteristics as the parent. The alternative-promising vegetative techniques of G. versteegii are using media because it is cheap and easy to obtain, and increase the achievement if additional hormones were used. The purpose of this research is to determine the optimum concentration of the NAA hormone for G. versteegii cuttings. The research method is done by cutting the saplings of G. versteegii on the shoots. The medium used are water without hormones (as control), water with hormones of NAA 100, 200, and 300 ppm. Observations 10 times, at the end of the observation carried out measurements on the root, percent of life, buds, dry stem weight, and dry root weight. The result showed that NAA hormone treatment influenced significantly on the growth of the roots, percent of life, dry stem weight and dry weight of roots of G. versteegii. Medium of water with the addition of NAA 300 ppm was the composition that can be used as a medium to trigger initial rooting.

A previously unrecorded native species, Scirpus radicans (Cyperaceae), was discovered in the southern part of Lithuania in 2020. Although this species has a large distribution area in other parts of Eurasia, it is currently recognised as threatened in many European countries. Recordings of S. radicans in Lithuania had been expected, as these plants do occur or have been reported to occur in neighbouring regions. The aim of this study was to analyse the distribution of S. radicans in southern Lithuania, to determine the occupied areas and the size of populations, to study their capacity of vegetative reproduction, their habitats and associated plant communities, as well as to perform an assessment of the species' conservation status within the country. We studied S. radicans populations at two sites on the shores of Lake Pabezninkai and of Lake Neteèius in the Varena District (southern Lithuania), from August to October 2020. A total of 993 individuals of S. radicans were counted and their stands comprised 0.73 ha. The density of individuals in the studied plots ranged from 0.02 to 0.78 plants/m. Only 0.5% of individuals at Lake Pabezninkai and 20.7% of individuals at Lake Neteèius were at the stage of generative reproduction. Individuals at the stage of vegetative reproduction comprised 56.4%, whereas generative individuals amounted to 1.7% of all studied plants. One to seven stolons developed per plant and the mean number of rosettes per stolon was 2.8 ± 1.2. Potentially, a total of ca.2860 rosettes could be expected from all individuals of the studied plots, but the actual realised rate of vegetative reproduction is unknown. A more detailed study of the reproductive capacities of S. radicans would be required for better understanding the causes of the lately observed decrease of this species in most of the countries of Central Europe. Our analysis of the associated plant communities has enabled us to confirm the presence of a Scirpetus radicantis Nowiński 1930 association previously not recorded in Lithuania. By assessing S. radicans in accordance with the IUCN Criteria, we conclude that this species should be classified as endangered (EN) in Lithuania. Based on this assessment, we propose to include this species on the list of legally protected species of Lithuania. Conservation of shallow lakes with sandy or muddy shores and with significant natural fluctuations of the water level is the main measure for ensuring the survival of S. radicans, as well as other rare and endangered species adapted to such a type of habitat. [ABSTRACT FROM AUTHOR]

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The response of compensatory growth is an important adaptive strategy for plants to grazing. However, most previous studies on compensatory growth of plants focused on the compensation of the biomass or the number of sexual reproductive offspring and neglected the compensatory growth of vegetative reproduction (VR). This is important not only for plant compensatory growth studies, but also for theoretical and practical studies of grassland production. The clonal tussock grass Hordeum brevisubulatum was selected as the research object. Four different clipping severities (unclipping and clipping stubble at heights of 15, 10, and 5 cm) at the jointing stage and flowering stage were implemented to study the effect of simulated grazing. To explore the effect of recovery growth time on plant growth after simulated grazing, three sampling times were used at different recovery times after simulated grazing (1, 3, and 7 weeks). We found that light and moderate grazing severity significantly increased the number of vegetative reproduction modules, the promotion of simulated grazing on the number of vegetative reproduction modules was higher in the jointing stage than the flowering stage, and the increase in simulated grazing severity decreased with prolonged recovery growth time. The number of tillers significantly decreased with the increase in simulated grazing in both the jointing and flowering stages at 1 week after damage, and the decreasing effect weakened with the prolonged recovery growth time. The bud number mainly showed over-compensation, the juvenile tiller number showed complete compensation, and the tiller number showed under-compensation at 1 and 3 weeks after recovery growth. The number of tillers showed complete compensation under different grazing severities in the jointing stage, while it showed under-compensation in the flowering stage at 7 weeks after recovery growth. Our results indicated that different grazing severities in the jointing stage could promote the output of tillers with matter production capacity from vegetative reproduction modules, as well as improve the capability of compensatory growth. Therefore, in plant production, there will be a sustainable development effect on the renewal and productivity of the H. brevisubulatum population, resulting in different grazing severities in the jointing stage.

