Photosynthetic activity, pigment composition and antioxidative response of two mustard (Brassica juncea) cultivars differing in photosynthetic capacity subjected to cadmium stress
Photosynthetic activity, pigment composition and antioxidative response of two mustard (Brassica juncea) cultivars differing in photosynthetic capacity subjected to cadmium stress
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DOI：
10.1016/j.jplph.2006.03.003
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发表时间：
2007-05-01
影响因子：
4.3
通讯作者：
Khan, Nafees A.
中科院分区：
文献类型：
--
作者：
Mobin, Mohammad;Khan, Nafees A.
研究了两种芥菜（Brassica juncea L.）不同品种的光合能力受到镉（Cd）胁迫。暴露于镉严重限制了RH-30的净光合速率（PN）相比，Varuna。这对应于碳酸酐酶（CA）和核酮糖-1，5-二磷酸羧化酶（Rubisco）的活性在两个品种的减少。Cd胁迫下，Varuna的叶绿素（a+B）和Chi a含量均下降，但Chl B的下降幅度更大，这是导致Varuna的Chl a：B比值升高的原因。此外，花色素苷的相对量保持较高的Varuna相比，RH-30，即使在高镉浓度的存在下，而脱镁叶绿素含量百分比增加RH-30在低镉浓度。较高浓度的Cd（1100 mg Cd kg（-1）土壤）导致两个品种过氧化氢（H2 O2）含量升高。然而，与RH-30相比，Varuna表现出较低的H2 O2含量。这反映在RH-30中细胞损伤增加，表现为硫代巴比妥酸反应物质（TBARS）含量和电解质渗漏增加。抗氧化酶，抗坏血酸过氧化物酶（APX），
Photosynthetic performance, contents of chlorophyll and associated pigments, cellular damage and activities of antioxidative enzymes were investigated in two mustard (Brassica juncea L.) cultivars differing in photosynthetic capacity subjected to cadmium (Cd) stress. Exposure to Cd severely restricted the net photosynthetic rate (PN) of RH-30 compared to Varuna. This corresponded to the reductions in the activities of carbonic anhydrase (CA) and ribulose-1,5-bisphosphate carboxylase (Rubisco) in both the cultivars. Decline in chlorophyll (Chl) (a+b) and Chi a content was observed but decrease in Chl b was more conspicuous in Varuna under Cd treatments, which was responsible for higher Chl a:b ratio. Additionally, the relative amount of anthocyanin remained higher in Varuna compared to RH-30 even in the presence of high Cd concentration, while percent pheophytin content increased in RH-30 at low Cd concentration. A higher concentration of Cd (1100 mg Cd kg(-1) soil) resulted in elevated hydrogen peroxide (H2O2) content in both the cultivars. However, Varuna exhibited lower content of H2O2 in comparison to RH-30. This was reflected in the increased cellular damage in RH-30, expressed by greater thiobarbituric acid reactive substances (TBARS) content and electrolyte leakage. The enhanced activities of antioxidative enzymes, ascorbate peroxidase (APX),