No abstract

Since CO2 is the fundamental substrate for photosynthesis, fluctuating concentrations have a direct effect on plant growth and metabolism. Accordingly, CO2 enrichment within a certain range was found to improve photosynthesis, yields and the quality of plants. In order to further understand the underlying impact of CO2 enrichment, this study employed an open-top chamber growth box model with the following two treatments: control treatment (CO2 concentration: 380 ± 30 μL/L) and CO2 enrichment (1200 ± 50 μL/L). The effects on leaf carbon assimilation, fruit yield and quality were subsequently determined. The net photosynthetic rate, intercellular CO2 concentration, dry matter accumulation and soluble sugar content in the oriental melon leaves increased significantly on day 5 of CO2 enrichment. Moreover, a significant increase in the activity of carbon assimilation-related enzymes Rubisco, RCA, FBPase and CA was also observed, with the upregulation of CmRubisco, CmRCA, CmFBPase and CmCA gene expression from day 15 of CO2 enrichment. Thus, the yield per plant and content of soluble sugars and soluble solids in the fruit also increased significantly. These findings suggest that CO2 enrichment has positive effects on oriental melon growth, increasing photosynthesis and the activity of photosynthetic carbon-assimilation-related enzymes and associated gene expression, thereby improving fruit yields and quality. These results provide a foundation for the CO2 enrichment of oriental melon cultivated in solar greenhouses in autumn/winter and winter/spring.

Summary To improve the thermal stability Lacto‐N‐biose (LNB), it was encapsulated by the OVA‐CMC microparticles system. When the mass ratio of OVA:CMC:LNB was 1.5:1:1, the particle size of microparticles was 623 ± 4 nm, and the encapsulation efficiency and loading efficiency of 83 ± 1.38% and 45 ± 0.92% respectively. Analysis with the scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT‐IR) and X‐ray diffraction (XRD) revealed that the OVA‐CMC‐LNB microparticles were spherical and uniformly distributed. The hydrogen bonding and electrostatic interactions were the main forces to assemble the microparticles. The results of the thermogravimetric analysis showed that the structure of microparticles remained stable at 240 °C. The residual amount of LNB in microparticles reached 94.3 ± 1.03% and 78.8 ± 2.38% after being heated at 90 °C for 10 and 30 min, and the thermal stability was greatly improved. In vitro simulated digestion experiments showed that the release rate of LNB in microparticles reached 95 ± 1.31%. These results provided a theoretical and technological approach for the construction of LNB delivery system improved thermal stability.