Root pruning is commonly used to facilitate seedling transplantation for the restoration of degraded or damaged ecosystems. However, little is known about how root growth coordinates morphology, physiology and defense functions following root pruning. We aim to elucidate whether and how root growth trades off with defense functioning after pruning. Seedlings of Platycladus orientalis, a tree species widely used in forest restoration, were subjected to root pruning treatment. A suite of root growth, morphological and physiological traits were measured after pruning in combination with proteomic analysis. Root growth was insensitive to pruning until at 504 h with a significant increase of 16.8%, whereas root physiology was activated rapidly after pruning. Key root morphological traits, such as root diameter, specific root length and root tissue density, showed no response to the pruning treatment. Plant defense syndromes such as reactive oxygen species-scavenging enzymes and defensive phytohormones such as jasmonic acid and abscisic acid, were recruited at six hours after pruning and recovered to the unpruned levels at 504 h. Compared with the controls, 271, 360 and 106 proteins were differentially expressed at 6, 72 and 504 h after root pruning, respectively. These proteins, associated with defense function, showed temporal patterns similar to the above defense syndromes. Our results suggest a root growth-defense tradeoff following root pruning in P. orientalis. This tradeoff was potentially due to the significant increase of indole-3-acetic acid, the phytohormone stimulating root branching, which occurred soon after pruning. Together, these results provide a holistic understanding of how root growth is coordinated with root morphology, physiology, and defense in response to root pruning.

Constructing interfacial sites in catalysts is an effective strategy to improve catalytic performance. Here, we insert cerium atoms into zirconia via a co-precipitation method. Cerium atoms exist in the form of a single atom in zirconia, and extensive atomic interfaces along with oxygen vacancies were generated, thus greatly improving the low-temperature reducibility and surface oxygen mobility of the inserted catalysts. DFT calculations verified that molecular oxygen was easily adsorbed on the defective tetragonal ZrO₂ (011) facets with an energy of −0.53 eV and the distance of the O–O bond was elongated to 1.46 Å, forming the highly active oxygen species with a superoxide-type character. By comparing with pure zirconia and the corresponding impregnated sample, the inserted catalyst not only exhibited excellent catalytic activity, high specific reaction rate and low activation energy, but also possessed satisfactory stability in long-term, water and sulfur resistance tests. In situ DRIFTS spectra further revealed that the defective atomic interface could elevate ring-opening ability and accelerate the toluene reaction process, thus significantly promoting the catalytic performance.

To reveal the effects of different land-use types on soil enzyme activities, soil samples were collected from 0–10, 10–20 and 20–30 cm soil layers to compare and analyze soil β-glucosidase (BG), urease (URE), protease (PROT) and catalase (CAT) activities in farmland (FL), abandoned land (AL) and three plantation forests: Platycladus orientalis (L.) Franco (PO), Robinia pseudoacacia L. (RP) and Quercus variabilis Bl. (QV) in the rocky mountainous region of North China. The results showed that the soil enzyme activities varied significantly under different land-use types, and the interannual mean values of FL and PO were remarkably higher than those of other land uses in the 0–30 cm soil layer, in which the soil BG and URE activities of FL were 22% and 12% higher than those of AL, and 428% and 179% higher than those of QV, respectively; the soil PROT and CAT activities of PO were 66% and 23% higher than those of AL, and 479% and 113% higher than those of QV, respectively. Soil BG, URE and PROT activities were all higher in June and lower in December, while soil CAT activity was slightly lower in June. The soil enzymatic activities all showed a notable decrease with the depth of the soil layer. Soil BG, URE, PROT and CAT activities were remarkably (p < 0.01) or significantly (p < 0.05) positively correlated with available nitrogen, available phosphorus, available potassium, dissolved organic carbon (DOC), NO₃⁻-N, soil organic carbon, water content, clay and silt volume fraction, and significantly negatively correlated with sand volume fraction. Soil DOC and pH were important factors influencing soil enzymatic activity, implying that changes in soil enzymatic activity under different land-use types may be the result of a combination of temperature, moisture and plant type. In conclusion, PO plantations are conducive to improving the physicochemical and biological properties of soil and enhance soil fertility, which is a reasonable land-use method to achieve sustainable development in the rocky mountainous region of North China.