氮素胁迫对枳生长发育及其氨基酸含量的影响

Effects of nitrogen stress on the development and amino acid content of trifoliate orange(Poncirus trifoliata(L.) Raf.)

以枳为试材，分析了氮素过量和氮素缺乏胁迫下枳的生长量和叶绿素、IAA、氨基酸含量的变化。结果表明：①胁迫120d后，氮过量处理叶绿素含量较对照升高了29.3％，氮缺乏处理较对照降低了29．9％；氮过量和氮缺乏胁迫下枳地上部鲜重和当年生枝梢长度均低于对照；氮过量胁迫后枳茎尖IAA含量比对照高9．9％，新梢的抽发和生长受到抑制。②叶片为枳各组织中氨基酸含量最丰富的组织；天冬氨酸为枳中含量最多的氨基酸，含量（干重）达1．7g／000g），半胱氨酸、酪氨酸、甲硫氨酸在各组织中的含量极少或检测不到；叶片和二年生茎中多数氨基酸含量在氮过量胁迫后下降，在氮缺乏胁迫后增加；当年生茎中多数氨基酸含量于氮过量胁迫后比对照增加0．8％~48．3％，氮缺乏胁迫后比对照减少15．0％～54．3％；氮过量和氮缺乏胁迫后须根中氨基酸含量均较对照减少，减少幅度为6．2％～30．2％，而氮胁迫下主根和侧根中各氨基酸未呈现统一的变化趋势。

The object of this study was to elucidate the effect of excess and deficiency nitrogen （N） on citrus growth, development and amino acid content. Using trifoliate orange as materials, the change of chlorophyll, growth, IAA and amino acid content were analyzed. The results showed, compare with CK, chlorophyll content increased 29.3% and decreased 29.9% respectively after 120 d excess and deficiency N stress; under both excess and deficiency N stress, the treated plant fresh weight of leaves and stems were lowered and new shoot length was shorter than that of CK; due to the IAA content in stem tip was 9.9% higher than that of CK, the growth of new shoot was restricted significantly under excess N stress. Amino acids analysis indicated that leaves possessed most of the amino acids among all tissues. Aspartate which the content was 1.7 g/（100 g） （dry weight） was the richest amino acid in trifoliate orange, but the content of cysteine, tyrosine and methionine were little or under detected. The content of most amino acids in leaves and biennial stems decreased under excess N stress, but increased under deficiency N stress. Compare to CK, the content of most amino acids in annual stems increased 0.8%-48.3% under excess N stress, but decreased 15.0%-54.3% under deficiency N stress. Under excess and deficiency N stress, the content of most amino acids in fibrous roots decreased 6.2%-30.2% compared to CK. However, the content of different amino acids in taproot and lateral roots did not showed congruous change trend under excess and deficiency N stress.