摘要
为揭示蒙古冰草对氮添加的响应机制,设置5个氮添加水平(0,0.8,1.6,2.4,4.0 g N·m^(-2)·a^(-1))对蒙古冰草进行为期2个月处理后,测定根系、叶片中可溶性糖、淀粉、碳(C)、氮(N)、磷(P)的含量,分析氮添加对蒙古冰草叶片、根系非结构性碳水化合物(NSCs)与C、N、P含量及其化学计量特征关系的影响。结果表明:2.4 g N·m^(-2)·a^(-1)的氮素添加显著提高了蒙古冰草叶片、根系NSCs含量与C、N、P含量,且不同器官的响应有显著差异性(P<0.05)。叶片NSCs含量与叶片N、可溶性糖、淀粉含量、C/P及N/P呈显著正相关关系,与叶片P含量、C/N呈显著负相关关系(P<0.05);根系NSCs含量与根系C、N、C/P、N/P、可溶性糖和淀粉含量呈显著正相关(P<0.05)。叶片与根系N/P是影响蒙古冰草体内可溶性糖积累的主要因子;根系N含量与叶片P含量共同影响淀粉含量;叶片P含量、根系N含量及根系N/P综合影响NSCs含量。综上,适量的氮添加会缓解研究区蒙古冰草的N限制,促进NSCs合成,而大量氮添加会导致N、P比例失衡,加剧P限制。因此,未来气候变化背景下蒙古冰草人工草地种植或退化草地恢复管理过程中需要考虑优化氮肥施用量与适当的磷添加。
This research investigated the physiological and ecological adaptive mechanisms of Agropyron mongolicum to nitrogen(N)addition.Soluble sugar,starch,carbon(C),N and phosphorus(P)contents in roots and leaves of A.mongolicum were determined at different levels of nitrogen addition(0,0.8,1.6,2.4 and 4.0 g N·m^(-2)·yr^(-1)).The effects of N addition on the non-structural carbohydrate(NSCs)content and the C∶N∶P stoichiometry in leaves and roots of A.mongolicum were analyzed.The results showed that adding the appropriate amount of N(2.4 g N·m^(-2)·yr^(-1))favoured the accumulation of NSCs and C,N and P contents in the leaves and roots of A.mongolicum,and the responses of different organs were significantly different(P<0.05).Leaf NSCs content was significantly positively correlated with leaf N,soluble sugar,starch content,C∶P and N∶P;And significantly negatively correlated with leaf P content and C∶N(P<0.05).Root NSCs content was significantly positively correlated with root C,N content,C∶P,N∶P,soluble sugar and starch content(P<0.05).Leaf and root N∶P were the main factors affecting the accumulation of soluble sugar;The N content of roots and P content of leaves collectively affected starch synthesis;Leaf P content,root N content and root N∶P were collectively the major factors affecting the accumulation of NSCs in A.mongolicum.In summary,appropriate N addition relieved N limitation,while the addition of large amounts of N produced an imbalance between N and P and exacerbated P limitation.Therefore,optimization of nitrogen fertilizer application and appropriate phosphorus addition should be considered in the establishment and management of artificial A.mongolicum grasslands and in the restoration of degraded grasslands under future climate change scenarios.
作者
许爱云
张丽华
王晓佳
马冲
李元景
曹兵
XU Ai-yun;ZHANG Li-hua;WANG Xiao-jia;MA Chong;LI Yuan-jing;CAO Bing(School of Agriculture,Ningxia University,Yinchuan 750021,China)
出处
《草业学报》
CSCD
北大核心
2023年第2期35-43,共9页
Acta Prataculturae Sinica
基金
宁夏高等学校一流学科建设(草学学科)项目(NXYLXK2017A01)
国家重点研发计划项目(2017YFC0504402)资助。
