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Fluorogenic dyes with high brightness, large turn‐on ratios, excellent photostability, favorable specificity, low cytotoxicity, and high membrane permeability are essential for high‐resolution fluorescence imaging in live cells. In this study, we endowed these desirable properties to a rhodamine derivative by simply replacing the N, N‐diethyl group with a pyrrole substituent. The resulting dye, Rh‐NH, exhibited doubled Stokes shifts (54 nm) and a red‐shift of more than 50 nm in fluorescence spectra compared to Rhodamine B. Rh‐NH preferentially exists in a non‐emissive but highly permeable spirolactone form. Upon binding to lysosomes, the collective effects of low pH, low polarity, and high viscosity endow Rh‐NH with significant fluorescence turn‐on, making it a suitable candidate for wash‐free, high‐contrast lysosome tracking. Consequently, Rh‐NH enabled us to successfully explore stimulated emission depletion (STED) super‐resolution imaging of lysosome dynamics, as well as fluorescence lifetime imaging of lysosomes in live cells. [ABSTRACT FROM AUTHOR]

Bright and colorful fluorescent polymers are ideal materials for a variety of applications. Although polymers could be made fluorescent by physical doping or chemical binding of fluorescent units, it is a great challenge to get colorful and highly emissive polymers with a single fluorophore. Here the development of a general and facile method to synthesize ultrabright and colorful polymers using a single twisted intramolecular charge transfer (TICT) probe is reported. By incorporating polymerizable, highly fluorescent, and environmental sensitive TICT probe, a series of colorful acrylic polymers (emission from 481 to 543 nm) with almost 100% fluorescence quantum yields are prepared. Like the solvatochromic effect, functional groups within side chains of acrylic polymers (including alkyl chain, tetrahydrofurfuryl group, and hydroxyl group) provide varied environmental polarity for the incorporated fluorophore, resulting in a series of colorful polymeric materials. Benefiting from the excellent photophysical properties, the polymers show great potential in encryption, cultural relics protection, white light‐emitting diode bulb making, and fingerprint identification. [ABSTRACT FROM AUTHOR]

The pursuit of sensitive fluorescent chromophores with integrated aggregation‐induced emission (AIE) and twisted intramolecular charge transfer (TICT) properties are attractive due to the tunable emission properties and increased intensity. However, this type of chromophore has yet to be exemplified mechanistically. In this study, a strategy is presented for manipulating the formation of TICT and the AIE effect through molecular engineering. The feasibility of TICT properties is validated by theoretical calculations and ultrafast spectroscopies. By precisely adjusting the hydrophobicity of the donor group, the fluorescence is significantly enhanced through the addition of poor solvent. These findings not only provide mechanistic elucidation for chromophores exhibiting integrated TICT and AIE properties in various environmental conditions but also underscore the critical factors for the systematic design of chromophores with high tunability and strong emissions. [ABSTRACT FROM AUTHOR]

Plants are vulnerable to many abiotic stresses, resulting in reduced plant productivity. Its adaptation to unfavorable environments relies on transmitting external stress signals into internal signaling pathways. A series of stress response mechanisms have been developed. Among them, brassinosteroids (BRs) are a class of steroid hormones that are widely involved in plant growth, development, and stress response. Via genetics, proteomics, and genomics studies, the major components of signaling and signaling pathways through a series of phosphorylation cascade reactions have been identified in model plants such as Arabidopsis. Numerous studies have shown that BRs play important roles in plant responses to drought, temperature, salt, heavy metals, and other environmental stresses. The application of BRs to improve plant stress resistance has become the focus of research in recent years, especially the regulation of stress via endogenous BRs. Therefore, this paper systematically summarizes the research progress related to endogenous BR levels and provides an overview of BR biosynthesis and the signaling pathway, as well as the function of endogenous BRs in the response to abiotic stresses. [ABSTRACT FROM AUTHOR]