Lavatera Arborea Research Articles

First Report of Puccinia modiolae Causing Rust Disease on Malva verticillata in Korea.

Malva verticillata (Malvaceae), commonly called Chinese mallow or whorled mallow, is an annual herb native to East Asia and is currently distributed worldwide. In Korea, this plant is cultivated as a leafy vegetable and cooked like spinach or used in soups and also as a medicine material. In March 2022, typical symptoms of rust disease were observed on M. verticillata in a plastic house (37°22'12″ N, 127°34'30" E) in Yeoju, Korea. Yellow or light green round chlorotic spots appeared on the upper surface of infected leaves, while reddish-brown or dark brown rust pustules formed on its lower surface. Infection occurred in 10% of M. verticillata plants surveyed, and disease severity ranged between 30-90%. A representative sample was deposited in the Kunsan National University Herbarium (KSNUH1762). Telia were mostly hypophyllous, reddish-brown to dark brown, round, mostly grouped, and 0.3-0.7 mm in diameter. Teliospores were mostly two-celled, but rarely one or three-celled, yellowish to light brown, fusoid, and 42.9-101 × 10.8- to 18.8 μm (average 72.7 ± 12.3 × 14.2 ± 1.92 μm [mean ± SD]; n = 50), with a smooth, hyaline to yellowish wall of 1.0-2.5 μm thickness. The morphological characteristics were similar to those reported for Puccinia modiolae (Aime and Abbasi 2018; Albu et al. 2019). To confirm the morphological identification, genomic DNA was extracted from the teliospores of an infected leaf. The internal transcribed spacer (ITS) with primers ITS5-u and ITS4rust (Pfunder and Schürch 2001) and the large subunit (LSU) rDNA with primers LRust1R and LRust3 (Beenken et al. 2012) were amplified for sequencing. The resulting sequences were deposited in GenBank with accession numbers ON631218 for ITS and ON631226 for LSU. BLASTn search showed that the Korean sample was identical to the ITS sequences of P. modiolae from Modiola caroliniana (MK458693-MK458697) and the LSU sequences from M. caroliniana, Malva sylvestris, and Alcea rosea (MH742976, MH742977, and MH742978). In the phylogenetic trees of the ITS and LSU sequences, the Korean sample was grouped with the reference sequences of P. modiolae, with the maximum supporting value. For the pathogenicity test, rust-infected leaf discs were placed on the upper or lower surfaces of leaves of three healthy M. verticillata. Three non-inoculated plants served as controls. Inoculated and non-inoculated plants were maintained in a growth chamber at 22°C, a 16/8 h light cycle, and 80% humidity. After three weeks, all inoculated plants developed evident rust symptoms on the upper and lower surfaces of the leaves on which the leaf discs were placed, whereas the control plants remained symptomless. The pathogen present on the inoculated plants was confirmed to be the same pathogen as that observed in the field, fulfilling Koch's postulates. Based on the morphological investigation, sequence analysis, and pathogenicity tests, P. modiolae was identified as the causal agent of rust disease on M. verticillata. To date, this pathogen has been reported on seven Malvaceae plants, including Alcea rosea, Althaea officinalis, Lavatera arborea, Malva parviflora, Malva sylvestris, Modiola caroliniana, and Modiola sp., in North and South America (Farr and Rossman 2022). However, it has not been reported in Asia or Korea. This study is the first report of rust disease on M. verticillata worldwide. Considering its high incidence rate and severe damage, this pathogen is a potential concern for the cultivation of M. verticillata in Korea. This finding could contribute to developing phytosanitary and control treatments for this disease.

Allelopathic effects of Cynara cardunculus L. leaf aqueous extracts on seed germination of some Mediterranean weed species

It is known that the presence of weeds causes serious losses to the agricultural production, both in quantitative and qualitative terms. The major problem in modern agriculture is the environmental impact of synthetic herbicides and the increase in herbicide- resistant weed species. Allelopathic compounds can be used to develop a sustainable weed management system based on natural products. The objective of this study was to evaluate the allelopathic potential of leaf aqueous extracts (40 and 80%) obtained from Cynara cardunculus L. plant species on seed germination and mean germination time of six common weeds in Mediterranean agroecosystems: Amaranthus retroflexus L., Diplotaxis erucoides (L.) DC., Portulaca oleracea L., Lavatera arborea L., Brassica campestris L. and Solanum nigrum L. Effects varied with the weed species and the concentrations of the extracts. On average, the aqueous leaf extracts significantly reduced the final percentage of seed germination compared to the control for A. retroflexus (–58.1%), D. erucoides (–43.9%) and P. oleracea (–42.5%). The rate of germination decreased with increasing extract concentration. In C. cardunculus L. var. sylvestris the autoallelopathic activity also was demonstrated. These results are very promising in order to produce a bioherbicide based on C. cardunculus allelochemicals.

