Sieve elements (SEs) represent one of the most specialized cell types in plants, yet several fundamental aspects of their structure, regulation, and physiological integration remain incompletely understood. Despite recent advances that refined our understanding of SE function, persistent questions and controversies remain concerning key aspects of SE biology, such as the disputed presence of a proteolytic machinery and a cytoskeleton, the functions of plastids and mitochondria, the roles of sieve-element reticulum (SER) and its membrane contact sites, the mechanisms and significance of sieve-element occlusion by SEOs and SEORs and phloem protein (PP) families, the nature and operation of Ca2+ channels involved in sieve-tube occlusion and electrical signal propagation, and the mechanisms that compensate for SE enucleation. Here, we examine current concepts of SE biology, with particular emphasis on unresolved, conflicting, and emergent issues. We highlight experimental and conceptual approaches that may help resolve outstanding questions and to test hypotheses derived from existing data sets. Rather than providing a comprehensive catalogue of phloem functions, this review aims to delineate key conceptual bottlenecks and to outline future directions required to achieve a mechanistic understanding of SE function within the living plant. To this end, several hypothetical models of SE-functioning are included for further exploration.
In agriculture, soil amendments like compost, manure, superabsorbent polymers (SAP) and biochar (BC) are already in use to mitigate the effects of water shortage and to obtain a higher yield and survivability. The present study focuses on the impact of BC and SAP under moderate and reduced soil water content (SWC) on the physiological and biochemical response of Chenopodium quinoa Willd. (cv. UDEC-5), a naturally drought-resistant and strategic crop in arid regions, with the aim of further improving its resilience and biomass production. Plants were grown in the presence or absence (control) of SAP (1% or 0.1% g/100 g SAP) or BC (3% g/100 g BC) by taking into account the smallest possible amount of irrigation necessary for optimal growth of the control. Sixty-five days after sowing, the reduced watering approaches started. The irrigation amount was reduced slowly until plants without any amendment showed a significant reduction in CO2/H2O gas exchange and further significant changes in 23 morphological, physiological and biochemical symptoms of water shortage. Each amendment already caused individual plant response in wet conditions: The soil amendments of SAP (1% and 0.1%) and BC had no significant effect on biomass production but caused changes in PS I (portion of oxidized and open centers in PS I), the C/N ratio and N content. The addition of SAP (0.1% and 1%) led to a decrease in gH+, ECStmAu & times; gH+, RD, RL, the Ci/Catm ratio and ETR/Agross ratio and to an increase in water use efficiency (WUE), especially in the 0.1% SAP treatment. In moderate conditions, 0.1% SAP and 3% BC caused a significant increase in both the LOP and C/N ratio. In the moderate treatments, the application of 0.1% SAP promoted an increased Anet, while 3% BC promoted a significant reduction in malondialdehyde (MDA). The results of the present quinoa experiment indicate the drought avoidance mechanism of the control under low SWC. The reduced transpiration led to increased WUE due to the efficient use of the substomatal CO2 reservoir under low Cs and low E. It could also be confirmed that quinoa plants balanced low soil water potential by the accumulation of compatible solutes to lower the LWP and LOP. Drought led, especially in leaves in the 1% SAP treatment, to significant reductions in CO2/H2O gas exchange (Anet, RD), decreases in Y (II) and ETR in PS II, and an increase in the ETR/A ratio and over-reduced centers in PS I, pointing to an increased appearance of reactive oxygen species (ROS) in the chloroplasts. The latter change was indicated by higher levels of lipid peroxidation (MDA). It could be shown that the response of the test species Chenopodium quinoa to the addition of BC and SAP proved to be highly adaptable. The plant reacted in a very coordinated and specific way to both the danger of oversupply of SAP soil amendments under water shortage conditions and an effective adaptation to a limited water supply with 3% BC and 0.1% SAP by increasing WUE and proline content. However, BC also had a mitigating effect on the level of reactive oxygen species (ROS). It can be assumed that this effect is based on a more plant-compatible, less one-sided ion composition of BC. The results presented indicate that SAP and BC can have an impact on the water and nutrient accessibility for plants. Therefore, optimal biomass production and plant response can only be reached if plant soil interactions and competition between SAP, BC and the plant roots are taken into account when planning for climate-resilient, water-saving agriculture.
