植物叶片是植物与环境发生气体交换的主要器官,其δ13C 差异主要受植物类型、温度、降水量、生长地水文环境以及植物体内有机质含量等因素影响,在这些因素诱导下会使植物体内有机质产生不同程度的碳同位素分馏.氨基酸作为自然界构成生命的基本单元之一,叶片内氨基酸碳稳定同位素值的变化可以反应植物生长过程的环境变换及自身代谢规律,单个氨基酸能记录更为精细准确的环境信息.为此本研究基于提取植物叶片内游离氨基酸的实验方法,以秦岭南北地区的植物为研究对象,探究了相同地区不同种类与不同地区相同种类两组植物叶片内特定氨基酸含量及其对应的δ13C值变化,获得如下认识:(1)气候处于相对较冷的环境,植物生长速度缓慢,氨基酸δ13C值较高;气温有上升趋势时,氨基酸δ13C值有所下降,温度与各氨基酸的δ13C值呈负相关性;(2)在植物正常生长情况下,叶片内单个氨基酸δ13C值规律有:δ13 CIle>δ13 CVal、δ13 CIle>δ13 CLeu、δ13 CTyr>δ13 CPhe;(3)环境胁迫影响下,叶片内 Phe 含量减少,其他氨基酸含量增加;δ13 CTyr相对贫化,其他氨基酸δ13C相对富集.
Plants leaves are the main organ of gas exchange between plants and environment.The differences of δ13 C in plant blades are mainly affected by plant types,temperature,pre-cipitation,hydrological environments,and organic matter content.These factors induce differ-ent degrees of carbon isotope fractionation of organic matter in plants.Carbon stabilization i-sotope of amino acids(δ13 CAAS)which is one of the basic units of natural life in leaves can re-flect the environmental transformation of plant growth and its own metabolic law,and single amino acid can record more precise and accurate environmental information.To this end,this study is based on the experimental method of extracting amino acids in plant leaves.There-fore,this study selected northern and southern areas of Qinling Mountains as the research site,and extracted free amino acids from higher plants leaves.The content of specific amino acids and correspondingδ13 C values in leaves of two groups of plants of different species in the same area and the same species in different areas were investigated,get the following con-clusions:(1)Plant growth rate was slow andδ13 CAAS were high in relatively cold climate;δ13 CAAS decreased when the temperature increased,andδ13 CAAS were negatively correlated with temperature;(2)Under normal plant growth,theδ13 C values of single amino acids in leaves are:δ13 CIle>δ13 CVal,δ13 CIle>δ13 CLeu,δ13 CTyr>δ13 CPhe;(3)Under the influence of environmen-tal stress,the content of Phe in leaves decreased,while the content of other amino acids in-creased;δ13 CTyr was relatively depleted,and δ13 C of other amino acids were relatively en-riched.