摘要
利用FACE(Free Air Carbon-dioxide Enrichment)平台技术,研究了低氮(LN150kg·hm-2)和常氮(NN250kg·hm-2)水平下,大气CO2浓度升高对水稻(OryzasativaL.)体内不同形态N素含量的影响。结果表明,CO2浓度升高促进了水稻茎、穗和根的生长而使水稻的总生物量显著增加;同时显著降低分蘖期根、茎、叶,抽穗期茎和成熟期叶、根中的N含量,而其降低量的50%￣181.8%归因于蛋白态N含量的降低,因此蛋白态N含量的降低是N含量下降的直接原因。此外,CO2浓度升高使整个生育期内水稻不同部位氨基酸态N含量普遍降低,而无机态N含量随生育期和植株部位不同的表现为降低或者升高,这可能是根系的N同化能力改变的结果。还讨论了高浓度CO2条件下水稻组织中蛋白态N含量降低的原因。
Effects of Free-air CO2 enrichment （FACE） on concentrations of various N forms in rice tissues at low N （LN 150 kgN·hm^-2） and normal N （ NN 250 kgN·hm^-2）, respectively, were studied under ambient air and elevated atmospheric pCO2 （Ambient＋ 200μmol·mol^-1） by the China FACE （Free-Air CO2 Enrichment）. At both N levels, elevated pCO2 led to significant decreases in N concentrations expressed on a dry, mass basis in roots, stems, leaves at tillering stage; in stems at heading stage and in leaves, roots at ripening stage, respectively, and 50%-181.8% of which was attributed to decreases in protein-N concentrations in these tissues as compared with ambient CO2 Thus. N concentration decreases in rice tissues could be partly accounted for by reductions in protein-N concentration. Accumulation of biomass could also lead to a ＇dilution＇ of N and resulted in lower N concentrations in plant tissues as plants had higher dry matter production of stems, ears and roots under elevated pCO2 Furthermore, free amino acid-N concentrations in most tissues declined during the whole growing season due to elevated pCO2, while inorganic N concentrations showed variable responses to elevated pCO2 through time. The decreases in free amino acid-N concentration in plant parts may be caused by the altered capability of synthesizing amino acids in rice roots due to CO2 enrichment and could have negative effect on protein synthesis. More experiments will be necessary to study the relationship between amino acid synthesis in rice roots and protein-N concentration in plant tissues under elevated pCO2.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2005年第5期833-837,共5页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(NSFC-40271061)
国家自然科学基金重大国际合作研究资助项目(NSFC-40120140814)
中国科学院重要知识创新重要方向项目(kzcx2-408)
973项目(CCDMCTE-2002CB412502)
973项目(2002CB14003)
作者简介
庞静（1973-）,女，山东茌平人，助理研究员．在读博士研究生，主要研究方向为土壤环境生物化学。E-mail：jpang@issas.ac.cn
