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Genus Senna belongs to the family of Fabaceae and comprises of about 250–300 accepted species extensively dispersed in tropical and subtropical regions. The Senna species is widely used in Africa, Asia, Europe and Latin America, some Senna species are well-known for their antimicrobial and anti-inflammatory activities with basis in traditional medicine to treat diabetes, microbial infections, malaria fever and other ailments. This review was extensively prepared by a comprehensive assessment of available literature via major scientific catalogues. The genus contains important metabolites such as alkaloids, anthraquinones, flavonoids, tannins, glycosides, steroids, terpenoids, saponins and volatile oils. The crude extracts and isolated metabolites from Senna displayed a wide range of in vitro and in vivo pharmacological activities such as antidiabetic, anti-gonorrhea, antimicrobial, antioxidant, antipyretic, antinociceptive, antidepressant and anti-inflammatory functions displayed by the genus Senna. The objective of this review is to critically explore the advances in the botanical, phytochemical, pharmacological and toxicological studies of the genus Senna, which will provide a useful bibliography for further investigations and applications in medicines. The review reveals that Senna species have been widely used for therapeutic purpose and substantial traditional evidence of their applications exist. Further studies should be tailored towards targeting active metabolites responsible for the pharmacological activities, structural elucidation and toxicological appraisals.

During a botanical career that has spanned more than 35 years – almost all that time based at The New York Botanical Garden –, Wm. Wayt Thomas has participated in over 100 field expeditions and published almost 200 scientific works including two edited volumes, advised or co-advised 15 doctoral students, and became one of the world authorities on the systematics of the Cyperaceae. His research programs set down roots in Brazil, where his work has led to major advances in our knowledge of the flora of the Atlantic Coastal Forests and had significant impacts on conservation in that region. He has held leadership positions in the Organization for Flora Neotropica and the Species Plantarum Project. He has made perhaps his greatest contributions in forging productive international scientific collaborations and in mentoring young scientists who are becoming leaders in the botanical community – and who attest to his pivotal impacts on their professional lives.

South Africa's unique flora and extensive use of African traditional medicines has created a unique research opportunity on medicinal plants for local and international scientists. In this paper, submitted to a special issue of South African Journal of Botany(SAJB) dedicated to “sub-Saharan Ethnobotany”, we aim to explore the research landscape on medicinal plant research as published in SAJB. A bibliometric assessment (1982–2017) showed that medicinal plant research represents 24% of the published volume in SAJB and that contributions on this topic are increasing exponentially. Although most papers are broad-basedinvitro screening studies, the range of topics covered is impressive. Antimicrobial (41%) and anti-oxidant (21%) studies dominate the research space with fewer studies focusing on diseases highly relevant to the African continent, e.g. malaria (3%) and tuberculosis (2%). Although the SAJB has contributed greatly to disseminating knowledge on important species (e.g. Aspalathus and Cyclopia) several taxa of potential economic relevance remain poorly investigated (e.g. Adansonia, Bulbine etc.). The citation footprint and authorship networks which have been established attest the pivotal role the SAJB has played to build research capacity and create awareness in this important field of research.

Recently, Brazilian Federal Police used forensic chemistry and forensic botany techniques on a case. Two packets containing fragmented plant matter were seized and sent for forensic analysis. Forensic chemistry, the gold standard for evaluating plant material suspected to contain illicit substances, did not find illicit materials. Gas chromatography coupled mass spectrometry (GC-MS) identified thujone in the botanical material. Thujone is a chemical compound naturally found in many plant species, notably Artemisia absinthium. Because doubt remained, we next used plant DNA barcoding methods. Total DNA from plant tissue fragments was extracted and five different DNA regions were amplified, sequenced, and analyzed using plant DNA barcoding methods. Genetic analysis yielded 30 good quality sequences representing five taxa. Most specimens were identified as A. absinthium. Few studies focus on practical forensic applications of plant DNA barcoding methods using a case solved in a forensic laboratory with its difficulties and limitations. To the best of our knowledge, this is the first study to report an effective joint effort of forensic chemistry and botany techniques to assess plant material in Brazil. The availability of a new technical approach for the genetic sequencing of plant species will enhance many forensic investigations and inspire similar initiatives.

Onobrychis viciifolia (sainfoin) is a forage legume crop with many positive agronomic, environmental, nutritional and nutraceutical attributes. Farmers also benefit from its drought tolerance in areas of low rainfall and light free draining soil, mainly due to its deep taproot. It is resistant to most common pest and diseases and is a valuable resource for pollinators, specifically cultivated for honey production in some regions. It has many benefits for animals, being highly palatable and without danger of bloat, which can be life-threatening to livestock. Its decline in Northern Europe started during the Green Revolution and was impacted by changes towards more intensive farming. Unlike other forage legume crops such as red clover and lucerne, sainfoin does not respond well to inputs and is difficult to establish and maintain. Sainfoin could be classified as an ‘orphan crop’ with very little genetic improvement or agronomic studies in the past 60 years. In the past 5–10 years, however, there has been a resurgence in interest and this has given rise to a number of studies and initiation of systematic improvement of the crop, which is indispensable to its reintroduction into the farmed environment. Interest has been driven in part by considerable evidence to suggest that condensed tannins present in the legume foliage, together with other polyphenol compounds, have positive effects on animal nutrition together with anthelmintic properties. These compounds are also thought to play a role in environmental benefits. There remain many challenges to address in order to optimize the potential for cultivation of sainfoin and its use as a beneficial forage crop. This review makes particular reference to a recently completed project; ‘Legume Plus’, funded by the European Union and embracing a multi-disciplinary approach to both understand and improve the crop for farmers. The present review covers results from both this project and other studies during the past 5 years, also drawing on historic studies of etymology, taxonomy, genetics, agronomy and botany, aiming to be a useful resource for research and for practical plant breeders and agronomists.

