棉花酶促抗氧化系统对逆境胁迫生理响应的研究进展

棉花生产中,逆境胁迫严重影响着棉花的产量和品质。逆境胁迫会导致棉株体内的活性氧增加,酶促抗氧化系统作为活性氧的清除系统,在棉花抗逆生理中发挥着重要作用。本文试图以对棉花的酶促抗氧化系统的简单介绍为基础,综述棉花酶促抗氧化系统对干旱、盐害和黄萎病等逆境胁迫的生理响应的研究进展,分析目前相关研究中存在的问题及其研究前景。     

低温胁迫下精胺对黄瓜幼苗抗氧化酶系统及膜脂过氧化的影响

研究了低温(5℃)胁迫下精胺对黄瓜幼苗叶片抗氧化酶系统和膜脂过氧化的影响。结果表明,外施精胺显著降低了低温胁迫下黄瓜幼苗叶片的丙二醛含量和电解质渗漏率、增强了超氧化物歧化酶、过氧化氢酶、过氧化物酶和抗坏血酸过氧化物酶活性,提高了抗坏血酸和脯氨酸含量,从而增强了植株抗氧化能力,减轻了细胞膜伤害,提高了黄瓜的抗寒力。     

不同基因型黄瓜幼苗对低温胁迫恢复过程的生理响应

为探讨不同基因型黄瓜幼苗在低温胁迫恢复过程中的生理变化,以‘津优30’和‘北极星’黄瓜为试材,在低温(10/5℃)胁迫处理3 d后进行常温(25/18℃)恢复,研究恢复过程中不同基因型黄瓜幼苗保护酶活性、抗氧化物质、活性氧以及渗透调节物质含量等变化。结果表明,随着恢复时间的延长,黄瓜幼苗保护酶活性、渗透调节物质及抗氧化物质含量等升高。耐冷性较强的‘津优30’黄瓜幼苗不仅保护酶(SOD,POD,CAT,APX)活性升高较快,而且抗氧化物质(GSH,ASA)和渗透调节物质(脯氨酸,可溶性糖,可溶性蛋白)迅速积累,显著高于耐冷性差的‘北极星’幼苗;在恢复3 d时,‘津优30’黄瓜幼苗保护酶SOD、POD、CAT及APX活性比‘北极星’分别高12.1%、19.5%、32.1%和28.6%,从而加快了细胞内活性氧的清除,有效降低其膜脂过氧化水平;在恢复5 d时,‘津优30’幼苗叶片电解质渗漏率和MDA含量分别恢复到对照水平的84.6%和76.1%,‘北极星’仅恢复到对照水平的74.7%及49.0%。低温胁迫后恢复对黄瓜幼苗也是一种逆境胁迫,耐冷性较强的黄瓜幼苗通过迅速提高保护酶活性、抗氧化物质和渗透调节物质含量,减少活性氧的积累和MDA的生成,提高其低温胁迫后恢复能力。     

低温胁迫对转高山离子芥CbPLDα、CbPLDβ基因烟草抗氧化酶系统的影响

为研究高山离子芥Cb PLDα、Cb PLDβ转基因烟草对低温胁迫的生理响应,采用4、0℃低温胁迫,揭示了Cb PLDα、Cb PLDβ基因在植物抵抗低温中的作用。结果表明:随着4℃胁迫时间的延长,野生型烟草和转基因烟草的丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性以及抗坏血酸过氧化物酶(APX)活性均呈增加趋势,过氧化物酶(POD)和过氧化氢酶(CAT)活性则呈先上升后下降趋势。0℃胁迫条件下,野生型烟草和转基因烟草的丙二醛(MDA)含量和过氧化氢酶(CAT)活性以及抗坏血酸过氧化物酶(APX)均先上升后下降,过氧化物酶(POD)和超氧化物歧化酶(SOD)活性呈增加趋势。Cb PLDα、Cb PLDβ转基因活性烟草的MDA含量显著低于野生型烟草植株,而抗氧化酶活性显著高于野生型烟草对照,且转基因烟草对0℃低温胁迫的响应更积极敏感。Cb PLDα、Cb PLDβ基因的导入提高了烟草幼苗的抗低温能力。     

Atfad8叶绿体转基因烟草对冷胁迫的生理响应

摘 要：采用5℃低温处理,研究Atfad8叶绿体转基因烟草对冷胁迫的生理响应。结果表明:随着低温胁迫时间的延长,烟草幼苗的丙二醛(MDA)含量和过氧化物酶(POD)活性呈增加趋势,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性先上升后下降。 Atfad8叶绿体转基因烟草的MDA含量明显低于对照植株,而抗氧化酶活性明显高于对照植株。Atfad8基因的导入提高了烟草幼苗的耐冷害能力。     

