柠檬酸对西瓜幼苗铝毒害的缓解作用

为了探究柠檬酸对西瓜幼苗铝毒害的缓解作用,本试验采用水培法,以早春红玉(耐铝型,HY)和早蜜王(铝敏感型,ZM)2个西瓜品种为材料,用不同柠檬酸浓度(200、400、800、1 200μmol·L~(-1))处理铝胁迫(1 500μmol·L~(-1))下的西瓜幼苗,研究不同柠檬酸浓度对西瓜幼苗生长和生理特性的影响。结果表明,铝胁迫对HY和ZM幼苗的生长和生理均产生了明显的毒害作用,与HY相比,ZM受毒害的程度更大。加入柠檬酸后,铝对HY和ZM的毒害作用得到了有效的缓解,且缓解效果存在浓度差异,在一定浓度范围内(≤800μmol·L~(-1)),随着柠檬酸浓度增加缓解效果增强,其中以800μmol·L~(-1)效果最佳;当浓度增至1 200μmol·L~(-1)时,缓解效果反而减弱。柠檬酸对ZM的缓解作用强于HY,同时随着处理时间的延长柠檬酸缓解效果越明显。综上所述,柠檬酸能够有效缓解铝对西瓜幼苗的毒害作用,以400~800μmol·L~(-1)解毒效果最佳。本研究结果为明确柠檬酸缓解西瓜铝毒害作用机制以及西瓜优质高产栽培提供了理论依据。     

土壤溶液性质对水溶性镍的西红柿毒害的影响

选取17种具有代表性的中国土壤,研究土壤溶液性质对土壤孔隙水以及0.01 mol/L CaCl2浸提液中镍(Ni)植物毒害的影响。结果发现,孔隙水中Ni(PW-Ni)对西红柿地上部分生物量50% 抑制的毒性阈值(EC50)变化范围为1.02 ~ 8.91 mg/L,最大值是最小值的 8.7倍;CaCl2-Ni的毒性阈值EC50变化范围为 0.77 ~ 20.40 mg/kg,最大值是最小值的26.5倍,表明土壤溶液性质对水溶性Ni的毒性阈值影响很大。土壤PW-Ni毒性主要受到K+、Mg2+、S的影响,基于这3个因子的回归方程可以较好预测PW-Ni对西红柿毒性阈值EC50,决定系数为0.71。当回归方程包括土壤溶液中溶解性有机碳(DOC)、pH、电导率(EC)、Ca2+、Na+ 时,其决定系数提高到0.84,说明其他因子对PW-Ni的毒性也存在一定的影响,利用这些土壤溶液性质可以较好预测PW-Ni的植物毒性阈值。     

油菜素内酯对龙葵幼苗Cd毒害耐受性的影响

以重金属超富集植物龙葵为试验材料,分析了油菜素内酯(BR)对幼苗镉(Cd)毒害耐受性影响的生理机制。Cd毒害导致龙葵幼苗出现氧化伤害,同时降低了幼苗超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性。表油菜素内酯(eBL,人工合成的BR)处理增加了龙葵幼苗对Cd毒害的敏感性,与eBL处理的结果相反,施用油菜素唑(Brz,BR合成的特异性抑制剂)增加了Cd毒害下龙葵幼苗的抗氧化酶活性,降低了ROS的累积,减少了幼苗的氧化伤害。Brz处理后幼苗株高和根长较Cd处理的对照分别增加29%和28%,MDA水平和Evans blue染色程度较Cd处理的对照分别降低37%和20%,进一步证明BR增加了Cd毒害下龙葵幼苗的氧化伤害,从而加重了Cd胁迫对幼苗生长的抑制作用。表明BR通过降低龙葵幼苗的抗氧化能力,增加了幼苗对Cd毒害的敏感性。     