Prof. Zhou Jun, Academician of Chinese Academy of Sciences (1999), is a phytochemist and medicinal chemist of China. He is one of the pioneers of Kunming Institute of Botany, CAS and a major founder of the State Key Laboratory of Phytochemistry and Plant Resources in West China. The chemical compositions of some TCM from genus of Dioscorea, Aconitum, Panax, Paris, Cynanchum, Gastrodia, Dendrobium etc. and family Asclepiadaceae, Caryophyllaceae, Hypoxidaceae etc. have been explored by Prof. Zhou′s team as steroids, triterpenoids, alkaloids, cyclic peptides and phenols etc., which revealed the main active composition of those TCM such as Panax notoginseng, Paris yunnanensis and Gastrodia elata.

Rheum australe (Himalayan Rhubarb) is a multipurpose, endemic and endangered medicinal herb of North Western Himalayas. It finds extensive use as a medicinal herb since antiquity in different traditional systems of medicine to cure a wide range of ailments related to the circulatory, digestive, endocrine, respiratory and skeletal systems as well as to treat various infectious diseases. The remedying properties of this plant species are ascribed to a set of diverse bioactive secondary metabolite constituents, particularly anthraquinones (emodin, chrysophanol, physcion, aloe-emodin and rhein) and stilbenoids (piceatannol, resveratrol), besides dietary flavonoids known for their putative health benefits. Recent studies demonstrate the pharmacological efficacy of some of these metabolites and/or their derivatives as lead molecules for the treatment of various human diseases. Present review comprehensively covers the literature available on R. australe from 1980 to early 2018. The review provides up-to-date information available on its botany for easy identification of the plant, and origin and historical perspective detailing its trade and commerce. Distribution, therapeutic potential in relation to traditional uses and pharmacology, phytochemistry and general biosynthesis of major chemical constituents are also discussed. Additionally, efficient and reproducible in vitro propagation studies holding vital significance in preserving the natural germplasm of the plant and for its industrial exploitation have also been highlighted. The review presents a detailed perspective for future studies to conserve and sustainably make use of this endangered plant species at a commercial scale.

Artemisia vulgaris is one of the important medicinal plant species of the genus Artemisia, which is usually known for its volatile oils. The genus Artemisia has become the subject of great interest due to its chemical and biological diversity as well as the discovery and isolation of promising anti-malarial drug artemisinin. A. vulgaris has a long history in treatment of human ailments by medicinal plants in various parts of the world. This medicinal plant possesses a broad spectrum of therapeutic properties including: anti-malarial, anti-inflammatory, anti-hypertensive, anti-oxidant, anti-tumoral, immunomodulatory, hepatoprotective, anti-spasmodic and anti-septic. These activities are mainly attributed to the presence of various classes of secondary metabolites, including flavonoids, sesquiterpene lactones, coumarins, acetylenes, phenolic acids, organic acids, mono- and sesquiterpenes. Studies related to A. vulgaris morphology, anatomy and phytochemistry has gained a significant interest for better understanding of production and accumulation of therapeutic compounds in this species. Recently, phytochemical and pharmacological investigations have corroborated the therapeutic potential of bioactive compounds of A. vulgaris. These findings provided further evidence for gaining deeper insight into the identification and isolation of novel compounds, which act as alternative sources of anti-malarial drugs in a cost-effective manner. Considering the rising demand and various medical applications of A. vulgaris, this review highlights the recent reports on the chemistry, biological activities and biotechnological interventions for controlled and continuous production of bioactive compounds from this plant species.

Maturity is the most important factor to determine the storage-life and quality of fruits like mangoes. Fruit maturity can be recognized by different attributes and among them skin color is the most significant criteria for judging maturity. Typically, human experts visually detect the fruit color to identify the maturity stages which is very prone to error. In this paper, a method of digital image processing has been proposed to classify mangoes into six maturity stages according to the United States department of agriculture (USDA) standard classification. The experimentation considers sample images of more than 100 mangoes of different stages. A total of 24 image features are extracted and then correlation based and information gain based evaluation has been performed in order to select the most informative feature sets. Categorization is done using the decision tree which provides up to 96% classification accuracy.

Ethnopharmacological relevance Himalayan paeony (Paeonia emodi Royle.) is an important species used to treat various diseases. This study aimed to compile the detailed traditional medicinal uses, phytochemistry, pharmacology and toxicological investigations on P. emodi. This study also highlights taxonomic validity, quality of experimental designs and shortcomings in previously reported information on Himalayan paeony. Methods The data was extracted from unpublished theses (Pakistan, China, India and Nepal), and different published research articles confined to pharmacology, phytochemistry and antimicrobial activities using different databases through specific keywords. The relevant information regarding medicinal uses, taxonomic/common names, part used, collection and identification source, authentication, voucher specimen number, plant extracts and their characterization, isolation and identification of phytochemicals, methods of study in silico, in vivo or in vitro, model organism used, dose and duration, minimal active concentration, zone of inhibition (antimicrobial study), bioactive compound(s), mechanism of action on single or multiple targets, and toxicological information. Results P. emodi is reported for diverse medicinal uses with pharmacological properties like antioxidant, nephroprotective, lipoxygenase inhibitory, cognition and oxidative stress release, cytotoxic, anti-inflammatory, antiepileptic, anticonvulsant, haemaglutination, alpha-chymotrypsin inhibitory, hepatoprotective, hepatic chromes and pharmacokinetics of carbamazepine expression, β-glucuronidase inhibitory, spasmolytic and spasmogenic, and airway relaxant. Data confined to its taxonomic validity, shows 10% studies with correct taxonomic name while 90% studies with incorrect taxonomic, pharmacopeial and common names. The literature reviewed, shows lack of collection source (11 reports), without proper source of identification (15 reports), 33 studies without voucher specimen number, 26 reports lack information on authentic herbarium submission and most of the studies (90%) without validation of taxonomic names using recognized databases. In reported methods, 67% studies without characterization of extracts, 25% lack proper dose, 40% without duration and 31% reports lack information on proper controls. Similarly, only 18% studies reports active compound(s) responsible for pharmacological activities, 14% studies show minimal active concentration, only 2.5% studies report mechanism of action on target while none of the reports mentioned in silico approach. Conclusion P. emodi is endemic to Himalayan region (Pakistan, China, India and Nepal) with diverse traditional therapeutic uses. Majority of reviewed studies showed confusion in its taxonomic validity, incomplete methodologies and ambiguous findings. Keeping in view the immense uses of P. emodi in various traditional medicinal systems, holistic pharmacological approaches in combination with reverse pharmacology, system biology, and “omics” technologies are recommended to improve the quality of research which leads to natural drug discovery development at global perspectives.

