Rising atmospheric CO(2) levels can dilute the nitrogen (N) resource in plant tissue, which is disadvantageous to many herbivorous insects. Aphids appear to be an exception that warrants further study. The effects of elevated CO(2) (750 ppm vs. 390 ppm) were evaluated on N assimilation and transamination by two Medicago truncatula genotypes, a N-fixing-deficient mutant (dnf1) and its wild-type control (Jemalong), with and without pea aphid (Acyrthosiphon pisum) infestation. Elevated CO(2) increased population abundance and feeding efficiency of aphids fed on Jemalong, but reduced those on dnf1. Without aphid infestation, elevated CO(2) increased photosynthetic rate, chlorophyll content, nodule number, biomass, and pod number for Jemalong, but only increased pod number and chlorophyll content for dnf1. Furthermore, aphid infested Jemalong plants had enhanced activities of N assimilation-related enzymes (glutamine synthetase, Glutamate synthase) and transamination-related enzymes (glutamate oxalate transaminase, glutamine phenylpyruvate transaminase), which presumably increased amino acid concentration in leaves and phloem sap under elevated CO(2). In contrast, aphid infested dnf1 plants had decreased activities of N assimilation-related enzymes and transmination-related enzymes and amino acid concentrations under elevated CO(2). Furthermore, elevated CO(2) up-regulated expression of genes relevant to amino acid metabolism in bacteriocytes of aphids associated with Jemalong, but down-regulated those associated with dnf1. Our results suggest that pea aphids actively elicit host responses that promote amino acid metabolism in both the host plant and in its bacteriocytes to favor the population growth of the aphid under elevated CO(2).

decryption processes. Furthermore, these traditional anti-counterfeiting strategies are easily duplicated and are unable to counter the growing number of forgery techniques because they are widely recognized. Therefore, there is an urgent need to develop new anti-counterfeiting materials and innovative encryption/decryption approaches to endow stored information with higher security.In recent decades, polymeric gels have been developed as novel materials with programmable 3D network structures that are adaptable and inclusive, showing great potential for applications in various fields such as soft robotics, tissue engineering and information storage. [12][13][14][15][16][17][18][19] Among these, smart gels that exhibit shape morphing or color changes when exposed to external stimuli (e.g., light, heat, electricity, magnetism, mechanical force, or chemicals) have gained much attention. [20][21][22][23] Owing to its unique stimulus-responsiveness, a smart polymeric gel has been proven to be an excellent candidate for information encryption/decryption, exhibiting dynamic information output and a much higher security level. In general, an anti-counterfeiting process consists of three steps: coding, encryption, and decryption. For smart gel-based information storage devices, the external stimulus is the key to the decryption, and the tunable optical properties of the gel are utilized for coding. In other words, the information loaded on the gel is invisible or fake under normal circumstances, and the recipient can obtain the desired message only when the encrypted message is exposed to a particular external stimulus.Although polymeric gel-based information storage devices (PGISDs) are still in their infancy, there has been strong worldwide interest in this field. However, no related review has provided an in-depth overview of gel-based information storage for anti-counterfeiting. This review provides a tutorial overview that summarizes the recent progress in PGISDs, focusing on the preparation methods for gels with adjustable optical properties, their encryption/decryption mechanisms, and how to improve the security level using their dimensions and colors. As depicted in Figure 1, anti-counterfeiting materials based on elaborate gel systems show excellent encryption/decryption behaviors by adjusting either their chemical colors in the presence or absence of UV irradiation or physical colors under visible light (absorption/transmittance, refraction/scattering, and interference/diffraction). Endowing gels that display polychromic colors with stored information can achieve multilevel Information security protection has a tremendous impact on human life, social stability and national security, leading to the rapid development of anti-counterfeiting materials and related techniques. However, the traditional stored information on hard or dry media is often static and lacks functions, which makes it challenging to deal with increasing and powerful counterfeiting technologies. Modified intelligent polymeric gels exhibit color...