Paulownia Species Research Articles

Hodnocení růstu jednoho druhu a dvou hybridů Paulownia spp. v nejteplejší oblasti jižní Moravy

The size of area of plantations of fast-growing tree species, established on agricultural land in the Czech Republic (CR), is on the rise. In order to gain saw timber, it is necessary to choose other species (example: Salix spp. and Populus spp., their resulting product is wood chips), one of which could be Paulownia spp. In 2015, an experimental plot with the species of Paulownia tomentosa and two hybrids of Paulownia Shan-Tong and Paulownia Hybrid 9501 were established in South Moravia. The plants were periodically pruned up to a height of 3 m. After six years, Paulownia Hybrid 9501 had mean height of 9.4 m and DBH of 12.8 cm, P. tomentosa 7.3 m and 10.3 cm, respectively, and P. Shan-Tong 5.2 m and 9 cm, respectively. These values are well below the average, in comparison with those declared by the sellers. The limited growth was presumably caused by less precipitation and a shorter growing season, in comparison with the climate characteristics of the humid subtropical zone in which Paulownia species originated. It appears that Paulownia Hybrid 9501 could grow in conditions similar to those in South Moravia, however, with a slower growth.

Novel Insight into the Prevention and Therapeutic Treatment of Paulownia Witches’ Broom: A Study on the Effect of Salicylic Acid on Disease Control and the Changes in the Paulownia Transcriptome and Proteome

Paulownia species not only have significant economic benefits but also show great potential in ecological conservation. However, they are highly susceptible to phytoplasma infections, causing Paulownia witches’ broom (PaWB), which severely restricts the development of the Paulownia industry. Salicylic acid (SA) plays a crucial role in plant disease resistance. However, there have been no reports on the effect of SA on PaWB. Due to the properties of SA, it may have potential in controlling PaWB. Based on the above speculation, the prevention and therapeutic effect of SA on PaWB and its effect on the PaWB-infected Paulownia transcriptome and proteome were studied in this work. The results indicated that 0.1 mmol/L was the optimal SA concentration for inhibiting the germination of Paulownia axillary buds. In terms of resistance physiological indicators, SA treatment significantly affected both Paulownia tomentosa infected (PTI) seedlings and Paulownia fortunei infected (PFI) seedlings, where the activities of peroxidase (POD) and superoxide dismutase (SOD) were enhanced. Malondialdehyde (MDA), O2−, and H2O2, however, were significantly reduced. Specifically, after SA treatment, SOD activity increased by 28% in PFI and 25% in PTI, and POD activity significantly increased by 61% in PFI and 58% in PTI. Moreover, the MDA content decreased by 30% in PFI and 23% in PTI, the H2O2 content decreased by 26% in PFI and 19% in PTI, and the O2− content decreased by 21% in PFI and 19% in PTI. Transcriptomic analysis showed that there were significant upregulations of MYB, NAC, and bHLH and other transcription factors after SA treatment. Moreover, genes involved in PaWB-related defense responses such as RAX2 also showed significant differences. Furthermore, proteomic analysis indicated that after SA treatment, proteins involved in signal transduction, protein synthesis modification, and disease defense were differentially expressed. This work provides a research foundation for the prevention and treatment of PaWB and offers references for exploring anti-PaWB methods.

Development of transgenic Paulownia trees expressing antimicrobial thionin genes for enhanced resistance to fungal infections using chitosan nanoparticles

There is an increasing focus on genetically altering Paulownia trees to enhance their resistance against fungal infections, given their rapid growth and quality wood production. The aim of this research was to establish a technique for incorporating two antimicrobial thionin genes, namely thionin-60 (thio-60) and thionin-63 (thio-63), into Paulownia tomentosa and Paulownia hybrid 9501 through the utilization of chitosan nanoparticles. The outcomes revealed the successful gene transfer into Paulownia trees utilizing chitosan nanoparticles. The effectiveness of thionin proteins against plant pathogens Fusarium and Aspergillus was examined, with a specific focus on Fusarium equiseti due to limited available data. In non-transgenic Paulownia species, the leaf weight inhibition percentage varied from 25 to 36 %, whereas in transgenic species, it ranged from 22 to 7 %. In general, Paulownia species expressing thio-60 displayed increased resistance to F. equiseti, while those expressing thio-63 exhibited heightened resistance to A. niger infection. The thionin proteins displayed a strong affinity for the phospholipid bilayer of the fungal cell membrane, demonstrating their capability to disrupt its structure. The transgenic plants created through this technique showed increased resistance to fungal infections. Thionin-60 demonstrated superior antifungal properties in comparison to thio-63, being more effective at disturbing the fungal cell membrane. These findings indicate that thio-60 holds potential as a novel antifungal agent and presents a promising approach for enhancing the antimicrobial traits of genetically modified Paulownia trees.