A brief history of laboratory research in botany is given with a focus on trends through time, impact on botanical research at The New York Botanical Garden, and its impact on the teaching of botany in university settings.

Patchouli (Pogostemon cablin Benth.) is an industrially valued aromatic medicinal plant currently having a huge demand for its essential oil. It is widely used in flavor and fragrance industries as well as in pharmaceuticals. Clonal propagation is therefore obligatory to obtain homogeneous patchouli plants from preferred germplasm in order to meet the global need. At present, farmers are showing keen interest towards its large scale cultivation mainly in the tropical and sub-tropical countries. Understanding the plant biology, chemistry and other uses allows better utilization of any industrial crops. Therefore, the present review discusses on the botany, agronomy and biotechnological aspects of patchouli. Also, the current market demand for patchouli raw material is being reviewed by highlighting the possible exploration of modern techniques in identifying the adulterants to authenticate this herb. This review provides a comprehensive information on both basic and applied aspects of patchouli crop cultivation and management. The applied aspect of patchouli biotechnology allows one to explore the newer potential for various industrial uses and improve the rural economy.

The Mediterranean region is abundant with geophyte species, many of which have been developed as ornamentals. In recent years attempts were made to grow Scilla hyacinthoides L. (Asparagaceae, subfamily Scilloideae) commercially, both as a cut flower and as a water-saving ornamental geophyte. Optimizing commercial production of S. hyacinthoides requires the study of growth and development of the vegetative plant, as well as the control of flower bud initiation and development. Like most Mediterranean plants, S. hyacinthoides life cycle is attuned to the annual rhythm which alternates between hot and dry summer, and cool and rainy winter. Plants are dormant during summer. In autumn the apical meristem becomes active and either begins producing leaves for the next season, or initiates inflorescence development. After the onset of inflorescence development, a new apical meristem is formed at the axil of the youngest leaf. Frequently, two apices are formed; one of them becomes a daughter bulb. Intrabulb development of the inflorescence was studied by histology and electron microscopy. The flowering occurs in spring. Floral initiation is temperature-dependent and is inhibited by low temperatures, but inflorescence differentiation and elongation is inhibited by high temperatures. Flowers are self-incompatible and exhibit several polymorphic traits, probably important in pollinator attraction. In summary, current research provides a basis for future studies on the florogenesis and ecophysiology in Scilla , as well as enabling future fine tuning of cultivation protocols for the flower industry.

Father Jerónimo Lobo SJ was on a mission to Ethiopia between 1624 and 1634, during which he travelled on foot through parts of Abyssinia and Eritrea. After a troubled period of life in India, he returned to Lisbon in 1657, where died in 1678. In Lisbon Lobo wrote one of his most important works, “Discurso das Palmeiras”, published in 1669 in an English translation by the Royal Society of London. In this work, Lobo described the morphology and uses of eight important palm trees. Two of these – “macomeira” (Hyphaene) and “trafolim” (Borassus) – were novelties to European botanists. An analysis of published works from this period, including lists of plants cultivated in botanical and private European gardens, indicates that when “Discurso” was published, printed descriptions of only some of the palms that Lobo described were available. At that period few palms were cultivated in British and Dutch gardens. The botanical novelties in Lobo's “Discurso” were most probably the reason for interest shown by the Royal Society. This remarkable seventeenth-century botanical account reflected Lobo's ability to observe nature (perhaps enhanced by academic training in Jesuit schools) during his walks through the Abyssinian empire.

Aloe L. (Xanthorrhoeaceae) is a genus of over 500 species found on the African continent, Arabian Peninsula, Madagascar and eastern Indian Ocean Islands. It is valued by people at many economic scales but verifiable data, with which to quantify the role of Aloe in local livelihoods and commercial trade, are scarce. For a speciose genus of appreciable ethnological value, few taxa have been known in formal and international trade. Leaf mesophyll and exudate from certain Aloe species support sizeable commercial industries that differ markedly in geographical focus, supply chain and taxa used. Leaf mesophyll is primarily sourced from plantations of the well-known A. vera in Mexico, the United States and parts of South America, and is generally used in products made in the same region. By contrast, leaf exudate is principally wild-harvested from A. ferox in South Africa and A. secundiflora in Kenya for export to Europe and Asia. To a much lesser extent, Aloe spp. are used commercially in foods and to produce honey. It is unclear to what degree Aloe spp. are traded as medicinal plants for traditional use throughout their range. Their popularity in horticulture as decorative and/or collectable ornamentals sustains a considerable international trade. Besides habitat loss, wild populations of many species of Aloe are threatened by exploitation for the succulent plant trade and a few species by over-utilisation for natural products, making rare, endemic and utility taxa an obvious priority for conservation. With the exception of Aloe vera, all species of Aloe are protected by the Convention on International Trade in Endangered Species (CITES). There is, nevertheless, considerable potential for commercially-valuable species of Aloe to be employed for rural development and poverty alleviation. The success of the expanded Aloe-based industries will depend on sustainable harvesting and other practices compliant with the Convention on Biological Diversity.