外源水杨酸对黑麦草幼苗盐胁迫的缓解效应研究

系统分析了黑麦草幼苗在0.2、0.4、0.6和0.8 mmol L-1水杨酸分别与150 mmol L-1 Na Cl盐胁迫复合作用下的生长指标与生理生化指标特征,探究了外源水杨酸对黑麦草幼苗盐胁迫的缓解效应。结果表明:施加不同浓度的外源水杨酸均能够显著缓解盐分对黑麦草幼苗的胁迫效应,盐胁迫下施加外源水杨酸,可使得黑麦草幼苗株高,地上、地下部分鲜重和干重均相对增加;加强了植物体内抗氧化酶系统,表现为超氧化物岐化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性显著提高;减弱了细胞膜脂过氧化作用并降低了质膜破坏程度,表现为细胞质膜透性和丙二醛含量均显著降低。0.6 mmol L-1是所设置的浓度梯度中最佳的水杨酸施用浓度;与单独150 mmol L-1 Na Cl盐胁迫相比,黑麦草幼苗株高增加43.38%,地上部分鲜、干重分别增加37.92%和31.36%,地下部分鲜、干重分别增加25.46%和15.32%;胁迫处理第3天,SOD活性增加17.20%,第9天,丙二醛(MDA)含量降低27.60%。     

水杨酸对废电池胁迫下绿豆幼苗抗氧化酶活性及生理特性的影响

采用室内有培养土的纸杯培养方法,研究了不同浓度水杨酸（SA）处理对废电池胁迫下,绿豆幼苗抗氧化酶及生理特性的影响。结果表明,废电池胁迫下,超氧化物歧化酶（SOD）活性升高,过氧化物酶（POD）活性降低,光合色素、可溶性蛋白含量下降,脯氨酸和丙二醛（MDA）含量升高,电导率增大,膜稳定性降低,显示出一定的毒害效应;低浓度（≤100mg·L-1）的外源SA处理能够明显增强废电池胁迫下绿豆叶片SOD、POD活性,改善多项指标,但随着SA浓度升高,SOD和POD酶活性逐渐降低。说明低浓度SA能通过刺激抗氧化酶活性,减轻氧化胁迫,缓解废电池对绿豆幼苗的毒害作用,但高浓度SA（≥100mg·L-1）缓解作用降低。     

氯苯对小麦抗氧化酶活性的影响

研究了不同浓度的 1 ,2 ,4 三氯苯对扬麦 1 0号和皖麦 3 8叶片和根系中超氧化物歧化酶 (SOD)和过氧化物酶 (POD)的影响。结果表明 :(1 )随 1 ,2 ,4 三氯苯浓度的升高 ,两小麦品种叶片中SOD和POD活性都逐步升高 ;(2 )随 1 ,2 ,4 三氯苯浓度的升高 ,两小麦品种根系SOD的活性亦逐步升高 ,而POD活性呈现先升高后降低的趋势 ;(3 ) 1 ,2 ,4 三氯苯诱导小麦叶中正常表达的POD和SOD同功酶活性较对照提高 ,并能诱导新的POD同功酶的表达。     

小麦幼苗根系抗氧化酶对镍胁迫的响应

为阐明Ni对小麦(Triticum aestivum L.)毒害的生理生化机理,研究了不同浓度Ni(0、50、100、200、400μmol·L-1)对小麦幼苗根系生长和活性氧代谢的影响。结果表明,50μmol·L-1Ni处理小麦幼苗6 d对根系生长和活性氧含量及抗氧化酶活性无显著影响。100~400μmol·L-1Ni处理时,随着Ni处理浓度增加,根系鲜重和长度逐渐降低,H2O2和MDA含量及O2-·产生速率则逐渐升高;超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)、谷胱甘肽转硫酶(GST)、谷胱甘肽过氧化物酶(GPX)和葡萄糖-6-磷酸脱氢酶(G6PDH)活性逐渐提高,抗坏血酸过氧化物酶(APX)活性先上升后下降,100μmol·L-1Ni浓度时APX活性最大;过氧化物酶(POD)活性则无显著变化。采用聚丙烯酰胺凝胶电泳分析抗氧化酶同工酶谱发现,100μmol·L-1Ni处理诱导新的同工酶带APX-3和APX-4;对照组SOD出现了2条同工酶带,G6PDH出现4条同工酶带;100和400μmol·L-1Ni处理增强SOD和G6PDH同工酶带活性。由此可见,过量Ni处理抑制小麦根系生长、诱导活性氧水平升高而导致氧化胁迫,而SOD、APX、GST和GPX等抗氧化酶活性增加可能是根系为抵御氧化胁迫而产生的一种适应性响应。     

