Moderate clipping stimulates over-compensatory growth of Leymus chinensis under saline-alkali stress through high allocation of biomass and nitrogen to shoots
Moderate clipping stimulates over-compensatory growth of Leymus chinensis under saline-alkali stress through high allocation of biomass and nitrogen to shoots
复制标题
适度修剪通过向芽的高分配生物量和氮刺激盐碱胁迫下羊草的过度补偿生长
DOI：
10.1007/s10725-020-00622-3
复制
发表时间：
2020-05-08
影响因子：
4.2
通讯作者：
Yang, Haijun
中科院分区：
文献类型：
--
作者：
Ma, Huimin;Zheng, Congcong;Yang, Haijun
羊草（Leymus chinensis）是松嫩平原的优势种，具有较强的抗放牧和耐盐碱胁迫能力。补偿性生长是植物在放牧或剪枝胁迫下的积极反应；然而，盐碱胁迫下植物氮素分配策略对植物补偿性生长的影响尚不清楚。采用2个盐碱水平和3个修剪水平的田间试验，结合地下n -15-尿素标记法。无论剪枝还是盐碱胁迫，适度剪枝都能显著促进羊草新吸收氮分配给枝条，导致羊草生物量高，生长过度。然而，在盐碱条件下，严重修剪使总N-15吸收量急剧下降20%，导致植株生长补偿不足，植株将更多的氮分配给茎基而不是其他器官，表现出保守的氮分配策略。结果表明，在不同的环境胁迫组合下，植物具有不同的氮素分配策略。
Leymus chinensis, a dominant species in the Songnen Plain of northeast China, has a strong ability to resist grazing and tolerate saline-alkali stress. Compensatory growth is a positive response of plants, when subjected to grazing or clipping stress; however, little information is available on how plant nitrogen allocation strategies affect compensatory growth under saline-alkali stress. A field experiment using two saline-alkali levels and three clipping levels was conducted in conjunction with the belowground N-15-urea labelling method. Irrespective of clipping and salt-alkali stress, moderate clipping significantly promoted allocation of newly-absorbed nitrogen (N) to shoots, resulting in high biomass and over-compensatory growth of L. chinensis. However, severe clipping dramatically decreased uptake of total N-15 by 20% under saline-alkali conditions, resulting in under-compensatory growth, and plants allocated more N to stem bases than to other plant organs, showing a conservative N allocation strategy. Our results suggest that plants have different nitrogen allocation strategies under different combinations of environmental stresses.