Effects of manganese-excess on CO2 assimilation, ribulose-1,5-bisphosphate carboxylase/oxygenase, carbohydrates and photosynthetic electron transport of leaves, and antioxidant systems of leaves and roots in Citrus grandis seedlings.
Effects of manganese-excess on CO2 assimilation, ribulose-1,5-bisphosphate carboxylase/oxygenase, carbohydrates and photosynthetic electron transport of leaves, and antioxidant systems of leaves and roots in Citrus grandis seedlings.
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DOI：
10.1186/1471-2229-10-42
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发表时间：
2010-03-07
影响因子：
5.3
通讯作者：
Yang GH
中科院分区：
文献类型：
--
作者：
Li Q;Chen LS;Jiang HX;Tang N;Yang LT;Lin ZH;Li Y;Yang GH
关于锰 (Mn) 过量对柑橘光合作用和抗氧化系统的影响知之甚少。用含有 2 μM（对照）或 500 μM（过量）MnSO4 的营养液灌溉酸柚（Citrus grandis）幼苗 17 周。本研究的目的是了解锰过量导致二氧化碳同化减少的机制，并检验锰诱导的抗氧化系统变化在根和叶之间存在差异的假设。 Mn过量降低了CO2同化和气孔导度，增加了细胞间CO2浓度，但不影响叶绿素（Chl）水平。锰过量的叶片中初始和总的核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）活性下降的程度低于二氧化碳同化。锰过量的叶片和对照之间葡萄糖、果糖、淀粉和总非结构碳水化合物的含量没有差异，而前者的蔗糖含量较高。 Mn 过量叶片的叶绿素 a 荧光 (OJIP) 瞬变显示 O 步增加，P 步减少，并伴有正 L 和 K 带。 Mn 过量降低了初级光化学的最大量子产率 (Fv/Fm) 和总性能指数 (PItot,abs)，但增加了 I 步 (VI) 的相对可变荧光和能量耗散。在蛋白质基础上，Mn过量的叶片表现出较高的单脱氢抗坏血酸还原酶（MDAR）、谷胱甘肽还原酶（GR）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和愈创木酚过氧化物酶（GPX）活性和抗氧化剂含量，相似的抗坏血酸过氧化物酶（APX）活性和较低的脱氢抗坏血酸还原酶（DHAR）活性；而Mn过量根系的抗氧化酶活性和抗氧化剂含量相似或较低。 Mn过量不影响根和叶的丙二醛（MDA）含量。锰过量会损害从光系统 II (PSII) 供体侧到光系统 I (PSI) 末端受体还原的整个光合电子传递链，从而限制还原当量的产生，从而限制 CO2 同化速率。锰过量的叶片中能量耗散和抗氧化系统均增强，而锰过量的根中的抗氧化系统没有上调，但仍保持较高的活性。锰过量的根和叶中的抗氧化系统为它们提供了足够的保护，使其免受氧化损伤。
Very little is known about the effects of manganese (Mn)-excess on citrus photosynthesis and antioxidant systems. Seedlings of sour pummelo (Citrus grandis) were irrigated for 17 weeks with nutrient solution containing 2 μM (control) or 500 μM (excess) MnSO4. The objective of this study were to understand the mechanisms by which Mn-excess leads to a decrease in CO2 assimilation and to test the hypothesis that Mn-induced changes in antioxidant systems differ between roots and leaves. Mn-excess decreased CO2 assimilation and stomatal conductance, increased intercellular CO2 concentration, but did not affect chlorophyll (Chl) level. Both initial and total ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity in Mn-excess leaves decreased to a lesser extent than CO2 assimilation. Contents of glucose, fructose, starch and total nonstructural carbohydrates did not differ between Mn-excess leaves and controls, while sucrose content was higher in the former. Chl a fluorescence (OJIP) transients from Mn-excess leaves showed increased O-step and decreased P-step, accompanied by positive L- and K-bands. Mn-excess decreased maximum quantum yield of primary photochemistry (Fv/Fm) and total performance index (PItot,abs), but increased relative variable fluorescence at I-steps (VI) and energy dissipation. On a protein basis, Mn-excess leaves displayed higher activities of monodehydroascorbate reductase (MDAR), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPX) and contents of antioxidants, similar ascorbate peroxidase (APX) activities and lower dehydroascorbate reductase (DHAR) activities; while Mn-excess roots had similar or lower activities of antioxidant enzymes and contents of antioxidants. Mn-excess did not affect malondialdehyde (MDA) content of roots and leaves. Mn-excess impaired the whole photosynthetic electron transport chain from the donor side of photosystem II (PSII) up to the reduction of end acceptors of photosystem I (PSI), thus limiting the production of reducing equivalents, and hence the rate of CO2 assimilation. Both the energy dissipation and the antioxidant systems were enhanced in Mn-excess leaves, while the antioxidant systems in Mn-excess roots were not up-regulated, but still remained high activity. The antioxidant systems in Mn-excess roots and leaves provided sufficient protection to them against oxidative damage.
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影响因子：
5.7
作者：
Demirevska-Kepova, K;Simova-Stoilova, L;Feller, U
通讯作者：
Feller, U
影响因子：
5.7
作者：
Doncheva, Sn.;Poschenrieder, C.;Barcelo, J.
通讯作者：
Barcelo, J.
DOI：
10.1016/0005-2728(90)90018-y
发表时间：
1990-02-02
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
CAO, J;GOVINDJEE
通讯作者：
GOVINDJEE
影响因子：
6.4
作者：
González, A;Lynch, JP
通讯作者：
Lynch, JP
影响因子：
2.9
作者：
GRIFFITH, OW
通讯作者：
GRIFFITH, OW