Abstract Human‐altered disturbance regimes and changing climatic conditions can reduce seed availability and suitable microsites, limiting seedling regeneration in recovering forest systems. Thus, resprouting plants, which can persist in situ, are expected to expand in dominance in many disturbance‐prone forests. However, resprouters may also be challenged by changing regimes, and the mechanisms determining facultative seedling recruitment by resprouting species, which will determine both the future spread and current persistence of these populations, are poorly understood. In the resprouter‐dominated forests of coastal California, interactions between wildfire and an emerging disease, sudden oak death (SOD), alter disturbance severity and tree mortality, which may shift forest regeneration trajectories. We examine this set of compound disturbances to (1) assess the influence of seed limitation, biotic competition, and abiotic conditions on seedling regeneration in resprouting populations; (2) investigate whether disease‐fire interactions alter postfire seedling regeneration, which have implications for future disease dynamics and shifts in forest composition. Following a wildfire that impacted a preexisting plot network in SOD‐affected forests, we monitored seedling abundances and survival over eight years. With pre‐ and postfire data, we assessed relationships between regeneration dynamics and disturbance severity, biotic, and abiotic variables, using Bayesian generalized linear models and mixed models. Our results indicate that postfire seedling regeneration by resprouting species was shaped by contrasting mechanisms reflecting seed limitation and competitive release. Seedling abundances declined with decreasing postfire survival of mature, conspecific stems, while belowground survival of resprouting genets had no effect. However, where seed sources persisted, seedling abundances and survival generally increased with the prefire severity of disease impacts, suggesting that decreased competition with adults may enhance seedling recruitment in this resprouter‐dominated system. Species’ regeneration responses varied with their relative susceptibility to SOD and suggest compositional shifts, which will determine future disease management and forest restoration actions. These results additionally highlight that mechanisms related to biotic competition, seed limitation, and opportunities for seedling recruitment beneath mature canopies may determine possible shifts in the occurrence of resprouting traits. This result has broad applications to other systems impacted by human‐altered regimes where asexual persistence may be predicted to be a beneficial life history strategy.

The dispersal of aquatic plant propagules is highly facilitated in streams due to flow. As many aquatic plants predominantly spread through vegetative propagules, the specific retention and thus drift distance of dispersed plant fragments largely contribute to the rapid spread along the course of a stream.We determined fragment retention for four aquatic plant species (Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum, Salvinia natans; representing four different common morpho‐structural groups) in sections of small to medium‐sized German streams with different levels of stream sinuosity.The number of fragments showed a logistic decline over drift distance. In two small streams, 90% of drifting fragments were retained at distances (D90) of only 5–9 m and 19–70 m, while higher D90 values of 116–903 m and 153–2,367 m were determined for sections of a medium‐sized stream. The likelihood of retention thereby decreased significantly with increasing stream size and was reduced in straightened stream sections.Differences in retention were more strongly related to fragment buoyancy rather than fragment size and morphology. Increasing buoyancy significantly lowered the likelihood of fragment retention over drift distance by a factor of 3–8, whereas contrasting effects were documented for size and morphology of fragments.The relevance of different obstacles was highly stream section‐specific and depended on obstacle abundance, distribution, and the degree of submergence/emergence.Our findings elucidate the dynamic retention patterns of plant fragments and highlight the strong interplay between extrinsic (stream) and intrinsic (fragment) properties. We conclude that straightened lowland streams of intermediate size promote the rapid dispersal of invasive aquatic plants and are particularly prone to invaders producing large amounts of small and highly buoyant plant fragments. Information on the species‐specific fragment colonisation dynamics in the field is further required to improve our understanding of the vegetative dispersal capacity of invasive aquatic plants in stream ecosystems. [ABSTRACT FROM AUTHOR]

Mutation rate estimates for vegetatively reproducing organisms are rare, despite their frequent occurrence across the tree of life. Here we report mutation rate estimates in two vegetatively reproducing duckweed species, Lemna minor and Spirodela polyrhiza. We use a modified approach to estimating mutation rates by taking into account the reduction in mutation detection power that occurs when new individuals are produced from multiple cell lineages. We estimate an extremely low per generation mutation rate in both species of duckweed and note that allelic coverage at de novo mutation sites is very skewed. We also find no substantial difference in mutation rate between mutation accumulation lines propagated under benign conditions and those grown under salt stress. Finally, we discuss the implications of interpreting mutation rate estimates in vegetatively propagating organisms. [ABSTRACT FROM AUTHOR]

Triquetrous murdannia is an annual stoloniferous weed commonly found in wheat‐rice rotation fields in China. Disturbance after wheat harvesting can fragment stolons of triquetrous murdannia, and the regeneration of these fragments may contribute to the spread of this weed. In this study, the regenerate capacity and response to pre‐emergence (PRE) herbicides of stolon fragment of triquetrous murdannia were evaluated in a screenhouse. The experiment consisted of two types of single node fragments (2‐cm stolon node and five‐leaf stolon tips) placed under different floating, flooding and burial depth conditions. Results indicated that floating depth did not influence the survival of the two types of fragments but significantly decreased their growth (stolon length, number of branches, and biomass). The stolon nodes were more sensitive to flooding than stolon tips; no stolon node survived at a flooding depth of 6 cm. The highest survival was observed for fragments placed on the soil surface, and no fragments buried to a depth of 2 cm survived. PRE application of benzobicyclon, butachlor, metazosulfuron, and triafamone significantly decreased the branching and biomass of the stolon nodes; however, only triafamone and metazosulfuron significantly inhibited the regeneration of the stolon tips. These results suggest that stolon fragments with one node are likely to promote vegetative reproduction in triquetrous murdannia, and thus, disturbance may contribute to the spread of this weed. Tillage to bury fragments below their maximum regeneration depth and application of an effective PRE herbicide could serve as important tools for managing triquetrous murdannia. [ABSTRACT FROM AUTHOR]