铅胁迫对芦竹抗氧化酶活性的影响

研究了在不同浓度Pb2+胁迫下,芦竹(Arund donax Linn.)体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)3种抗氧化酶活性随时间的变化情况。结果显示,芦竹遭受Pb2+胁迫初期,3种酶活性较对照值有明显增高;随着污染浓度加大和时间延长,3种酶活性又出现下降,降低程度与受污染浓度和时间有关。Pb2+胁迫初期,芦竹幼苗体内的抗氧化能力增强,表现出对抗氧化酶的激活效应,但随着植物生长,Pb2+在植物体内迁移,其叶片内抗氧化能力降低,表现出对抗氧化酶的抑制效应。抗氧化酶活性产生的效应强弱及维持期长短与Pb2+胁迫浓度有关,胁迫初期一般是Pb2+浓度高,抗氧化酶活性升高明显;胁迫后期Pb2+浓度低,活性维持期长。Pb2+胁迫对过氧化氢酶和过氧化物酶的影响没有超氧化物歧化酶的影响显著,但3种酶活性的变化趋势基本一致。     

硅、钙对水土保持植物荞麦铝毒的缓解效应

采取水培法,研究了铝胁迫下不同水平的钙或硅对荞麦真叶期和初花期铝毒害的缓解效应。结果显示:在Al3 胁迫下,增加钙或硅的供应可减轻Al3 对植物的毒害,显著削弱因Al3 处理导致的根系活力、可溶性蛋白质含量和过氧化物酶(POD)活性的下降以及丙二醛含量的上升,在初花期能完全消除Al3 对可溶性蛋白质形成的抑制效应并促进其形成,有效提高植株抗逆性。但随着Al3 浓度的提高,Ca2 和硅的缓解效应有限。Ca2 的缓解效果略强于硅。     

镉胁迫对芦竹抗氧化酶活性的影响

本文研究了在不同浓度Cd2+胁迫条件下,芦竹(Arundo donaxL.)体内抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT、过氧化物酶POD)活性随时间的变化情况。结果显示,芦竹遭受Cd2+胁迫前期3种酶活性较对照值有明显增高;随着污染浓度提高和时间延长,酶活性出现下降,降低程度与受污染浓度和时间有关。研究表明,Cd金属胁迫初期,芦竹幼苗体内的抗氧化能力增强,表现出对抗氧化酶的激活效应,但随着植物生长,金属向植物体内迁移,植物器官内抗氧化能力降低,表现出抑制效应。     

矿物质调理剂中铝的稳定性及其对酸性土壤的改良作用

通过室内土壤培养试验和模拟酸雨浸泡试验,研究了3种含铝量不同的矿物质调理剂中铝的稳定性及其对酸性土壤的改良效果。该类调理剂是利用钾长石、白云石和石灰石等合理配伍后经高温焙烧而制得,呈弱碱性,富含有效钙、镁、钾、硅等营养元素。试验结果表明,施入0.5~2 g/kg调理剂培养60 d后,土壤pH由4.98升高到5.04~5.42,交换性铝含量下降37.40%~68.90%,吸附态羟基铝含量稍有增加,但毒害性铝和活性铝总量分别降低了5.37%~9.50%和4.33%~12.08%,提高土壤中交换性钙、镁、钾和有效硅的含量。同时模拟酸雨浸泡试验中铝溶出量明显降低。该类矿物质调理剂能中和土壤酸度、缓解铝毒和增加土壤养分;调理剂中铝稳定性较高,不会对土壤铝毒产生叠加效应,可安全应用于农业生产。     

不同机械改土方式对白浆土物理特性及酶活性的影响

白浆土是我国东北地区主要低产土壤之一,土体中白浆层通气透水能力极差,生物酶活性很低,导致土壤表旱表涝严重,旱田作物根系有效土层一般只有20 cm左右。自20世纪80年代开始,包括深松在内的机械改土逐渐演变为白浆土的主要改良方式。为了探讨不同机械改土方式的改土效果,研究采用3种机械改土方式,依次为普通深松犁、秸秆心土混合犁、心土间隔混拌犁,并以普通深松犁为对照,在典型白浆土上开展改土试验。机械作业后,分别测定土壤物理性质及土壤酶活性。结果表明:秸秆心土混合犁、心土间隔混拌犁处理后,白浆层的硬度降低至7~9 kg cm-2,远低于对照白浆层硬度10~14 kg cm-2;固相分别为47.74%、50.13%,均低于对照53.16%;容重与对照相比分别降低了14.01%、10.19%。与对照相比,秸秆心土混合犁、心土间隔混拌犁降低了白浆层过氧化氢酶活性,秸秆心土混合犁处理降低了白浆层脲酶和蔗糖酶活性、增加了淀积层脲酶和蔗糖酶活性;两个处理与对照相比大豆分别增产21.34%、4.94%。秸秆心土混合犁、心土间隔混拌犁改善了土壤不良的理化性质,同时对土壤酶活性有很大的影响。研究为机械改良白浆土的评价方法探索了新途径。     