Paulownia trees as a sustainable solution for CO2 mitigation: assessing progress toward 2050 climate goals

Due to the progressive climate change on our planet, scientists are interested in solving this issue since it threatens not only certain regions or countries but also the world’s ecosystems and economies. Therefore, minimizing carbon dioxide (CO2) emissions and reducing atmospheric levels are global priorities. Thus, it is necessary at this moment to develop an appropriate approach to reduce or stabilize CO2 levels in the atmosphere. However, CO2 capture projects are long-term, low-profitable, and high-risk environmental projects. Consequently, it is necessary to find an appropriate and sustainable CO2 capture approach that is efficient in reducing atmospheric CO2 levels while having a safe impact on the environment. Although carbon (C) is the key basic component used to produce biological compounds by photosynthetic organisms in terrestrial plants, the C pathway is a key factor affecting the capture of CO2 by photosynthetic organisms. Among photosynthetic organisms, Paulownia, a multipurpose tree, is popular around the world for its timber and its potential role in CO2 sequestration. Paulownia spp. belongs to the Paulowniaceae family and comprises a group of trees. These trees are primarily found in southeastern Asia, particularly in China, and have been intentionally grown for more than two millennia due to their ornamental, cultural, and medicinal value. The number of Paulownia species varies depending on taxonomic classification, ranging from 6 to 17. Among them, Paulownia tomentosa, Paulownia elongata, Paulownia fortunei, and Paulownia catalpifolia are the most widely recognized and favored species. The present review provides a comprehensive technical-economic scenario for the capture of one million tons of CO2 by Paulownia trees (as a terrestrial plant model, grown on 2,400 ha−1). P. tomentosa can be utilized in agroforestry systems to mitigate greenhouse gas (GHG) emissions within urban cities and emphasize the carbon storage potential of agroforestry. In conclusion, Paulownia trees as an environmental mass project showed great encouragement to investors and governments to expand these types of projects to achieve global climate goals by 2050.

Effect of the particle geometry on lightweight particleboard from Paulownia using high-frequency pressing technology

ABSTRACT This study investigates the manufacture of lightweight single-layer particleboard (PB) made of the low-density wood species paulownia (Paulownia tomentosa) using high-frequency (HF) pressing technology. Paulownia round timber was chipped to particles with two different thickness levels (0.35 and 0.53 mm). The particles were classified into fraction B (> 0.5 ≤ 2.00 mm) and C (> 2 ≤ 4 mm) according to the mesh size of the sieve. Next to the particle size the influence of the board density (300 and 400 kg/m³) on the pressing process and the PB properties was analyzed. Using the HF press, PB were produced with a press speed of 6–9 s/mm. With increasing density, the values of the mechanical properties increased. PB made from larger particles showed higher modulus of rupture (MOR), the modulus of elasticity (MOE) and the internal bond strength (IB), but also more affinity to water absorption. PB with a density of 400 kg/m³ met the requirement for lightweight PB type LP2.

Peculiarities of plant growth, development, and chemical composition of the Paulownia biomass

