PHYSIOLOGICAL RESPONSES OF TWO MOSS SPECIES TO THE COMBINED STRESS OF WATER DEFICIT AND ELEVATED NITROGEN DEPOSITION. I. SECONDARY METABOLISM
PHYSIOLOGICAL RESPONSES OF TWO MOSS SPECIES TO THE COMBINED STRESS OF WATER DEFICIT AND ELEVATED NITROGEN DEPOSITION. I. SECONDARY METABOLISM
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两种苔藓物种对水分亏缺和氮沉降升高的综合胁迫的生理反应。
DOI：
10.1086/681023
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发表时间：
2015-06-01
影响因子：
2.3
通讯作者：
Liu, Wei-qiu
中科院分区：
文献类型：
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作者：
Liu, Bin-yang;Lei, Chun-yi;Liu, Wei-qiu
研究的前提。苔藓中的次生代谢产物可以保护苔藓免受病原体或食草动物的攻击，但对它们在非生物胁迫中的作用却知之甚少。因此，我们研究了水分亏缺和高氮(N)对两种苔藓次生代谢的影响。以KNO_3或NH_4Cl为底物，对卷叶Pogonatum Cirratum亚种进行处理。以20~60 kg N·hm~(-2)处理1年，然后停水12d，再进行10d恢复处理。分别在保水处理和恢复处理后测定氧化应激指标(超氧化物歧化酶[SOD]、丙二醛[MDA])和次生代谢指标。氨氮和硝酸盐供应促进了SOD活性和MDA的积累，促进了苯丙烷类化合物、三萜类和总生物碱的合成。缺水胁迫诱导了两种苔藓植物的氧化胁迫，施氮加剧了氧化胁迫。水分亏缺抑制了超氧化物歧化酶和L-苯丙氨酸解氨酶的活性，并改变了它们的苯丙素谱(存在种间差异)。水分亏缺促进了垂叶苔藓中三萜类物质的积累，而促进了两种苔藓中生物碱的积累。经过10d恢复期后，氮素处理总体上仍对超氧化物歧化酶活性和次生代谢物含量有显著影响，水分亏缺对部分酚类和生物碱的含量仍有影响。而水分亏缺处理的马尾松恢复后，其超氧化物歧化酶活性有所恢复，表明其在水分胁迫的恢复过程中可能起着重要作用。这两种苔藓的次生代谢与它们的抗氧化机制密切相关。苯丙烷类、三萜类和生物碱可能标志着苔藓对胁迫的反应，因此为苔藓的环境监测提供了一种有用的方法。
Premise of research. It has been well documented that secondary metabolites in mosses can protect mosses from pathogen or herbivore attacks, but their functions in abiotic stress are poorly understood. Thus, we have investigated effects of water deficit and high nitrogen (N) on secondary metabolism in two moss species.Methodology. KNO3 or NH4Cl was supplied to Pogonatum cirratum subsp. fuscatum and Hypnum plumaeforme at rates of 20-60 kg N hm(-2) for 1 yr, water was then withheld for 12 d, and finally a 10-d recovery treatment was applied. Indexes of oxidative stress (superoxide dismutase [SOD], malondialdehyde [MDA]) and secondary metabolism were determined after the water-withholding and recovery treatments, respectively.Pivotal results. Both ammonium and nitrate supply stimulated SOD activity and MDA accumulation as well as the synthesis of phenylpropanoids, triterpenes, and total alkaloids. Water-deficit stress induced oxidative stress in both moss species, and N application exacerbated the oxidative stress. Water deficit inhibited SOD and L-phenylalanine ammonia-lyase activities and changed their phenylpropanoid profiles (with interspecific differences). Triterpene accumulation was stimulated by water deficit in H. plumaeforme (but not in P. cirratum), while alkaloid accumulation was stimulated in both mosses. After the 10-d recovery period, the N treatments generally still had significant effects on SOD activity and secondary metabolite contents, and water deficit still had effects on contents of some phenolics and alkaloids. However, SOD activity in the water-deficit-treated P. cirratum samples was restored after recovery, indicating that it may play an important role in recovery from stress induced by water deficit.Conclusions. The secondary metabolism of both mosses is intimately linked to their antioxidant mechanisms. Phenylpropanoids, triterpenes, and alkaloids may mark moss responses to stress and therefore present a useful method for environmental monitoring in the mosses.