Effect of nickel and grafting combination on yield,fruit quality,antioxidative enzyme activities,lipid peroxidation,and mineral composition of tomato

Soil contamination by heavy metals negatively affects crop productivity, besides representing serious threat to human health. Grafting tomato onto appropriate rootstocks may raise Ni tolerance through limiting heavy metal uptake by roots and/or its translocation to the shoot and by detoxification. A greenhouse experiment was conducted to determine the influence of long‐term Ni exposure (0, 25, or 50 µM) on crop productivity, fruit quality, leaf chlorophyll content, fluorescence, electrolyte leakage, catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX) activities in leaf, proline content, membrane lipid peroxidation, and mineral composition of tomato plants cv. Ikram, either self‐grafted or grafted onto three rootstocks: Black Beauty, Unifort, and Maxifort. Significant reduction in yield was observed in response to an increase in Ni concentration with more detrimental effects at 50 µM Ni. The fruit dry matter and total soluble solids content increased under severe Ni stress. The depression of crop performance under Ni toxicity was attributed to a decrease in leaf pigments (SPAD index), efficiency of PSII, macro‐ and microelements, and increase in lipid peroxidation and membrane damage. Plants grafted onto tomato rootstocks Maxifort and Unifort exhibited higher chlorophyll content, photochemical activity of PSII, antioxidant activity of APX and GPX, lower accumulation of MDA, and a better nutritional status (higher Ca and Fe, and lower Ni) in the leaf tissues in comparison with self‐grafted plants and those grafted onto Black Beauty. Plants grafted onto tomato rootstocks Unifort and especially Maxifort could minimize the nickel toxicity by improving nutritional status and detoxification processes.     

Silicon alleviates nickel toxicity in cotton seedlings through enhancing growth,photosynthesis, and suppressing Ni uptake and oxidative stress

Cotton (Gossypium hirsutum L.) is a well-known and economically most beneficial crop worldwide while nickel (Ni) toxicity is a widespread problem in crops grown on Ni-contaminated soils. We investigated the response of silicon (Si) in cotton under Ni stress with respect to growth, biomass, gas exchange attributes, enzymatic activities, and Ni uptake and accumulation. For this, plants were grown in hydroponics for 12 weeks with three levels of Ni (0, 50, and 100 µM) in the presence or absence of 1 mM Si. Results showed that Ni significantly reduced the plant growth, biomass, gas exchange attributes, and pigment contents while Si application mitigated these adverse effects under Ni stress. Nickel stress significantly decreased antioxidant enzymes’ activities while increased malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and electrolyte leakage (EC) in leaves and roots. The application of Si enhanced the activities of antioxidant enzymes and reduced MDA, H₂O₂, and EC in plants. Nickel application significantly increased Ni concentration and accumulation in leaf, stem, and roots while Si application significantly decreased Ni in these plant parts. The present study indicates that Si could improve cotton growth under Ni stress by lowering Ni uptake and reactive oxygen species (ROS) and by increasing antioxidant enzymes activities.     

Alleviation of manganese toxicity and manganese-induced iron deficiency in barley by additional potassium supply in nutrient solution

Barley plants were grown hydroponically at two levels of K (3.0 and 30 mm) and Fe (1.0 and 10 μm) in the presence of excess Mn (25 μm) for 14 d in a phytotron. Plants grown under adequate K level (3.0 mm) were characterized by brown spots on old leaves, desiccation of old leaves, interveinal chlorosis on young leaves, browning of roots, and release of phytosiderophores (PS) from roots. These symptoms were more pronounced in the plants grown under suboptimal Fe level (1.0 p,M) than in the plants grown under adequate Fe level (10 μm). Plants grown in 10 μm Fe with additional K (30 mm) produced a larger amount of dry matter and released less PS than the plants grown under adequate K level (3.0 mm), and did not show leaf injury symptoms and root browning. On the other hand, the additional K supply in the presence of 1.0 μM Fe decreased the severity of brown spots, prevented leaf desiccation, and increased the leaf chlorophyll content, which was not sufficient for the regreening of chlorotic leaves. These results suggested that the additional K alleviated the symptoms of Mn toxicity depending on the Fe concentration in the nutrient solution. The concentration (per g dry matter) and accumulation (per plant) of Mn in shoots and roots of plants grown in 10 μm Fe and 30 mm K were much lower than those of the plants grown in 10 μm Fe and 3.0 mm K, indicating that additional K repressed the absorption of Mn. The concentration and accumulation of Fe in the shoots and roots of the plants grown in 10 μm Fe and 30 mm K were higher than those of the plants grown in 10 μm Fe and 3.0 mm K, indicating that the additional K increased the absorption of Fe under excess Mn level in the nutrient solution. The release of PS, chlorophyll content, and shoot Fe concentration were closely correlated.     