Purpose. To establish the peculiarities of plant growth, development, and chemical composition of the paulownia biomass of two species in the Right Bank Forest Steppe of Ukraine. Methods. Field, laboratory, measuring and weighing, mathematical and statistical. Results. The biological properties of two Paulownia species, namely Clone in vitro-112 and Paulownia tomentosa, were studied. The maximum number of leaves per plant at the end of the vegetation season was 24–26 in Clone in vitro-112 and 22–24 in Paulownia tomentosa. Leaf area per plant was 5.0–5.5 m2 and 4.0–4.5 m2, respectively. The main period of wood accumulation falls during the first three years of vegetation, and during this period, biomass productivity indicators are the highest. Five-year wood yield per tree was about 0.35 m3 in Clone in vitro-112 and 0.24 m3 in Paulownia tomentosa. The research determined the optimal content of nutrients, the lack or excess of which negatively affects biomass quality. Nitrogen is mostly concentrated in leaves (2.3–2.6%) and petioles (0.67–1.1%). The content of phosphorus was quite low: 0.33–0.36% in leaves and 0.22–0.23% in petioles. Plants contain a significant amount of potassium in the leaves: 1.25% in Clone in vitro-112 and 0.75% in Paulownia tomentosa. Conclusions. Clone in vitro-112 can be recommended for cultivation in the Right Bank Forest Steppe Zone of Ukraine. One hectare can produce 200–250 m3 of industrial wood and the same amount of branch biomass for 5–6 years. Branches are suitable for the production of fuel pellets and chips with low ash content (0.8–1.5%). At the same time, leaves and petioles of paulownia have an increased ash content (3.9–7.1%) due to the higher content of nutrients, in particular nitrogen. Therefore, it is not advisable to use them as feedstock for the production of solid biofuel, but they are suitable for the production of biogas.

Paulownia Siebold & Zucc түрлері жапырақтарының салыстырмалы морфологиялық-анатомиялық ерекшеліктері

Мақалада Алматы қаласы жағдайында өсірілген Paulownia Siebold & Zucc түрлерінің гибридтері Shan Tong және FTE жапырақтарының морфологиялық және анатомиялық құрылысының ерекшеліктері алғаш рет сипатталды. Бұл ағаш түрі Оңтүстік-Шығыс Азия елдерінде табиғи жағдайда кеңінен тараған. Қазіргі уақытта көптеген елдерде өсіріліп, жерсіндірілуде. Жұмыстың өзектілігі: Paulownia ағашын орман өнеркәсібінде, биоотын және биогаз алу мақсатында, биоремедиант ретінде және медицинада емдік қасиеттерін кеңінен қолданады. Қазақстан жағдайында жаңадан өсіріліп, жерсіндірілуде, сол себептен жергілікті экологиялық жағдайда Paulownia түрлері гибридтеріне биологиялық-экологиялық зерттеулер жүргізілмеген. Практикалық маңыздылығын ескерсек, орманға тапшы еліміз үшін бұл ағаштың мүмкіндіктерін пайдалану аса қажет. Жұмыстың мақсат-міндеттері: Paulownia өсімдігінің Shan Tong және FTE гибридтер жапырақтарының морфологиялық-анатомиялық ерекшіліктерін зерттеп, салыстыру. Зерттеу әдістері: морфометриялық көрсеткіштері мен мүшелерінің морфологиялық құрылымы жалпы қабылданған әдістеме бойынша жүргізілді. Микроскопиялық талдау үшін фиксация Страсбургер-Флемминг әдісімен жасалды. Нәтижесі: Shan Tong және FTE жапырақтарының анатомиялық құрылысының диагностикалық белгілерін анықтауда биологиялық активті заттардың шоғырлану орындары белгіленді, сондай-ақ, гликозидтер бағаналы және борпылдақ мезофилде шоғырланғандығы айқындалды. Микроскопиялық кесінділерден жапырақтың анатомиялық құрылысында қарапайым көп клеткалы бір ядролы трихомалар, бір клеткалы безді түктер, құмыра тәрізді тармақталмаған, көп клеткалы, бір ядролы ірі трихомалар кездесетіндігі анықталды. Салыстыру барысында FTE гибриді жапырағының морфометрикалық көрсеткіштері Shan Tong гибриді жапырағының морфометрикалық көрсеткіштеріне қарағанда жоғары екендігі белгілі болды, айырмашылық тек бағаналы мезофилдің қалыңдығында байқалды. Алынған нәтижелер Paulownia туысы түрлері жапырағының анатомиялық ерекшелігін айқындап, деректерді растауға, нақтылауға және толықтыруға мүмкіндік береді. Алынған мәліметтерді Paulownia туысы түрлерін практикалық қолданыста жүйелі зерттеулер үшін қолдануға болады.

