氮沉降对镉胁迫下南方四季杨生物量积累和光合生理的影响
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摘要
为了探讨氮(N)沉降对植物镉(Cd)耐受性的影响,采用盆栽模拟试验,研究了低N(30 kg·hm~(-2)·a~(-1))、中N(60 kg·hm~(-2)·a~(-1))、高N(90 kg·hm~(-2)·a~(-1))3种施氮量处理下,受Cd胁迫(100 mg·kg~(-1))的南方四季杨(Populus deltoides×P.nigra)幼苗生物量积累、气体交换特征、叶绿素荧光参数、叶片绿度(S_(P,A,D))和丙二醛(MDA)质量摩尔浓度、可溶性蛋白质量浓度的差异。结果表明:单独Cd处理显著降低了根、茎、叶生物量的积累。交互作用下,低N和中N处理对各器官生物量积累影响不显著,高N处理显著提高了根、茎、叶生物量的积累。单独Cd显著降低了除胞间二氧化碳摩尔分数之外的所有气体交换参数。交互作用下,低N处理显著升高了幼苗的净光合速率(P_N);中N处理显著提高了幼苗的P_N、气孔导度(G_s)、蒸腾速率(T_r);高N处理对各参数无影响。单独Cd处理显著降低了光系统Ⅱ的实际光量子产量(Φ_(P,S,II))和S_(P,A,D)值,升高了非光化学淬灭系数(q_N)。交互条件下,中N和低N处理提高了S_(P,A,D)值,低N处理降低了q_N,而高N处理对这些参数没有显著影响。单独Cd处理显著升高了叶片的MDA质量摩尔浓度。交互作用下,MDA质量摩尔浓度随着N沉降量的增加先降低后升高,可溶性蛋白质量浓度在Cd和中N处理的交互作用下显著升高。由此可见,N对Cd胁迫的缓解作用与N沉降量和植物自身氮素亏缺状态密切相关。
We investigated the effects of simulated N deposition on growth of Populus deltoides×P.nigra seedlings exposed to cadmium(100 mg·kg~(-1)).We used a pot experiment,with N deposition levels as 0(Control),30(Low-N),60(Middle-N),and 90 kg·hm~(-2)·a~(-1)(High-N),respectively.We measured biomass accumulation,gas exchange characteristics,chlorophyll fluorescence characteristics,leaf greenness indication(S_(P,A,D))andmalondialdehyde(MDA)molarity,soluble protein content.We found that biomass accumulation of root,stem and leaf were significantly decreased in Cd~(2+)treatment.In N deposition and Cd~(2+)combined treatment,there were no significant differences on biomass accumulation among Low-N,Middle-N and Control,but root,stem and leaf biomass in High-N were significantly increased.All gas exchanged parameters except intercellular carbon dioxide(C_i)molarity were decreased in Cd~(2+).In the combined treatment,net photosynthetic rate(P_N)was significantly increased in Low-N,and P_N,stomatal conductance(G_s)and transpiration rate(T_r)were significantly increased in Middle-N,while gas exchange parameters were no changes in High-N.We further found that actual photochemical efficiency(Φ_(P,S,II))and S_(P,A,D)were significantly decreased in Cd~(2+)treatment.In the combined treatment,S_(P,A,D)was increased in Low-N and Middle-N,and photochemical quenching coefficient(q_N)were decreased in Low-N,while these parameters had no changes in High-N.MDA molarity was increased in Cd~(2+)treatment.In the combined treatment,MDA molarity was decreased at first,then increased with simulated N deposition level increasing.Soluble protein content was increased at combined treatment of Cd~(2+)and Middle-N.Therefore,the mitigative effect of N deposition to Cd~(2+)was be closely related to the level of simulated N deposition and plant nitrogen deficiency.
