[Studies on ANN models of determination of tea polyphenol and amylose in tea by near-infrared spectroscopy].

The objectives of the present paper were to build the models for the determination of tea polyphenol (TP) and tea amylose (TA) in tea by near-infrared spectroscopy (NIR). According to the range of 7432.3-6155.7 cm(-1) and 5484.6-4192.5 cm(-1) of NIR spectra, the models are built for determining the contents of TP and TA in tea with the input layer, hidden layer and node ((8, 4, 1) and (7, 5, 1) respectively) in network structure by the artificial neural network. The correlation coefficient (r), the root mean square error of cross validation (RMSECV) and the root mean square error of prediction (RMSEP) were selected as the indexes for evaluating the performance of calibration models. The results show that r, RMSECV and RSECV by the model samples for TP and TA are 0.9847, 0.460 and 0.123, and 0.9470, 0.136 and 0.224 respectively, and r, RMSEP and RSEP by the prediction samples for TP and TA are 0.9804, 0.529 and 0.017, and 0.9682, 0.111 and 0.0298 respectively. These indicated that the NIRANN models can be used to determine the contents of TP and TA in tea.

[Purification and some characteristics of germins G and psiG from wheat].

By affinity chromatography, germins G and psiG were purified from roots of wheat seedling and wheat embryos imbibition for 4 h. Characterization of the germins G and psiG were studied. The results showed that G and psiG were stable at temperatures lower than 60 degrees C, and had an optimum pH at 3.5. The Km value of G for oxalate was 0.084 mmol/L, while that of psiG was 0.053 mmol/L. Oxalate showed substrate inhibition effect above 0.2 mmol/L on G and psiG. EDTA, NH(+)(4), Mn(2+), Mg(2+), Na(+) and K(+) at a concentration of 0.1 mmol/L had no effect on OxO activity. CO(2-)(3), NO(-)(3) and SO(2-)(4) at a concentration of 0.1 mmol/L inhibited partially the activities of G and psiG, 0.1 mmol/L Cu(2+), Fe(2+), Al(3+) completely inhibited the activities of G and psiG, but addition of 0.1 mmol/L EDTA partially relieved the inhibition, which indicated that metal cations may make the oxalate unavailable by chelating it. H(2)PO(-)(4) and HPO(2-)(4) inhibited the activity of G, but had no effect on psiG. Riboflavin, FMN and FAD inhibited psiG, but FMN and FAD had no effect on G.

[Pseudogermin activity during maturation and germination of wheat seeds].

The OxO activities of psiG during maturation and germination of wheat seeds were measured by SDS-PAGE followed by OxO activity staining. The results showed that there was no expression of G and G', but only that of psiG during wheat seeds maturation (Fig. 2). 10 days after anthesis, the OxO activity of psiG was observed in glumes, palea, lemma, seed coat and pericarp, then the OxO activities in glumes, lemma, seed coat and pericarp increased rapidly and remained high until the seeds matured (Fig. 2). Basing on the observation that psiG was expressed mainly in the tissues abundant in lignin when cell growth just stopped, it was suggested that psiG may function in promoting lignification of cell wall of glumes, palea, lemma, seed coat and pericarp by producing H(2)O(2) by oxidation oxalate. During wheat seeds germination, psiG was present in vascular transition region in addition to G and G' in Zhongyu 5 (Fig. 3), but it was not necessary for germination.