The dynamics of volunteer motivations for engaging in the management of invasive plants: insights from a mixed-methods study on Scottish seabird islands

Volunteers play an important role in the management of natural habitats. Understanding what motivates volunteers to join conservation initiatives and how motivations change over time is essential to enhance the environmental and social benefits of their engagement. Using a repeated qualitative survey and semi-structured interviews, we explore volunteers’ initial and sustained motivations in the management of the invasive tree mallow (Lavatera arborea) on Scottish seabird islands. Caring for nature, the performance of volunteering activities, and social interactions were the main drivers of involvement. Over time, motivations were shaped by the interplay between individual expectations and experiences with the social and ecological context. They changed from identifiable functions to more complex attachments to the place and the group. We discuss the limitations of functional methodologies in making sense of these attachments and of the performative nature of environmental volunteering. We then explore the practical implications of the dynamics of volunteering motivations.

Incorporation of the invasive mallow Lavatera arborea into the food web of an active seabird island

This study investigated the role of the invasive mallow Lavatera arborea in the terrestrial ecosystem of a flourishing seabird island in SE New Zealand using natural abundance stable isotope ratios (13C/12C; 15N/14N, reported as δ13C and δ15N). Foliage samples of L. arborea came from transects encompassing three distinct environments (plateau, slope, storm-washed flat) across the island. Samples of potential marine nutrient sources (beach-cast kelp; seabirds using the island) were also collected, to contextualise the L. arborea data. Samples of invertebrate taxa (exotic and indigenous) from multiple ecosystem guilds were hand-collected; a bee, a sap-sucking Homoptera, a litter-feeding tenebrionid beetle, various carrion-feeding flies, a predatory carabid beetle, a salticid spider, and (from a seabird cadaver) Dermestes sp. exuviae. Discarded skins from the gecko Hoplodactylus maculatus were collected from moulting sites. Highly enriched δ15N values showed that L. arborea from all three environments utilised seabird N, even though breeding seabirds were absent from the storm-washed flat. The isotopic signatures of the Homoptera, and the tenebrionid and carabid beetles could be accounted for entirely by food webs based on L. arborea. Bee and salticid spider isotopic signatures could be accounted for by varying contributions from L. arborea. The flies and Dermestes were (as expected) linked to carrion from either the island or the adjacent mainland. In contrast, gecko data indicated direct dependence on seabirds, although the exact relationship was unclear. Our study therefore showed that L. arborea is an integral part of the terrestrial ecosystem of the island across multiple trophic levels from pollinators to top-level predators.

Multiple anthropogenic changes cause biodiversity loss through plant invasion

AbstractNon‐native invasive plants are a widely acknowledged threat to global biodiversity. However, our understanding of the mechanisms underlying plant invasion, and the relative importance of multiple rather than single drivers, remains poor. Here, we provide a case study using time‐series data to reconstruct patterns of change, and field experiments to test for causality. We show how, over a 50‐year period, a series of unrelated human‐induced changes created highly favorable conditions for the non‐native tree mallow (Lavatera arborea) to turn invasive, causing loss of native vegetation and seabird breeding habitat. The combination of three drivers: human‐introduced disease, climate warming and a fisheries‐mediated increase in seabird populations, removed major constraints on plant population growth, (i.e. grazer control, climatic control, germination opportunity and nutrient limitation). Collectively, these changes created optimal conditions for the rapid expansion of tree mallow. The resulting dramatic impact on both the native vegetation and breeding seabirds, notably puffins (Fratercula arctica), exemplifies how non‐native invasive plant species can transform terrestrial ecosystems. While climate change is regarded as a key factor behind plant invasion, we highlight that multiple rather than single factors may be critical to biodiversity loss.

Cytochemical Localization of Sodium and H+ATPase in the Salt Gland of Tree Mallow, Lavatera arborea L.

Cytochemical Localization of Sodium and H+ATPase in the Salt Gland of Tree Mallow, Lavatera arborea L.