Academic Abstract Without recognizing how past failures bias subsequent choices, managers risk decisions that waste resources or prematurely abandon promising opportunities. This study draws on risk-type preference-shift theory and extends it with individual and organizational boundary conditions to examine how distinct failure experiences shape managers' willingness to persist with underperforming innovation projects. We conceptualize failure as a dichotomy, distinguishing commission errors (flops) from omission errors (missed opportunities). Our findings from two studies indicate that a recent commission error reduces the likelihood of persisting, while an omission error increases it. At the individual level, action-oriented decision-makers show a larger reduction in persistence after experiencing a commission error. Furthermore, rational thinkers do not differ in susceptibility to past failures; instead, they weigh specific attributes of the ongoing project more heavily when deciding whether to persist. At the organizational level, we observe that this effect depends on an organization's strategic orientation, that is, an exploratory orientation weakens (strengthens) the negative (positive) impact of commission (omission) errors. In contrast, an exploitative orientation amplifies the negative effects of commission errors. Together, these findings advance risk-type preference-shift theory and provide managers with clear guidance on when prior failures will lead them to persist with or abandon innovation projects.Managerial Abstract Decisions about whether to continue funding an underperforming innovation project are influenced by the most recent failure. After a flop, persistence decreases; after a missed opportunity, persistence increases. Action-oriented decision-makers emphasize the decline following a flop. State-oriented decision-makers are largely unaffected by a prior flop. Rational thinkers do not differ in their reactions to past failures but place greater emphasis on current project attributes, particularly proximity to completion and innovativeness. An exploration orientation reduces reactions to flops and boosts persistence after missed opportunities. An exploitation orientation increases the tendency to exit after flops. We recommend that companies and their managers keep a failure log that distinguishes between flops and missed opportunities; conduct structured postlaunch and postmortem reviews to classify failure types; seek neutral second opinions when previous failures might bias judgments; use reframing prompts to avoid anchoring on past outcomes; assemble review panels that include action- and state-oriented managers and involve rational thinkers for projects that are near completion or highly innovative; in exploratory settings, verify whether continued investment aligns with strategy rather than serving as a fallback for earlier inaction; in exploitative settings, implement delayed second-look procedures to prevent premature termination of projects with hidden potential.
Electro-chemo-mechanical degradation phenomena at the CAM|solid electrolyte interface lead to both impedance growth and capacity fading in solid state batteries (SSBs). Driven by this, protective coatings on cathode active materials (CAMs) have emerged as a key strategy to mitigate interfacial degradation in SSB composite cathodes. Currently, the development of novel protective CAM coatings is hindered by poor comparability and benchmarking issues, due to non-standardized testing protocols. Moreover, even within a single laboratory, coating optimization remains challenging, as performance strongly depends on processing parameters that cannot be efficiently explored through long-term cycling alone. Here, we present a systematic benchmarking approach to isolate and quantify the coating effect on interfacial stability. Our two-step workflow combines X-ray photoelectron spectroscopy (XPS) for pre-characterization of coating coverage and thickness with a standardized, time-efficient electrochemical testing protocol that delivers quantitative results within one week. We demonstrate that even short-term benchmarking can reveal significant performance differences across coatings and process routes. In addition, we critically discuss challenges associated with long-term testing and impedance analysis, as well as general considerations regarding interlaboratory benchmarking and the comparability of CAM coatings. Overall, the proposed approach provides a framework to guide coating optimization and accelerate the development of stable, high-performance SSBs.
Solid-state batteries (SSBs) with lithium metal anodes offer high energy density and safety but are limited by lithium dendrite formation arising from unstable Li/solid electrolyte (SE) interfaces. Here, a universal electro-chemo-mechanical interface engineering strategy is proposed to suppress dendrite growth. Parallel redox reactions between weak acids and lithium release hydrogen, avoiding the formation of electron-conductive species. An in situ formed LiI/Li2O/LiPAA composite interlayer with a graded structure stabilizes sulfide SE interfaces, blocks electron transport, and converts garnet SEs from lithiophobic to lithiophilic, reducing interfacial resistance by an order of magnitude. The interlayer also inhibits dendrite penetration in polymer SEs due to balanced rigidity and flexibility. As a result, uniform lithium deposition is achieved in symmetric and full cells. This work provides fundamental insight into SE interfacial chemistry and demonstrates a broadly applicable strategy for dendrite-free lithium metal SSBs.