Diospyros lycioides Desf. (D. lycioides) is traditionally used as herbal medicine against various human and animal ailments in tropical Africa. The present paper reviewed information on botany, medicinal uses, phytochemistry and pharmacological activities of D. lycioides. This review was compiled using scientific literature from electronic search engine such as PubMed, Scopus, ScienceDirect, Springerlink, BioMed Central, Scielo, Medline and Science domain. Additional literatures were obtained from book chapters, books, dissertations, websites and other scientific publications. D. lycioides is used as traditional medicine in 50% of the countries where the species is native in tropical Africa. This study recorded 22 medicinal uses of D. lycioides which included abdominal pains, infertility in women, sexually transmitted infections, and used as chewing sticks (or mouthwash), toothbrushes and ethnoveterinary medicine. D. lycioides extracts demonstrated anti-adhesive, anti-inflammatory, antimetastatic, antioxidant, antifungal, antiproliferative, mutagenicity and antibacterial activities. Future research should focus on the pharmacological properties, phytochemistry, clinical trials and pharmacokinetics of D. lycioides which will enhance the therapeutic potential of the species.

Virtual Issues consist of previously published papers that are repackaged into an online themed collection. With appropriate marketing, and making them free for a limited time, these issues are a powerful tool that allow all readers to rediscover and access content already published. Release of this Virtual Issue of Australian Journal of Botany was timed to coincide with the 11th Australasian Plant Conservation Conference (APCC11), held on 14–18 November at the Royal Botanic Gardens, Melbourne. For more information, please visit: http://www.publish.csiro.au/bt/content/VirtualIssues.

We describe Solanum baretiae sp. nov., a new species of Solanum section Anarrhichomenum, named in honor of Jeanne Baret, who sailed as the assistant to botanist Philibert Commerson on Louis Antoine de Bougainville’s global circumnavigation (1766–1769). The species is similar to S. chimborazense, but differs inlarger flowers, more flowers per inflorescence, and different patterns of pubescence on the filaments (pubescent adaxially and glabrous abaxially) and style (papillose to sparsely pubescent). A description, illustration, photos, and comparisons to similar species are included. Also included is a preliminary conservation assessment, along with a brief account of the important role played by Baret during the expedition. The new species appears to be restricted to the Amotape-Huancabamba zone, an area of southern Ecuador and northern Peru known for its exceptional biodiversity.

Quaternary (last 2.6 million years) botany involves studying plant megafossils (e.g. tree stumps), macrofossils (e.g. seeds, leaves), and microfossils (e.g. pollen, spores) preserved in peat bogs a...

This article comments on:Krizek BA, Bantle AT, Heflin JM, Han H, Freese NH, Loraine AE. 2021. AINTEGUMENTA and AINTEGUMENTA-LIKE6 directly regulate floral homeotic, growth, and vascular development genes in young Arabidopsis flowers. Journal of Experimental Botany 72, 5478–5493.

This article comments on: Fernández Farnocchia RB, Benech-Arnold RL, Mantese A, Batlla D. 2021. Optimization of timing of next-generation emergence in Amaranthus hybridus is determined via modulation of seed dormancy by the maternal environment. Journal of Experimental Botany 72, 4283–4297.

This article comments on:Tang T, Botwright Acuña T, Spielmeyer W and Richards RA. 2021. Effect of gibberellin-sensitive Rht18 and gibberellin-insensitive Rht-D1b dwarfing genes on vegetative and reproductive growth in bread wheat. Journal of Experimental Botany 72,445–458.

Heavy metals like cadmium (Cd) are a serious threat for living organisms due to increased global environmental pollution. Aloe ferox Mill. is a very important species of the genus Aloe, especially from a medical point of view, because it is a source of biologically active substances and it is often used in the traditional medicine. Since the knowledge about the effect of heavy metals, like Cd on growth of Aloe species is scarce, this study showed the effect of Cd on anatomical, morphological and physiological properties of this important medicinal plant species. We found that Cd affected the leaf morphology and decreased biomass of the aboveground plant part. Cd also affected cuticle deposition and increased the number of stomata in the abaxial and adaxial epidermis of leaves. Roots treated with Cd showed lower lignification and decreased level of membrane lipids peroxidation than control roots. Cadmium concentration was the highest in the roots; however, relatively high portion of Cd is being translocated to the leaves. This might be dangerous as Aloe is well known medicinal plant with content of active secondary metabolites mainly in the leaves.

Aloe dhufarensis Lavranos is an important medicinal plant, however, the endophytic microorganisms associated with this plant and their antagonistic activities are not known. In this study, endophytic fungi and bacteria were isolated from the leaf tissues of A. dhufarensis and their antagonistic activity against the plant pathogens Fusarium sp. and Cladosporium sp. were evaluated using a dual culture assay. A total of 3 fungal endophytes and 12 bacterial endophytes were isolated from the leaf tissue segments of A. dhufarensis. Among them, two endophytic fungal isolates designated as SQUCC-F2-2 and SQUCC-F3-1 exhibited inhibitory activity against the phytopathogenic fungi tested. In addition, scanning electron microscopy analysis showed that they induced shriveling, pit formation and disintegration of the hyphae of the phytopathogenic fungi. These two endophytic fungal isolates were identified as Sarocladium kiliense (SQUCC-F2-2) and Penicillium oxalicum (SQUCC-F3-1) on the basis of nuclear ribosomal DNA internal transcribed spacer (ITS) region. Analysis of the metabolites produced by these endophytes revealed the presence of fatty acids, fatty acid methyl esters, furfuryl alcohol, 1,2-diols and amide, which have been identified in the literature as antimicrobial compounds. P. oxalicum produced 7 compounds, of which 2-Furanmethanol, Dodecanoic acid and Tetradecanoic acid were dominant. S. kiliense produced 8 compounds with 2,3-Butanediol as the main constituent. This is the first report of endophytic fungi of A. dhufarensis with antagonistic activity against phytopathogenic fungi.

