不同林龄杉木氮素的获取策略  

Nitrogen acquisition strategies of Cunninghamia lanceolata at different ages

作　　者：李常诚 李倩茹[1,2] 徐兴良[1] 欧阳华[1] 

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [2]中国科学院大学,北京100049

出　　处：《生态学报》2016年第9期2620-2625,共6页Acta Ecologica Sinica

基　　金：国家重点基础研究发展计划(973计划)项目(2012CB416903);国家自然科学基金重点项目(31130009)

摘　　要：为了探讨不同林龄杉木人工林氮素获取策略,选择了江西千烟洲森林生态研究站红壤区的3种林龄杉木人工林(5年生幼龄林、13年生中龄林和30年生成熟林)作为研究对象,利用稳定性同位素^(15)N示踪技术研究了它们的氮素吸收策略。结果表明,杉木对硝态氮的吸收受林龄影响,成熟林的吸收速率最高,为(5.72±0.24)μg N g^(-1)干重h^(-1),而中龄林和幼龄林的吸收速率相当,分别为(1.57±0.13)μg N g^(-1)干重h^(-1)和(2.36±0.22)μg N g^(-1)干重h^(-1)。幼龄林((34.33±1.20)μg N g^(-1)干重h^(-1))和成熟林((34.18±2.32)μg N g^(-1)干重h^(-1))对铵态氮的吸收速率相似,均显著高于中龄林((23.33±1.39)μg N g^(-1)干重h^(-1))。杉木对甘氨酸的吸收不受林龄的影响。3种年龄的杉木均对铵态氮表现出强的获取能力,其中成熟林杉木对硝态氮的获取能力明显弱于对铵态氮的获取,但却强于对甘氨酸的获取。这样的结果反映了林龄能影响杉木人工林对无机氮的吸收,但未影响对有机氮的吸收;杉木偏好吸收铵态氮,对硝态氮和甘氨酸的吸收很少。如果能把氮素形态考虑进对杉木人工林的施肥管理当中,那么可能会极大地改善杉木的生产力。To clarify whether stand age can affect nitrogen （N） acquisition strategies by plants, inorganic and organic N uptake by Chinese fir （ Cunninghamia lanceolata） plantation at three growth stages （five-year old for young plantation forest; thirteen-year old for mid-aged plantation forest; thirty-year old for mature plantation forest ） was measured in Qianyanzhou Ecological Experimental Station with a short-term 15^N labeling experiment. We found that stand age altered -1^ h 1 nitrate uptake by Chinese fir, the mature trees demonstrated the highest uptake rate （（5.72±0.24）μg N g d.w. root d.w. root h^-1）, while the trees at the middle age （ （1.57±0.13） μg N g^-1 d.w. root h^-1） showed the similar uptake rate to the youngest （2.36±0.22 μg N g^-1 d.w. root h^-1 ）. Uptake rates of ammonium for the mature trees （（34.33±1.20） μg N g^-1 d.w. root h^-1） and the youngest （（34.18±2.32） p.g N g^-1 d.w. root h-I） were similar and significantly higher than for the mid-aged trees （ （23.33± 1.39） μg N g^-1 d.w. root h^-1 ）. Uptake of glycine by the Chinese fir was not affected by their ages. We concluded that Chinese fir trees prefer to take up ammonium, and uptake rates of nitrate for the mature trees were significantly lower than ammonium but higher than glyeine. These findings reflect that stand ages can affect their uptake of inorganic N not of organic N and Chinese fir preferentially take up ammonium, showing the lower uptake rates of nitrate and glycine. This suggests that wood production could be greatly improved if N forms are considered for fertilization of Chinese fir.

关 键 词：林龄 杉木 氮素获取 15^N示踪技术 无机氮 有机氮 

分 类 号：S791.27[农业科学—林木遗传育种]