转PvP5CS1基因拟南芥植株对干旱和盐胁迫的反应

为探索普通菜豆脯氨酸合成酶基因P5CS1在植物渗透胁迫中的作用,本研究应用农杆菌介导法,将PvP5CS1基因转入拟南芥,获得6株阳性转基因株系;通过检测转基因植株与野生型植株在干旱和盐胁迫下种子发芽率,幼苗脯氨酸含量、株系电导率、相对根长和成株死亡率,分析了PvP5CS1基因的表达对改善拟南芥抗渗透胁迫的效应。结果表明,在150 mmol L^-1 NaCl和150 mmol L^-1甘露醇渗透胁迫下,转基因植株平均相对发芽率分别是野生型的1.6倍和1.62倍;150、250 mmol L^-1甘露醇和150 mmol L^-1 NaCl处理下,转基因拟南芥植株平均脯氨酸含量分别是野生型的2.68、1.30和1.30倍;平均相对电导率分别是野生型植株的85%、77%和85%;平均相对根长分别是野生型植株的1.2、1.3和1.2倍;300 mmol L^-1 NaCl处理下,转基因植株的平均死亡率为42%,显著低于野生型(90%)(P<0.05);干旱胁迫下,转基因植株的平均死亡率为56%,显著低于野生型(70%)(P<0.05),说明PvP5CS1基因在拟南芥中的表达明显改善了转基因植株的抗旱性和耐盐性。     

邻苯二甲酸酯对小麦幼苗生理指标的影响

[目的]研究邻苯二甲酸酯对小麦幼苗生理指标的影响。[方法]在不同浓度和不同时间处理条件下研究邻苯二甲酸酯对小麦幼苗叶片的可溶性糖（WSS）、叶绿素、脯氨酸（Pro）和丙二醛（MDA）含量及过氧化氢酶（CAT）和过氧化物酶（POD）活性的影响。[结果]在邻苯二甲酸酯胁迫下,不同生理指标所表现出的抗性能力不同。当邻苯二甲酸酯浓度为96μg/kg时,POD、CAT活性及Pro、MDA含量都开始表现出显著抗性反应,抵抗环境胁迫;当邻苯二甲酸酯浓度为384μg/kg时,WSS含量略有下降,虽然不显著,但小麦幼苗细胞可能受到了严重伤害,并且影响到了细胞的正常生理代谢。[结论]该研究为进一步了解邻苯二甲酸酯对小麦幼苗危害的影响机制奠定了基础,为降低土壤邻苯二甲酸酯污染及保障粮食生产的安全性提供了理论依据。     

脯氨酸对高温胁迫下猕猴桃苗抗热性相关生理指标的影响

以美味猕猴桃品种秦美的组培苗为试材,研究了脯氨酸对高温胁迫下猕猴桃苗抗热性相关生理指标的影响。结果表明,脯氨酸可抑制高温胁迫下猕猴桃叶细胞膜透性和丙二醛（MDA）含量的增大,且增强了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）和抗血酸过氧化物酶（APX）的活性,与此同时也增加了抗坏血酸（AsA）和还原型谷胱甘肽（GSH）的含量。     

玉米抗旱种质资源的筛选

玉米抗旱性是典型的数量遗传性状,遗传基础比较复杂,但抗旱性可通过形态表现和生理指标进行鉴定。通过模拟干旱胁迫条件,在一定干旱压力下对玉米进行发芽试验,筛选出的材料在苗期采取反复干旱措施,依据形态特征和生理指标,最终确定抗旱材料,为进一步选育抗旱杂交种提供理论依据和技术支持。     

脯氨酸对高温胁迫下黄瓜幼苗活性氧代谢和渗调物质含量的影响

以抗热性较弱的黄瓜品种新泰密刺为材料,研究了外源脯氨酸(Proline,Pro)对高温胁迫下黄瓜幼苗叶片活性氧代谢和渗透调节物质含量的影响。结果表明,高温胁迫下,黄瓜幼苗叶片的超氧阴离子(O2-.)产生速率、丙二醛(MDA)含量和电解质渗透率(EL)显著升高,细胞膜受到了明显的过氧化伤害;Pro预处理通过提高超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,增强了对活性氧(ROS)的清除能力,有效地缓解了由高温胁迫诱导的膜脂过氧化伤害;同时,Pro预处理提高了游离Pro、可溶性糖和可溶性蛋白的含量,增强了植株的渗透调节能力,从而维持了植株体内的水分平衡。结果说明,外源Pro通过提高高温胁迫下黄瓜幼苗叶片抗氧化酶活性和渗透调节物质含量,来降低体内ROS水平,提高植株的渗透调节能力,从而缓解高温胁迫对黄瓜叶片的膜脂过氧化伤害。     

Biochemical changes in dormant grapevine shoot tissues in response to chilling: Possible role in dormancy release

