养分回收加剧了氮沉降背景下盐渍化草地优势植物内在氮磷的失衡  

Nutrient resorption exacerbates nitrogen-phosphorus imbalances in plants under increasing nitrogen addition in a saline-alkaline grassland

作　　者：Yuan Su Shuaikai Wu Jie Hao Huajie Diao Kuanhu Dong Changhui Wang 

机构地区：[1]Shanxi Key Laboratory of Grassland Ecological Protection and Native Grass Germplasm Innovation,College of Grassland Science,Shanxi Agricultural University,Taigu 030801,China [2]Youyu Loess Plateau Grassland Ecosystem National Research Station,Shanxi Agricultural University,Taigu 030801,China

出　　处：《Journal of Plant Ecology》2024年第1期111-120,共10页植物生态学报（英文版）

基　　金：This work was supported by National Natural Science Foundation of China(32371670);the High-Level Talents Project of Shanxi Agricultural University(2021XG008);Award Fund for Work of Excellent Researchers in Shanxi Province(SXBYKY2022042);Science and Technology Innovation Foundation of Shanxi Agricultural University(2021BQ64).

摘　　要：在落叶之前,从衰老组织中重新吸收养分被认为是植物适应养分缺乏的一种策略。然而,养分重吸收如何调节植物体内氮(N)和磷(P)的平衡仍不清楚,特别是在土壤氮有效性增加的情况下。本文研究了不同速率(0、1、2、4、8、16、24和32 g N m^(-2)yr^(-1))氮添加对中国北方盐渍化草地优势植物赖草(Leymus secalinus)叶片和茎秆养分回收的影响,以及养分回收在调控植物内部氮磷平衡的作用。研究结果表明:氮添加6年后,随着施氮量的增加,绿色和衰老组织(叶和茎)的N浓度和氮磷比均呈上升趋势。随着施氮量的增加,绿色组织中P浓度降低,而衰老组织中P浓度无显著变化。N重吸收效率(NRE)、P重吸收效率(PRE)和NRE:PRE比值沿N添加梯度显著降低。此外,我们发现衰老组织(叶和茎)氮磷比比绿色组织(叶和茎)氮磷比对氮素添加的响应更敏感,植物内在氮磷失衡的加剧主要是由于不成比例的减少养分重吸收,尤其是NRE。总的来说,我们的研究表明,NRE和PRE的差异进一步加剧了植物凋落物内部氮磷的失衡。Reabsorbing nutrients from senescent tissues before leaf falling has been recognized as a strategy to adapt to nutrient deficiency.However,how nutrient resorption modulates the nitrogen(N)-phosphorus(P)balance inside plants remains unclear,especially under increased soil N availability.We examined the impacts of N addition at varying rates(0-32 g N m^(-2)yr^(-1))on nutrient resorption and the performance of nutrient resorption on controlling the internal N-P balance in the leaf and stem of a dominant grass species,Leymus secalinus,in a saline-alkaline grassland in northern China.After 6 years of N addition,N concentration and N:P ratio in green and senesced tissues(leaf and stem)rose with increasing N addition.The P concentration in green tissues decreased,but did not significantly change in senesced tissues with increasing N addition.The N resorption efficiency(NRE),P resorption efficiency(PRE),and NRE:PRE ratio significantly decreased along the N addition gradient.Moreover,we found more sensitive responses of N:P ratio in senesced tissues than in green tissues;such exacerbation of plant internal N-P imbalances mainly resulted from a disproportionate reduction in nutrient resorption,especially NRE.Overall,our study suggested that differences in NRE and PRE further exacerbated the internal N-P imbalances in plant litters.

关 键 词：生态化学计量学 氮添加 氮磷失衡 重吸收效率 重吸收能力 重吸收比 盐渍化草地 

分 类 号：Q94[生物学—植物学]