Invasive plant suppresses charismatic seabird – the construction of attitudes towards biodiversity management options

Public attitudes towards biodiversity issues and the value judgments underlying biodiversity management and conservation are still poorly understood. This has raised serious concerns regarding the effective use of public participation in biodiversity policy making. We conducted quantitative face-to-face interviews with members of the general public in southeast Scotland to assess attitudes towards biodiversity management and examine attitude formation. For this, we applied social psychological attitude–behaviour theories to a case study investigating biodiversity management options for an island ecosystem in which the abundance of a charismatic seabird, the Atlantic puffin ( Fratercula arctica) is compromised by the expansion of a tall invasive plant, tree mallow ( Lavatera arborea). We found that attitudes as expressed by members of the public are informed by both value- and knowledge-based elements. Our research provides clear support for the notion that, in a conservation context, value-based principles matter to the public. Out of a set of seven conservation-related values, ‘balance’ and ‘naturalness’ were important factors that related strongly to the respondents’ attitudes. These relationships were even stronger for individuals emotionally involved with the topic. Other value-based principles such as uniqueness, autochthony and endangeredness of the species involved appeared to be of lesser relevance. The findings provide evidence that attitudes can be considered as distinct constructs that offer valuable and meaningful information to biodiversity policymakers and managers, and allow empirical insights into the way value judgments influence biodiversity management and conservation.

Observations on the experimental destruction and substructural organisation of the pollen wall of some selected Gymnosperms and Angiosperms

Degradation of mature pollen walls by treatment with potassium permanganate was undertaken in Lavatera arborea (Malvaceae), Oenothera speciosa (Onagraceae) and Stangeria eriopus (Stangeriaceae) in order to investigate the substructural organisation of their exines. In Lavatera arborea the cores of the columellae are eroded so that they appear as hollow tubes and radially oriented rod-like elements (tufts) are revealed in the ectexine and endexine. An oxidative treatment with glacial acetic acid revealed clusters of darkly contrasted Sporopollenin Acceptor Particles (SAPs) along the surface of the columellae. This indicates that the cores of the columellae are formed independently of SAPs, whereas the sporopollenin in the outer parts of the columellae is receptor-dependent and is much more resistant to oxidation. After oxidative treatment of Oenothera pollen only the outlines of the three layers – of tectum, columellae and endexine, represented by the boundary layer, are visible, together with a complex system of tuft-tubules. The binder elements of tufts and the boundary layer of all exine strata are resistant to degradation and are interpreted as containing sporopollenin laid down on SAPs rather than the receptor-independent material of the remainding exine. Oxidative treatment of the alveolate exine of Stangeria eriopus results in progressive erosion with the duration of treatment. The binder zones of tufts and the tectal part of the exine, which are the walls of the alveolae and also their boundary layer, are the most resistant to oxidation and correspond to SAPs. The core subunits of tufts, that is the central parts of the alveolae, do not resist oxidation and are interpreted as sites of receptor-independent sporopollenin. Thus, in spite of the very different exine structure in Lavatera arborea, Stangeria eriopus and Oenothera speciosa, the exines of these species, on the substructural level, react to oxidative treatment in a similar way. We conclude that the alternative models of exine substructure proposed by various authors differ mainly in terminology rather than in substance.

A recovery plan for Roseate Terns in the East Atlantic: an international programme

SummaryIn 1987 an action plan for the recovery of the European populations of Roseate Tern Sterna dougallii was launched. Intervention on the breeding grounds has included the wardening of sites to prevent human disturbance, the provision of nest-boxes to discourage predation, patrolling and controlling to reduce predator presence, planting of Lavatera arborea to shelter nesting birds, and use of the media to establish local interest and commitment. Intervention in the wintering area has focused on Ghana and the reduction there of trapping pressure, through the “Save the Seashore Birds Project-Ghana”, which has involved site protection, legal reform, training, surveys and education programmes.