At leaf fall, one-year-old shoots of cv. Superior Seedless table grape were collected and cut into single-node sections. These cuttings were subjected to 0, 100, 200, 300, 400 or 500 h of chilling at 5 °C to simulate natural chilling accumulation. After each treatment, one group of cuttings was forced to break buds while a second group was used to study biochemical changes taking place in the bud and underlying internode tissues. Carbohydrates, free polyamines and proline concentrations were determined and amylolitic and invertase (EC 3.2.1.26) activities were estimated. Low temperature treatment caused a hydrolysis of starch concomitant with an accumulation of sucrose. There was also a rapid build-up of proline, putrescine (Put) and spermidine (Spd) which reached their maximum levels at 300 positive chill units (PCU). Afterwards, as buds approached chilling satisfaction (400 and 500 PCU), hexoses accumulated in the buds while sucrose concentration increased considerably in both structures. Proline and Put, however, decreased in both tissues. Spd level remained high, while spermine (Spm) increased slightly. Changes in starch concentration seem to be controlled by α-amylase (EC 3.2.1.1). Sucrolytic activity, consisting mainly in the acid invertase form, changed inversely to sucrose concentrations. Nevertheless, at chilling satisfaction both sucrose content and invertase activity remained high in the buds implying a possible import of sucrose into the bud which acted as a strong utilizing sink. Our data suggest that limited budbreak due to a lack of chilling may be due to low hexoses availability. However, as buds approached chilling satisfaction, a high acid invertase activity, high soluble sugars concentration and a decrease in Put to Spd plus Spm ratio appear to be correlated with bud dormancy release and improve budbreak. Furthermore, endodormancy can be divided into two phases: the first one (from 0 to 300 PCU) is an acclimation period; the second (from 300 to 500 PCU) is a beginning of growth resumption.     

桂西北岩溶地区植物丙二醛和脯氨酸含量比较

[目的]从桂西北岩溶地区常见石山植物中筛选出生态-经济综合效益较好的优良先锋种。[方法]用硫代巴比妥酸法、磺基水杨酸法分别对65种常见石山植物叶片中的丙二醛和脯氨酸含量进行了测定,用数理统计方法对丙二醛和脯氨酸含量的相关性进行分析,并对65种石山植物进行聚类分析。[结果]石山植物叶片中的丙二醛含量为0.0052～0.0381μmol/g,不同植物之间丙二醛含量差异较大;所测定的植物叶片中的脯氨酸含量为4.347～374.956μg/ml,不同树种之间脯氨酸含量差异也较大;丙二醛和脯氨酸含量可以作为岩溶地区先锋植物选择的参考指标,但在选择先锋植物时不仅应考虑物种自身的生物学特性,还应考虑岩溶环境的差异性和生态经济效益以及物种的合理配置。[结论]黄连木、任豆、台湾相思、伊桐、国槐等可以作为桂西北岩溶地区石山绿化首选的优良先锋树种,与广西石山造林和植被恢复的实际情况比较一致。     

间歇升温对冷藏桃果实游离脯氨酸含量和冷害的影响

观察分析了间歇升温对冷藏大久保桃果实游离脯氨酸含量、细胞膜透性及冷害的影响,结果表明:冷藏(2±1℃)30d及4d货架期(25—28℃)后,升温24h和36h的桃果实未发生冷害,脯氨酸含量在货架期下降;升温12h和对照的果实冷害严重,脯氨酸含量在货架期急剧上升,显著和极显著高于前两个处理,冷害越严重,值越大。细胞膜透性与冷害发生及严重程度无关,冷藏期间升温处理果实的膜透性大于对照,货架期结束时,各处理间无显著差异。     

大豆脯氨酸生物合成相关基因Glyma01g24530的功能预测及表达分析

干旱胁迫下的脯氨酸积累在许多植物中都存在,人们普遍认为脯氨酸含量的提高促进了植物对干旱胁迫的抵抗能力。拟南芥中研究发现,△1-吡咯啉-5-羧酸合成酶基因P5CS1是一种限速酶用来催化脯氨酸生物合成,对脯氨酸非常重要。本研究通过生物信息学及荧光定量PCR对大豆中的P5CS1同源基因Glyma01g24530进行了初步的功能分析和表达模式验证。结果发现:Glyma01g24530具有保守的N端乙酰谷氨酸合成酶激酶结构域和N端乙酰谷氨酸合成酶激酶结构域,系统进化树显示与各植物中P5CS家族成员相似性很高,启动子顺式作用元件序列分析表明该基因存在逆境胁迫、光反应等元件。表达模式分析显示Glyma01g24530可以被干旱、盐诱导表达,并在多数组织中表达。     

Effects of proline on antioxidant system in leaves of grapevine (Vitis vinifera L.) exposed to oxidative stress by H2O2

Although proline is one of the major computable organic solutes that accumulate in many plant species in abiotic stresses, a hot debate continues about whether proline accumulation is a reaction to abiotic stress, or a plant's response is associated with stress tolerance. The effects of proline on antioxidative system in grape leaves of Vitis vinifera L. cv., ‘Öküzgözü’ exposed to oxidative stress by H₂O₂ was investigated. Endogenous proline, hydrogen peroxide (H₂O₂), malondialdehyde (MDA) concentrations, percentage of electrolyte leakage (EL), and some of the antioxidant enzyme activities; such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (POD) were measured spectrophotometrically. Inhibitory effect of H₂O₂ on antioxidant enzyme activities, MDA, and EL was found. In the presence of proline, SOD and CAT activities decreased, while POD and APX activities increased. Proline pre-treatment resulted in a decrease in cellular H₂O₂ content, MDA, and EL, while cellular concentration of proline increased. Based on the finding, it was suggested that proline and H₂O₂ could play an important role in oxidative stress injury of grapevine leaves grown in vitro culture. Also, proline might have a direct positive effect on antioxidant enzyme system, membrane phase change, MDA, and EL.