山黧豆根适应铕环境生理代谢的表达

Expression of biological metabolism adapt to Europium Ions (Eu^(3+)) environment in Lathyrus sativus roots

对培植在砂基中的山黧豆 LathyrussativusL. 幼苗经0.5mmol·L-1Eu3+和水 对照 根灌处理后,用扫描电镜和X-射线能量色散谱仪顺序定位检测根横断面表皮、外皮层、内皮层、维管柱各元素的百分含量;同时测定了与检测元素相关的根内活性氧、多胺产生生理活性指标.由于Eu3+的影响,使其根内响应产生生理代谢机制的变化,分布在根横断面不同组织中的各元素的百分含量不一样,主要是对生物活性中起作用的P、S、Ca、Mn4种元素影响较大,与测定的其它元素相比较,代谢利用率高;元素由低活性部位向高活性部位流动,表现出各元素由外向内,由表皮吸收运送到维管柱韧皮部、筛管运至植物各器官被利用的规律性.同时,由于Eu3+价态变化引起二者相关酶中离子的价态变化,致使植物体内自由基和多胺产生机制的响应变化,二者之间存在着一定的互补性,二者比值始终维持在一定的比例水平上,是Eu3+影响二者之间存在着的共同活性位点起作用的结果.

Scanning electron microscope and energydispersive Xray analysis were used to study the distributions of all kinds of elements in epidermis,exodermis,endodermis and vascular cylinder of fracture face in the roots of Lathyrus sativus which were irrigated by 0.5 mmol·L-1 Eu3+ or water in sand.Some index of the biological activity related to the elements binding with reactive oxygen species and polyamine,were determined too.After treated by Eu3+,the mechanism adapt to metabolism in Lathyrus sativus roots varied and the percentage of tissular distributions of elements in fracture face was changed.The atomic percentages of P,S,Ca and Mn were influenced more than those of other elements.The four mobile and reusable elements possessing high utilization efficiency,had the regularity of transporting from low active site to high active site and from epidermis to various organs through the phloem of vascular cylinder and sieve vessel.The change of valence of Eu3+ resulted in the change of the mechanisms which produced reactive oxygen species and polyamine through influencing the valence of ions binding with the related enzymes.The more polyamine perhaps complemented the more reactive oxygen species and their ratio maintained a relative constant value.Eu3+ functioned through influencing their common active sites.