18 p.-9 fig., Premise: Light and gravity are fundamental cues for plant development. Our understanding of the effects of light stimuli on plants in space, without gravity, is key to providing conditions for plants to acclimate to the environment. Here we tested the hypothesis that the alterations caused by the absence of gravity in root meristematic cells can be counteracted by light., Methods: Seedlings of wild‐type Arabidopsis thaliana and two mutants of the essential nucleolar protein nucleolin (nuc1, nuc2) were grown in simulated microgravity,either under a white light photoperiod or under continuous darkness. Key variables of cell proliferation (cell cycle regulation), cell growth (ribosome biogenesis),and auxin transport were measured in the root meristem using in situ cellular markers and transcriptomic methods and compared with those of a 1 g control., Results: The incorporation of a photoperiod regime was sufficient to attenuate or suppress the effects caused by gravitational stress at the cellular level in the root meristem. In all cases, values for variables recorded from samples receiving light stimuli in simulated microgravity were closer to values from the controls than values from samples grown in darkness. Differential sensitivities were obtained for the two nucleolin mutants., Conclusions: Light signals may totally or partially replace gravity signals, significantly improving plant growth and development in microgravity. Despite that, molecular alterations are still compatible with the expected acclimation mechanisms, which need to be better understood. The differential sensitivity of nuc1 and nuc2 mutants to gravitational stress points to new strategies to produce more resilient plants to travel with humans in new extraterrestrial endeavors., This work was funded by the Agencia Estatal de Investigación of the Spanish Ministry of Science an Innovation, Grants#ESP2015‐64323‐R and #RTI2018‐099309‐B‐I00 (co‐funded by EU‐ERDF) to F.J.M., and Bonus Recherche from the UPVD to J.S.V. The use of the facilities of microgravity simulation was provided by the ESA‐CORA‐Ground Based Facilities Program, contract Ref. #4000105761 to F.J.M. and R.H. A.M. was recipient of a contract of the Program for Young Researchers Training of the Agencia Estatal de Investigación of the Spanish Ministry of Science an Innovation Ref. #BES‐2013‐063933.

Background The fern Dicranopteris linearis is a hyperaccumulator of rare earth elements (REEs), aluminium (Al) and silicon (Si). However, the physiological mechanisms of tissue-level tolerance of high concentrations of REE and Al, and possible interactions with Si, are currently incompletely known. Methods A particle-induced X-ray emission (μPIXE) microprobe with the Maia detector, scanning electron microscopy with energy-dispersive spectroscopy and chemical speciation modelling were used to decipher the localization and biochemistry of REEs, Al and Si in D. linearis during uptake, translocation and sequestration processes. Results In the roots >80 % of REEs and Al were in apoplastic fractions, among which the REEs were most significantly co-localized with Si and phosphorus (P) in the epidermis. In the xylem sap, REEs were nearly 100 % present as REEH3SiO42+, without significant differences between the REEs, while 24–45 % of Al was present as Al-citrate and only 1.7–16 % Al was present as AlH3SiO42+. In the pinnules, REEs were mainly concentrated in necrotic lesions and in the epidermis, and REEs and Al were possibly co-deposited within phytoliths (SiO2). Different REEs had similar spatial localizations in the epidermis and exodermis of roots, the necrosis, veins and epidermis of pinnae of D. linearis. Conclusions We posit that Si plays a critical role in REE and Al tolerance within the root apoplast, transport within the vascular bundle and sequestration within the blade of D. linearis.

Premise Floral rewards are essential in understanding floral function and evolution of the relationships between flowers and pollinators. Whether sugars are present in stigmatic exudates in Anthurium and whether it has floral nectaries have remained controversial because of the scarcity of structural studies. To solve these questions, we investigated the floral anatomy of A. andraeanum to elucidate whether (1) tepals are secretory organs, (2) tepals possess a structurally recognizable nectary, and (3) tepalar secretion differs from stigmatic secretion. Methods Floral structure was assessed through light and electron microscopy of samples of immature, pistillate, and staminate flowers. The dynamics of the starch reserve was investigated using histochemical tests, and the sugar content in the floral exudates was assessed using thin-layer chromatography. Results Sugar analysis did not detect sucrose, glucose, or fructose in stigmatic secretions, but confirmed their presence in tepalar secretions. Stigmatic secretion was produced by secretory stigmatic papillae; tepalar exudates were produced by nonvascularized nectaries in the apex of tepals. These nectaries were characterized by modified stomata and cells with cytoplasm rich in organelles, and a high content of calcium oxalate crystals. Conclusions Our results showed for the first time nectaries on tepals and true nectar secretion for A. andraeanum. Stigmatic secretion appears to be a distinct substance, and its often-reported sugar content seems to be a result of sample contamination. Nectar and stigmatic secretions have been often mistaken in other Anthurium species and deserve a revision for this genus.

International audience; Here we describe Bulbophyllum mascarenense sp. nov., a new endemic species from the Mascarenes, and assess its conservation status. This taxon has previously been confused with B. nutans var. nutans and has also been erroneously identified in the Mascarenes as B. minutum auct. non Thouars, the latter a Malagasy endemic. Bulbophyllum mascarenense is known from tropical humid native vegetation between 400 and 1200 m elevation, being abundant on the island of Réunion, but less so on Mauritius. Using the Red List Categories and Criteria of the International Union for Conservation of Nature, this new species should be considered as “Least Concern”.