Within-branch photosynthetic gradients are more related to the coordinated investments of nitrogen and water than leaf mass per area

Nitrogen (N) and water are key resources for leaf photosynthesis and the growth of whole plants. Within-branch leaves need different amounts of N and water to support their differing photosynthetic capacities according to light exposure. To test this scheme, we measured the within-branch investments of N and water and their effects on photosynthetic traits in two deciduous tree species Paulownia tomentosa and Broussonetia papyrifera. We found that leaf photosynthetic capacity gradually increased from branch bottom to top (i.e. from shade to sun leaves). Concomitantly, stomatal conductance (gs) and leaf N content gradually increased, owing to the symport of water and inorganic mineral from root to leaf. Variation of leaf N content led to large gradients of mesophyll conductance, maximum velocity of Rubisco for carboxylation, maximum electron transport rate and leaf mass per area (LMA). Correlation analysis indicated that the within-branch difference in photosynthetic capacity was mainly related to gs and leaf N content, with a relatively minor contribution of LMA. Furthermore, the simultaneous increases of gs and leaf N content enhanced photosynthetic N use efficiency (PNUE) but hardly affected water use efficiency. Therefore, within-branch adjustment of N and water investments is an important strategy used by plants to optimize the overall photosynthetic carbon gain and PNUE.

Innovative hydrogels use in the germination and growth of tree species Paulownia tomentosa and Cupressus sempervirens

Innovative hydrogels use in the germination and growth of tree species Paulownia tomentosa and Cupressus sempervirens

Innovative hydrogels use in the germination and growth of tree species Paulownia tomentosa and Cupressus sempervirens

Research goal: This article presents the results of a research project aimed at demonstrating the effects and benefits of using an organic ingredient, hydrogel (Hydro Start), to improve the germination and growth of Paulownia tomentosa and Cupressus sempervirens seedlings. Materials and Methods: The experiments started in May 2022 and were conducted in the CREA-OF greenhouses in Pescia (PT) on seeded plants of Paulownia tomentosa and Cupressus sempervirens. The seeds were placed in pots with various hydrogel capsules to determine whether there were any effects on germination and plant growth. Agronomic analyses of the seeds and plants, microbiological analyses and substrate evaluation were also conducted. Results and Discussion: The experiment showed that the use of hydrogel can improve the quality and resistance of sown plants of Paulownia tomentosa and Cupressus sempervirens. In general, the improvement in average germination time and plant growth was proportional to the number of hydrogel capsules inserted into the substrate at the time of sowing; this also influenced the microbial colonisation of the soil. Studies show that the water retained by the hydrogel forms a water reserve in the soil that can increase the water uptake efficiency of plants. Mixing superabsorbent materials (hydrogels) with soils or growing media can significantly increase the water-holding capacity of the soil. Water is available to plants for a longer period of time, making them more resistant, especially during transplanting. Furthermore, the incorporation of hydrogels into the soil or growing media allows for improved germination, plant growth and nutrient and water uptake. Conclusions: Research shows that hydrogels can be used in a variety of ways due to their ability to retain water. These innovations can also ensure and promote plant survival in drought conditions. The results show that new hydrogels need to be evaluated not only for their physical properties, but also for their biological attributes related to the positive and negative aspects that bind microorganisms to plants.

Paulownia Organs as Interesting New Sources of Bioactive Compounds.

Paulownia spp. is a genus of trees in the Paulowniaceae family. It is native to southeastern Asia (especially China), where it has been cultivated for decorative, cultural, and medicinal purposes for over 2000 years. Depending on taxonomic classification, there are 6 to 17 species of Paulownia; P. tomentosa, P. elongata, P. fortunei, and P. catalpifolia are considered the most popular. Nowadays, Paulownia trees are planted in Asia, Europe, North America, and Australia for commercial, medical, and decorative purposes. Lately, growing interest in Paulownia has led to the development of various hybrids, the best-known being Clone in vitro 112, Shan Tong, Sundsu 11, and Cotevisa 2. Paulownia Clone in vitro 112 is an artificially created hybrid of two species of Paulownia: P. elongata and P. fortunei. The present review of selected papers from electronic databases including PubMed, ScienceDirect, and SCOPUS before 15 November 2022 describes the phytochemical characteristics, biological properties, and economic significance of various organs from different Paulownia species and hybrids, including P. tomentosa, P. elongata, P. fortunei, and Paulownia Clone in vitro 112. Many compounds from Paulownia demonstrate various biological activities and are promising candidates for natural preparations; for example, the leaves of Clone in vitro 112 have anti-radical and anticoagulant potential. However, further in vivo studies are needed to clarify the exact mechanism of action of the active substances and their long-term effects.