甜菜幼苗叶片抗氧化系统对干旱胁迫的响应

以抗旱性不同的甜菜品种HI0466和KWS9454为供试材料,在不同水分处理条件下研究了甜菜抗氧化系统生理指标对苗期不同程度水分亏缺的响应机制及其与甜菜抗旱性的关系。结果表明:持续水分胁迫下甜菜幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等保护酶活性及抗氧化物质还原型谷胱甘肽(GSH)、抗坏血酸(AsA)含量基本呈现出先升高后下降的趋势,而类胡萝卜素(Car)含量逐步降低。由于抗旱甜菜品种在水分胁迫下各生理指标具有增幅大或降幅较小的特征,因此在胁迫加重时抗旱甜菜品种可维持较高的SOD、POD、CAT活性及Car、AsA含量,以降低膜质过氧化程度,使得其丙二醛(MDA)含量维持在较低水平,但在品种间差异明显。主成分分析结果表明,干旱胁迫条件下SOD、POD活性,MDA、AsA含量均可作为甜菜品种苗期抗旱性鉴定的有效生理指标。     

硅对盐胁迫下黄瓜幼苗细胞膜伤害及其保护酶活性的影响

以抗盐性不同的两个黄瓜品种为材料,研究硅对NaCl胁迫下黄瓜幼苗细胞膜伤害及其保护酶活性的影响。结果表明:盐胁迫下细胞的膜质过氧化程度明显加剧,丙二醛(MDA)含量显著增加;超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性均有不同程度的下降。外源硅降低了幼苗叶片质膜透性,提高了盐胁迫下黄瓜幼苗体内SOD、POD酶活性,但对CAT活性影响不大。     

转逆境诱导型启动子SWPA2驱动Cu/Zn SOD和APX基因甘薯(Ipomoea batatas(L).)Lam.)耐盐性

本研究以盐胁迫下逆境诱导型启动子SWPA2驱动转Cu/Zn SOD和APX基因甘薯叶片一些生理指标的变化研究转基因甘薯耐盐性.结果表明:无胁迫时,转基因甘薯叶的生理指标与未转基因植株无明显差异.相同胁迫条件下,转基因甘薯叶的超氧化物歧化酶(SOD),抗坏血酸过氧化物酶(APX),过氧化物酶(POD),过氧化氢酶(CAT...     

外源水杨酸对干旱胁迫下茅苍术光合参数和抗氧化酶活性的影响

为培育优质茅苍术种质资源,提高道地产区茅苍术的耐旱性,本研究以茅苍术植株为材料,在干旱胁迫条件下,使用1.0 mmol/L水杨酸(SA)喷施处理茅苍术叶面,检测其光合作用参数及保护酶系统等相关生理指标动态变化,讨论茅苍术在干旱条件下施用水杨酸对其光合系统保护和对其抗氧化能力的影响。结果显示,水杨酸一定程度上能够缓解干旱胁迫对茅苍术植株生长的胁迫效应。干旱胁迫下茅苍术经水杨酸处理后,净光合速率(Pn)、胞间二氧化碳浓度(Ci)、蒸腾速率(Tr)和气孔导度(Gs)值升高;过氧化物酶(POD)和超氧化物歧化酶(SOD)活性升高;过氧化氢酶(CAT)活性先升后降;相对电导率和丙二醛(MDA)含量降低。研究表明,干旱胁迫对茅苍术光合系统和保护酶系统会造成伤害,水杨酸可以通过保护茅苍术光合系统和调节其保护酶系统,缓解干旱胁迫对茅苍术带来的危害,提高茅苍术抗氧化和抗旱能力。     

高温干燥对白菜种子生命物质破坏机理的研究

采用恒温恒湿干燥箱和生理生化实验台进行干燥和分离,测试了白菜种子内部的过氧化氢酶(CAT)、过氧化物酶(POD)活性的变化,分析了高温干燥对种子生命特性的影响,结果表明,这些生命活性指标呈现钟罩型的变化趋势。随着胁迫时间延长,种子内部酶促保卫系统受到破坏,丙二醛(MDA)等有毒代谢物质含量迅速增加,最终使种子失去生命力。     

