CO_2倍增对不同氮水平下小麦幼苗根系及叶片NR活性的影响  

Responses of Root and Leaf NR Activity in Wheat Seedling to Elevated CO_2 Concentration under Different N Levels

作　　者：宋淑英[1,2,3] 许育彬[1,2,3] 李世清[2,3] 王佩玲[3,4] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨陵712100 [2]中国科学院水利部水土保持研究所,陕西杨陵712100 [3]西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨陵712100 [4]西北农林科技大学林学院,陕西杨凌712100

出　　处：《西北植物学报》2010年第11期2203-2209,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：陕西省自然科学基金(SJ08C104);西北农林科技大学基本科研业务费(QN2009083)

摘　　要：以小麦品种‘小偃22’幼苗为材料,采用开顶式气室和水培实验研究了不同供氮水平(2.5、5.0、10.0和15.0 mmol.L-1)下小麦幼苗植株生长量、根系形态、有机碳分泌速率和硝酸还原酶(NR)活性对大气CO2浓度升高的响应。结果显示,大气CO2浓度倍增均增加了小麦幼苗各生长阶段根冠生物量以及根系长度、面积、有机碳分泌速率和叶片NR活性。随供氮水平的提高,各生长阶段幼苗根冠生物量、根长和面积以及叶片NR活性呈上升趋势,而有机碳分泌速率呈下降趋势;根冠比变化不同阶段表现不一致,一叶一心期呈下降趋势,二叶一心期和三叶一心期分别以15.0和10.0 mmol.L-1氮水平较高。研究表明,大气CO2浓度升高可促进小麦幼苗根系生长和有机碳分泌速率,提高其氮素同化能力;增加介质供氮有利于高CO2浓度条件下小麦幼苗根冠生长和氮素同化,提高根冠比,减少根系有机碳过度分泌引起的碳损耗。Hydroponics was employed to investigate the responses of root growth and organic carbon excretion,leaf NR activity in wheat seedling to elevated CO2 concentration.The seedlings of wheat variety ＇Xiaoyan 22＇ were planted in open top chamber（OTCs） under two atmospheric CO2 concentrations（375 and 750 μmol·mol-1） and 4 nitrogen levels（2.5,5.0,10.0,15.0 mmol·L-1）.The biomass of root and shoot,root length,area and organic carbon excretion rate,and leaf NR activity in wheat seedling were measured.The results showed that compared with the background CO2 concentration,elevated CO2 increased biomass of root and shoot,root length and area,root organic carbon excretion rate and content,and leaf NR activity in wheat seedling at one-leaf,two-leaf and three-leaf stages under 4 nitrogen levels,but it enhanced the ratio of root/shoot only under 10.0 mmol·L-1 N level at two-leaf and three-leaf stages.With the increase of nitrogen levels,biomass of root and shoot,root length and area,leaf NR activity were increased,while root organic carbon excretion rate were deceased,the change of root/shoot ratio was different at three stages.The ratio of root/shoot decreased with increasing nitrogen levels at one-leaf stage and obtained a higher value under 15.0 and 10.0 mmol·L-1 N level at two-leaf and three-leaf stages,respectively.The effect of different levels on NR activity was more significant at one-leaf stage.Therefore,Enhanced CO2 concentration would promote root and shoot growth,root organic carbon excretion and leaf NR activity.Increasing nitrogen level could improve the growth of root and shoot,nitrogen assimilation and root/shoot ratio in the CO2 enrichment,and reduce carbon loss of root for organic carbon excretion.

关 键 词：小麦 大气CO2浓度升高 介质供氮 根系生长 有机碳分泌 硝酸还原酶活性 

分 类 号：Q945.79[生物学—植物学]