Growth of three species of Paulownia in the Ecuadorian Littoral

In Ecuador, the reduction of forests is evident, so it is necessary to evaluate fast-growing forest species that can meet growing demands, avoiding deforestation in areas where forests of the region are still maintained. The objective was to evaluate the growth of three species of the genus Paulownia in three localities of the Ecuadorian Coast as a medium-term alternative for productive and afforestation purposes. Diameter, height and volume were evaluated in three locations with two planting frames for three Paulownia species (Paulownia fortunei Hemsl; Paulownia elongata SYHu; Paulownia hibrido and a control (Gmelina arborea Roxb) with three replications. Data were recorded in the second year of planting. The Paulownia species were surpassed by G. arborea in the evaluated variables. In the humid tropics localities, there was no statistical difference between Paulownia species contrasting with the dry tropics locality in which P. eloganta in the 3 x 3 m plantation frame that presented the best values. Paulownia species did not exceed the control. The best results were achieved in the localities of Los Ríos and Santo Domingo; however, they should not be considered an alternative for productive purposes and afforestation in the humid tropics of Ecuador.

New cellular T-DNAs in naturally transgenic plants

Naturally transgenic plants represent the result of Agrobacterium-mediated gene transfer. T-DNA of soil bacteria Agrobacterium integrated into plants genome is called cellular T-DNA (cT-DNA) [1]. Today, more than 50 species of naturally transgenic plants, or natural GMO (nGMO) are known [2, 3]. The function of cT-DNA in plants remains unknown. It is assumed that the fixation of transgenes could give plants different selective advantages depending on which genes had been integrated into the plant [4]. In order to clarify this issue, it is necessary to study more naturally transgenic plants. Until recently, the list of nGM plants contained less than 2 dozen species, but a search through genomic and transriptomic sequencing data made it possible to more than double this list [2]. In this work, we used the same approach, looking for cT-DNA genes in whole genome sequencing data that have appeared in the NCBI WGS since 2021. We found 14 new species of naturally transgenic plants, among which the most extended cT-DNAs were found in Triadica sebifera, Lonicera japonica, and Lonicera maackii. The cT-DNAs in these species are organized as imperfect inverted repeats. In the genomes of the species Paulownia fortunei, Apocynum venetum, Elaeagnus angustifolia, Erythroxylum havanense, E. densum, E. daphnites, E. cataractarum, Ceriops decandra, Camellia oleifera, Silene uniflora, short cT-DNAs containing only opine synthesis genes were found. We also estimated the approximate age of the cT-DNAs. The first described examples date back to the Late Paleogene, and the process continues to the present. Thus, we can conclude that natural GMOs are a widespread phenomenon, many aspects of which remain unclear, requiring additional research on the topic.
 The article was made with support of the Ministry of Science and Higher Education of the Russian Federation in accordance with agreement No. 075-15-2022-322 dated 22.04.2022 on providing a grant in the form of subsidies from the federal budget of the Russian Federation. The grant was provided for state support for the creation and development of a world-class scientific center, Agrotechnologies for the Future.

C4 photosynthesis in Paulownia? A case of inaccurate citations

Societal Impact StatementC4 photosynthesis is an ultra‐efficient mode of photosynthesis found in some of our most productive crop species yet is notably rare in trees. Given C4 photosynthesis is associated with high yield in herbaceous species, especially under hot and dry conditions, C4 trees may seem an attractive prospect for biomass production and carbon sequestration in a rapidly changing climate. This may explain why some in the literature have optimistically linked C4 photosynthesis with the exceptionally fast‐growing tree Paulownia. However, this claim is lacking in evidence and represents an example of poor citation practices leading to the spread of misinformation.Summary The rapid growth of trees in genus Paulownia (Paulowniaceae) has been attributed in the literature to their use of C4 photosynthesis, a complex trait that confers increased photosynthetic efficiency under certain environmental conditions. After careful examination of citations used to support the idea that Paulownia species use C4 photosynthesis, we find that there is no data underpinning this claim. Despite this, many investment schemes utilise information about the physiology of Paulownia, including photosynthetic type, to legitimise the use of Paulownia trees for financial investment and carbon offsetting. This study uses leaf physiology, anatomy and stable isotope data to determine whether or not three species in Paulownia (Paulownia tomentosa, Paulownia fortunei and Paulownia kawakamii) use C4 photosynthesis. These data are compared with existing data for C3 and C4 woody species in the literature. We show that the leaf physiology, anatomy and stable isotope phenotypes of the three Paulownia trees considered in the study are not consistent with those of C4 plants. Our findings highlight how inaccurate citation of scientific findings can contribute to the spread of misinformation beyond the scientific community, as some of those promoting investments in Paulownia plantations reference the photosynthetic superiority of Paulownia as a means to legitimise its use in carbon offsetting.

