Explore the vast range of titles available.

As important components in saline agriculture, halophytes can help to provide food for a growing world population. In addition to being potential crops in their own right, halophytes are also potential sources of salt-resistance genes that might help plant breeders and molecular biologists increase the salt tolerance of conventional crop plants. One especially promising halophyte is Suaeda salsa, a euhalophytic herb that occurs both on inland saline soils and in the intertidal zone. The species produces dimorphic seeds: black seeds are sensitive to salinity and remain dormant in light under high salt concentrations, while brown seeds can germinate under high salinity (e.g. 600 mm NaCl) regardless of light. Consequently, the species is useful for studying the mechanisms by which dimorphic seeds are adapted to saline environments. S. salsa has succulent leaves and is highly salt tolerant (e.g. its optimal NaCl concentration for growth is 200 mm). A series of S. salsa genes related to salt tolerance have been cloned and their functions tested: these include SsNHX1, SsHKT1, SsAPX, SsCAT1, SsP5CS and SsBADH. The species is economically important because its fresh branches have high value as a vegetable, and its seed oil is edible and rich in unsaturated fatty acids. Because it can remove salts and heavy metals from saline soils, S. salsa can also be used in the restoration of salinized or contaminated saline land. Because of its economic and ecological value in saline agriculture, S. salsa is one of the most important halophytes in China. In this review, the value of S. salsa as a source of food, medicine and forage is discussed. Its uses in the restoration of salinized or contaminated land and as a source of salt-resistance genes are also considered.

Are evolutionary outcomes predictable? Adaptations that show repeated evolutionary convergence across the Tree of Life provide a special opportunity to dissect the context surrounding their origins, and identify any commonalities that may predict why certain traits evolved many times in particular clades and yet never evolved in others. The remarkable convergence of C₄ and Crassulacean Acid Metabolism (CAM) photosynthesis in vascular plants makes them exceptional model systems for understanding the repeated evolution of complex phenotypes. This review highlights what we have learned about the recurring assembly of C₄ and CAM, focusing on the increasingly predictable stepwise evolutionary integration of anatomy and biochemistry. With the caveat that we currently understand C₄ evolution better than we do CAM, I propose a general model that explains and unites C₄ and CAM evolutionary trajectories. Available data suggest that anatomical modifications are the ‘rate-limiting step’ in each trajectory, which in large part determines the evolutionary accessibility of both syndromes. The idea that organismal structure exerts a primary influence on innovation is discussed in the context of other systems. Whether the rate-limiting step occurs early or late in the evolutionary assembly of a new phenotype may have profound implications for its distribution across the Tree of Life.

The aim of the present review was to reconsider basic information about various functional aspects related to plant water content and provide evidence that the usefulness of measuring absolute water content in plant sciences is undervalued. First, general questions about water status in plants as well as methods for determining water content and their associated problems were discussed. After a brief overview of the structural organization of water in plant tissues, attention was paid to the water content of different parts of plants. Looking at the influence of environmental factors on plant water status, the differences caused by air humidity, mineral supply, biotic effects, salinity, and specific life forms (clonal and succulent plants) were analyzed. Finally, it was concluded that the expression of absolute water content on a dry biomass basis makes easily noticeable functional sense, but the physiological meaning and ecological significance of the drastic differences in plant water content need to be further elucidated.

Succulent plants are iconic components of the florae of many terrestrial ecosystems, but despite having caused fascination and prompted investigation for centuries, they still harbour many secrets in terms of physiological function and evolution. Tackling these mysteries is important, as this will not only provide insights into the dynamics and details of the convergent evolution of a major adaptive syndrome, but also inform efforts to conserve endangered biodiversity and utilize the unique physiological characteristics of succulents for biofuel and biomass production. Here I review advances in the phylogeny and organismal biology of succulent plants, and discuss how insights from recent work in the wider fields of plant hydraulics and photosynthetic physiology may relate to succulents. The potential for the exploration of mechanistic relationships between anatomical structure and physiological function to improve our understanding of the constraints that have shaped the evolution of succulence is highlighted. Finally, attention is drawn to how new methodologies and technologies provide exciting opportunities to address the wide range of outstanding questions in succulent plant biology.