Measurements of agronomic and fruit quality traits in a multi-environment trial using a multi-parental advanced generation intercross population identify QTLs for plasticity and QTL × environment interactions in response to abiotic stresses in tomato., Deciphering the genetic basis of phenotypic plasticity and genotype × environment interactions (G×E) is of primary importance for plant breeding in the context of global climate change. Tomato (Solanum lycopersicum) is a widely cultivated crop that can grow in different geographical habitats and that displays a great capacity for expressing phenotypic plasticity. We used a multi-parental advanced generation intercross (MAGIC) tomato population to explore G×E and plasticity for multiple traits measured in a multi-environment trial (MET) comprising optimal cultural conditions together with water deficit, salinity, and heat stress over 12 environments. Substantial G×E was observed for all the traits measured. Different plasticity parameters were estimated by employing Finlay–Wilkinson and factorial regression models and these were used together with genotypic means for quantitative trait loci (QTL) mapping analyses. In addition, mixed linear models were also used to investigate the presence of QTL × environment interactions. The results highlighted a complex genetic architecture of tomato plasticity and G×E. Candidate genes that might be involved in the occurrence of G×E are proposed, paving the way for functional characterization of stress response genes in tomato and for breeding climate-adapted cultivars.

This article comments on: Tsogtbaatar E, Cocuron J-C, Alonso AP. 2020. Non-conventional pathways enable pennycress (Thlaspi arvense L.) embryos to achieve high biosynthetic efficiency. Journal of Experimental Botany 71, 3037–3051.

Nitrogen (N)-fixing soybean plants use the ureides allantoin and allantoic acid as major long-distance transport forms of N, but in non-fixing, non-nodulated plants amino acids mainly serve in source-to-sink N allocation. However, some ureides are still synthesized in roots of non-fixing soybean, and our study addresses the role of ureide transport processes in those plants. In previous work, legume ureide permeases (UPSs) were identified that are involved in cellular import of allantoin and allantoic acid. Here, UPS1 from common bean was expressed in the soybean phloem, which resulted in enhanced source-to-sink transport of ureides in the transgenic plants. This was accompanied by increased ureide synthesis and elevated allantoin and allantoic acid root-to-sink transport. Interestingly, amino acid assimilation, xylem transport, and phloem partitioning to sinks were also strongly up-regulated. In addition, photosynthesis and sucrose phloem transport were improved in the transgenic plants. These combined changes in source physiology and assimilate partitioning resulted in increased vegetative growth and improved seed numbers. Overall, the results support that ureide transport processes in non-fixing plants affect source N and carbon acquisition and assimilation as well as source-to-sink translocation of N and carbon assimilates with consequences for plant growth and seed development., UPS1 phloem loading function represents a bottleneck in long-distance ureide transport, affects N and C acquisition and metabolism, and leads to rebalancing of whole-plant amino acid and sucrose partitioning.

This article comments on: van Rooijen R, Schulze S, Petzsch P, Westhoff P. 2020. Targeted misexpression of NAC052, acting in H3K4 demethylation, alters leaf morphological and anatomical traits in Arabidopsis thaliana. Journal of Experimental Botany 71, 1434–1448.

Fruit maturation and softening are critical traits that control fruit shelf-life. In the climacteric tomato (Solanum lycopersicum L.) fruit, ethylene plays a key role in fruit ripening and softening. We characterized two related proteins with contrasting impact on ethylene production, ACC oxidase 1 (SlACO1) and SlE8. We found SlACO1 and SlE8 to be highly expressed during fruit ripening. To identify loss-of-function alleles, we analysed the tomato genetic diversity but we did not find any natural mutations impairing the function of these proteins. We also found the two loci evolving under purifying selection. To engineer hypomorphic alleles, we used TILLING (target-induced local lesions in genomes) to screen a tomato ethylmethane sulfonate-mutagenized population. We found 13 mutants that we phenotyped for ethylene production, shelf-life, firmness, conductivity, and soluble solid content in tomato fruits. The data demonstrated that slaco1-1 and slaco1-2 alleles could be used to improve fruit shelf-life, and that sle8-1 and sle8-2 alleles could be used to accelerate ripening. This study highlights further the importance of SlACO1 and SlE8 in ethylene production in tomato fruit and how they might be used for post-harvest fruit preservation or speeding up fruit maturation.

Premise Pollinator foraging behavior can influence pollen dispersal and gene flow. In many plant species a pollinator trips a flower by applying pressure to release its sexual organs. We propose that differences in tripping rate among grooming pollinators could generate distinct pollen deposition curves, the pattern of pollen deposition over successive flowers visited. This study compares the pollen deposition curves of two grooming pollinators, a social bumble bee and a solitary leafcutting bee, with distinct tripping rates on Medicago sativa flowers. We predict a steeper deposition curve for pollen moved by leafcutting bees, the pollinator with the higher tripping rate. Methods Medicago sativa plants carrying a gene (GUS) whose product is easily detected by staining, were used as pollen donors. After visiting the GUS plants, a bee was released on a linear array of conventional M. sativa plants. The number of GUS pollen grains deposited over successive flowers visited or over cumulative distances was examined. Distinct mixed effect Poisson regression models, illustrating different rates of decay in pollen deposition, were fitted to the pollen data for each bee species. Results Pollen decay was steeper for leafcutting bees relative to bumble bees for both models of flowers visited and cumulative distance, as predicted by their higher tripping rate. Conclusions This is the first report of a difference in pollen deposition curves between two bee species, both grooming pollinators. Such differences could lead to distinct impacts of bee species on gene flow, genetic differentiation, introgression, and ultimately speciation.

This review describes the scientific basis of a research and breeding pathway designed to boost genetic gains in wheat under drought and heat stress., Despite being the world’s most widely grown crop, research investments in wheat (Triticum aestivum and Triticum durum) fall behind those in other staple crops. Current yield gains will not meet 2050 needs, and climate stresses compound this challenge. However, there is good evidence that heat and drought resilience can be boosted through translating promising ideas into novel breeding technologies using powerful new tools in genetics and remote sensing, for example. Such technologies can also be applied to identify climate resilience traits from among the vast and largely untapped reserve of wheat genetic resources in collections worldwide. This review describes multi-pronged research opportunities at the focus of the Heat and Drought Wheat Improvement Consortium (coordinated by CIMMYT), which together create a pipeline to boost heat and drought resilience, specifically: improving crop design targets using big data approaches; developing phenomic tools for field-based screening and research; applying genomic technologies to elucidate the bases of climate resilience traits; and applying these outputs in developing next-generation breeding methods. The global impact of these outputs will be validated through the International Wheat Improvement Network, a global germplasm development and testing system that contributes key productivity traits to approximately half of the global wheat-growing area.

