春季白皮松实生苗的脱锻炼与再锻炼

春季测定二年生白皮松实生苗脱锻炼期间针叶和茎的抗寒性和估测脱锻炼结束后经低温(4℃)处理1周后幼苗的再锻炼能力,以及测定低温处理前后不同器官干物质含量的结果表明:脱锻炼后,一年生针叶的最小抗寒性为-10.4℃,一年生茎为-6.7℃.在低温诱导下,白皮松苗具有再锻炼能力,一年生针叶和茎的抗寒性分别增强约7和9℃;一年生针叶和茎的抗寒性均高于当年生的.再锻炼期间,一年生针叶和茎的抗寒性与干物质含量呈正相关.     

低温锻炼后桑树幼苗光合作用和抗氧化酶对冷胁迫的响应

以桑树品种“秋雨”为试验材料,研究了桑树幼苗在低温锻炼、冷胁迫和常温恢复期间的光合作用和抗氧化酶活性的变化.结果表明: 12 ℃3 d低温锻炼明显提高了桑树幼苗的抗冷性.3 ℃3 d冷胁迫下,12 ℃3 d低温锻炼后的桑树幼苗叶片净光合速率(P_n)、气孔导度(G_s)和PSⅡ 最大光化学效率(F_v/F_m)明显高于对照(未经低温锻炼)处理的桑树幼苗,而且其在常温下的恢复也较对照桑树幼苗迅速.在12 ℃ 3 d低温锻炼和3 ℃ 3 d冷胁迫期间,桑树幼苗叶片脯氨酸和可溶性糖含量明显增加,而经低温锻炼的桑树幼苗叶片丙二醛(MDA)含量明显低于未经低温锻炼的桑树幼苗,经低温锻炼的桑树幼苗叶片抗坏血酸过氧化物酶(APX)活性则明显高于未经低温锻炼的桑树幼苗.说明渗透调节物质含量增加和APX活性提高在低温锻炼诱导桑树幼苗的抗冷性上发挥着重要的作用.     

葡萄幼苗在温度胁迫交叉适应过程中对水杨酸的应答

在温度锻炼诱导葡萄幼苗对交叉温度逆境的适应过程中叶片内源SA变化的结果表明,0℃低温胁迫期间,葡萄幼苗叶片细胞膜系统受到严重伤害,丙二醛(MDA)含量明显升高;此时自由态SA含量呈波动性变化,并随着胁迫进程的延长,内源SA含量明显低于正常叶片水平。而经过高温锻炼的幼苗,在低温胁迫初期自由态SA含量迅速达到一个高峰,之后回落并保持在正常叶片的SA水平,MDA含量也相应降低且相对稳定。结合态SA的变化相对较平稳,并且总SA含量变化趋势与自由态SA含量的变化趋势相吻合。在45℃高温胁迫期间,经过低温锻炼的幼苗的上述各项指标的变化规律与经过高温锻炼的幼苗在低温胁迫期间的变化趋势相似。     

甜杨6-磷酸葡萄糖脱氢酶在抗冻性低温诱导中的作用

对-20℃低温锻炼及脱锻炼过程中甜杨(Populus suaveolens)幼苗的G6PDH、SOD和POD活性、MDA含量和半致死温度(LT50)进行了测定和分析.结果发现,低温锻炼在一定程度上提高了幼苗6-磷酸葡萄糖脱氢酶(G6PDH)、SOD和POD活性,降低了MDA含量和幼苗半致死温度(LT50).另外,将幼苗放回常温(脱锻炼)2 d能引起幼苗的G6PDH、SOD和POD活性的显著下降,并使LT50和MDA含量的迅速回升.结果表明,低温锻炼中G6PDH活性的增加有助于SOD和POD活性的提高,进而对幼苗的LT50和MDA含量的降低有明显的促进作用,G6PDH可能参与了SOD和POD活性的调节和抗冻性的低温诱导.     

低温处理下不同禾本科牧草的生理变化及其抗寒性比较

研究牧草根系抗寒性的动态变化,对寒冷地区的牧草引种筛选意义重大.试验以美国引进的禾本科牧草高山早熟禾(Poa Aalpine)、俄罗斯野麦(Elymus junceus)、无芒冰草(Agropyron inerme)、爱达荷冰草(Agropyron inerme)(品种名Secar)和爱达荷冰草(Agropyron inerme)(品种名Goldar)为研究材料,人工控温进行低温抗寒锻炼、冷冻处理和解冻恢复生长,测定每一阶段下根系中MDA、可溶性蛋白质、可溶性糖和脯氨酸的含量及SOD活性.结果表明,MDA含量在抗寒锻炼后略有增加,随后维持基本稳定;SOD活性在抗寒锻炼后升高,冷冻处理后显著降低;返青后又显著升高(P＜0.05);可溶性蛋白质、可溶性糖和脯氨酸含量在抗寒锻炼和冷冻处理后升高,返青后降低;其中,SOD活性、可溶性糖和脯氨酸的含量随处理不同变幅较大,MDA和可溶性蛋白质的含量随处理不同变幅较小.运用Fuzzy数学中隶属函数法进行抗寒性综合评判,得出抗寒性强弱顺序为:高山早熟禾＞俄罗斯野麦＞爱达荷冰草(Secar)＞无芒冰草＞爱达荷冰草(Goldar).     

