抑制剂和安全剂对高羊茅根中酶活性和菲代谢的影响

以高羊茅(Festuca arundinacea)为供试植物,利用水培体系研究了抑制剂和安全剂对植物根中过氧化物酶(POD)和多酚氧化酶(PPO)活性以及菲代谢的影响。供试安全剂为浓度0.3%的NaCl,抑制剂为浓度2.00 mg/L的Vc。结果表明,2.00 mg/L的Vc作用下,1—16d,高羊茅根的菲含量显著高于对照处理,而供试安全剂对植物根中菲含量的影响不显著。抑制剂作用下植物根部的PPO和POD活性显著降低;16d,抑制剂作用下的植物根部PPO和POD活性为对照组的1/6和1/9,表现出强抑制效应。而安全剂作用下植物根部PPO和POD活性则略高于对照组,但差异不显著（P＜0.05）。植物体内酶的初始活性是影响植物代谢PAHs菲的关键因素。抑制剂主要通过调节酶活性来影响根系代谢菲,其对植物根中PPO和POD活性的抑制效率与根部菲代谢抑制效率显著正相关。     

钙对黄果柑果实3种抗氧化酶活性的影响

黄果柑为桔和橙的天然杂交种。以5年生黄果柑果树为材料,设置9个不同钙处理,研究钙对黄果柑果实成熟后期3种抗氧化酶(CAT、POD和SOD)活性的影响。结果表明:叶面、果面喷钙后增大了黄果柑成熟后叶片、果皮和果肉中钙的含量,且显著高于CK。钙处理后黄果柑果实抗氧化酶活性显著高于CK,果实成熟后10 d CAT和SOD活性出现一个高峰,之后迅速降低。果实成熟后POD活性显著低于对照,但始终保持较高水平。表明钙能有效地调控黄果柑果实3种抗氧化酶的活性,增强黄果柑果实活性氧清除能力。综合比较不同钙处理对黄果柑果实SOD、POD和CAT活性影响可见,以1.0 g/L氯化钙对3种抗氧化酶活性的调控作用最有效。     

Does exogenous application of 24-epibrassinolide ameliorate salt induced growth inhibition in wheat (Triticum aestivum L.)?

A greenhouse experiment was conducted to assess whether exogenously applied 24-epibrassionlide (24-epiBL) could alleviate the adverse effects of salt on wheat. Two hexaploid wheat (Triticum aestivum L.) cultivars, S-24 (salt tolerant) and MH-97 (moderately salt sensitive), were grown under control (0 mM NaCl in full strength Hoagland’s nutrient solution) or saline conditions (150 mM of NaCl in full strength Hoagland’s nutrient solution). After 41 days growth of wheat plants under saline conditions, 24-epiBL was applied as a foliar spray. Four levels of BR were used as 0 (water spray), 0.0125, 0.025, and 0.0375 mg l⁻¹. Application of 24-epiBL increased plant biomass and leaf area per plant of both cultivars under non-saline conditions. However, under saline conditions, improvement in growth due to exogenous 24-epiBL was observed only in S-24. Photosynthetic rate was reduced due to salt stress in both cultivars, but this inhibitory effect was ameliorated significantly by the exogenous application of 24-epiBL. Exogenously applied 24-epiBL also enhanced the photosystem-II efficiency in both cultivars measured as F _v /F _m ratio. Although the activities of antioxidant enzymes, Superoxide dismutase (SOD), Peroxidase (POD) and Catalase (CAT) were increased due to salt stress in both wheat cultivars, exogenously applied 24-epiBL had a varying effect on the antioxidant system. The activity of SOD remained unaffected in both cultivars due to 24-epiBL application, but that of POD and CAT was promoted in the salt stressed plants of cv. S-24 only. In conclusion, improvement in growth in both wheat cultivars due to foliar applied 24-epiBL was found to be associated with 24-epiBL-induced enhancement in photosynthetic capacity. The 24-epiBL-induced regulation of antioxidant enzymes or growth under saline conditions was cultivar specific.     

小麦辐射突变体及原始品种不同发育期酯酶、过氧化物酶同工酶分析

采用不同发育时期的小麦辐射突变体及原始品种材料对其酯酶（EST）、过氧化物酶（POD）酶谱进行了比较研究,并对一些农艺性状之间的相关性进行了测定。结果表明,第一套材料（南大2419、鄂麦6号、81-61562、82-2291）的株高和粒重分别与过氧化物酶和酯酶的活性在一定时期呈相反的变化趋势,第二套材料（St-2422／464、62027、80-15678）则无明显规律性关系。不同时期起主要作用的谱带不同。     

元江芦荟与皂质芦荟的杂交育种及POD同工酶比较

以元江芦荟(AloeyuanjiangensisXiong,ZhengetLiu)和皂质芦荟(A.saponaria(Ait.)Haw.)为亲本进行了远缘有性杂交试验,获得了19株F1代植株。对F1代植株与亲本进行了外部形态比较;同时与亲本种及同属的华芦荟(中国芦荟)(A.chinensis(Haw.)Baker)和库拉索芦荟(A.veraL.)进行了过氧化物酶同工酶(POD)比较。其结果表明,F1代与亲本在外部形态上存在明显差异;POD同工酶酶谱显示,F1代与各个种间具有较高的相似程度,且各个种又具有各自特征酶带。这证实了F1是元江芦荟与皂质芦荟的杂种(A.yuanjiangensis×A.saponaria)。     

