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Drosera is a small insectivorous plant whose antennae can fold up, encircle, and prey. The rapid movement of the antennae is achieved by the synergistic effect of a double‐layer structure with the antennae contracts on the front and expands on the back. In this work, a drosera‐inspired dual‐actuating double‐layer hydrogel actuator is proposed, in which the temperature‐responsive poly(N, N‐diethyl acrylamide) (PDEAAm) layer acts as the main actuation layer and a moisture‐responsive poly(acrylamide) (PAAm) layer acts as the auxiliary actuation layer. In a water environment with low temperature, both the PAAm and PDEAAm layers absorb water and expand with a swelling property. When the temperature exceeds the lower critical solution temperature of PDEAAm, the PDEAAm layer undergoes a hydrophilic–hydrophobic transition and shrinks rapidly. Therefore, the synergistic effect of the double‐layer hydrogel enables the double‐layer hydrogel to achieve a large bending angle at high temperature. In addition, when designing and fabricating shape‐patterned double‐layer hydrogels, complex shape changes can be achieved. Due to the physical and chemical properties, the actuator can be used to grab, transport, and release objects. This drosera‐inspired double‐layer hydrogel actuator has high practical value, which may provide new insights for the design and manufacture of artificial intelligence materials.

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Research Highlights: Soil enzymes have a significant impact on the production of glomalin-related soil protein (GRSP), directly and indirectly affecting the nutrient metabolism balance, but there is little available information on ecological stoichiometry in soil aggregates. Background and Objectives: Vegetation restoration changes community structure and species composition in ecosystems, thus changing the physicochemical properties of soil. Soil aggregate is the most basic physical structure of the soil. Therefore, in order to understand dynamic changes in soil aggregate nutrients as vegetation restoration progresses, we set out to investigate the nutrient distribution and utilization in aggregates, and how enzymes respond to the nutrient changes in achieving a nutritional balance along successive stages of vegetation restoration. Materials and Methods: We collected and analyzed soil from plots representing six different stages of a vegetation restoration chronosequence (0, 30, 60, 100, 130, and 160 years) after farmland abandonment on the Loess Plateau, China. We investigated soil nutrient stoichiometry, GRSP, and enzyme stoichiometry in the different successional stages. Results: The results revealed that soil organic carbon, total nitrogen, enzyme activity, and GRSP increased with vegetation recovery age, but not total phosphorus, and not all enzymes reached their maximum in the climax forest community. The easily extractable GRSP/total GRSP ratio was the largest at the shrub community stage, indicating that glomalin degradation was the lowest at this stage. Ecological stoichiometry revealed N-limitation decreased and P-limitation increased with increasing vegetation restoration age. Soil enzymes had a significant impact on the GRSP production, directly and indirectly affecting nutrient metabolism balance. Conclusions: Further study of arbuscular mycorrhizal fungi to identify changes in their category and composition is needed for a better understanding of how soil enzymes affect their release of GRSP, in order to maintain a nutrient balance along successive stages of vegetation restoration.

In order to promote the application range, double‐network hydrogels are usually fabricated to improve the mechanical properties. In this work, chitosan (CS) single‐network hydrogels were prepared firstly and sodium alginate (SA) was introduced as the second network. According to scanning electron microscopy (SEM), the microstructures of the CS and SA single‐network were identified as three‐dimensional network of pore and fiber structure, respectively. The microstructure maintained the pore structure after the formation of CS/SA double‐network due to the small amount of SA. The size of the pores was reduced, indicating the cross‐linking of the double‐network. The rheological results indicated that CS/SA double‐network with small amount of SA could enhance the mechanical strength of the hydrogel effectively. Finally, the in vitro release was operated, verifying the sustained release ability of the double‐network hydrogel. In addition, only small amount of the drug could be release in physiological environment (pH 7.4), while a quickly release was obtained in pathological tissue (pH 5.5), decreasing the side effect of the drug.

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Soil ecoenzymatic stoichiometry reflects the nutrient flow of ecosystems. While knowledge exists on how the secondary succession of plants affects soil physicochemical properties and soil ecoenzymatic activity, less is known about how soil ecoenzymatics change during this process. We investigated five typical stages of the entire succession process of vegetation on the Loess Plateau, China. These stages included: (1) farmland stage (0 years), (2) grassland stage (30 years), (3) shrub land stage (60 years), ( 4) the pioneer forest stage (100 years), ( 5) the climax community stage (160 years). Soil ecoenzymatic activity, microbial biomass, and soil physicochemical properties were measured. Our research showed secondary succession significantly changed soil enzyme activity, and the metabolic activity of soil microorganisms significantly declines as secondary succession progresses. N limitation in the soil microbial community was weak initially and then gained strength. P nutrient limitation was strong initially, and then weakened. Soil ecoenzymatic C : N : P acquisition ratios deviated from 1 : 1 : 1. Thus, secondary succession on the Loess Plateau is nutrient dependent, but not homeostatic. Soil physicochemical properties and plants were important factors for soil enzyme activities. In addition, soil available nutrients were better than soil total nutrients to reveal changes in soil ecoenzymatic activities and stoichiometry.This study demonstrated the regularity of soil nutrient cycling during the secondary succession of vegetation, providing new insights on the mechanisms of nutrient flow.

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