低温锻炼对冰温贮藏牡丹切花抗冷性的影响

以牡丹品种‘玉面桃花’、‘清香白’和‘凤丹’切花为试验材料,测定室温对照(15~18℃保湿贮藏3d,RTS)、低温锻炼[(4±1)℃保湿贮藏3d,CAS]、冰温贮藏[(4±1)℃保湿贮藏3d,然后转入(-4±1)℃保湿贮藏3d,ITS]3种处理的牡丹切花花枝不同器官(花瓣、花药、子房、萼片、叶柄、叶片、茎杆)的过冷点(SCP)和冰点温度(FP),以及花瓣和叶片束缚水与渗透调节物质含量变化,明确低温锻炼对其切花抗冷能力的影响,为牡丹切花储运及销售过程中冰温贮藏温度控制提供参考依据。结果表明:经4℃低温锻炼3d的牡丹切花与室温对照相比,低温锻炼处理使3个牡丹切花不同组织的SCP和FP显著降低,但花瓣和叶片的束缚水、可溶性蛋白质、可溶性糖和脯氨酸含量均得到提高;冷锻炼后转入冰温贮藏处理进一步提高了牡丹切花花瓣和叶片的束缚水和可溶性蛋白质含量。研究发现,4℃低温锻炼显著提高了牡丹切花的抗冷性,使花枝能够更好地适应30~150d长期贮藏的-3~-4℃冰温环境。     

两种石蒜生长发育期鳞茎可溶性糖、蛋白质及POD活性的变化

以中国石蒜(Lycoris chinensis)与石蒜(Lycoris radiata)为材料,研究其生长发育期鳞茎可溶性糖、蛋白质含量及POD活性的变化。结果表明,在花芽分化前期,2种石蒜鳞茎可溶性糖、可溶性蛋白质含量均增加,并出现峰值,但从花芽分化后期直到花期结束,可溶性糖含量均持续下降;在花期,2种石蒜鳞茎可溶性蛋白质含量均处于高水平,花谢后明显下降;石蒜展叶期间鳞茎可溶性蛋白质含量明显增加,而中国石蒜花谢后可溶性蛋白质含量处于低水平。在花芽分化前期,2种石蒜鳞茎POD活性呈直线上升,但后期POD活性略有降低;花期后,2种石蒜鳞茎POD活性出现短暂的低谷,随后随着气温的降低而出现一致性上升。     

伊贝母组织培养形态发生过程中几种糖类含量及淀粉酶和蔗糖酶活力动态研究

培养5天,伊贝母鳞茎外植体内淀粉含量明显增加,淀粉酶活力降低,随着细胞脱分化,组织内淀粉含量降低,淀粉酶活力增高;低温培养阶段,淀粉大量积累,淀粉酶活力降低;芽原基形成时期,淀粉含量急剧下降,淀粉酶活力增高;再生植株形成时,淀粉含量及淀粉酶活力趋于稳定。培养初期及低温培养期间,当淀粉大量积累时,蔗糖酶活力增高,蔗糖被分解利用;培养15—25天,蔗糖含量升高,蔗糖酶活力降低;芽原基形成时,蔗糖含量下降,蔗糖酶活力增高;根原基形成时,果糖含量急剧下降。在整个组织培养过程中,β—淀粉酶活力始终高于a—淀粉酶,而且变化幅度大。     

红树植物秋茄和桐花树抗寒力的越冬变化

采用电导法定量测定了福建省九龙江口红树植物秋茄和桐花树抗寒力的越冬变化 ,探讨了抗寒力与水分、叶绿素、可溶性蛋白质含量及过氧化物酶活性的相关性 .结果表明 ,1 988年 9月至 1 989年 4月越冬期间 ,秋茄和桐花树抗寒力随气温下降而增强 ,分别于1月和 1 2月达到最大 ,低温处理 1h ,半致死温度为 - 9.3℃和 - 9.0℃ ;其后 ,抗寒力随气温回升而迅速下降 .冬季秋茄和桐花树抗寒力的提高与束缚水含量增加或自由水含量减少密切相关 ,并伴随可溶性蛋白质含量的增加和过氧化物酶活性的增强 .束缚水与自由水、叶绿素a与b含量的比值变化可以反映红树植物抗寒力变化 :两种比值越高 ,抗寒力越强 .     

