Annals of Botany

BACKGROUND AND AIMS: Internal root aeration is essential for root growth in waterlogged conditions. Aerenchyma provides a path for oxygen to diffuse to the roots. In most wetland species, including rice, a barrier to radial oxygen loss (ROL) allows more of the oxygen to diffuse to the root tip, enabling root growth into anoxic soil. Most dryland crops, including barley, do not form a root ROL barrier. We previously found that abscisic acid (ABA) signalling is involved in the induction of ROL barrier formation in rice during waterlogging...

BACKGROUND AND AIMS: Plant breeders are increasingly turning to crop wild relatives (CWRs) to ensure food security in a rapidly changing environment. However, CWR populations are confronted with various human-induced threats, including hybridisation with their nearby cultivated crops. This might be especially a problem for wild coffee species, which often occur near coffee cultivation areas. Here, we briefly review the evidence for wild Coffea arabica (cultivated as Arabica coffee) and Coffea canephora (cultivated as Robusta coffee) and then focussed on C...

BACKGROUND AND AIMS: Fire may favour plant flowering by opening the vegetation and increasing abiotic resource availability. Increased floral display size can attract more pollinators and increase the absolute fruit and seed production immediately after the fire. However, anthropogenic increases in fire frequency may alter these responses. We aim to assess the effects of fire on pollination and reproductive success of plants at the global scale. METHODS: We performed a systematic literature review and meta-analyses to examine overall fire effects as well as different fire parameters on pollination and on plant reproduction...

BACKGROUND AND AIMS: There is growing interest in the functional ecology of poikilohydric nonvascular photoautotrophs (NVPs), including 'cryptogamic' bryophytes and lichens. These organisms are structurally important in many ecosystems, contributing substantially to ecosystem function and services, while also being sensitive to climate change. Previous research has quantified the climate change response of poikilohydric NVPs using predictive bioclimatic models with standard climate variables including precipitation totals and temperature averages...

BACKGROUND AND AIMS: Infection by the hemi-parasitic plant Striga hermonthica causes severe host-plant damage and seed production losses. Increased availability of essential plant nutrients reduces infection. Whether, how and to what extent, it also reduces striga-induced host-plant damage is not well studied. METHODS: Effects of improved macro- and micronutrient supply on host-plant performance under striga-free and infected conditions were investigated in greenhouse pot assays...

BACKGROUND AND AIMS: Introgressive hybridization poses a challenge to taxonomic and phylogenetic understanding of taxa, particularly when there are high numbers of co-occurring, intercrossable species. The genus Quercus exemplifies this situation. Oaks are highly diverse in sympatry and cross freely, creating syngameons of interfertile species. Although a well-resolved, dated phylogeny is available for the American oak clade, evolutionary relationships within many of the more recently derived clades remain to be defined, particularly for the young and exceptionally diverse Mexican white oak clade...

No abstract text is available yet for this article.

BACKGROUND AND AIMS: Understanding biomass allocation among plant organs is crucial for comprehending plant growth optimization, survival and responses to global change drivers. Yet, mechanisms governing mass allocation in vascular plants from extreme elevations exposed to cold and drought stresses remain poorly understood. METHODOLOGY: We analyzed organ mass weights and fractions in 258 Himalayan herbaceous species across diverse habitats (wetland, steppe, alpine), growth forms (annual, perennial taprooted, rhizomatous, cushiony), and climatic gradients (3500-6150 m elevation) to explore whether biomass distribution adhered to fixed allometric or optimal partitioning rules, and how variation in size, phylogeny, and ecological preferences influence their strategies for resource allocation...

BACKGROUND AND AIMS: Vascular patterning is intimately related to plant form and function. Here, using barley (Hordeum vulgare) as a model, we studied the vascular anatomy of the spike-type inflorescence. The main aim of the present work was to clarify the relationship between rachis (spike axis) vasculature and spike size, define vascular dynamics, the implications for transport capacity and its interaction with the spikelets. METHODS: We employed serial transversal internode sections to determine the internode area, vascular area, and vein number along the rachis of several barley lines...