Demonstration of crassulacean acid metabolism (CAM) in species with low usage of this system relative to C₃-photosynthetic CO₂ assimilation can be challenging experimentally but provides crucial information on the early steps of CAM evolution. Here, weakly expressed CAM was detected in the well-known pantropical coastal, leaf-succulent herb Sesuvium portulacastrum, demonstrating that CAM is present in the Sesuvioideae, the only sub-family of the Aizoaceae in which it had not yet been shown conclusively. In outdoor plots in Panama, leaves and stems of S. portulacastrum consistently exhibited a small degree of nocturnal acidification which, in leaves, increased during the dry season. In potted plants, nocturnal acidification was mainly facultative, as levels of acidification increased in a reversible manner following the imposition of short-term water-stress. In drought-stressed plants, nocturnal net CO₂ exchange approached the CO₂-compensation point, consistent with low rates of CO₂ dark fixation sufficient to eliminate respiratory carbon loss. Detection of low-level CAM in S. portulacastrum adds to the growing number of species that cannot be considered C₃ plants sensu stricto, although they obtain CO₂ principally via the C₃ pathway. Knowledge about the presence/absence of low-level CAM is critical when assessing trajectories of CAM evolution in lineages. The genus Sesuvium is of particular interest because it also contains C₄ species.

Main conclusionAuto-fluorescent condensed tannins specifically accumulated in mesophyll cells of non-salt secretor mangroves are involved in the compartmentation of Na+ and osmotic regulation, contributing to their salt tolerance.Salinity is a major abiotic stress affecting the distribution and growth of mangrove plants. The salt exclusion mechanism from salt secretor mangrove leaves is quite known; however, salt management strategies in non-salt secretor leaves remain unclear. In this study, we reported the auto-fluorescent inclusions (AFIs) specifically accumulated in mesophyll cells (MCs) of four non-salt secretor mangroves but absent in three salt secretors. The AFIs increased with the leaf development under natural condition, and applied NaCl concentrations applied in the lab. The AFIs in MCs were isolated and identified as condensed tannin accretions (CTAs) using the dye dimethyl-amino-cinnamaldehyde (DMACA), specific for condensed tannin (CT), both in situ leaf cross sections and in the purified AFIs. Fluorescence microscopy and transmission electron microscope (TEM) analysis indicated that the CTAs originated from the inflated chloroplasts. The CTAs had an obvious membrane and could induce changes in shape and fluorescence intensity in hypotonic and hypertonic NaCl solutions, suggesting CTAs might have osmotic regulation ability and play an important role in the osmotic regulation in MCs. The purified CTAs were labeled by the fluorescent sodium-binding benzofuran isophthalate acetoxymethyl ester (SBFI-AM), confirming they were involved in the compartmentation of excess Na+ in MCs. This study provided a new view on the salt resistance-associated strategies in mangroves.

Succulence is an adaptation to low water availability characterised by the presence of water-storage tissues that alleviate water stress under low water availability. The succulent syndrome has evolved convergently in over 80 plant families and is associated with anatomical, physiological and biochemical traits. Despite the alleged importance of cell wall traits in drought responses, their significance in the succulent syndrome has long been overlooked. Here, by analyzing published pressure–volume curves, we show that elastic adjustment, whereby plants change cell wall elasticity, is uniquely beneficial to succulents for avoiding turgor loss. In addition, we used comprehensive microarray polymer profiling (CoMPP) to assess the biochemical composition of cell walls in leaves. Across phylogenetically diverse species, we uncover several differences in cell wall biochemistry between succulent and non-succulent leaves, pointing to the existence of a ‘succulent glycome’. We also highlight the glycomic diversity among succulent plants, with some glycomic features being restricted to certain succulent lineages. In conclusion, we suggest that cell wall biomechanics and biochemistry should be considered among the characteristic traits that make up the succulent syndrome.

