结实期氮磷营养水平对水稻根系和籽粒氨基酸含量的影响

以扬稻6号(籼稻)和扬粳9538(粳稻)为材料，在水培条件下自抽穗至成熟以0N (不施N)、1/2N (标准Espino营养液的1/2N)、0P (不施P)、1/2P (标准Espino营养液的1/2P)以及对照 (全NP，标准Espino营养液的N、P量) 5种处理，研究了根系分泌氨基酸和籽粒氨基酸含量与组分的变化。结果表明，结实期水稻根系分泌的各种氨基酸含量均随灌浆进程而逐渐降低。与对照相比，结实期氮素胁迫(0N)明显降低根系分泌的各种氨基酸和籽粒中各种氨基酸的含量；磷胁迫(0P)则显著增加了根系酸性和中性氨基酸的分泌，但显著降低籽粒氨基酸总量、必需氨基酸及其他氨基酸含量。结实前中期(抽穗后10 d和20 d)根系分泌的氨基酸与籽粒氨基酸相对含量、根系分泌的碱性氨基酸与籽粒的千粒重呈显著或极显著负相关。表明结实期根系分泌的氨基酸与籽粒氨基酸及粒重有密切关系；N、P营养水平对根系分泌的氨基酸和籽粒氨基酸组分和含量有调控作用，进而影响产量和稻米的营养品质。

Effect of Nitrogen and Phosphorus on the Amino Acids in Root Exudates and Grains of Rice during Grain Filling

Nitrogen (N) and phosphorus (P) play important roles in regulating plant growth and development. The purpose of this study was to investigate how N and P nutrients affect amino acids in the root exudates and grains of rice using two rice cultivars, Yangdao 6 (indica) and Yangjing 9538 (japonica), with five treatments, 0N (without N), 1/2N (1/2 N of the standard Espino nutrition solution), 0P (without P), 1/2P (1/2 P of the standard Espino nutrition solution), and CK (standard Espino nutrition solution) during the grain filling period. The concentrations and components of amino acids in root exudates and grains were measured, and their relations were analyzed. The results showed that the concentration of each amino acid in root exudates decreased gradually with the process in grain-filling. Nitrogen stress (0N) during grain filling significantly reduced concentrations of the each amino acid in root exudates and grains. Phosphorus stress (0P) significantly increased concentrations of acidic and neutral amino acids in root exudates, whereas significantly reduced the contents of total amino acids, essential amino acids, and other amino acids in grains. The concentrations of amino acids in root exudates were significantly and negatively correlated with the relative content of amino acids in grains, and the concentration of alkali amino acids in root exudates was significantly and negatively correlated with 1 000-grain weight. The results suggest that the concentration and components of amino acids in root exudates are closely associ-ated with those in grains and with grain weight. N and P nutrients play a role in regulating the concentrations/contents and com-ponents of amino acids in roots and grains, and by which influence grain yield and nutrient quality of rice.