采后热处理技术在果蔬贮藏保鲜上的应用

概述了热处理在果蔬贮藏保鲜研究和实践中的应用。研究涉及热处理对果蔬硬度、风味、颜色和失重等贮藏品质的影响，以及对果蔬呼吸强度、乙烯及相关酶、保护酶和蛋白质合成等生理生化的影响，果蔬贮藏保鲜中热处理可以控制果蔬虫害、果蔬采后病害以及减轻果蔬的冷害，提出了热处理在果蔬贮藏保鲜方面的应用前景。     

1-MCP处理对黄瓜冷藏期间保鲜效果的影响

以“叶三”黄瓜果实为材料,采用10 ppm1-MCP处理24 h后,与对照(CK)同时转入0℃低温冷藏,并对低温贮藏过程中的黄瓜感官品质、组织相对电导率、可滴定酸(TA)、Vc含量和失重率的变化进行了研究,结果表明,1-MCP处理可抑制低温贮藏中黄瓜相对电导率的上升,减缓黄瓜果实冷害症状的发展,同时延缓Vc和可滴定酸的下降速率,维持黄瓜较好品质。     

二苯胺控制采后果蔬生理病害的机制

二苯胺是一种常用于控制苹果虎皮病的抗氧化剂,并且在控制其他果蔬的采后生理病害上也有一定效果。本文综述了二苯胺在控制青花椒冷害、苹果虎皮病、鸭梨黑心病及其他果蔬采后生理病害的作用机理和应用现状,探讨了二苯胺结合低氧、1—MCP及热处理等其他采后处理方法增强效果的可能性,提出今后二苯胺应用于控制果蔬贮藏期生理病害的研究方向。     

Biochemical and proteomic analysis of ‘Kyoho’ grape (Vitis labruscana) berries during cold storage

Low temperature storage is widely used to maintain the quality of postharvest fruit and extend their shelf-life. In this study, changes in specific metabolites and protein expression profiles of grape berries under cold storage were investigated by liquid chromatography and proteomic studies, respectively. During cold storage, total soluble solids and reducing sugars accumulation was accompanied by a decline in organic acids and phenols contents. A comparative analysis of the proteomes of grape berries during cold storage was performed using a two-dimensional electrophoresis (2-DE) proteomic approach. Seventy-nine differentially regulated proteins during cold storage were successfully identified by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry, and classified into eight main categories based on their biological function. Down-regulation of proteins associated with glycolysis and the Krebs cycle, and up-regulation of cell wall polysaccharide degradation-related enzymes provided molecular evidence that soluble sugar and carbohydrate metabolism play a crucial role in postharvest regulation. In addition, cold storage increased the expression abundance of several stress related proteins such as heat shock proteins, proteasome and antioxidant enzymes, suggesting a physiological adaptation to low temperature was induced in grape berries. This study contributes to a better understanding of the cellular events in grape berries under cold storage and provides potentially useful information for maintaining fruit quality and minimizing postharvest losses.     

Postharvest performance of the yellow-fleshed ‘Hort16A’ kiwifruit in relation to fruit maturation

Postharvest performance of fruit is dependent on the maturity or physiological state of the fruit at harvest in conjunction with the postharvest management applied. For yellow-fleshed kiwifruit, the flesh colour is a significant quality attribute, and for ‘Hort16A’, flesh colour has been used for timing harvest. Variability in the postharvest performance of ‘Hort16A’ kiwifruit suggests that flesh colour alone is not as strongly indicative of postharvest performance as soluble solids content (SSC) was found to be for ‘Hayward’ kiwifruit 30 years ago. The postharvest performance of ‘Hort16A’ kiwifruit, assessed as the fruit firmness and chilling injury expression during storage, has been associated with a range of fruit characteristics: flesh colour, SSC, firmness, seed colour, fresh weight, dry matter, starch and soluble carbohydrates measured at harvest throughout maturation. The changing responses of the fruit SSC to temperature, and softening to ethylene, have also been determined. The data illustrate the complex nature of ‘Hort16A’ fruit maturation, even when looking only at simple, easy-to-measure fruit attributes. While a yellow flesh colour is a commercial necessity for ‘Hort16A’ kiwifruit, flesh colour is not a robust indicator of postharvest performance and is not tightly linked to SSC or firmness. Changes in the capacity of fruit to respond to temperature or ethylene are not reflected in on-vine changes. Softening in storage is strongly linked to the softening rate occurring on the vine at the time of harvest. Any association between at-harvest characteristics and chilling susceptibility is less clear, and chilling tolerance appears more associated with the completion of growth and carbohydrate accumulation than with increased soluble solids accumulation rates as in ‘Hayward’. Approaches to extend the understanding of the link between maturation, harvest indices and postharvest performance are discussed.     

