One-time application of controlled-release bulk blending fertilizer enhances yield,quality and photosynthetic efficiency in late japonica rice

Controlled-release urea(CRU)releases nitrogen(N)at the same pace that rice takes it up,which can effectively improve N use efficiency,increase rice yield and improve rice quality.However,few studies have described the effects of CRU application on the photosynthetic rate and endogenous enzyme activities of rice.Accordingly,a twoyear field trial was conducted with a total of seven treatments:CK,no N fertilizer;BBF,regular blended fertilizer;RBBF,20%N-reduced regular blended fertilizer;CRF1,70%CRU+30%regular urea one-time base application;CRF2,60%CRU+40%regular urea one-time base application;RCRF1,CRF1 treatment with 20%N reduction;and RCRF2,CRF2 treatment with 20%N reduction.Each treatment was conducted in triplicate.The results showed that the N recovery efficiency(NRE)of the controlled-release bulk blending fertilizer(CRBBF)treatments was significantly greater over the two years.There were significant yield increases of 4.1–5.9%under the CRF1treatment and 5.6–7.6%under the CRF2 treatment compared to the BBF treatment,but the differences between the reduced-N treatments RBBF and RCRF2 were not significant.Photosynthetic rates under the CRF1 and CRF2treatments were significantly higher than under the other treatments,and they had significantly greater RuBPCase,RuBisCO,glutamate synthase(GOGAT)and glutamine synthetase(GS)enzyme activities.Additionally,the soil NH_(4)^(+)-N and NO_(3)^(–)-N contents under the CRBBF treatments were significantly higher at the late growth stage of rice,which was more in-line with the fertilizer requirements of rice throughout the reproductive period.CRBBF also led to some improvement in rice quality.Compared with the BBF and RBBF treatments,the protein contents under the CRBBF treatments were reduced but the milling,appearance,eating and cooking qualities of the rice were improved.These results showed that the application of CRBBF can improve the NRE,photosynthetic rate and endogenous enzyme activities of rice,ensuring sufficient N nutrition and photosynthetic material production during rice growth and thereby achieving improved rice yield and quality.

Effects of edible whole citrus fruits on endogenous antioxidant enzymes of HepG2 cells

The effects of eating fresh citrus fruits including two varieties of mandarins,one of sweet oranges,one of grapefruit,two of pomelo,and one of kumquat cultivated in China on endogenous antioxidant enzymes were investigated by in vitro digestion and HepG2 cells.The correlations between enzyme activity and cell uptake of phytochemicals and cellular antioxidant capacities were analyzed.The results showed that most fresh citrus fruits increased the endogenous antioxidant activity.Bairoumiyou,Hongroumiyou,Ponkan,and Jinju after digestion significantly increased the activity of catalase(P<0.05).Hongroumiyou,Bairoumiyou,Ponkan navel orange,and Jinju after digestion significantly increased glutathione peroxidases(GPxs)activity(P<0.05),while Huyou and satsuma could not increase the activity of GPxs after digestion.Thioredoxin oxidoreductase activity was improved significantly by most of the digested whole citrus fruits except Ponkan(P<0.05)and thioredoxin oxidoreductase added whole citrus fruits had a higher increase than added citrus fruits extracts.The results indicated that edible whole citrus fruits had similar effects as extracts on enzymes.