Effect of salt stress on tomato plant and the role of calcium

Abstract

Salinity is one of the serious abiotic stresses that has adverse effects on plant growth. The aim of this study was to investigate the effect of sodium chloride (NaCl) on germination and growth parameters of tomato plant as well as the role of Ca²⁺as an ameliorating agent. 100?mM NaCl and two concentrations of calcium (5 and 10?mM) were applied to tomato seeds and seedlings. This study was carried out in a Completely Randomized Design (CRD) with a total of six treatments each comprising of three replicates. The application of 100?mM of NaCl delayed the germination time by 27.6%, reduced the seedling length and seedling vigor by 24.33% and germination stress tolerance by 27.6% as compared to control. Salinity also reduced the plant growth (root and shoot length, root fresh and dry weight, shoot fresh and dry weight, membrane stability, relative water content and leaf area), whereas the application of calcium mitigated the negative effects of salinity on germination and growth to a greater extent. With increased calcium concentration, growth and germination increased significantly both alone and in the salt-affected plant. 10?mM calcium showed best results and enhanced the promptness index by 20.7%, seedling length and vigor by 15.1% and GSI by 20.7%. It also improved root fresh and dry weight, shoot fresh and dry weight, relative water content and leaf area. Similarly, 5?mM calcium also increased plant height and membrane stability index. The present study suggests that application of Ca²⁺ enhanced the growth of tomato plant under saline conditions.     

碱性材料对修复与改良酸性硫酸盐土壤障碍因子的研究

采用盆栽试验研究了不同碱性材料(石灰、自研改良剂、钙镁磷肥)对酸性硫酸盐土壤主要障碍因子的修复及其对水稻生长的影响。结果表明,不同碱性材料对土壤理化特性、土壤养分有效性和水稻生长的影响存在明显差异。与常规施肥(NPK)处理相比,自研改良剂(SAM)和钙镁磷肥(CMP1)处理土壤p H增加了1.25和0.92个单位,土壤速效磷含量分别增加了3.1倍和2.6倍,土壤有效铁、有效锰、交换性H+、Al3+含量均大幅下降。SAM与CMP1处理通过提供足够的有效磷并补充钙、镁等元素,有效改善了根系生长环境,从而有效控制铁、锰、铝等元素向地上部转运,进而对作物的生长起到促进作用。SAM和CMP1处理较NPK处理有效促进了关键生育期水稻根系活力并显著增加了水稻籽粒产量,增幅分别达121.1%和105.1%。石灰效果次之。综上,初步认为碱性材料改良酸性硫酸盐土壤的关键在于保证了充足有效磷的同时,提高了土壤p H,降低了土壤金属的毒害。本试验条件下,钙镁磷肥对修复和改良酸性硫酸盐土壤障碍因子效果非常明显,但其成本是自研改良剂的3倍,因此,基于改良剂的成本与长期适用性考虑,自研改良剂可能是该类土壤改良的最佳选择。     

Amelioration of a calcareous saline-sodic soil by gypsum and forage plants

A field experiment was carried out at the University of Agriculture, Faisalabad (Pakistan) during 1988–90 to evaluate the comparative efficiency of chemical and biological methods for the reclamation of a calcareous saline-sodic soil (pHs

1 pHs = pH of saturated soil paste

= 8.2–8.6; ECe

2 ECe = Electrical conductivity of the saturation extract

= 7.4–9.0 dS m⁻¹; SAR

3 SAR = Sodium adsorption ratio

= 55.6–73.0 for upper 30 cm layer). Five treatments were assessed, three involved cropping: sesbania (Sesbania aculeata), sordan (Sorghum bicolor x Sorghum sudanese), and kallar grass (Leptochola fusca) and two were non-cropped (control and gypsum at 100.0 per cent GR-15·0 cm) were employed. Water of low electrolyte concentration (EC = 0.27 dS m⁻¹) was used for irrigation and leaching. Sesbania and kallar grass were found to be effective biotic materials for soil reclamation. These plant species produced substantial biomass and also improved the soil environment by lowering the EC and SAR of the soil. Sordan was relatively less-effective due to its sensitivity to high temperature and sodicity during germination and early seedling stages. After two cropping seasons, wheat (cultivar LU 26S) was sown as a test crop. Efficiency of treatments as indicated by wheat grain yield was in the order: sesbania = gypsum > kallar grass > sordan > control.     