We investigated the effects of simulated N deposition on growth of Populus deltoides×P.nigra seedlings exposed to cadmium(100 mg·kg~(-1)).We used a pot experiment,with N deposition levels as 0(Control),30(Low-N),60(Middle-N),and 90 kg·hm~(-2)·a~(-1)(High-N),respectively.We measured biomass accumulation,gas exchange characteristics,chlorophyll fluorescence characteristics,leaf greenness indication(S_(P,A,D))andmalondialdehyde(MDA)molarity,soluble protein content.We found that biomass accumulation of root,stem and leaf were significantly decreased in Cd~(2+)treatment.In N deposition and Cd~(2+)combined treatment,there were no significant differences on biomass accumulation among Low-N,Middle-N and Control,but root,stem and leaf biomass in High-N were significantly increased.All gas exchanged parameters except intercellular carbon dioxide(C_i)molarity were decreased in Cd~(2+).In the combined treatment,net photosynthetic rate(P_N)was significantly increased in Low-N,and P_N,stomatal conductance(G_s)and transpiration rate(T_r)were significantly increased in Middle-N,while gas exchange parameters were no changes in High-N.We further found that actual photochemical efficiency(Φ_(P,S,II))and S_(P,A,D)were significantly decreased in Cd~(2+)treatment.In the combined treatment,S_(P,A,D)was increased in Low-N and Middle-N,and photochemical quenching coefficient(q_N)were decreased in Low-N,while these parameters had no changes in High-N.MDA molarity was increased in Cd~(2+)treatment.In the combined treatment,MDA molarity was decreased at first,then increased with simulated N deposition level increasing.Soluble protein content was increased at combined treatment of Cd~(2+)and Middle-N.Therefore,the mitigative effect of N deposition to Cd~(2+)was be closely related to the level of simulated N deposition and plant nitrogen deficiency.
引文
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[2] LV C,TIAN H. Spatial and temporal patterns of nitrogen deposition in China:Synthesis of observational data[J]. Journal of Geophysical Research:Atmospheres,2007,112:1984-2012.
[3]李亚藏,曹玲,王庆成.镉对山梨和山荆子叶片气体交换和叶绿素荧光参数的影响[J].东北林业大学学报,2013,41(11):22-24.
[4]臧畅,吕志强,董莲春,等.不同性别桑树幼苗对镉与酸雨复合处理的生长响应及镉积累差异[J].应用生态学报,2018,29(3):969-975.
[5] KOPYRA M,GWOZDZ E A. Nitric oxide stimulates seed germination and counteracts the inhibitory effect of heavy metals and salinity on root growth of LupiNus luteus[J]. Plant Physiology and Biochemistry,2003,41(11):1011-1017.
[6]鲁显楷,莫江明,李德军,等.鼎湖山主要林下层植物光合生理特性对模拟N沉降的响应[J].北京林业大学学报,2007,29(6):1-9.
[7]刘侯俊,李雪平,韩晓日,等.铁镉互作对水稻脂质过氧化及抗氧化酶活性的影响[J].应用生态学报,2013,24(8):2179-2185.
[8] CHEN L H,ZHANG D J,YANG W Q,et al. Sex-specific responses of Populus deltoides to glomus intraradices colonization and Cd pollution[J]. Chemosphere,2016,155:196-206.
[9]张帆,万雪琴,翟晶.镉处理下增施N对杨树叶绿素合成和叶绿体超微结构的影响[J].核农学报,2014,28(3):485-491.
[10]周晓兵,张元明,王莎莎,等.模拟氮沉降和干旱对准噶尔盆地两种一年生荒漠植物生长和光合生理的影响[J].植物生态学报,2010,34(12):1394-1403.
[11]陈良华.滇杨(Populus yuNNaNeNsis)雌雄植株对环境胁迫的生理生态响应差异[D].北京:中国科学院大学,2011.
[12] FINKEMEIER I,KLUGE C,METWALLY A,et al. Alterations in Cd-induced gene expression under nitrogen deficiency in Hordeum vulgare[J]. Plant Cell&Environment,2003,26(6):821-833.
[13] PANKOVIC D,PLESNICAR M,ARSENIJEVIC-MAKSIMOVIC'I,et al. Effects of nitrogen nutrition on photosynthesis in Cd-treated punflower plants[J]. Annals of Botany,2000,86(4):841-847.
[14] CLARK C M,TILMAN D. Loss of plant species after chronic low-level nitrogen deposition to prairie grasslands[J]. Nature,2008,451:712-715.
[15]谭长强,何琴飞,秦玉燕,等.施氮对镉胁迫下杂交相思树生长及镉吸收分配的影响[J].植物营养与肥料学报,2017,23(5):1326-1334.