兴安落叶松游离氨基酸的动态变化与损伤因子的关系

为研究不同损伤因子及其不同损伤程度对落叶松游离氨基酸组分及其含量的影响,用剪叶和落叶松毛虫(Dendrolimussuperans)取食损伤兴安落叶松(Larixgmelinii)幼苗,使用HPLC柱前AccQ.Tag衍生法测定针叶内游离氨基酸的组成及含量的变化。结果表明,松针中含有17种游离氨基酸,以苯丙氨酸含量最高,损伤15d后,剪叶4枝比对照增加36.6%,虫害4枝增加的百分率达到98.3%。剪叶4枝15d后及虫害4枝5d后,损伤25%与50%之间氨基酸总含量差异显著(P0.05),且昆虫取食4枝25%、50%、75%后松针内游离氨基酸总含量的变化趋势与剪叶处理后总氨基酸含量的变化一致,均在处理10d后呈现较高的含量,虽虫害后的氨基酸总含量高于剪叶损伤后的总含量,但二者之间差异不显著。剪叶4枝、8枝、12枝3个损伤程度后针叶内的游离氨基酸含量无显著差异,说明剪叶4枝即能超过落叶松的耐受阈值,达到防御诱导效应。两种处理下多种游离氨基酸的含量均有下降,其中8种氨基酸含量存在显著差异(P0.05),即丝氨酸、谷氨酸、甘氨酸、组氨酸、脯氨酸、半胱氨酸、赖氨酸和苯丙氨酸。表明人工模拟剪叶的损伤方式与虫害都可诱导松树氨基酸组分及含量的变化,而间接影响害虫的生长发育。

Relation between dynamic changes of free amino acid contents in Larix gmelinii needles and injuring factors

Larix gmelinii seedlings under the stresses of cutting needles and caterpillar (Dendrolimus superans) feeding were selected as object for this research. The purpose is to discuss the components and contents of free amino acids with the time which through treatment of cutting needles in different degrees and insect feeding. The change of free amino acid contents in needles was detected by HPLC. The results showed that there were 17 free amino acids in needles. The content of Phenylalanine was at the most, while increased 36.6% in healthy needles on 4 branches after cutting needles compared with control, and increased 98.3% after the treatment of caterpillar feeding 15 days later. The content of total amino acids between induced 25% and 50% in healthy needles had different significance (P<0.05) after needles were cut 4 branches 15days later and fed by caterpillar 5 days later, and the variation of total amino acids quantity presented the same trend within 5 days to 15 days by two treatments and at 10 days which is the maximum content induced,. while the total quantity of amino acids after the treatment of caterpillar feeding was higher than cutting needles induced 25%, 50% and 75% needles on 4 branches, but had no significant difference. Contents of free amino acids in healthy needles after needles on 4, 8 and 12 branches were cut had no significant difference, which showed that larch needles were cut 4 branches could exceed the tolerance threshold and reach defense-induced effects.The contents of many free amino acids decreased and 8 amino acids in undamaged needles changed significantly (P<0.05), which were Serine, Glutamate, Glycine, Histidine, Proline, Cysteine, Lysine and Phenylalanine separately. It showed that artificial leaf-cutting ways and larva feeding could induce changes of free amino acids of larch, and affect the growth and development of insects indirectly.