Soziologie und Ökologie von Oxalis pes-caprae L. im Mittelmeergebiet unter besonderer Berücksichtigung von Malta

In this paper the ecology and sociology of the neophyt Oxalis pes-caprae coming from South Africa is pomted out. In the centre of interest is the Island of Malta, where the species was introduced to Europe for the first time 190 years ago. Because of its formation of numerous bulbills Oxalis pes-caprae is a dangerous weed in the coastal areas of the western and especially the central Mediterranean region. In Malta Oxalis pes-caprae is one of the most frequent species. The centre of its occurrence is in, respectively at old walls surrounding the fields. Its great phenotypical plasticity - the length of the overground shoot is up to 70 cm - enables her to acquire the full light without accepting the disadvantages of rapidly parching wall crevices. Oxalis pes-caprae is able to build tight weed layers in communities of tall herbs (Urtico-Smyrnietum, Lavatera arborea Community) as well as under trees, respectively under Arundo donax. The behaviour of the species in Italy, in the Iberian peninsula as well as in North Africa is pointed out by literature and own investigations. There Oxalis pes-caprae occurs mainly in irrigated cultures of Citrus but also in river accompanying woods as well as in Ricinus communis scrubs.

The Possible Role of Phosphate in the Salinity Tolerance of Lavatera Arborea

(1) The growth of Lavatera arborea was investigated in sand culture by subjecting the seedlings to three salinity and phosphate treatments in a 3 x 3 factorial design. (2) Additional phosphate enhanced growth in non-saline and saline conditions, but growth was most in 40% sea water with additional phosphate. (3) The limit of salt tolerance of this species without additional phosphate was about 50% sea water but the limit was increased with additional phosphate. (4) Phosphate enhanced root growth at high salinity and resulted in increased potassium, calcium, magnesium and phosphorus contents in the shoot. (5) The results are discussed in relation to the halophytic nature and the salt tolerance of the species.

The Effect of Salinity and Nutrient Level on the Growth of Lavatera Arborea

The effects of salinity (sea water) and of marine and soil micro-organisms on the seedling growth of Lavatera arborea L. were investigated. In addition, the effect of the type of nutrient medium used to cultivate the young plants and its influence on subsequent growth was investigated along with the effects of three levels of soil fertility. Low salinity significantly enhanced growth both in terms of total dry weight, lpaf area and relative growth rate while high salinity retarded growth. Generally, as salinity increased so did leaf area ratio. Root growth was more adversely affected by salinity than shoot growth both at the seedling and the young plant stages. Micro-organisms either in the sea water or in the soil had no direct effect on seedling growth. With young plants raised in 0% sea water, every increase in salinity caused a reduction in their subsequent growth, but with those raised in 25% sea water, 12-25% sea water caused a stimulation of growth. Succulence of the petiole also increased as salinity increased. Increase in levels of soil fertility (mineral nutrients) resulted in an increase in growth. The results help to explain in part why L. arborea is well adapted to grow along the British coast on rubbish dumps.

An Experimental Investigation into the Ecology of Some Maritime Cliff Species: I. Field Observations

(1) Background information on the phytosociological, edaphic and climatic relationships of six maritime species is given as a basis from which to make an experimental study of factors influencing their distributions. (2) Crithmum maritimum, Spergularia rupicola and Inula crithmoides are members of the Crithmo-Spergularietum association of maritime crevices in southern Britain. (3) Ligusticum scoticum is a member of the equivalent northern Armeria maritimaGrimmia maritima association. Overlap of this association with the CrithmoSpergularietum occurs in south-west Scotland only. (4) Lavatera arborea is characteristically found in the Atriplici-Betetum association of bird cliffs, but also occurs in highly maritime rubbish tips, both in southern Britain. (5) Daucus carota ssp. gummifer is found in maritime grasslands and heaths in southern Britain. (6) Soil analysis suggests that five of the six species should be tolerant of high salinities, whilst Daucus should tolerate moderate salinities. Inula is found on soils with a high calcium content. (7) The maritime climate is characterized by a smaller temperature range and far fewer frosts than in inland areas, together with a very much higher frequency of gales. (8) It is suggested that the six maritime species studied may be restricted to sea cliffs, not because of a requirement for a saline environment, but because they are more tolerant of salinity than are competitors, whilst being sensitive to cold.

The Effect of Acid Soil on the Germination and Early Growth of Some Maritime Cliff Species

The effects of an acid soil (pH 4.0) on the germination and seedling growth of Crithmum maritimum L. Spergularia rupicola Lebel ex Le Jolis, Daucus carota spp. gummifer L. and Lavatera arborea L. were investigated. Germination and seedling growth were significantly inhibited. Poor seedling growth was usually attended by discolouration of leaves and distortion of root development. Salinised acid soil caused greater growth retardation than unsalinised one. As in many other calcicolous species, acidity, low nutrient concentration and aluminium toxicity were primarily responsible for the poor growth. However, these factors varied from species to species. The results help to explain the reduced abundance of the maritime cliff species on acid soils.