UV-B辐射对黄芩幼苗生长及生理生化指标的影响

Effects of UV-B radiation on growth and physiological-biochemical indexes of Scutellaria baicalensis seedlings

对经过11.8μW.cm-2UV-B连续辐照7 d后黄芩(Scutellaria baicalensis Georgi)幼苗的生长及一些生理生化指标进行了测定和分析。结果表明:经11.8μW.cm-2UV-B辐照7 d后,黄芩幼苗的平均株高和单株平均干质量分别为8.1 cm和0.026 g,与对照无显著差异(P>0.05);叶片的叶绿素a、叶绿素b、总叶绿素及类胡萝卜素含量分别为2.89、1.04、3.93和0.48 mg.g-1,均极显著低于对照(P<0.01);叶绿素a/b比值以及类胡萝卜素/总叶绿素比值分别为2.78和0.122,分别显著或极显著高于对照(P<0.05,P<0.01);叶片中的CAT和POD活性均极显著高于对照(P<0.01),分别为2 412和2 208 U.g-1;SOD活性(1 228 U.g-1.h-1)较对照略有升高,但差异不显著(P>0.05);叶片中的抗坏血酸(ASA)及游离脯氨酸含量均显著高于对照(P<0.05),分别为11.5 mg.g-1和57.7μg.g-1;MDA含量高于对照,紫外吸收物相对含量和苯丙氨酸解氨酶(PAL)活性均低于对照,但差异不显著(P>0.05)。研究结果显示,11.8μW.cm-2UV-B连续辐照7 d对黄芩幼苗的生长无显著抑制作用,黄芩幼苗能够通过自身的抗氧化系统有效减轻UV-B辐射产生的氧化损伤,对UV-B辐射表现出一定的耐受能力。

The growth indexes and some physiological-biochemical indexes of Scutellaria baicalensis Georgi seedlings radiated continuously for 7 d with 11.8 μW· cm-2 UV-B were determined and analyzed.The results show that after radiated with 11.8 μW·cm-2 UV-B for 7 d,average height and dry weight of individual of S.baicalensis seedlings are 8.1 cm and 0.026 g,respectively,and have no significant difference with the control（P0.05）.The contents of chlorophyll a（Chla）,chlorophyll b（Chlb）,totalchlorophyll（Chl） andcarotenoid（Car） inleavesare 2.89,1.04,3.93 and 0.48 mg·g-1,respectively,and those allare extremelysignificantly lower thanthose ofthe control（P0.01）.While ratios of Chla/Chlb and Car/Chl are 2.78 and 0.122,respectively,which are significantly and extremely significantly higher than those of the control（P0.05,P0.01）,respectively.CAT and POD activities in leaves are extremely significantly higher than those of the control（P0.01） and reach 2 412 and 2 208 U·g-1,respectively,and SOD activity（1 228 U·g-1·h-1） in leaves enhances slightly comparing with the control but the difference is not significant（P0.05）.Contents of ascorbic acid（ASA） and free proline in leaves are significantly higher than those of the control（P0.05）,with the value of 11.5 mg·g-1 and 57.7 μg·g-1,respectively.MDA content is higher while UV-Absorbing compound relative content and phenylalanine ammonia-lyase（PAL） activity are lower than those of the control,but the differences are all not significant（P0.05）.It is suggested that the continuous radiation for 7 d with 11.8 μW·cm-2 UV-B has no obvious inhibition to the growth of S.baicalensis seedlings,and the oxidative damages caused by UV-B radiation can effectively reduce by means of own antioxidant system.Thus,S.baicalensis seedling exhibits a certain tolerance ability to UV-B radiation.