The presence of two meristematic cell populations in the root and shoot apex allows plants to grow indefinitely. Due to its simple and predictable tissue organization, the Arabidopsis root apical meristem remains an ideal model to study mechanisms such as stem cell specification, asymmetric cell division, and differentiation in plants. The root stem cell niche consists of a quiescent organizing centre surrounded by mitotically active stem cells, which originate all root tissues. The transcription factors PLETHORA, SCARECROW, and WOX5 form signalling hubs that integrate multiple inputs from an increasing number of proteins implicated in the regulation of stem cell niche function. Recently, locally produced auxin was added to the list of important mobile factors in the stem cell niche. In addition, protein–protein interaction data elegantly demonstrate how parallel pathways can meet in a common objective. Here we discuss how multiple networks converge to specify and maintain the root stem cell niche., An updated overview of the main gene networks converging for the specification and maintenance of the Arabidopsis root stem cell niche.

Because plants capture water and nutrients through roots, it was proposed that changes in root systems architecture (RSA) might underpin the 3-fold increase in maize (Zea mays L.) grain yield over the last century. Here we show that both RSA and yield have changed with decades of maize breeding, but not the crop water uptake. Results from X-ray phenotyping in controlled environments showed that single cross (SX) hybrids have smaller root systems than double cross (DX) hybrids for root diameters between 2465 µm and 181µm (P, Emerging opportunity to continue long-term genetic gain in maize yield in the US corn belt by improving the balance between canopy, root, and reproductive growth and development.

Background and Aims The pacaya palm is a dioecious neotropical palm species that is exploited in Latin America for its male inflorescence, which is edible when immature. It is cultivated, in a non-intensive manner, in Guatemala, where a morphotype occurs that produces much larger, more highly branched inflorescences compared with wild palms. We sought to identify molecular factors underlying this phenotypic divergence, which is likely to be a product of domestication. Methods We performed RNA-seq-based studies on immature pacaya palm male inflorescences in order to identify genes that might be directly or indirectly affected in their expression in relation to domestication. We also measured the accumulation of a range of soluble sugar molecules to provide information on the biochemical status of the two different types of material. Key Results A total of 408 genes were found to display significantly different expression levels between the wild and cultivated morphotypes. Three different functional categories were found to be enriched in the gene set that was upregulated in the cultivated morphotype: redox balance; secondary metabolism; and transport. Several sugars were found to accumulate at higher levels in inflorescences of the cultivated morphotype, in particular myo-inositol, fructose and glucose. Conclusions The observed upregulation of redox-related genes in the cultivated morphotype is corroborated by the observation of higher myo-inositol accumulation, which has been shown to be associated with enhanced scavenging of reactive oxygen species in other plants and which may affect meristem activity.

The FW2.2 gene is associated with the major quantitative trait locus (QTL) governing fruit size in tomato, and acts by negatively controlling cell division during fruit development. FW2.2 belongs to a multigene family named the CELL NUMBER REGULATOR (CNR) family. CNR proteins harbour the uncharacterized PLAC8 motif made of two conserved cysteine-rich domains separated by a variable region that are predicted to be transmembrane segments, and indeed FW2.2 localizes to the plasma membrane. Although FW2.2 was cloned more than two decades ago, the molecular mechanisms of action remain unknown. In particular, how FW2.2 functions to regulate cell cycle and fruit growth, and thus fruit size, is as yet not understood. Here we review current knowledge on PLAC8-containing CNR/FWL proteins in plants, which are described to participate in organogenesis and the regulation of organ size, especially in fruits, and in cadmium resistance, ion homeostasis, and/or Ca2+ signalling. Within the plasma membrane FW2.2 and some CNR/FWLs are localized in microdomains, which is supported by recent data from interactomics studies. Hence FW2.2 and CNR/FWL could be involved in a transport function of signalling molecules across membranes, influencing organ growth via a cell to cell trafficking mechanism.

The CGIAR crop improvement (CI) programs, unlike commercial CI programs, which are mainly geared to profit though meeting farmers’ needs, are charged with meeting multiple objectives with target populations that include both farmers and the community at large. We compiled the opinions from >30 experts in the private and public sector on key strategies, methodologies, and activities that could the help CGIAR meet the challenges of providing farmers with improved varieties while simultaneously meeting the goals of: (i) nutrition, health, and food security; (ii) poverty reduction, livelihoods, and jobs; (iii) gender equality, youth, and inclusion; (iv) climate adaptation and mitigation; and (v) environmental health and biodiversity. We review the crop improvement processes starting with crop choice, moving through to breeding objectives, production of potential new varieties, selection, and finally adoption by farmers. The importance of multidisciplinary teams working towards common objectives is stressed as a key factor to success. The role of the distinct disciplines, actors, and their interactions throughout the process from crop choice through to adoption by farmers is discussed and illustrated., This document arose from the urgent need to join forces (across nations and research disciplines) and stand together to improve the prospects for the most vulnerable population on the globe whose well-being depends on agricultural production. Here, we learn from the past, and draft future strategic guidelines that will facilitate efforts of the CGIAR institutions (https://www.cgiar.org/) to enhance the livelihoods of the less privileged through crop improvement.

