Senescence-induced changes in apoplastic and bulk tissue ammonia concentrations of ryegrass leaves
Senescence-induced changes in apoplastic and bulk tissue ammonia concentrations of ryegrass leaves
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DOI：
10.1046/j.1469-8137.2003.00902.x
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发表时间：
2003-12-01
期刊：
影响因子：
9.4
通讯作者：
Schjoerring, JK
中科院分区：
文献类型：
--
作者：
Mattsson, M;Schjoerring, JK
测定了氮素和碳素状态不同的黑麦草(Lolium Perenne)完整(贴生)和离体叶衰老过程中质外体和整体组织中NH4+和H+的浓度。根据质外体溶液和块状组织中[NH4+]与[H+]的比值，估算衰老叶片释放NH3的潜力。与绿叶相比，有衰老视觉症状的叶片在质外体溶液和块状组织提取物中的[NH4+]值高2~3倍，pH低0.5-1个单位。在高氮低C/N比(约10)的离体叶中，在黑暗中衰老4-9d后，质外体[NH_4+]从40微米左右增加到2毫米，而整体组织水分[NH_4~+]增加到30毫米。在所有病例中，可塑伽玛值均为
Apoplastic and bulk tissue concentrations of NH4+ and H+ were measured during senescence of intact (attached) and excised ryegrass (Lolium perenne) leaves differing in nitrogen and carbon status. The potential for NH3 emission from the senescing leaves was estimated on the basis of the ratio between [NH4+] and [H+], designated the Gamma-value, in apoplastic solution and bulk tissue.Attached leaves with visual symptoms of senescence showed two to three times higher [NH4+] and 0.5-1 unit lower pH in both apoplastic solution and bulk tissue extracts compared with green leaves. The Gamma-values were, in all cases, low in attached leaves, ranging from 20 to 300 in the apoplastic solution and 500-900 in the bulk tissue.In excised leaves with high nitrogen status and low C : N ratio (approximate to 10), apoplastic [NH4+] increased from around 40 muM to 2 mM after senescence in darkness for 4-9 d. Bulk tissue water [NH4+] increased in the same period to >30 mM. Apoplastic Gamma-values were in all cases