Nutrient resorption in Caragana microphylla along a chronosequence of plantations: Implications for desertified land restoration in North China
Nutrient resorption in Caragana microphylla along a chronosequence of plantations: Implications for desertified land restoration in North China
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小叶锦鸡儿养分吸收随人工林时间顺序的变化：对华北荒漠化土地恢复的启示
DOI：
10.1016/j.ecoleng.2012.12.061
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发表时间：
2013-04-01
影响因子：
3.8
通讯作者：
Zhang, Tonghui
中科院分区：
文献类型：
--
作者：
Li, Yulin;Chen, Jing;Zhang, Tonghui
叶片死亡和脱落前的养分再吸收是植物抵御养分限制的重要能量保存机制。而豆科固氮植物能够通过生物化学固定获得氮素，因此对土壤氮素有效性的依赖性较低，因此可能吸收较少的氮素。小叶锦鸡儿（Caragana microphylla）是我国北方半干旱地区科尔沁桑迪的优势豆科固氮灌木，广泛应用于植被恢复工程中。在本研究中，绿色和衰老的叶片养分浓度的C。比较了不同林龄（11、19、27和36年）小叶章养分再吸收的沿着规律，并探讨了养分再吸收是否受土壤养分有效性的影响。结果表明，C.人工林年龄对养分吸收的影响。N、P吸收效率分别从11年生林的40%和68%下降到36年生林的32.0%和55%，而衰老叶片的N、P含量（吸收能力指标）从17.5和0.56 mg g（-1）增加，11年生林分中的含量分别为24.8和0.91 mg g（-1）。此外，灌木林个体对氮、磷的吸收能力与林内和林间灌木林冠下土壤速效氮、磷含量呈负相关。这表明在低养分的土壤中，叶片中的N和P被吸收的较多。在营养贫乏的环境中，小叶植物对日常营养吸收的依赖性较小，因此能够适应严重荒漠化的地区。此外，C.在本研究中，小叶表现出氮的不完全再吸收，这表明衰老的落叶返回高度可分解的凋落物到土壤中，从而间接提高土壤养分的有效性。因此，种植豆科固氮灌木C.小叶(C)2012爱思唯尔有限公司版权所有。
Resorption of nutrients before leaf death and abscission is an important energy conservation mechanism employed by plants to endure nutrient limitation. However, leguminous N-fixing plants are able to acquire N through biochemical fixation, so are less dependent of soil N availability, and thus probably resorb less N. In the semi-arid Horqin Sandy Land of North China, Caragana microphylla, a leguminous N-fixing shrub, is the dominant plant species and is widely used in vegetation re-establishment programs to stabilize shifting sand. In this study, green- and senesced-leaf nutrient concentrations of C. microphylla were examined to compare nutrient resorption patterns along an age sequence of plantations (11, 19, 27 and 36 years, respectively) and to detect if nutrient resorption was affected by soil nutrient availability. The results showed that there were significant effects (p < 0.01) of C. microphylla plantation age on nutrient resorption. N and P resorption efficiency decreased from 40% and 68%, respectively in the 11-yr old plantation to 32.0% and 55% in the 36-yr old plantation, while N and P concentrations of senesced leaves (indicators of resorption proficiency) increased from 17.5 and 0.56 mg g(-1), respectively in the 11-yr old plantation to 24.8 and 0.91 mg g(-1) in the 36-yr old plantation. Furthermore, N and P resorption proficiency of individual shrubs were negatively related to available N and Pin the soil under the shrub canopy within and among plantations. This indicates that more foliar N and P was resorbed in lower nutrient sites and implies that C. microphylla in nutrient-poor environments is less dependent on day-to-day nutrient uptake and thereby adapted to severely desertified regions. Additionally, C. microphylla in the present study showed incomplete resorption of nitrogen, which suggests senesced-leaf fall returns highly decomposable litter to the soil, and thereby indirectly improves soil nutrient availability. The restoration of desertified land, therefore, may be accelerated with plantations of the N-fixing leguminous shrub C. microphylla. (C) 2012 Elsevier B.V. All rights reserved.