Effect of Sulfated Chitooligosaccharides on Wheat Seedlings (Triticum aestivum L.) under Salt Stress

In this study, sulfated chitooligosaccharide (SCOS) was applied to wheat seedlings to investigate its effect on the plants’ defense response under salt stress. The antioxidant enzyme activities, chlorophyll contents, and fluorescence characters of wheat seedlings were determined at a certain time. The results showed that treatment with exogenous SCOS could decrease the content of malondialdehyde, increase the chlorophyll contents, and modulate fluorescence characters in wheat seedlings under salt stress. In addition, SCOS was able to regulate the activities of antioxidant enzymes containing superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase. Similarly, the mRNA expression levels of several antioxidant enzymes were efficiently modulated by SCOS. The results indicated that SCOS could alleviate the damage of salt stress by adjusting the antioxidant enzyme activities of plant. The effect of SCOS on the photochemical efficiency of wheat seedlings was associated with its enhanced capacity for antioxidant enzymes, which prevented structure degradation of the photosynthetic apparatus under NaCl stress. Furthermore, the effective activities of alleviating salt stress indicated the activities of SCOS were closely related with the sulfate group

Irreversible Solvatochromic Zn-Nanopaper Based on Zn(II) Terpyridine Assembly and Oxidized Nanofibrillated Cellulose

A new irreversible solvatochromic Zn-nanopaper has been produced through the coordination-driven assembly of Zn­(II)-terpyridine complex (Zn-tpy) on the surface of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibril (tCNF). The Zn-tpy as a photoactive center exhibits a changed emission color from greenish-blue to yellow after coordination with the carboxylate anion on the surface of tCNF. Theoretic calculations support that the longer wavelength emission is the result of a metal–ligand charge transfer. When exposed to solvents and then dried, the coordination bond between the Zn-tpy and tCNF experienced a dynamic, reversible process, where the lowest-energy excited state emitted by the Zn-tpy was “inverted”, which is a typical phenomenon of irreversible solvatochromism. The shifts of the emission colors of the Zn-nanopaper appeared result from its exposure to specific solvents and occurred in a matter of minutes. After solvent exposure, it was found that the emission colors of the nanopaper are not recovered to its original state. The different emissive Zn-nanopapers are easily prepared by post-processing using a solvatochromic process. This highly transparent Zn-nanopaper with post-processable emission offers unprecedented potential applications in the areas of memory devices, fluorescent switches, and organic light-emitting diodes (OLEDs)

miRNA and mRNA Expression Profiles Reveal Insight into Chitosan-Mediated Regulation of Plant Growth

Chitosan has been numerously studied as a plant growth regulator and stress tolerance inducer. To investigate the roles of chitosan as bioregulator on plant and unravel its possible metabolic responses mechanisms, we simultaneously investigated mRNAs and microRNAs (miRNAs) expression profiles of wheat seedlings in response to chitosan heptamer. We found 400 chitosan-responsive differentially expressed genes, including 268 up-regulated and 132 down-regulated mRNAs, many of which were related to photosynthesis, primary carbon and nitrogen metabolism, defense responses, and transcription factors. Moreover, miRNAs also participate in chitosan-mediated regulation on plant growth. We identified 87 known and 21 novel miRNAs, among which 56 miRNAs were induced or repressed by chitosan heptamer, such as miRNA156, miRNA159a, miRNA164, miRNA171a, miRNA319, and miRNA1127. The integrative analysis of miRNA and mRNA expression profiles in this case provides fundamental information for further investigation of regulation mechanisms of chitosan on plant growth and will facilitate its application in agriculture

Irreversible Solvatochromic Zn-Nanopaper Based on Zn(II) Terpyridine Assembly and Oxidized Nanofibrillated Cellulose

A new irreversible solvatochromic Zn-nanopaper has been produced through the coordination-driven assembly of Zn­(II)-terpyridine complex (Zn-tpy) on the surface of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibril (tCNF). The Zn-tpy as a photoactive center exhibits a changed emission color from greenish-blue to yellow after coordination with the carboxylate anion on the surface of tCNF. Theoretic calculations support that the longer wavelength emission is the result of a metal–ligand charge transfer. When exposed to solvents and then dried, the coordination bond between the Zn-tpy and tCNF experienced a dynamic, reversible process, where the lowest-energy excited state emitted by the Zn-tpy was “inverted”, which is a typical phenomenon of irreversible solvatochromism. The shifts of the emission colors of the Zn-nanopaper appeared result from its exposure to specific solvents and occurred in a matter of minutes. After solvent exposure, it was found that the emission colors of the nanopaper are not recovered to its original state. The different emissive Zn-nanopapers are easily prepared by post-processing using a solvatochromic process. This highly transparent Zn-nanopaper with post-processable emission offers unprecedented potential applications in the areas of memory devices, fluorescent switches, and organic light-emitting diodes (OLEDs)

miRNA and mRNA Expression Profiles Reveal Insight into Chitosan-Mediated Regulation of Plant Growth

Chitosan has been numerously studied as a plant growth regulator and stress tolerance inducer. To investigate the roles of chitosan as bioregulator on plant and unravel its possible metabolic responses mechanisms, we simultaneously investigated mRNAs and microRNAs (miRNAs) expression profiles of wheat seedlings in response to chitosan heptamer. We found 400 chitosan-responsive differentially expressed genes, including 268 up-regulated and 132 down-regulated mRNAs, many of which were related to photosynthesis, primary carbon and nitrogen metabolism, defense responses, and transcription factors. Moreover, miRNAs also participate in chitosan-mediated regulation on plant growth. We identified 87 known and 21 novel miRNAs, among which 56 miRNAs were induced or repressed by chitosan heptamer, such as miRNA156, miRNA159a, miRNA164, miRNA171a, miRNA319, and miRNA1127. The integrative analysis of miRNA and mRNA expression profiles in this case provides fundamental information for further investigation of regulation mechanisms of chitosan on plant growth and will facilitate its application in agriculture