Yumei Zhou

Coating high concentrations of copper (Cu) on the inner wall of containers prevents root entanglement by inhibiting root tip elongation. However, it remains uncertain whether roots near and far from the container wall differentially absorb Cu, thereby triggering varied defense responses. Two-year-old Camphora officinarum were planted in containers coated with 120 (T1) and 200 (T2) g L⁻¹ Cu(OH)₂ with latex as the carrier. After six months of treatment, obvious root entanglement in containers only coated with latex (T0) and control containers was observed, while no entanglement in T1 and T2. Cu(OH)₂ treatment increased soil and root Cu concentration, which exhibited significant position differences (near-wall vs. far-wall) in T1 and T2. Root Cu concentration near the container wall in T1 and T2 was 3.5 and 3.0 times higher than that far from the container wall, and 19.3 and 32.1 times higher than that in the control. Oxidative stress biomarkers increased with increasing root Cu concentration with the highest levels near the container wall in T2. Excessive Cu increased antioxidant enzyme activities and non-enzymatic antioxidant contents with higher superoxide dismutase, glutathione reductase, glutathione peroxidase, ascorbate peroxidase, ascorbate acid, and reduced glutathione in T1 and higher dehydroascorbate reductase and monodehydroascorbate in T2. Overall, antioxidant enzyme activity in roots was higher near the container wall in T1 while far from the container wall in T2. Excessive and uneven Cu distribution and oxidative stress biomarkers effectively inhibited peripheral root elongation and entanglement. During this process, although antioxidant defense responses were induced, defense capacity was impaired by supra-optimal Cu.

Natto is a functional food, but it produces an unpleasant smell during the fermentation process. To eliminate the unacceptable smell, Lactobacillus bulgaricus and Bacillus subtilis were used to co-ferment soybeans in this study. The optimal conditions of co-fermentation anaerobic fermentation were: fermentation time 20 h, temperature 35 °C, strain ratio 1:1, and inoculum amount 4%. After optimization, fibrinolytic activity, antioxidant activity, polyphenol content, and γ-polyglutamic acid (γ-PGA) yield of Natto were increased by 15.2%, 10.9%, 29.1%, and 72.3%. It also introduced a wealth of probiotics with lactic acid bacteria up to 1.45 X 10¹⁰cfu/g. The co-fermented natto had unique fruity and lactic flavor, and high sensory score based on the flavor and sensory analysis. The activity and value of natto have been increased through co-fermentation, making it possible to improve natto. The online version contains supplementary material available at 10.1007/s13197-024-06062-5.

Small size construction and demolition waste (CDW) is rarely reused and consequently causes environmental problems. CDW can increase aeration porosity of soil due to the big surface area and water absorption. In order to investigate the feasibility and function of CDW as a component of container substrate, we mixed four small sizes CDW (Duranta repens cuttings, clay soil (CS) and pure CDW (CW) as the controls. Cluster analysis and principal component analysis (PCA) were performed to screen the most suitable particle size and proportion of CDW for plant growth and physiological function. The substrate containing 50% 3–6 mm CDW (S6) had the higher aeration porosity, lower water loss, better water retention and permeability, and therefore higher PCA score. The total branch length of plants in the S6 was increased by 18% and 71%, leaf area by 116% and 444%, and net photosynthetic rate by 10% and 59% compared to CS and CW, respectively. The suitable CDW has potential to improve substrate properties and can effectively improve plant growth. Meanwhile, the reuse of CDW can partially alleviate the problem of construction waste disposal and environmental pollution, and provide reference for the research on the combination of CDW and landscaping.

Tundra is one of the most sensitive biomes to climate warming. Understanding plant eco-physiological responses to warming is critical because these traits can give feedback on the effects of climate-warming on tundra ecosystem. We used open-top chambers following the criteria of the International Tundra Experiment to passively warm air and soil temperatures year round in alpine tundra. Leaf size, photosynthesis and anatomy of three dominant species were investigated during the growing seasons after 7 years of continuous warming. Warming increased the maximal light-saturated photosynthetic rate (P_max) by 43.6% for Dryas. octopetala var. asiatica and by 26.7% for Rhododendron confertissimum across the whole growing season, while warming did not significantly affect the P_max of V. uliginosum. The leaf size of Dr. octopetala var. asiatica and Rh. confertissimum was increased by warming. No marked effects of warming on anatomical traits of Dr. octopetala var. asiatica were observed. Warming decreased the leaf thickness of Rh. confertissimum and Vaccinium uliginosum. This study highlights the species-specific responses to climate warming. Our results imply that Dr. octopetala var. asiatica could be more dominant because it, mainly in terms of leaf photosynthetic capacity and size, seems to have advantages over the other two species in a warming world.