用电感耦合等离子体原子发射光谱仪( ICP - OES) 测定了甘薯21个品种(系) 5个产地200多份样品中的铁、锌、钙、硒四种有益矿物质营养元素含量。结果表明:铁、锌、钙和硒四种矿物成分含量存在明显的基因型差异,其平均含量分别为38.97、49.02、889.70、0.1472mg/kg(干基) ,相应的变幅依次为1.97～167.86、11.68～245.40、37.63～1925.6 和0.01～0.51 mg/kg (干基) 。不同肉色甘薯铁、锌、钙和硒含量差异不显著;除铁外,锌、钙和硒含量产地间均存在显著差异。

The effects of zucchini yellow mosaic virus (ZYMV) infection and pretreatments with salicylic acid (SA) on biomass accumulation of pumpkin (Cucurbita pepo cv. Eskandarani) were investigated. The response of photosynthesis, transpiration and the activities of antioxidant enzymes in leaves was also considered. Significant reductions in growth parameters (i.e. leaf area, biomass and shoot height), photosynthesis and chlorophyll a and b content were detected in ZYMV-infected leaves in comparison to healthy controls. Antioxidant enzyme activities were increased up to 3-fold for peroxidase (POD), 2-fold for ascorbate peroxidase (APX) and catalase (CAT) activities and 1.3-fold for SOD activity by virus infection. ZYMV infection also caused increases in H2O2 and malondialdehyde (MDA) contents. These results suggest that ZYMV infection causes oxidative stress in pumpkin leaves leading to the development of epidemiological symptoms. Interestingly, spraying pumpkin leaves with SA led to recovery from the undesirable effects of ZYMV infection. Leaves treated with 100 mM SA three days before inoculation had the appearance of healthy leaves. No distinct disease symptoms were observed on the leaves treated with 100 mM SA followed by inoculation with ZYMV. In non-infected plants, SA application increased activities of POD and superoxide dismutase (SOD) and inhibited APX and CAT activities. In contrast, SA treatment followed by ZYMV inoculation stimulated SOD activity and inhibited activities of POD, APX and CAT. In addition, MDA displayed an inverse relation, indicating inhibition of lipid peroxidation in cells under SA treatment. It is suggested that the role of SA in inducing plant defense mechanisms against ZYMV infection might have occurred through the SA-antioxidant system. Such interference might occur through inhibition or activation of some antioxidant enzymes, reduction of lipid peroxidation and induction of H2O2 accumulation following SA application.

A rapid predictive method based on near-infrared reflectance (NIR) spectroscopy (NIRS) was developed to measure sweetpotato starch physiochemical quality and pasting properties. The starch samples were scanned by NIRS and analyzed for quality properties by reference methods, respectively. Results of statistical modeling indicated that NIRS was reasonably accurate in predicting amylase content (AC), amylose percent (AP), total starch content (TSC), protein content (PRC), phosphorus content (PHC), solubility (SOL), swelling power (SP), average granule diameter (AGD), big granule percent (BGP), small granule percent (SGP), crystallinity (CRY), peak viscosity (PKV), hot paste viscosity (HPV), setback (SB), and pasting temperature (Ptemp) with high coefficients of determination (RSQ = 0.85–0.92) and relatively low standard errors of prediction. The results showed that NIR analysis was sufficiently accurate and effective for rapid evaluation of starch physicochemical properties in sweetpotato. The NIR-based protocol developed in this study can be used for screening large number of starch samples in food enterprises and sweetpotato breeding programs.