Soil salinization is a growing environmental concern of arid regions, but the salt-accumulator species like Salsola imbricata offer a promising solution for phytoremediation of affected soils. In this context, ten naturally occurring populations of S. imbricata from salt-prone arid environments of Cholistan Desert were evaluated for phytoremediation traits, including (i) hypersaline populations (ECe 31.6 to 21.3 dS m⁻ 1 ), (ii) moderately saline populations (ECe 16.0 to 12.2 dS m⁻ 1 ), and (iii) non-saline populations (ECe 2.5 to 1.7 dS m⁻ 1 ). The populations of S. imbricata collected from the highest salinity sites, Rahim Yar Khan (RYK) and Sadiqabad (SA), exhibited restricted growth habits but demonstrated increased accumulation of K⁺, Ca 2 ⁺, Na⁺, and Cl⁻. These populations showed larger root cross-sectional areas with more prominent xylem vessels and cortical region. Sclerification was notably intense in the roots and stems of population. In the leaves, specific adaptations included a reduced lamina area and enhanced succulence due to the development of storage parenchyma. Notable traits associated with the phytoremediation potential of S. imbricata populations included deeper root systems, taller plant, intensive sclerification around storage and conducting tissues, succulent leaves, salt-excreting trichomes, wider xylem vessels, and the accumulation of noxious ions. Furthermore, the RYK and SA populations displayed higher bioconcentration factors, translocation factors, and dilution factors for Na⁺ and Cl⁻, which are considered key traits for effective phytoremediation. The S. imbricata populations in highly saline environments demonstrate superior salt tolerance and efficient toxic salt management, making them ideal for rehabilitating saline, uncultivated lands through green reclamation.

An important goal in plant community ecology is to understand how species traits determine demographic performance. Several functional traits have been shown to correlate with growth and mortality rates in trees, but less is known about how the relationships between functional traits and demographic rates change with tree size. We examined the associations of functional traits with growth and mortality across 43 tree species in the Fushan 25‐ha subtropical rain forest plot in northern Taiwan. We estimated the 95th percentile maximum stem diameter, wood density and six leaf functional traits (leaf area, specific leaf area, thickness, succulence, and mass‐based nitrogen and phosphorus contents) obtained from leaves on juvenile and adult individuals of each species. To quantify size‐dependent changes in growth and mortality, relative growth rate (RGR) and mortality were estimated as a function of stem diameter using hierarchical Bayesian models. These rate estimates were then correlated with functional traits at a range of stem diameter classes. Relationships between functional traits and demographic rates varied with tree size. Maximum size was positively correlated with RGR across a wide range of tree sizes. Wood density was negatively correlated with RGR and mortality for small‐sized trees. Leaf traits such as leaf area and specific leaf area at juvenile and adult stages were associated more strongly with demographic rates for corresponding sizes than from other sizes. Synthesis. The observed size‐dependent changes in the trait–demography relationships are possibly due to the effects of developmental and environmental changes with increasing tree size. The underlying effects of functional traits on demographic performance vary with tree size, and this should influence dynamics in a tree community.

Aims To explore the mechanisms responsible for salt tolerance in Brassicaceae species, a multifactorial approach was used to clarify the functional traits underlying the differential salt tolerance in two Lepidium species, namely the halophyte L. latifolium and its glycophyte relative, L. sativum . Methods Parameters related to photosynthesis, nitrogen assimilation, ion accumulation, water relations and succulence, osmotic adjustment, phenolics metabolism, antioxidative defense, nitric oxide (NO) level and the expression of Na + antiporter ( SOS1 and NHX ) were analyzed in plants grown under salt stress in hydroponics. Results In addition to significant differences regarding the majority of salt tolerance indicators, a characteristic early boost, 52 h after exposure to salt, was observed in the concentration of H 2 O 2 and NO in the halophyte, which was almost absent in the glycophyte. Following the application of detrended component analysis, discrimination between the glycophyte and halophyte could only be performed via temporal curves in the antioxdative components and NO, and less effectively, by phenolics metabolism. Conclusion H 2 O 2 and NO signaling and the adaptive modification of phenolics metabolism play crucial roles in determining the halophytic behavior of L. latifolium . These data may result in new insights concerning the studies on halophytism in the Brassicaceae.