He-Ne激光对增强UV-B辐射后小麦幼苗光合作用的影响

Effects of He-Ne laser on photosynthesis of wheat seedlings exposed to enhanced UV-B radiation

关键词:  He-Ne激光  UV-B辐射  小麦  电子传递速率  光合作用

Key words:  He-Ne laser  UV-B  wheat  the electron transport rate  photosynthesis

摘要:

以“晋麦8号”小麦幼苗为研究材料,分别采用He-Ne激光(辐照剂量为5 mW·mm^-2)、增强UV-B(辐射剂量为10.08 kJ·m^-2·d^-1)以及二者的复合辐照进行处理。循坏处理不同天数(4、5、6、7、8 d)后,利用电导仪、低温荧光测定法检测了小麦叶绿体电子传递速率、膜透性和荧光发射光谱的变化; 采用紫外分光光度计法分别测量了小麦叶肉细胞磷酸烯醇式丙酮酸羧化酶(PEPC)、碳酸酐酶(CA)、乙醇酸氧化酶(GO)、苹果酸脱氢酶(MDH)、叶绿素酶(chlase)和ATPase的活性。结果表明:增强UV-B辐射会使叶绿体的电子传递速率、膜透性、PEPC、CA和ATPase的活性下降,GO、MDH和chlase的活性升高,从而影响叶绿体激发能的分配,导致光合作用活性降低; 而低剂量的He-Ne激光辐照可以部分修复增强UV-B辐射对小麦叶绿体光合作用活性引起的损伤。

Abstract:

The wheat seedlings(jinmai 8)were exposed to He-Ne laser(5 mW·mm^-2),enhanced UV-B radiation(10.08kJ·m^-2·d^-1)and the combined He-Ne laser irradiation and enhanced UV-B radiation. After being treated for different days(4,5,6,7,8 d)circularly,the changes of the rate of electron transport and relative permeability of chloroplasts membrane,fluorescence emission spectrum were tested with electric conductor and low temperature fluorescence spectrometry. The activities of phosphoenolpyruvate carboxylase(PEPC),carbonic anhydrase(CA),glycolate oxidase(GO),malate dehydrogenase(MDH),chlorophyllase(chlase)and ATPase were measured by photometer. The results showed that the rate of electron transport,the activities of PEPC,CA and ATPase had declined by enhanced UV-B radiation. However,the relative permeability of chloroplasts membrane,the activities of GO,MDH and chlase had increased by enhanced UV-B radiation. Distribution of excitation energy also changed. So the photosynthetic activities of chloroplasts were almost lost. However,the certain dose of He-Ne laser irradiation could partly repaire these damages induced by enhanced UV-B radiation.