过氧化钙及硅钙肥改良潜育化稻田土壤的效果研究

【目的】潜育化水稻土是我国最主要的低产水稻土类型,长期渍水导致的土壤缺氧及活性还原物质过度积累是其最主要特征,这严重影响了水稻的根系发育和产量提高。本研究以鄱阳湖区潜育化稻田土壤为对象,通过田间试验研究过氧化钙和硅钙肥单施或配施对潜育化稻田土壤的改良效果,旨在为探索潜育化稻田的轻简化改良方法提供理论依据。【方法】田间试验于2012 2013年在鄱阳湖区潜育化双季稻田进行,试验设单施化肥(T1)、化肥+硅钙肥(T2)、化肥+过氧化钙(T3)和化肥+硅钙肥+过氧化钙(T4)4个处理。通过2年4季的田间试验研究了过氧化钙和硅钙肥单施或配施对鄱阳湖区潜育化稻田水稻产量、土壤还原物质总量及土壤物理化学性质的影响,分析了过氧化钙和硅钙肥改良潜育化稻田土壤的效果和应用前景。【结果】过氧化钙和硅钙肥单施或配施均可以提高潜育化稻田的水稻产量,二者配施每季可以提高水稻产量1.06 t/hm22.06 t/hm2,并可促进磷、钾养分向籽粒转移。施硅钙肥对土壤还原物质总量没有明显影响,而施过氧化钙可以显著降低土壤还原物质总量,二者配施可以减少耕层土壤还原物质总量1 cmol/kg以上。随着土层的加深,土壤还原物质总量呈增加的趋势。硅钙肥与过氧化钙配施可以明显提高小于10 mm的中小团聚体的含量。施硅钙肥或过氧化钙对土壤养分含量没有明显影响,但二者配施可以明显提高土壤有机碳、速效磷的含量,但对腐殖质碳、速效钾和全氮含量影响不明显。【结论】施用硅钙肥可以提高潜育化稻田的水稻产量,但对土壤还原物质总量没有明显影响。施用过氧化钙既可以提高水稻产量,又可以降低潜育化稻田的潜育化程度。而硅钙肥和过氧化钙配施不仅可以明显提高水稻产量、降低潜育化稻田的潜育化程度,还可以改善土壤养分供应状况和土壤结构。因此,施用过氧化钙和硅钙肥可以作为改良鄱阳湖区潜育化稻田土壤的一种参考方法。     

Influence of Cadmium Toxicity on Growth and Antioxidant Enzyme Activity in Rice Cultivars with Different Grain Cadmium Accumulation

Abstract

The effect of cadmium (Cd) toxicity on growth, lipid peroxidation, and antioxidant enzymes was studied using two rice cultivars, Bing 97252 with low and Xiushui 63 with high grain Cd accumulation. Plants were exposed to 0–5 μ M Cd in hydroponic culture. Cadmium stress inhibited plant height and chlorophyll content and altered melondialdehyde (MDA) content and the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Roots and shoots responded differently to Cd in terms of antioxidant enzyme activity. Generally, the activities of SOD, POD, and CAT decreased with increase in Cd level, while the activity of MDA increased with increase in Cd level. With the increase in Cd concentration in nutrient solution, MDA content in shoots and roots of Xiushui 63 increased at a much higher rate than did that of Bing 97252 at both growth stages. At booting stage, a decrease of 46%–52% in SOD activity was noted in plant roots grown under 5 μ M Cd, while at tillering stage the decrease was 13%–19% compared with the control. A significant decrease in chlorophyll content and plant height was noted under higher Cd treatment (1.0 and 5.0 μ mol) at two stages. The higher MDA and lower chlorophyll content in the cultivar Xiushui 63 showed that it is more sensitive to Cd than the cultivar Bing 97252.