Abies gracilis Kom. (Pinaceae) is one of the rarest and endangered conifers in the Russian flora, which must be cultivated ex situ to ensure its survival. Cuttings of A. gracilis do not take root without biostimulants. We used a selection of biostimulants, concentrations, and conditions of their use to significantly increase Abies gracilis rooting, and to accelerate the production of planting material, and to reduce rooting time to one season. We tested 4 rooting systems: IBA, IBA with glucose and glycine, and original biostimulants (S-try and S-5). The original S-5 biostimulating system had the most balanced ratio of components. The number of rooted samples increased 2.7 times and the length of roots increased 1.8 time when using S-5 as compared to IBA. S-try and S-5—original biostimulant systems were synthesized and collected in 2011 and 2014, respectively, and were tested in St. Petersburg Forest Technical University. [ABSTRACT FROM AUTHOR]

The response of compensatory growth is an important adaptive strategy for plants to grazing. However, most previous studies on compensatory growth of plants focused on the compensation of the biomass or the number of sexual reproductive offspring and neglected the compensatory growth of vegetative reproduction (VR). This is important not only for plant compensatory growth studies, but also for theoretical and practical studies of grassland production. The clonal tussock grass Hordeum brevisubulatum was selected as the research object. Four different clipping severities (unclipping and clipping stubble at heights of 15, 10, and 5 cm) at the jointing stage and flowering stage were implemented to study the effect of simulated grazing. To explore the effect of recovery growth time on plant growth after simulated grazing, three sampling times were used at different recovery times after simulated grazing (1, 3, and 7 weeks). We found that light and moderate grazing severity significantly increased the number of vegetative reproduction modules, the promotion of simulated grazing on the number of vegetative reproduction modules was higher in the jointing stage than the flowering stage, and the increase in simulated grazing severity decreased with prolonged recovery growth time. The number of tillers significantly decreased with the increase in simulated grazing in both the jointing and flowering stages at 1 week after damage, and the decreasing effect weakened with the prolonged recovery growth time. The bud number mainly showed over-compensation, the juvenile tiller number showed complete compensation, and the tiller number showed under-compensation at 1 and 3 weeks after recovery growth. The number of tillers showed complete compensation under different grazing severities in the jointing stage, while it showed under-compensation in the flowering stage at 7 weeks after recovery growth. Our results indicated that different grazing severities in the jointing stage could promote the output of tillers with matter production capacity from vegetative reproduction modules, as well as improve the capability of compensatory growth. Therefore, in plant production, there will be a sustainable development effect on the renewal and productivity of the H. brevisubulatum population, resulting in different grazing severities in the jointing stage. [ABSTRACT FROM AUTHOR]

Invasive alien plant species are frequently grown as ornamental plants in gardens. Until recently, in Slovenia, there were neither specific collection centres for a safe disposal of invasive plant species, nor any legislation that defined procedures for their removal and disposal. We investigated in two experiments how to dispose of pieces of selected invasive plant species, with the aim to prevent their survival and further dispersion. In the first experiment, we chose eight species that are known for spreading by either growing from pieces of cut stem (Cornus sericea, Parthenocissus quinquefolia, Buddleja davidii) or through subterranean rhizomes and tubers (Solidago canadensis, Solidago gigantea, Rudbeckia laciniata, Helianthus tuberosus, Symphyotrichum novae-angliae). The plant fragments were exposed to three different storage treatments: drying, composting on an open compost heap, and storage in black bin liners, all of which can be used in the home garden. After 5 months of storage, the materials were planted in box planters, and their development was monitored. Drying and composting was highly efficient for disposal, as the conditions destroyed the majority of the plant material. However, storage in a bin liner was inefficient because it did not kill any of the plant species tested, and did not delay their growth of new roots. In the second experiment we investigated selected woody invasive plants (Cornus sericea, Parthenocissus quinquefolia, Buddleja davidii, Acer negundo, Forsythia × intermedia) to determine whether their branch fragments can sprout new roots, and whether shredding of their branches represents an efficient dispersal pathway. These dried fragments did not grow roots under any circumstances, while freshly shredded fragments rooted in some cases. Therefore, the use of mulch that has not been treated properly might allow dispersal of woody invasive plants. We can conclude that not all recommended treatments for invasive plant disposal are equally successful to prohibit plant survival and further spread. [ABSTRACT FROM AUTHOR]