Quality characteristics of the selected variant of Paulownia tomentosa (Robust4) wood cultivated in Hungary

Besides the continuously increasing demand for wood, the significant increase in its price also contributes to the increasingly broader use of fast-growing wood species and cultivars. Newer variants are continue to be cross-bred as a result. In case of a new variant within a species, it is questionable how it would adapt to a particular climatic environment and the quality of wood it would yield. The characteristics of the Paulownia tomentosa (Robust4) wood obtained from Hungarian plantations of are generally identical to those of the Paulownia tomentosa. The value of the air dry density - as typically for paulownia species- are very low i.e. 273 kg/m3. Its strength values (compressive strength: 9,6 MPa; tensile strength: 39,3 MPa; bending strength: 41,7 MPa; modulus of elasticity: 4116 MPa; impact bending strength: 1,4 J/cm2) also reach, and in some cases, exceed those of the Paulownia tomentosa (Thunb.) Steud. and the Paulownia Clone in vitro 112 variant. Based on these, we can expect the same wood quality from the Robust4 version as from the other paulownia variants.

Micropropagation of Paulownia tomentosa (Thunb.) Steud

Conservation of biological diversity is one of the most important tasks in the field of nature protection, which is given great attention all over the world. One of the pеrspective solutions to this problem in the world for strengthening soil structure and landscaping is the use of plants of the Paulownia species. Paulownia tomentosa is one of the fastest growing trees that is not demanding on soil quality. This type of trees has frost-resistant and winter-hardy qualities, which are necessary for the development and reproduction of plants in various soil and climatic conditions of the Republic of Kazakhstan. The introduction of effective technologies for micropropagation of perspective plants is relevant for the rational use of unique genetic resources, replenishment of the collection fund. The article presents experimental data on micropropagation of Paulownia tomentosa. Sterilization conditions for the introduction of various plant explants into in vitro culture have been selected. The best explants for introduction into in vitro culture and plant regeneration were the apical meristem and internodes of the plant. The well-established method of cultivating explants made it possible to carry out micropropagation in a short time and obtain clonal planting material for the MEBG collection fund.

The Influence of Age on the Wood Properties of Paulownia tomentosa (Thunb.) Steud.

Forests in Portugal are highly dependent on a short number of wood species, and new species with higher profitability are needed. The Paulownia species has generated great interest due to its fast-growing and relatively good wood properties. However, environmental factors have shown that Paulownia grows differently in each case. This study intends to determine the properties of young Paulownia trees from Portuguese plantations to determine the best age to cut the trees according to their use. The chemical composition (extractives in dichloromethane, ethanol and water, lignin, α-cellulose, and hemicelluloses), heating value, elemental analysis (CHNO), inorganic elements and thermogravimetric analyses (TGA), and the most important mechanical and physical properties (density, MOE, bending strength, water absorption equilibrium, moisture content, and dimensional changes) were determined for 1-, 3-, and 5-year-old trees. The results show that, chemically, the extractives increased while hemicelluloses decreased with age, and no trend was found for lignin and α-cellulose. The physical and mechanical properties increased with age, except for the MOE and bending strength. The 5-year-old samples presented the best features for pellet production, namely, calorific power, elemental composition CHNO and sulfur, and inorganic elements.

Qualitative and Quantitative Analysis of Secondary Metabolites in Morphological Parts of Paulownia Clon In Vitro 112® and Their Anticoagulant Properties in Whole Human Blood.