GB对低温胁迫黄瓜叶绿体及SOD、POD同工酶的影响

采用电镜观察和聚丙烯酰胺垂直板电泳法,研究了GB对低温胁迫下黄瓜幼苗叶绿体超微结构和SOD、POD同工酶的影响。结果表明,低温胁迫下,GB可使黄瓜幼苗叶绿体膜结构保持完好,而对照的叶绿体基粒破坏严重;与对照相比,GB处理对SOD、POD同工酶谱带数目均无影响,但POD同工酶的P2(Rf0．24)、P3(Rf0．30)、P4(Rf0．36)酶带的活性增加,SOD同工酶的S1(Rf0．14)、S5(Rf0．58)酶带活性较高,保持了黄瓜幼苗体内相对较高的抗氧化酶活性。GB可保护膜的完整性和稳定性,从而提高黄瓜幼苗的抗冷性。     

盐胁迫下小麦过氧化物酶同工酶、全蛋白变化的研究

以蛋白质含量不同的两种小麦幼苗为材料,研究了经高浓度的盐胁迫后过氧化物酶(POD)同工酶、全蛋白质的变化。结果表明,植物处于高盐环境时,会诱导或抑制某些同工酶的产生,控制蛋白质的增加和降低,以适应盐胁迫下细胞内特殊的代谢反应,从而达到抵抗盐渍侵害的目的。     

枯草芽孢杆菌和丙环唑对采后苹果炭疽病的防治效果

研究了离子束诱变的枯草芽孢杆菌B-24和丙环唑等对苹果采后炭疽病的防治效果及其几种防御酶活性的影响。结果表明:丙环唑对苹果炭疽病菌丝有明显的抑制效果,抑制浓度EC50为0.067μg/mL。代森锰锌的抑制作用最弱,其EC50为1806.984μg/mL。不同化学药剂和不同浓度的药剂之间,对苹果炭疽病的保护防效有显著差异。丙环唑对苹果炭疽病的防效最好,对寄主酶活的诱导作用也最强,能诱导苹果果实POD和PPO活性显著升高。代森锰锌防效差,POD活性和对照接近。同一药剂,浓度高的防效好,果实中酶活性也高。枯草芽孢杆菌在离体条件下活菌液对苹果炭疽病菌的抑制效果最好,抑制率为100%,表现出明显的拮抗作用。活体试验表明枯草芽孢杆菌能明显减轻苹果果实炭疽病的发生,接种枯草芽孢杆菌能诱导苹果果实POD和PPO活性的升高。     

Seasonal dynamics of foliar antioxidative enzymes and total anthocyanins in natural populations of Iris pumila L.

Aims Plants in their natural habitats frequently cope with a multitude of abiotic stresses, such as high light intensity, extreme temperatures and water deficit, which often co-occur during periods of drought, especially in semi-arid and arid regions. Exposure of plants to stressful environmental conditions usually induce overproduction of reactive oxygen species (ROS) that, as highly toxic derivatives of O 2, can assault all cell macromolecules, leading to the disruption of cellular homeostasis and, consequently, the uncoupling of major metabolic processes, the photosynthesis and photorespiration. In order to minimize ROS-mediated cellular damage, plants have evolved highly efficient antioxidative defense systems that include both enzymatic and non-enzymatic components. Since abiotic stress can also operate as a strong evolutionary force that shapes adaptations in natural plant populations, the aim of this study was to examine the seasonal variation patterns of two distinct antioxidative systems, ROS-scavenging enzymes and anthocyanin pigments, in the leaf tissue of a steppe plant, Iris pumila, as expressed under contrasting light conditions that the species regularly experiences in the wild.Methods We selected two natural populations of I.pumila inhabiting the alternative radiation environments in the Deliblato Sands, a sun-exposed dune site and a woodland understory. The specific activity of three antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) and the content of total anthocyanins were examined in leaves of I.pumila plants collected from each of the 31 Iris clones (17 in the exposed population and 14 in the shaded population) once during each of the three seasons, spring, summer and autumn in 2004. Specifically, a fully expanded leaf was cut from each clonal plant between 15:00 and 16:00 h, immediately frozen in liquid nitrogen and stored at ?70°C until preparation.Important findings Generally, all three antioxidative enzymes were up-regulated in summer-harvested leaves compared to their spring or autumn counterparts, as was observed for the concentration of foliar anthocyanins, indicating that strengthening of antioxidant systems was the key mechanism for long-term acclimatization of I.pumila plants to stressful environmental conditions within their natural ecological niches. When plants from contrasting radiation environments were compared, SOD and CAT activities appeared to be greater in shade-exposed than in sun-exposed leaves. Conversely, POD activity and the content of foliar anthocyanins were notably higher in foliage experiencing full sunlight relative to those developed under vegetation canopy, suggesting the synergistic function of these two molecules in protecting leaf cells against photoinhibitory and photooxidative effects of strong light.