The early diverged Magnoliaceae shows a historical temperate-tropical distribution among lineages indicating divergent evolution, yet which ecophysiological traits are phylogenetically conserved, and whether these traits are involved in correlated evolution remain unclear. Integrating phylogeny and 20 ecophysiological traits of 27 species, from the four largest sections of Magnoliaceae, we tested the phylogenetic signals of these traits and the correlated evolution between trait pairs. Phylogenetic niche conservatism (PNC) in water-conducting and nutrient-use related traits was identified, and correlated evolution of several key functional traits was demonstrated. Among the three evergreen sections of tropical origin, Gwillimia had the lowest hydraulic-photosynthetic capacity and the highest drought tolerance compared with Manglietia and Michelia. Contrastingly, the temperate centred deciduous section, Yulania, showed high rates of hydraulic conductivity and photosynthesis at the cost of drought tolerance. This study elucidated the regulation of hydraulic and photosynthetic processes in the temperate-tropical adaptations for Magnoliaceae species, which led to strong phylogenetic signals and PNC in ecophysiological traits across divergent lineages of Magnoliaceae.
Summary1. Vulnerability segmentation hypothesis proposes that plant branches are more resistant to cavitation than their terminal leaves, namely, the difference in vulnerability to cavitation between branches and their terminal leaves is positive (P50leaf-branch>0). This allows leaves to act as "safety valves" to protect hydraulic pathway from dysfunction. 2. Recent studies showed that several species from humid regions have negative values of P50leaf-branch, indicating a lack of vulnerability segmentation in these species (LVS species). 3. We hypothesize that compared with species from humid regions, vulnerability segmentation is critical and necessary for arid species to survive droughts, but LVS species may take compensatory hydraulic strategies to maintain safety margins during drought periods. 4. We compile branch and leaf hydraulic trait data of 69 broadleaved woody species belonging to different biomes with contrasting climatic conditions as indicated by variable aridity index (AI), and we find that P50leaf-branch becomes small and even negative with the increase of AI. Although leaves of LVS species may lose their function as "safety valves", their deep rooting, great hydraulic conductivity, and/or high stem capacitance features are critical for them to maintain hydraulic safety. 5. The results indicate that vulnerability segmentation is evidently common for species from arid regions, but not necessarily the case for some species from humid regions. With robust cavitation-resistant leaves and effective hydraulic compensatory strategies, LVS species can maintain water supply and the functionality of leaves, thus giving them a hydraulic advantage over counterparts in the face of potential drought stress.
Detection of disease biomarkers within complex biological media is a substantial outstanding challenge because of severe biofouling and nonspecific adsorptions. Herein, a reliable strategy for sensitive and low-fouling detection of a biomarker, adenosine triphosphate (ATP) in biological samples was developed through the formation of a mixed self-assembled sensing interface, which was constructed by simultaneously self-assembling polyethylene glycol (PEG) and ATP aptamer onto the self-polymerized polydopamine-modified electrode surface. The developed aptasensor exhibited high selectivity and sensitivity toward the detection of ATP, and the linear range was 0.1-1000 pM, with a detection limit down to 0.1 pM. Moreover, owing to the presence of PEG within the sensing interface, the aptasensor was capable of sensing ATP in complex biological media such as human plasma with significantly reduced nonspecific adsorption effect. Assaying ATP in real biological samples including breast cancer cell lysates further proved the feasibility of this biosensor for practical application.
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