BACKGROUND AND AIMS: The quartz fields of the Greater Cape Floristic Region (GCFR) are arid and island-like special habitats, hosting about 142 habitat-specialized plant species of which 81% are local endemics, characterized by a rapid turnover of species between and among sites. We use several phylogenetic community metrics to i) examine species diversity and phylogenetic structure within and among quartz fields; ii) investigate whether quartz field specialists are evolutionarily drawn from local species pools, while the alternative hypothesis posits that there is no significant evolutionary connection between quartz field specialists and the local species pools; and iii) determine whether there is an association between certain traits and the presence of species in quartz fields...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

BACKGROUND AND AIMS: Plant water status is important for fruit development, as many fleshy fruits contain large amounts of water. However, there is no information on vascular flows of Persea americana 'Hass' avocado. The aims of this research were to explore the impact of drought stress on the water relations of the 'Hass' avocado plant, and its fruit growth. METHODS: Well-watered and water-stressed 'Hass' avocado plants were compared. Over four weeks, water flows through the shoot and fruit pedicel were monitored using external sap flow gauges...

BACKGROUND AND AIMS: Secondary cell wall (SCW) thickening is a major cellular developmental stage determine wood structure and properties. Although the molecular regulation of cell wall deposition during tracheary element differentiation has been well established in primary growth systems, less is known about the gene regulatory processes involved in the multi-layered SCW thickening of mature trees. METHODS: Using third-generation (long-read single-molecule real-time, SMRT) and second-generation (short-read sequencing by synthesis, SBS) sequencing methods, we established a Pinus bungeana transcriptome resource with comprehensive functional and structural annotation for the first time...

BACKGROUND AND AIMS: Extrafloral nectaries are nectar-secreting structures present on vegetative parts of the plants which provide indirect defences against herbivore attack. Extrafloral nectaries in Clerodendrum chinense are patelliform-shaped specialised trichomatous structures. However, complete portrayal of patelliform extrafloral nectaries in general and C. chinense in particular, is not yet established for gaining a fundamental insight into the cellular physiological machinery involved in nectar biosynthesis and secretory process...

BACKGROUND AND AIMS: The grass genus Urochloa (Brachiaria) sensu lato includes forage crops that are important for beef and dairy industries in tropical and sub-tropical Africa, South America, and Oceania/Australia. Economically important species include U. brizantha, U. decumbens, U. humidicola, U. mutica, U. arrecta, U. trichopus, U. mosambicensis, and Megathyrsus maximus, all native to the African continent. Perennial growth habits, large, fast growing palatable leaves, intra- and interspecific morphological variability, apomictic reproductive systems, and frequent polyploidy are widely shared within the genus...

BACKGROUND AND AIMS: Orchid seeds are reputed to be short-lived under dry, cold storage conditions, potentially limiting the use of conventional seed banks for long-term ex-situ conservation. This work explores whether Cattleya seeds are long-lived or not during conventional storage (pre-dried to c. 12% RH, then stored at -18 ºC). METHODS: We explored the possible interaction of factors influencing seed lifespan in eight species of the genus Cattleya using physiological (germination and vigour), biochemical (gas chromatography), biophysical (differential scanning calorimetry, DSC) and morphometric methods...

BACKGROUND AND AIMS: Variation in architectural traits related to the spatial and angular distribution of leaf area can have considerable impacts on canopy-scale fluxes contributing to water-use efficiency (WUE). These architectural traits are frequent targets for crop improvement, and for improving understanding and predictions of net ecosystem carbon and water fluxes. METHODS: A three-dimensional, leaf-resolving model along with a range of virtually-generated hypothetical canopies were used to quantify interactions between canopy structure and WUE by examining its response to variation of leaf inclination independent of leaf azimuth, canopy heterogeneity, vegetation density, and physiological parameters...

BACKGROUND AND AIMS: Kalanchoideae is one of three subfamilies within Crassulaceae and contains four genera. Despite previous efforts, the phylogeny of Kalanchoideae remains inadequately resolved with persistent issues including low support, unstructured topologies, and polytomies. This study aimed to address two central objectives: (1) resolving the pending phylogenetic questions within Kalanchoideae by, using organelle-scale "barcodes" (plastomes) and nuclear data; and (2) investigating interspecific diversity patterns among Kalanchoideae plastomes...

BACKGROUND AND AIMS: Xylella fastidiosa (Xf) is the xylem-dwelling bacterium associated with Pierce's Disease (PD), which causes mortality in agriculturally important species, such as grapevine (Vitis vinifera L.). Development of PD symptoms in grapevines depends on the ability of Xf to produce cell wall-degrading enzymes to break up intervessel pit membranes and systematically spread through xylem vessel network. Our objective was to investigate whether PD resistance could be mechanistically linked to xylem vessel network local connectivity...