摘要
[目的]随着全球O_(3)浓度升高,O_(3)胁迫对植物影响的研究已成为研究的热点之一。我国的相关研究较少,主要以农作物为主,且大多局限在北方地区。本研究探讨O_(3)胁迫下,亚热带三种楠木幼苗光合作用的变化规律及其可见伤害症状,以期为后续研究提供理论依据。[方法]以一年生亚热带乡土树种桢楠、闽楠和刨花楠幼苗为材料,采用开顶式气室(OTCs),研究低浓度O_(3)、环境大气、100 n L·L-1O_(3)、150 n L·L-1O_(3)处理对光合作用的影响及伤害症状。[结果]研究表明:(1)O_(3)胁迫下,三种楠木幼苗的光合作用受到一定的抑制,气孔导度和净光合速率的相关性降低,对光合有效辐射的利用范围整体减小,出现了明显的光抑制现象。O_(3)浓度越高,对桢楠和刨花楠光合作用的抑制效果越明显,而100 n L·L-1O_(3)处理对闽楠光合作用的抑制效果较150 n L·L-1O_(3)处理明显。环境大气中的O_(3)浓度均值较低,但由于其较高的O_(3)浓度峰值,仍对三种楠木幼苗的光合作用产生了一定的抑制。与环境大气相比,低浓度O_(3)处理通过消除较高的O_(3)浓度峰值从而缓解了O_(3)对光合作用的不利影响。(2)O_(3)胁迫下,桢楠叶片出现褪绿、黄斑和坏死斑的症状,闽楠叶片出现褪绿、黄斑和水渍的症状,刨花楠叶片出现红褐色斑、水渍、坏死斑、卷曲皱缩、失水萎蔫的症状。三种楠木幼苗叶片的伤害症状随O_(3)浓度的增加而更明显。[结论]三种楠木幼苗叶片的光合作用均受到O_(3)的抑制,并出现了伤害症状,可作为O_(3)污染的指示树种。光合作用对O_(3)敏感性的关系为:刨花楠>闽楠>桢楠,其中刨花楠对O_(3)更敏感,伤害症状也较多样,因此指示O_(3)污染的效果更好。
[Objective]To study the effects of O_(3)on the change law of photosynthesis and occurrence of visible symptoms.[Methods]One-year-old seedlings of Phoebe zhennan S.Lee et FNWei,Phoebe bournei(Hemsl.)Yang and Machilus pauhoi Kanehira,the native tree species in subtropical regions,were exposed to the O_(3)concentrations gradient consisting of low O_(3)treatment,non-filtered treatment,100 n L·L-1and 150 n L·L-1O_(3)by using open-top chambers.[Results](1)the decrease in photosynthesis of the three tree species was related to non-stomatal factors.Elevated O_(3)caused a decrease in the degree of correlation between net photosynthetic rate and stomatal con-ductance,reduced the using range of photosynthetically available radiation(PAR)as a whole,induced obviously the photo inhibition and weakened the photosynthetic acclimation of plants accordingly.The negative effects on Phoebe zhennan and Machilus pauhoi seedlings were more serious with higher O_(3)concentration,however,the negative effects of 100 n L·L-1O_(3)on Phoebe bournei were more serious than 150 n L·L^(-1)O_(3).In non-filtered treatment,although the mean O_(3)concentration was low,to some extent,O_(3)had negative effects on seedlings as a result of its higher peak O_(3)concentration.Relative to non-filtered treatment,low O_(3)treatment reduced the damage of O_(3)by eliminating relative high O_(3)peak concentration.(2)Under O_(3)stress,obvious visible symptoms were found in the three tree species,including chlorosis,macular and necrosis in the leaves of Phoebe zhennan,chlorosis,macular and water stains in the leaves of Phoebe bournei,brown-red spots,water stains,necrosis,crimp and wilt in the leaves of Machilus pauhoi.[Conclusion]Elevated O_(3)resulted in the decrease of photosynthesis and visible symptoms in the leaves of the three tree species,and all these species can be used as bioindicators of O_(3)pollution.Sensitive degree to O_(3)among the three tree species was determined based on photosynthesis:Machilus pauhoi Phoebe bournei Phoebe zhennan.Machilus pauhoi has better indicating effect due to greater O_(3)-sensitivity and more serious injury symptoms.
作者
于浩
尚鹤
陈展
曹吉鑫
YU Hao;SHANG He;CHEN Zhan;CAO Ji-xin(Key Laboratory of Forest Ecology and Environment of State Forestry Administration,Research Institute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry,Beijing 100091,China)
出处
《林业科学研究》
CSCD
北大核心
2016年第6期902-910,共9页
Forest Research
基金
国家林业公益性行业专项“森林对O3和大气N沉降胁迫的响应”(201304313)
国家自然科学基金“亚热带典型针叶和阔叶树种细根动态和周转对大气臭氧胁迫的响应研究”(31370606)