Plants need to cope with strong variations of nitrogen availability in the soil. Although many molecular players are being discovered concerning how plants perceive NO(3)(−) provision, it is less clear how plants recognize a lack of nitrogen. Following nitrogen removal, plants activate their nitrogen starvation response (NSR), which is characterized by the activation of very high-affinity nitrate transport systems (NRT2.4 and NRT2.5) and other sentinel genes involved in N remobilization such as GDH3. Using a combination of functional genomics via transcription factor perturbation and molecular physiology studies, we show that the transcription factors belonging to the HHO subfamily are important regulators of NSR through two potential mechanisms. First, HHOs directly repress the high-affinity nitrate transporters, NRT2.4 and NRT2.5. hho mutants display increased high-affinity nitrate transport activity, opening up promising perspectives for biotechnological applications. Second, we show that reactive oxygen species (ROS) are important to control NSR in wild-type plants and that HRS1 and HHO1 overexpressors and mutants are affected in their ROS content, defining a potential feed-forward branch of the signaling pathway. Taken together, our results define the relationships of two types of molecular players controlling the NSR, namely ROS and the HHO transcription factors. This work (i) up opens perspectives on a poorly understood nutrient-related signaling pathway and (ii) defines targets for molecular breeding of plants with enhanced NO(3)(−) uptake.

International audience; The adaptation of plants to their environment requires tight regulation of metabolism and growth processes through central and highly connected signalling pathways. The signalling cascade involving the evolutionarily conserved Target of Rapamycin (TOR) represents just such a central regulatory hub, and research on this protein kinase in plants has progressed significantly during the past decade. TOR is now firmly established as a central player in plant responses to the availability of nutrients such as sugars, stresses including those from pathogens, and hormones. Moreover plant-specific targets and regulators have recently been identified. The reviews in this special issue explore the various facets of regulation exerted by this fascinating kinase as well as its potential for crop improvement.

eXtra Botany Special Issue Editorial (special issue of Journal of Experimental Botany, produced following the ‘8th International Symposium on Plant Senescence’ in Jeju, South Korea, 2016); International audience; Virtually all of the cells, tissues and organs in plants age, senesce and eventually die. Senescence is regarded as an evolutionarily acquired process that is critical for plant fitness, and understanding its detailed molecular nature is not only fundamental but also pivotal for the improvement of crop yield and postharvest storage. Impressive progress has been made in revealing new molecular regulatory mechanisms in recent years. In this special issue, reviews span this emerging knowledge - derived from unique biological processes in different types of plant senescence - and highlight key molecular pathways and network-based regulatory mechanisms, as well as their evolutionary implications. The issue also addresses future research perspectives, including new technologies and approaches.

Chlorophyll breakdown is a fundamental process in nature. The elucidation of the involved pathways was the outstanding scientific achievement of the late Stefan Hörtensteiner, to whom this paper is dedicated., With the finest biochemical and molecular approaches, convincing explorative strategies, and long-term vision, Stefan Hörtensteiner succeeded in elucidating the biochemical pathway responsible for chlorophyll degradation. After having contributed to the identification of key chlorophyll degradation products in the course of the past 25 years, he gradually identified and characterized most of the crucial players in the PAO/phyllobilin degradation pathway of chlorophyll. He was one of the brightest plant biochemists of his generation, and his work opened doors to a better understanding of plant senescence, tetrapyrrole homeostasis, and their complex regulation. He sadly passed away on 5 December 2020, aged 57.

While most ferns avoid freezing as they have a tropical distribution or shed their fronds, wintergreen species in temperate and boreoalpine ecosystems have to deal with sub-zero temperatures. Increasing evidence has revealed overlapping mechanisms of desiccation and freezing tolerance in angiosperms, but the physiological mechanisms behind freezing tolerance in ferns are far from clear. We evaluated photochemical and hydraulic parameters in five wintergreen fern species differing in their ability to tolerate desiccation. We assessed frond freezing tolerance, ice nucleation temperature and propagation pattern, and xylem anatomical traits. Dynamics of photochemical performance and xanthophyll cycle were evaluated during freeze-thaw events under controlled conditions and, in selected species, in the field. Only desiccation-tolerant species, which possessed a greater fraction of narrow tracheids (18 μm) than sensitive species, tolerated freezing. Frond freezing occurred in the field at -3.4 ± 0.9 °C (SD) irrespective of freezing tolerance, freezable water content, or tracheid properties. Even in complete darkness, maximal photochemical efficiency of photosystem II was down-regulated concomitantly with zeaxanthin accumulation in response to freezing. This was reversible upon re-warming only in tolerant species. Our results suggest that adaptation for freezing tolerance is associated with desiccation tolerance through complementary xylem properties (which may prevent risk of irreversible cavitation) and effective photoprotection mechanisms. The latter includes de-epoxidation of xanthophylls in darkness, a process evidenced for the first time directly in the field.

The influence of aquaporin (AQP) activity on plant water movement remains unclear, especially in plants subject to unfavorable conditions. We applied a multitiered approach at a range of plant scales to (i) characterize the resistances controlling water transport under drought, flooding, and flooding plus salinity conditions; (ii) quantify the respective effects of AQP activity and xylem structure on root (Kroot), stem (Kstem), and leaf (Kleaf) conductances; and (iii) evaluate the impact of AQP-regulated transport capacity on gas exchange. We found that drought, flooding, and flooding plus salinity reduced Kroot and root AQP activity in Pinus taeda, whereas Kroot of the flood-tolerant Taxodium distichum did not decline under flooding. The extent of the AQP control of transport efficiency varied among organs and species, ranging from 35–55% in Kroot to 10–30% in Kstem and Kleaf. In response to treatments, AQP-mediated inhibition of Kroot rather than changes in xylem acclimation controlled the fluctuations in Kroot. The reduction in stomatal conductance and its sensitivity to vapor pressure deficit were direct responses to decreased whole-plant conductance triggered by lower Kroot and larger resistance belowground. Our results provide new mechanistic and functional insights on plant hydraulics that are essential to quantifying the influences of future stress on ecosystem function.