Effect of salicylic acid on jasmonic acid-related defense response of pea seedlings to wounding

Interactions between jasmonic acid (JA) and salicylic acid (SA) signaling pathways play important roles in the regulation and fine-tuning of induced defenses which are activated by pathogen, insect attack, or wounding. In this study, endogenous SA and JA level in pea seedlings presented opposite trends in response to wounding. Results exhibited that SA impaired the resistance to wounding of pea seedlings by means of suppressing the action of JA. Based on the fact that the wound-induced PPO activity was suppressed by SA, it could be concluded further that SA had negative effect on JA-related defense response. However, synergy between JA and SA also existed in phenolic metabolism related to PAL. Moreover, endogenous SA and salicylic acid 2-O-β-d-glucose (SAG) levels in wounded pea seedlings also appeared opposite variation tendency, and newly synthesised SAG was detected. In contrast to SA, SAG showed some synergistic action in JA-related defense response in terms of MDA, PPO activity and PAL activity, which was quite different from SA. In conclusion, these results revealed both the negative effect and some synergistic effect of SA on JA-related defense of pea in response to wounding, particularly the role of SAG.     

低温条件下磷化氢熏蒸对玫瑰采后品质的影响

研究了2℃下磷化氢熏蒸对黑魔术玫瑰处理期间呼吸强度、失重率及瓶插期间生理指标的影响。结果表明:低温磷化氢熏蒸处理会增强贮藏期间的呼吸强度,但对失重率、色泽、瓶插寿命无显著影响。1.52mg/L浓度下的熏蒸处理对玫瑰瓶插初期可溶性蛋白质含量、丙二醛(MDA)积累、电导率无显著影响,但是3.04mg/L浓度下会引起玫瑰瓶插初期可溶性蛋白质含量下降、丙二醛积累和电导率的提高。低温磷化氢熏蒸可以用于鲜切黑魔术玫瑰的检疫处理。     

水杨酸对茄子幼苗抗寒性的影响

分别以2.5,5.0,7.5mmol/L水杨酸(SA)溶液对4片真叶期茄子幼苗进行叶面喷施,研究SA对茄子幼苗抗寒性的影响。结果表明:与对照(25℃)和空白处理相比,3种SA浓度喷施的幼苗经5℃低温处理2d后,叶片中SOD和POD活性增大,CAT活性降幅减少,MDA含量降低,脯氨酸含量升高。认为SA处理可增强茄子幼苗的耐寒性,且以7.5mmol/L的效果最明显。     

盐胁迫下两种草坪草膜脂过氧化和抗氧化酶比较

Salinity stress is a major factor limiting the growth of turfgrass irrigated with recycled wastewater. The change in lipid peroxidation in terms of malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxide (APX) and glutathione reductase (GR) in the shoots and roots of Kentucky bluegrass and tall fescue were investigated under salinity stress. Plants were subjected to 0, 50, 100, 150 and 200 mmol L 1 NaCl for 40 d. The MDA content under salinity stress was lower in tall fescue than in Kentucky bluegrass in both shoots and roots. Activities of SOD in the shoots of both species increased with salinity stress. The activities of CAT and APX decreased in Kentucky bluegrass, but no significant difference in the activities of CAT and APX was observed in tall fescue. The activities of SOD, CAT and APX in the shoots of tall fescue were higher than those in Kentucky bluegrass. In the roots of Kentucky bluegrass, SOD and GR activities increased and CAT and APX activities decreased in comparison with the control. In the roots of tall fescue, salinity increased the activities of SOD, CAT, and APX. These results suggested that tall fescue exhibited a more effective protection mechanism and mitigated oxidative stress and lipid peroxidation by maintaining higher SOD, CAT and APX activities than Kentucky bluegrass.     

Cadmium Stress in Barley: Growth,Leaf Pigment,and Protein Composition and Detoxification of Reactive Oxygen Species

Barley seedlings (Hordeum vulgare L., cv. ‘Obzor’) were exposed for 5 d to 0, 5, 50, and 500 μM CdCl₂ in nutrient solution. Cadmium (Cd) treatment caused a reduction of plant length, biomass, and leaf pigment content. The level of soluble leaf proteins was not changed significantly. SDS-PAGE revealed a slight diminution of Rubisco subunits and the appearance of a new low molecular mass band after exposure to 50 or 500 μM Cd. The antioxidative protection in leaves under Cd toxicity was studied in its complexity. Slightly diminished superoxide dismutase, enhanced catalase, and drastically increased total peroxidase activities were found at the highest Cd level. Ascorbate peroxidase activity was not changed significantly. The isoenzyme patterns of the antioxidant enzymes under study were only slightly altered without synthesis of new isoforms. The content of oxidized ascorbate increased during exposure to 50 and 500 μM Cd. The level of H₂O₂ rose only at 500 μM Cd without accumulation of malondialdehyde and oxidized proteins. Non-protein thiol groups increased up to four-fold after exposure to 50 and 500 μM Cd. The results are in accordance with the induction of mechanisms allowing an immobilization and sequestration of Cd in barley leaves, and suggest only minor effects via oxidative damage.     

