| Colored rice refers to caryopsis with a pigment such as red and black.Studies have shown that anthocyanins,proanthocyanidins,total phenols,flavonoids and other secondary metabolites in colored rice are higher than white rice,which is a high-quality health food.At present,the demand for colored rice is increasing,but its output is low and there is no reasonable nitrogen application rate.In this paper,YunnanHei and Honglangman were used as test materials,and five nitrogen fertilizer levels were set(N0:0 kg·hm-2,N1:90 kg·hm-2,N2:135 kg·hm-2,N3:180 kg hm-2,N4:225 kg·hm-2)To investigate the pigment content and its related enzymes of colored rice under different nitrogen levels:phenylalanine ammonia-lyase?PAL?,chalcone isomerase?CHI?,leucoanthocyanin reductase?LAR?and anthocyanin reductase?ANR?were studied.The effects of different nitrogen application rates on photosynthetic characteristics and yield of colored rice were studied.Provide theoretical basis for high quality cultivation of colored rice.The main results are as follows:1.The effect of nitrogen application rate on the pigment content of colored rice.With the increase of nitrogen application rate,the content of secondary metabolites in YunnanHeimi and Honglangman caryopsis increased first and then decreased.YunnanHeimi:Under the treatment of N3(180kg·hm-2),the content of anthocyanins,total phenols and flavonoids was the highest,which was 49.07%,20.32%and 52.08%higher than that of N0 treatment,and the proanthocyanidin content of caryopsis was N2(The treatment of 135kg·hm-2)reached the highest value,which was 55.76%higher than that of N0 treatment.Honglangman:Under N2 treatment,the content of proanthocyanidins and total phenols was the highest,which was 23.54%and 26.90%higher than that of N0 treatment.The content of anthocyanins and flavonoids in caryopsisw as the highest under N3 treatment,which was 15.13%higher than that of N0 treatment.9.20%.2.The variation of pigment accumulation in colored rice.The content of anthocyanins,proanthocyanidins,total phenols and flavonoids in colored rice stalks continued to accumulate with the progress of grouting.The highest in the middle and late filling?24-30 days post anthesis?,and decreased at maturity?36 days post anthesis?.That is,the trend of rising first and then falling.YunnanHeimi:anthocyanins reached the maximum at 30 days post anthesis,proanthocyanidins reached the maximum at 24days post anthesis,and total phenol reached the maximum at 30 days post anthesis;Honglangman:anthocyanins reached a maximum at 24 days post anthesis.The proanthocyanidins reached the maximum at 30 days post anthesis,and the total phenols reached the maximum at 24 days post anthesis;the flavonoids of both varieties reached the maximum at 24 days post anthesis.3.Relationship between pigment accumulation of colored rice and related enzyme activities.The synthesis of anthocyanins,proanthocyanidins,total phenols and flavonoids in colored rice is closely related to the enzymatic activities of PAL,CHI,LAR and ANR.The content of anthocyanin in YunnanHeimi was significantly or significantly positively correlated with PAL,LAR and ANR activities.The content of proanthocyanidins was significantly positively correlated with the activities of PAL,LAR and ANR.The total phenolic content was significantly or extremely positive with PAL and LAR activities.The flavonoid content was significantly positively correlated with PAL and CHI activities.The content of anthocyanin in Honglangman was positively correlated with CHI and ANR activities.The content of proanthocyanidins was significantly or significantly positively correlated with CHI,LAR and ANR activities.The total phenolic content was significantly positively correlated with PAL,CHI and ANR activities.The content of flavonoids was significantly positively correlated with the activities of PAL,CHI and ANR.4.Effects of nitrogen application rate on photosynthetic characteristics of colored rice leaves.Studies have shown that in the various periods after flowering,YunnanHeimi in the range of 0-180 kg·hm-2,with the increase of nitrogen application rate,the net photosynthetic rate of leaves increased,the stomatal conductance increased,the transpiration rate increased,and the SPAD value increased.The cell gap carbon dioxide concentration decreased;the nitrogen application rate increased to 225 kg·hm-2,the net photosynthetic rate,transpiration rate,stomatal conductance and stomatal limit value of the leaves were significantly decreased,the intercellular carbon dioxide concentration was significantly decreased,and the photosynthesis of the leaves was not affected.Stomatal restriction.Honglangman in the range of 0-135 kg·hm-2,with the increase of nitrogen application rate,the net photosynthetic rate of leaves increased,stomatal conductance increased,transpiration rate increased,SPAD value increased,cell gap carbon dioxide concentration decreased;nitrogen application rate When increased to 180 kg·hm-2,the net photosynthetic rate,transpiration rate,stomatal conductance and stomatal limitation of the leaves were significantly decreased,the carbon dioxide concentration in the intercellular space was significantly decreased,and the photosynthesis of leaves was restricted by non-stoma.5.Nitrogen fertilizer can significantly increase the effective panicle,panicle number and 1000-grain weight per unit area of colored rice to increase grain yield.Yunnan Heimi had the highest grain yield in N3(180kg·hm-2)treatment,which increased by 15.69%,7.51%,0.30%,and 7.66%,respectively,compared with N0,N1,N2,and N4,and Honglangman was N2(135 kg·hm-2)The grain yield was the highest,which was 16.42%,16.70%,0.42%,and 16.10%higher than that of N0,N1,N3,and N4,respectively.Therefore,under the conditions of this experiment,the optimum nitrogen application rate of Yunnan Heimi is 180kg·hm-2,and the most suitable nitrogen application rate of Honglangman is 135 kg·hm-2. |
PDF Full Text Request