Effects Of Low Light On Key Enzymes Activities Of Nitrogen Metabolism And Nutritional Quality In Rice During Grain-filling Stage

The rice varieties of Koshihikari(Japonica), Akita Komachi(Japonica), IR72(Indica) and Gang-you527(Indica hybrid rice) were used in this essay.They were shaded during grain-filling stage and the CK was natural light. Studying the effects of low light on key enzymes of nitrogen metabolism and quality in rice in grain-filling stage,the results were as follows:1 Effect of low light on GS activityGS activities of the four varieties of grains were present first increasing and then decreasing trend,the rice varieties of Indica earlier 7 days than the rice varieties of Japonica to the peak and the rice varieties of Japonica were higer than the rice varieties of Indica at the same treatement. The activities of GS in Koshihikari,Akita Komachi,Gang-you527 and IR72 grains were lower than the CK under shading treatment,and the greater the degree of shading,the lower the enzyme activities.Compared to CK,the GS total activities of grains increased or decreased extremely significantly both under 25% shading and 50% shading.The author believed that the GS was not a key enzyme in grain nitrogen metabolism to restrain the synthesis of protein.2 Effect of low light on GOT and GPT activityExcept Akita Komachi,the GOT activities of grains showed a slight increase early and decrease in the later.The GOT activities of grains of the other three varieties decreased gradually,the sequence of degree of decrease being Koshihikari>IR72>Gang-you527;but the GOT activities of four varieties of grains were in the same trends that decreased gradually,the sequence of degree of decrease being Koshihikari>IR72>Akita Komachi,Gang-you527.Look from the whole range of change,the greatest change of GOT and GPT activities was Koshihikari.The GOT and GPT activities of four varieties of grains under shading were all higher than CK and the greater the degree of shading,the higher the enzyme activities.Compared to CK,the GOT and GPT total activities of grains increased extremely significantly under different shading.3 Effect of low light on soluble protein in grainsThe soluble protein content of four varieties of grains were in the same trends that decreased gradually,and the greatest change of soluble protein content was Koshihikari.The soluble protein content of four varieties under shading were all higher than the CK and the greater the degree of shading, the higher content of soluble proteins. Compared to CK,the content of soluble protein increased extremely significantly under different shading.4 Effect of low light on protein and amino acidThe protein content and total content of amino acid of four varieties were in the same trends. The protein content and total content of amino acid under shading were all higher than CK, and gradually incresed with the degree of shading. Compared to CK, they increased significantly or extremely significantly in different shading. The content of amino acids components(except for individual amino acids) also increased with the degree of shading, and they all reached significantly or extremely significantly level compare with CK.5 Effect of low light on rice amyloseAmylose content and protein content was negatively correlated.The amylose content under shading were all lower than CK,and gradually decreased with the degree of shading,the law was obvious. The amylose content of four varieties of grain in order of:IR72>Gang-you527>Akita Komachi>Koshihikari.