The ameliorative effect of ascorbic acid on the oxidative status,live weight and recovery rate in road transport stressed goats in a hot humid tropical environment

The ameliorative effect of ascorbic acid (AA) on live weight following transportation is vital in animal husbandry. This study investigated the influence of AA on live weight, rectal temperature (rt), and oxidative status of transport stressed goats in a hot humid tropical environment. Twenty‐four goats were divided into four groups, A, B, C and D of six animals each. Group A were administered AA 100 mg/kg intramuscularly 30 min prior to 3.5 h transportation. Group B was administered AA following transportation. Group C were transported but not administered AA as positive controls while group D were not transported but were administered normal saline as negative controls. Live weight, rt and blood samples were collected before, immediately post‐transport (pt), 24 h, 3 days, 7 days and 10 days pt. Plasma was used for malondialdehyde (MDA) analysis while hemolysates were used for superoxide dismutase (SOD) analysis. There was minimal live weight loss in group A compared to groups B and C. Group A recorded reduced MDA activities and increased SOD activities compared to groups B and C which recorded significantly high MDA activities. This study revealed that AA administration ameliorated the stress responses induced by transportation in animals in hot humid tropical environments. The administration of AA to goats prior to transportation could ameliorate stress and enhance productivity.     

油菜素内酯对辣椒果实贮藏及抗氧化能力的影响

为探究油菜素内酯(BR)对辣椒果实贮藏效果及抗氧化能力的影响,采用浓度为1、10、20和30 μmol·L-1的24-表油菜素内酯(24-epibrassinolide,EBR)处理辣椒果实,然后分别在温度4℃和25℃,湿度70％～80％下贮藏,检测果实失重率、腐烂率和冷害指数以及最适EBR浓度处理下辣椒果实丙二醛(MDA)和总抗氧化能力的变化.研究结果表明,EBR处理浓度20 μmol.L-1,温度4℃较适宜辣椒贮藏,能有效降低辣椒的失重率和腐烂率,且出现腐烂的时间延迟.在4℃低温下,较其他3种浓度的EBR处理,20.tmol.L-1处理的辣椒冷害指数降低,出现冷害现象的时间延迟.与对照相比,外源最适EBR处理,有效抑制了辣椒果实MDA含量的积累,减缓了总抗氧化能力的下降,其中4℃+ 20μmol.L-1 EBR处理,显著抑制了辣椒果实MDA含量的积累和总抗氧化能力的降低,较好地保持了辣椒果实中抗氧化酶的活性,保护细胞膜的完整性和功能性,减少营养的流失,维持辣椒的感官品质和营养品质,延长辣椒的贮藏时间.该研究为辣椒果实的贮藏保鲜提供新的参考与路径.     

外源NO对铜、镉胁迫下狭叶香蒲生理反应的影响

为研究外源一氧化氮(NO)对狭叶香蒲耐Cu、Cd胁迫的影响,进而揭示其缓解Cu、Cd胁迫的生理机制,以狭叶香蒲幼苗为试材,在Cu或Cd的胁迫下,分别添加0μmol/L、50μmol/L、75μmol/L和100μmol/L SNP(硝普钠,为NO供体),检测叶片和根系中抗氧化酶活性以及丙二醛(MDA)、抗坏血酸、蛋白质和叶绿素含量。结果表明:在25 mg/L Cu2+或1.5 mg/L Cd2+处理下施加不同浓度的SNP引起反应的生理指标有所不同,总体表现为叶片和根中超氧化物歧化酶(SOD)、过氧化物酶(POD)活性和蛋白质、抗坏血酸含量升高,MDA含量下降,叶绿素含量不受影响。说明外源NO能在一定程度上缓解Cu及Cd胁迫对狭叶香蒲幼苗造成的伤害。     

不同抗氧化剂对米糠毛油氧化稳定性的影响

本试验以酸值（AV）、过氧化值（POV）和丙二醛（MDA）含量作为评价指标,研究乙氧基喹啉、叔丁基羟基茴香醚（BHA）、二叔丁基羟基甲苯（BHT）三种抗氧化剂按不同组合或单体的形式添加到油脂中对米糠毛油抗氧化性能的影响。结果表明：与对照组相比添加不同抗氧化剂或抗氧化剂组合,米糠毛油AV无显著变化;POV随着时间延长不断提高,19 d后抗氧化剂添加组POV增速较对照组缓慢,且复合抗氧化剂抗氧化效果优于单体抗氧化剂。添加单体抗氧化剂后油脂MDA含量与对照组相比有所降低,复合抗氧化剂组MDA含量均低于单体组。结果提示,复合抗氧化剂的抗氧化效果优于单一抗氧化剂,单一抗氧化剂中以乙氧基喹啉效果最好,复合抗氧化剂则以0.15%乙氧基喹啉和0.015%BHA复配使用效果最好。