Effects Of High Temperature On Main Amino Acids Metabolism Enzymes Activities And Nutritional Quality At Rice Grain-filling Stage

The rice conventional Japonica rice variety Koshihikari and conventional Indica rice variety IR72were selected as the materials and the the test of artificial temperature control was used to construct high temperature(HT) and normal temperature(CK) to study on the effect of HT on the the main amino acids metabolism enzymes activities and nutritional quality in grains during rice grain filling. The results were as followes.1. The GS activities in grains changed as no rule during rice grain filling, and the GS average activities(the average of the6times measured) decreased extremely remarkably under the HT, as compared to CK. The GOGAT activities in grains changed as an unimodal curve during rice grain filling, and the GOGAT average activities were higher than that of CK, without the remarkable difference.2. The AST activities in grains changed as an unimodal curve during rice grain filling, and the AST average activities increased remarkably or extremely remarkably under the HT, as compared to CK. The AK activities in grains also changed as an unimodal curve during rice grain filling, and the AK average activities increased extremely remarkably under HT.3. The ALT activities in grains changed as an unimodal curve during rice grain filling as a whole, and the AST average activities increased extremely remarkably under HT, as compared to CK.4. In conventional Japonica rice variety Koshihikari under the HT, the content ofGlu family amino acids(Glu, Arg and Pro) increased remarkably, the content of Asp family amino acids(Asp, Thr, Met and Lys) increased remarkably, while there is no remarkable difference of Ile content between HT and CK, the content of Ala family amino acids(Ala, Val and Leu) increased remarkably, and the content of amino acids and protein increased extremely remarkably. In conventional Indica rice variety IR72under the HT, the content of Glu family amino acids(Glu and Arg) increased remarkably, while there is no remarkable difference of Pro content between HT and CK, the content of Asp family amino acids(Asp, Lys and Ile) increased extremely remarkably, the Thr content increased remarkably, while there is no remarkable difference of Met content between HT and CK, the content of Ala family amino acids(Ala, Val, Leu) increased extremely remarkably, and the content of amino acids and protein increased extremely remarkably. The rate of the content of essential amino acids/protein(P) in rice increased as a whole under HT during rice grain filling. The rate of Thr/P, Met/P, Lys/P, Ile/P, Val/P, Leu/P and Phe/P in conventional Japonica rice variety Koshihikari increased by0.92%,0.12%,0.01%,0.61%,1.44%,0.94%and0.21%,respectively, as compared to CK. The rate of Thr/P, Lys/P, Ile/P, Val/P, Leu/P and Phe/P in conventional Japonica rice variety Koshihikari increased by0.43%,0.03%,0.28%,0.47%,0.20%and1.13%, respectively, as compared to CK, while the rate of Met/P decreased by0.41%.5. The results indicated that HT during rice filling was benefit for the increase of relative content of protein components and Asp-family amino acids, the accumulation of glutelin and Asp-family amino acids, and the improvement of the ratio of part of Asp-family amino acids in crude protein. However, the income of protein components and part of Asp-family amino acids in spikelet decreased under HT during rice grain filling.6. The value of Peak viscosityand Breakdown in rice RVA under HT during rice grain filling decreased and the value of Trough, Final viscosity andSetback increased. The eating quality of rice decreased under HT.7. It existed no remarkably correlation between protein content and breakdown, through and setback, which suggested that the decline of eating quality of rice under HT was not regulated by protein content. It’s existed remarkably positive correlation between Phe and setback and trough, and negative correlation between Phe and breakdown, suggested that Phe was the main amino acid which affect the eating quality of rice. It existed remarkably or extremely remarkably negative correlation between most amino acids and peak viscosity, remarkably or extremely remarkably remarkably or extremely remarkably between most amino acids and final viscosity and setback, suggested that the decline of eating quality under may be regulated by peak viscosity, final viscosity and setback which was affected by amino acids.