It is not easy to find data in the scientific literature on the quantitative content of individual phytochemicals. It is possible to find groups of compounds and even individual compounds rather easily, but it is not known what their concentration is in cultivated or wild plants. Therefore, the subject of this study was to determine the content of individual compounds in the new Paulownia species, Oxytree, developed in a biotechnology laboratory in 2008 at La Mancha University in Spain. Six secondary metabolites were isolated, and their chemical structure was confirmed by spectral methods. An analytical method was developed, which was then used to determine the content of individual compounds in leaves, twigs, flowers and fruits of Paulownia Clon in Vitro 112®. No flavonoids were found in twigs and fruits of Oxytree, while the highest phenylethanoid glycosides were found in twigs. In this study, we also focused on biological properties (anticoagulant or procoagulant) of extract and four fractions (A–D) of different chemical composition from Paulownia Clon in Vitro 112 leaves using whole human blood. These properties were determined based on the thrombus-formation analysis system (T-TAS), which imitates in vivo conditions to assess whole blood thrombogenecity. We observed that three fractions (A, C and D) from leaves decrease AUC10 measured by T-TAS. In addition, fraction D rich in triterpenoids showed the strongest anticoagulant activity. However, in order to clarify the exact mechanism of action of the active substances present in this plant, studies closer to physiological conditions, i.e., in vivo studies, should be performed, which will also allow to determine the effects of their long-term effects.

Morfometrijske karakteristiki listova vrsta Paulownia elongata S. Y. Hu. i Paulownia fortunei Seem. Hemsl. u odnosu na prihranjivanje na različitim staništima

The paper presents the results of the analysis dealing with the impact of plant fertilisation in the first year after planting on the leaf morphological characteristics. The analysis was conducted within the research into the potential introduction and adaptation of paulownia to different sites in Serbia. The results related to the effects of fertilisation on the quality of plant leaves are useful for the cultivation of certain types of soil where the morphometric analysis of leaves reveals structure-function relationships, i.e., more detailed indicators of the species' adaptability. The research was conducted in two localities. Sample plots with Paulownia elongata S. Y. Hu. and Paulownia fortunei Seem. Hemsl. were established in Obrenovac and Pambukovica, where leaf material was collected for laboratory analysis. The following morphometric leaf characteristics were measured: leaf area, leaf perimeter, leaf lamina length, central nerve length, maximum leaf width, leaf width at 1 cm from the base of the leaf, petiole length, distance between the 3rd and 4th nerve, the number of nerves to the left side of the midrib, and the number of veins to the right side of the midrib. The obtained results of leaf morphometric measurements were statistically processed in the Statgraphics software. Based on the results of measuring the leaf morphometric characteristics, fertilisation has a positive effect on the size of the leaves of the studied paulownia species.

Titanium dioxide nanoparticles affect somatic embryo initiation, development, and biochemical composition in Paulownia sp. seedlings

Paulownia is a fast-growing tree with multiple uses. The present study was conducted to determine the most appropriate concentration of TiO2 nanoparticles (titanium dioxide) for the induction of somatic embryogenesis and regeneration, reduction of free radicals, and the increase of antioxidant enzymes. Variables examined included explants (leaf and petiole), Paulownia species (Paulownia shantung, Paulownia elongate and Paulownia fortune), and concentrations of TiO2 nanoparticle. The results showed significant effect of TiO2 on callus induction for all the three species. For Paulownia shantung, the callus formation for the samples in the medium containing 60 mg/L of TiO2 was 100% while for the samples in the control condition (without TiO2) it was 25%. The highest of somatic embryogenesis was observed for Paulownia shantung. However, the highest levels of flavonoids, anthocyanins, carotenoids, and chlorophyll a, b, and total chlorophyll were observed in induced and regenerated embryos at a concentration of 60 mg/L titanium dioxide nanoparticles. By increasing the concentration of TiO2, the amount of leaf soluble protein decreased. At the concentration of 60 mg/L TiO2 the density, number and regeneration of somatic embryo induction increased compared to the studied treatments. The largest ratio of seedling rooting was observed in ½MS (Reduction to half the entire MS medium content) supplemented with 1.5 mg/L IBA. The results can introduce lead to a novel protocol to proliferate healthy plantlets of Paulownia in a short time. Therefore, the present study led to the development of an effective and useful protocol for somatic embryo induction, regeneration, and increase of antioxidants in regenerated seedlings in the shortest time applying titanium dioxide concentration in the culture medium.