Department of Botany , University of Lucknow , Lucknow 226007 , India.
AoB Plants. 2010;2010:plq002. doi: 10.1093/aobpla/plq002. Epub 2010 Feb 15.
Nitric oxide (NO) has been reported to alleviate Fe-deficiency effects, possibly by enhancing the functional Fe status of plants. This study examines changes in tissue Fe status and oxidative metabolism in Fe-deficient maize (Zea mays L.) plants enriched with NO using sodium nitroprusside (SNP) as a source.
Measurements included changes in concentrations of H(2)O(2), non-protein thiols, levels of lipid peroxidation and activities of superoxide dismutase (SOD) and of the Fe-requiring antioxidant haem enzymes catalase, peroxidase and ascorbate peroxidases. Internal NO in Fe-deficient maize plants was manipulated with SNP and the NO scavenger, methylene blue (MB). A key control was treatment with sodium ferrocyanide (SF), a non-NO-supplying analogue of SNP.
SNP but not SF caused re-greening of leaves in Fe-deficient maize plants over 10-20 days, increased in vivo NO content, raised chlorophyll and carotenoid concentrations, promoted growth in dry weight, increased the activities of H(2)O(2)-scavenging haem enzymes and enhanced lipid peroxidation, while decreasing SOD activity and H(2)O(2) concentrations. The NO scavenger, MB, blocked the effects of the SNP. Although SNP and SF each donated Fe and increased active Fe, only SNP increased leaf chlorophyll.
NO plays a role in Fe nutrition, independently of its effect on total or active Fe status. The most probable mechanism of NO involvement is to increase the intracellular availability of Fe by means of modulating redox. This is likely to be achieved by enhancing the chemical reduction of foliar Fe(III) to Fe(II).
一氧化氮（NO）被报道可缓解缺铁效应，可能是通过增强植物的功能性铁状态。本研究使用硝普酸钠（SNP）作为来源，通过 NO 来丰富缺铁玉米（Zea mays L.）植物，检测组织铁状态和氧化代谢的变化。
测量包括 H 2 O 2 浓度、非蛋白巯基、脂质过氧化水平以及超氧化物歧化酶（SOD）和需要铁的抗氧化血红素酶过氧化氢酶、过氧化物酶和抗坏血酸过氧化物酶的活性的变化。用 SNP 和 NO 清除剂亚甲基蓝（MB）处理缺铁玉米植株中的内源性 NO。以亚铁氰化钠（SF）作为 SNP 的非 NO 供体类似物进行关键对照处理。
SNP 但不是 SF 导致缺铁玉米植株在 10-20 天内重新变绿，增加体内 NO 含量，提高叶绿素和类胡萝卜素浓度，促进干重生长，增加 H 2 O 2 清除血红素酶的活性，并增强脂质过氧化，同时降低 SOD 活性和 H 2 O 2 浓度。NO 清除剂 MB 阻断了 SNP 的作用。虽然 SNP 和 SF 都提供了铁并增加了活性铁，但只有 SNP 增加了叶片叶绿素。
NO 在铁营养中发挥作用，独立于其对总铁或活性铁状态的影响。NO 参与的最可能机制是通过调节氧化还原来增加细胞内铁的可用性。这可能是通过增强叶片 Fe(III)向 Fe(II)的化学还原来实现的。
