摘要
由于臭氧层逐渐变薄,到达地球表面UV-B辐射不断增加,因UV-B辐射改变的太阳光谱将会对陆地植物造成不同程度的伤害。本试验以高粱龙杂5为材料,对二叶一心高粱进行四种剂量UV-B处理,恢复2d采用光合仪测定光合参数,并取样测定抗氧化酶活性。随着UV-B剂量的升高,高粱叶片褐化损伤加重,植株矮化,鲜重和干重显著降低;花青素含量显著升高,叶绿素和类胡萝卜素含量显著减少,净光合速率和叶绿素荧光参数显著下降。同时,随UV-B剂量升高,高粱幼苗气孔导度、胞间CO_2浓度和蒸腾速率表现为"降-升-降"变化;POD和CAT活性呈现"降-升-降"变化;SOD和GR活性呈现"降-升"变化,APX和GPX呈现"升-降-升"变化。在供试的四种剂量中,UV-B处理6h(相当2.4J·m^(-2))的高粱幼苗净光合急剧下降,其他光合指标以及抗氧化酶活性也表现出明显转折。结果表明,增强的UV-B辐射直接导致高粱光合色素、净光合速率和叶绿素荧光参数的改变;高粱抗氧化系统对高、低剂量UV-B响应机制不同,其中ASA-GSH循环对低剂量UV-B反应更敏感,高剂量UV-B辐射不仅破坏高粱光合作用,而且启动植物酶促和非酶抗氧化系统,导致叶片褐化坏死,植株生物量累积减少、株高矮化,甚至死亡。
The UV-B radiation on the surface of our planet has been enhanced due to gradual thinning of ozone layer.The change of solar spectrum UV-B radiation will cause damage to all kinds of terrestrial plants at certain degree.In this paper,taking breeding sorghum(Sorghum bicolor(L.Moench))variety Longza No.5 as sample,40μW·cm^(-2) UV-B radiation treatment was conducted on sorghum seedlings at two-leaf and one-heart stage and different time courses;then after a 2d recovering,photosynthetic parameters were measured with a photosynthetic apparatus;the activities of antioxidant enzymes were detected as well.Our results revealed that,as the dosages of UV-B increasing,leaf browning injury was aggravated,plants dwarfing and significantly were reduced fresh weight and dry weight were observed;anthocyanin content was significantly increased;chlorophyll and carotenoid content significantly were reduced and net photosynthetic rate and chlorophyll fluorescence parameters were decreased.Meanwhile,with the increase in UV-B dosages,stomatal conductance,intercellular CO_2 concentration and transpiration rate showed"down-up-down"trend;the activities of SOD and GR presented"down-up"changes;activities of POD and CAT demonstrated"down-up-down",and APX,GPX showed an "up-down-up"pattern.It is worth to note that,under the four-dose treatment,a sharp decline in net photosynthesis in sorghum seedlings was observed at 6h UV-B treatment(equals to 2.4J·m^(-2)),and an obvious turning point was also found for other photosynthetic parameters and activities of antioxidant enzymes at the same time point.In summary,the results indicated that the enhanced UV-B radiation directly accounted for the damages in photosynthesis system including photosynthetic pigment content,net photosynthetic rate and chlorophyll fluorescence parameters of sorghum;the antioxidant system showed different responses to UV-B radiation below or above 6h treatment:ASA-GSH cycle was more sensitive to low-dose UV-B radiation,while high-dose UV-B radiation not only undermined the photosynthesis system,but also triggered plant enzymatic and non-enzymatic antioxidant systems,resulting in leaf browning and necrosis,biomass accumulation reduction,plant dwarfing and even death.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2016年第5期1389-1395,共7页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(31101429)
农业部公益性项目(201303007)
黑龙江省教育厅科学技术研究项目(12511360)
黑龙江八一农垦大学引进人才科研启动基金项目(201101005)
黑龙江八一农垦大学研究生创新项目(201301003)
黑龙江八一农垦大学大学生创新创业项目(201201008)资助