Changes in bioactive compounds and response to postharvest storage conditions in purple eggplants as affected by fruit developmental stage

Fruit maturity stage at harvest influences the response to postharvest storage conditions and bioactive compounds content. In this work fruit from two purple eggplant cultivars (Monarca and Perla Negra) were harvested at 12, 15, 18, 20 and 23 d after fruit set (designated as stages I through V) and changes in size, dry weight, calyx area, cell wall material (AIR, alcohol insoluble residue), firmness, respiration, and antioxidants (peel anthocyanins and pulp carotenoids, ascorbic acid, phenolics and chlorogenic acid) were determined. In a second set of experiments the postharvest performance of fruit harvested at stages I (“baby” eggplants), III and IV (traditional harvest stages) during storage at 0 or 10 °C was assessed. Fruit growth continued until late ripening in contrast to calyx expansion and peel anthocyanin accumulation, which were relatively earlier events. Fruit dry weight decreased between stages I and III, remaining constant afterwards. “Baby” eggplants had higher antioxidant capacity, chlorogenic acid (ChA), carotenoids and ascorbic acid contents than late-harvested fruit. ChA predominated in pulp placental tissues at stage I, spreading throughout the fruit core at as ripening progressed. No marked differences in dry mass, antioxidant capacity or responses to postharvest storage regimes were found between fruit harvested at stages III and IV. Late pickings increased yields and led to less dense fruit, which had lower respiration rates. Within this harvest window, storage at 10 °C maximized quality maintenance. In contrast “baby” eggplants stored better at 0 °C. Understanding the developmental changes in bioactive compounds and postharvest performance may help in the maximization of fruit antioxidant properties as well as in the selection of the optimal handling conditions for each ontogenic stage.     

Effects of a phospholipase D inhibitor on postharvest enzymatic browning and oxidative stress of litchi fruit

Membrane lipid degradation catalyzed by phospholipase D (PLD) results in postharvest browning and senescence of litchi fruit. The effects of n-butanol, a specific PLD inhibitor, on enzymatic browning and oxidative stress during storage of litchi fruit at room temperature were evaluated. n-Butanol-treated fruit had a lower browning index and disease index than untreated fruit. n-Butanol treatment also decreased PLD activity. As a result, the decompartmentalization of litchi polyphenoloxidase and substrates was reduced. The conversion of substrates (−)-epicatechin and procyanidin A₂ into quinones was slowed down and enzymatic browning of litchi pericarp tissues was lower after 6 d storage. Additionally, n-butanol-treated fruit possessed significantly lower malondialdehyde contents than untreated fruit after 4 d storage. Analysis of antioxidative enzyme activities showed that n-butanol treatment inhibited oxidative stress mainly by maintaining high catalase activity in litchi pericarp tissues. Consequently, senescence of litchi fruit during storage was moderated.     

Effect of postharvest biofumigation on fungal decay,sensory quality,and antioxidant levels of blueberry fruit

Postharvest decay, caused by various fungal pathogens, is an important concern in commercial blueberry production, but current options for managing postharvest diseases are limited for this crop. Four plant essential oils (cinnamon oil, linalool, p-cymene, and peppermint leaf oil) and the plant oil-derived biofungicides Sporan (rosemary and wintergreen oils) and Sporatec (rosemary, clove, and thyme oils) were evaluated as postharvest biofumigants to manage fungal decay under refrigerated holding conditions. Hand-harvested Tifblue rabbiteye blueberry fruit were inoculated at the stem end with conidial suspensions of Alternaria alternata, Botrytis cinerea, Colletotrichum acutatum, or sterile deionized water (check inoculation) and subjected to biofumigation treatments under refrigeration (7 °C) for 1 wk. Sporatec volatiles reduced disease incidence significantly (P < 0.05) in most cases, whereas other treatments had no consistent effect on postharvest decay. Sensory analysis of uninoculated, biofumigated berries was performed utilizing a trained sensory panel, and biofumigation was found to have significant negative impacts on several sensory attributes such as sourness, astringency, juiciness, bitterness, and blueberry-like flavor. Biofumigated fruit were also analyzed for antioxidant capacity and individual anthocyanins, and no consistent effects on these antioxidant-related variables were found in treated berries. Because of limited efficacy in reducing postharvest decay, negative impacts on sensory qualities, and failure to increase antioxidant levels, the potential for postharvest biofumigation of blueberries under refrigerated holding conditions appears limited.