| 大气氮沉降提高低磷土壤条件下马尾松菌根共生和磷效率的原因 |
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| 引用本文： | 庞丽,周志春,张一,丰忠平.大气氮沉降提高低磷土壤条件下马尾松菌根共生和磷效率的原因[J].植物营养与肥料学报,2016,22(1):225-235. |
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| 作者姓名： | 庞丽 周志春 张一 丰忠平 |
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| 作者单位： | 1.中国林业科学研究院亚热带林业研究所,浙江省林木育种技术研究重点实验室,国家林业局马尾松工程技术研究中心,浙江富阳 311400; |
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| 基金项目： | “十二五”国家科技支撑计划项目(2012BAD01B02)，国家自然科学基金项目(31370671)，浙江省农业新品种选育重大科技专项竹木育种协作组重点项目(2012C12908-12)，贵州省科学技术厅、安顺市人民政府、安顺学院联合科技基金项目[黔科合 LH 字(2014)7497]资助。 |
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| 摘 要： | 【目的】菌根共生是提高植物磷(P)营养高效利用的重要机制之一。近年来大气氮(N)沉降的增加,导致森林土壤有效氮含量增加、 N/P比发生改变,将影响菌根共生植物的生长和磷效率。【方法】以马尾松优良家系作为试验材料,NH4NO3作为外加氮源,设置模拟氮沉降与同质低磷(介质表层与深层均缺磷)、 异质低磷 (介质表层磷丰富、 深层缺磷)耦合条件下马尾松外生菌根共生的盆栽实验,系统研究模拟氮沉降对低磷胁迫下马尾松家系菌根化苗生长和磷效率的影响。【结果】 1)模拟氮沉降对马尾松菌根共生的影响与土壤磷素环境有关。在表层和深层磷素均极为匮乏的同质低磷条件下,氮沉降降低了苗木菌根侵染率和侵染程度,然而提高了菌根共生对马尾松生长和磷效率作用的有效性,马尾松的生长量和生物量均显著增加。在表层磷丰富、 深层缺磷的异质低磷条件下,菌根共生对马尾松苗木生长有抑制作用,然而氮沉降降低了其抑制程度,高氮较低氮处理对菌根侵染苗木和菌根化苗生物量积累的抑制程度小; 2)同质低磷下,模拟氮沉降显著降低了菌根化苗的根系生长,但增加了根系APase活性和有机酸分泌量,尤其是有机酸分泌量增加了近3倍。相关性分析表明,有机酸分泌对菌根化苗生长的贡献显著高于APase,这是氮沉降促进马尾松生长的主要原因之一。异质低磷下,模拟氮沉降处理后苗木深层菌根的生长发育程度较表层好,深层根的根尖数显著增加。有机酸分泌的增加提高了苗木的磷效率,促进了菌根化苗木的生长; 3)不同低磷环境下,氮沉降的增加均降低了土壤磷的相对有效性,菌根通过增加马尾松苗木对土壤磷的吸收和利用, 从而改善磷素营养促进马尾松生长发育。两种磷素环境下,马尾松菌根化苗生长对模拟氮沉降均较敏感; 4)马尾松菌根化苗生长对模拟氮沉降的响应存在显著的家系差异。【结论】大气氮沉降可改善马尾松的氮素营养,增加菌根作用的有效性,从而促进马尾松对磷的吸收,进而促进了林木的生长。不同马尾松品种对氮沉降的反应有差异,筛选高氮-低磷环境下菌根共生能力强的马尾松基因型,将成为提高土壤磷素生物学利用效率的重要途径。
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| 关 键 词： | 马尾松 家系 低磷胁迫 氮沉降 菌根共生 磷效率 |
| 收稿时间： | 2014-06-26 |
Effects of atmospheric N sedimentation on growth and P efficiency of Pinus Massoniana mycorrhizal seedlings under low P stress |
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| PANG Li,ZHOU Zhi-chun,ZHANG Yi,FENG Zhong-ping.Effects of atmospheric N sedimentation on growth and P efficiency of Pinus Massoniana mycorrhizal seedlings under low P stress[J].Plant Nutrition and Fertilizer Science,2016,22(1):225-235. |
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| Authors: | PANG Li ZHOU Zhi-chun ZHANG Yi FENG Zhong-ping |
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| Institution: | 1.Research Institute of Subtropical Forestry CAF,Chinese Academy of Forestry/Zhejiang Provincial Key Laboratory of Tree Breeding/Engineering Research Conter of Masson Pine of State Forestry Administration,Fuyang,Zhejiang 311400,China; |
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| Abstract: | Objectives] The increased atmospheric N sedimentation in recent years has brought the increased N availability and N/ P ratio in forest soils, which would impact growth and P efficiency of mycorrhizal symbiosis plant. Methods] Taking breeding population of Pinus massoniana as test materials, a pot experiment was conducted to simulate two P conditions, i. e. homogeneous low P availability vs. heterogeneous low P among soil layers, in combination with two N sedimentation levels on growth and P efficiency of Pinus massoniana mycorrhizal seedlings. Results] 1) The effects of the simulated N sedimentation on growth of mycorrhizal seedlings are relevant to the soil P environment. Under the homogeneous low P condition, N sedimentation reduces the degree of mycorrhizal colonization and infection rates, and significantly increases growth and biomass of Pinus massoniana. Under the heterogeneous low P condition, the N deposition improves root infection by mycorrhizal fungi, and reduces the inhibitory effect of mycorrhizal symbiosis on growth of Pinus massoniana; 2) Under the homogeneous low P condition, the simulated N deposition significantly reduces the root growth of mycorrhizal seedlings, and increases the root APase activity and the secretion of organic acids, especially organic acids secretion (increased nearly three-fold). Correlation analysis shows that organic acid secretion contribution to the growth of mycorrhizal seedlings is significantly higher than APase activity. Under the heterogeneous low P condition, the development degree of the underlying roots of mycorrhizal is greater than that of the surface roots. The increased secretion of organic acids promotes growth of mycorrhizal seedlings; 3) Under different low P environments, the increased N sedimentation decreases the effectiveness of soil P. Mycorrhizal increase the P absorption and utilization and further promote growth of Pinus massoniana; 4 ) Significant variations among families in growth response of Pinus massoniana mycorrhizal seedlings to the simulated N deposition are observed. Conclusion] Atmospheric N sedimentation is able to improve the nutrition of N for mycorrhizal seedlings, and stimulate the degree of mycorrhizal colonization and infection rates, resulting in more absorption of P from soils and the increase of biomass. There are differences to the response of N sedimentation among the different mycorrhizal cultivars, screening of high mycorrhizal symbiosis ability of Pinus massoniana genotypes will be an efficient way to improve soil P biological utilization efficiency. |
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| Keywords: | Pinus massoniana family low P stress N deposition mycorrhizal symbiosis P efficiency |
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