Carbon dioxide enrichment moderates salinity-induced effects on nitrogen acquisition and assimilation and their impact on growth in barley plants

详细信息    查看全文

• 作者：Usue Pé ; rez-Ló ; pez^a ; ^{usue.perez@ehu.es} ; Anabel Robredo^a ; ^{anabel.robredo@ehu.es} ; Jon Miranda-Apodaca^a ; ^{jon.miranda@ehu.es} ; Maite Lacuesta^b ; ^{maite.lacuesta@ehu.es} ; Alberto Muñ ; oz-Rueda^a ; ^{a.munoz-rueda@ehu.es} ; Amaia Mena-Petite^a ; ^{amaia.mena@ehu.es}
• 关键词：A ; photosynthetic rate ; ATP ; adenosine 5&prime ; -triphosphate ; DW ; dry weight ; ¦Ä15N ; nitrogen natural isotopic signature ; ¦¤15N ; nitrogen isotope discrimination ; EDTA ; ethylenediaminetetraacetic acid ; GS ; glutamine synthetase ; NH4+ ; ammonium ; NiR ; nitrite
• 刊名：Environmental and Experimental Botany
• 出版年：2013
• 出版时间：March, 2013
• 年：2013
• 卷：87
• 期：Complete
• 页码：148-158
• 全文大小：843 K

文摘

Both salt stress and high carbon dioxide (CO₂) levels can affect plant nitrogen (N) metabolism by acting in parallel, decreasing N metabolism; or acting in opposite directions, with salt stress decreasing N metabolism and elevated CO₂ levels enhancing it. The objective of this work was to analyse the effect of salinity on N acquisition, distribution, and assimilation, the consequences of these effects on growth in barley (Hordeum vulgare L., cv. Iranis), and the possible effects on these processes provoked by elevated CO₂ levels. Several steps of N metabolism were studied in H. vulgare plants exposed to 0, 80, 160, or 240 mM NaCl under ambient (350 ¦Ìmol mol^?1) or elevated (700 ¦Ìmol mol^?1) CO₂. Salt stress reduced the N uptake (NUR) and translocation (NTR) rates and nitrate reductase (EC 1.7.1.1) activity, altering plant N isotope discrimination (¦¤¹⁵N). Although salt stress increased glutamine synthetase (EC 6.3.1.2) activity, N and protein content, and photosynthetic nitrogen use efficiency decreased. The decrease in nitrate reductase activity was related to decreases in NUR and NTR, while ¦¤¹⁵N correlated with the NUR and with the nitrate reductase activity. Under mild salt stress, N metabolism was better maintained under elevated CO₂ levels than under ambient CO₂ levels, since NUR, NTR, photosynthetic nitrogen use efficiency, and nitrate reductase activity were less affected, yielding lower ¦¤¹⁵N and higher growth. In addition, growth was negatively correlated with ¦¤¹⁵N indicating that the ¦¤¹⁵N determination may allow the estimation of barley growth. As a consequence of all these results, barley plants subjected to elevated CO₂ levels will likely overcome mild saline conditions because of their capacity to maintain efficiency in N metabolism.