低温胁迫下凤眼莲叶片的适应——脱落酸和可溶性蛋白质含量升高

本文报道低温胁迫下风眼莲叶片脱落酸(ABA)、可溶性蛋白质和水势的测定结果。低温胁迫时脱落酸和可溶性蛋白质含量远高于对照,(前者含量最高可达对照的4倍,后者可达到对照的2.75倍),而且脱落酸和蛋白质含量随温度降低而升高。蛋白质的生物合成抑制剂亚胺环己酮证明,可溶性蛋白质含量升高,原因是有部分是新合成的。在各种低温处理下获得了几乎相同于对照的叶片水势。我们推测:低温胁迫下,脱落酸水平的相应变化不是由于低温诱导水分胁迫所致,而是低温胁迫本身诱导。     

等渗盐胁迫对番茄抗氧化酶和ATP酶及焦磷酸酶活性的影响

用Ca(NO3)2 80 mmol/L和NaCl 120 mmol/L等渗溶液处理番茄幼苗后,细胞质和叶绿体中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性升高,并且NaCl胁迫的作用明显高于Ca(NO3)2胁迫.Ca(NO3)2处理提高了线粒体中SOD、CAT、APX的活性,而NaCl处理降低了它们的活性.根系质膜H -ATPase、液泡膜H -ATPase、焦磷酸酶(H -PPase)的活性和叶片丙二醛(MDA)及脯氨酸含量在两种盐胁迫后明显增加.NaCl处理对植株生长的抑制程度明显高于Ca(NO3)2处理.     

模拟增温对青藏高原多年冻土区小嵩草和藏嵩草生长与抗氧化特征的影响

采用开顶式增温小室(OTCs)方法模拟气候变暖,分别选取青藏高原腹地风火山地区高寒小嵩草草甸和高寒藏嵩草沼泽草甸优势物种小嵩草和藏嵩草为研究对象,对比分析增温处理下两种优势物种叶片的形态与生理特征变化,从而探索高寒植物对气候变暖的内在响应机理.结果表明: 增温显著增加了小嵩草叶片长度(40.0%)和叶片数量(72.7%),也显著增加了藏嵩草株高(11.9%)和叶片长度(19.3%),促进了两种优势植物的形态生长和地上生物量增加.增温处理下小嵩草和藏嵩草叶片的膜透性(电导率),活性氧(过氧化氢和超氧阴离子自由基),超氧化物歧化酶、过氧化物酶、抗坏血酸过氧化物酶和过氧化氢酶活性,丙二醛含量均没有显著变化.但抗坏血酸和游离脯氨酸含量在藏嵩草叶片内分别显著增加了29.8%和53.8%,而在小嵩草叶片内没有明显变化.可见,增温下小嵩草和藏嵩草均能够维持正常的抗氧化水平,以维持该区域优势植物生长;但藏嵩草生理过程对增温更加敏感.     

Evaluation of physiological responses and tolerance to low-temperature stress of four Iceland poppy (Papaver nudicaule) varieties

Iceland poppy (Papaver nudicaule) is a boreal flowering plant and native to subpolar regions of Europe, Asia and North America, and the mountains of Central Asia. To investigate response and tolerance to low-temperature stress, the four varieties of Iceland poppy, Champagne Bubbles (CB), Domestic Variety (DV), Wonderland (WL), and Garden Gnome (GG), were subjected to low-temperature treatment from 0°C to ?9°C. The relative electrical conductivities in four varieties increased along with the decrease in temperature. Treated by ?3°C, the morphological changes of seedlings at different time points were investigated. Four varieties were differentially injured by freezing temperature. The dynamic accumulations of malondialdehyde (MDA), free proline (FP), soluble proteins (SP), and activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) during low-temperature treatment were measured and compared. A minor change in SP content during treatment was found, whereas MDA and FP were significantly induced. Complex patterns of activity alternations of SOD, POD, and CAT were found. Based on the calculation of semi-lethal temperature and comprehensive physiological parameters investigation, the tolerance of four varieties was evaluated as CB?>?GG and DV?>?WL.     

青藏高原几种高寒植物的抗寒生理特性

研究了青藏高原高寒地区3种多年生植物在生长过程中植物叶组织的可溶性糖、脯氨酸和丙二醛（MDA）含量、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性的变化及其生理特性。结果表明;矮嵩草（Kobresia humilis）、垂穗披碱草（Elymus nutans）和黑褐苔草（Carex atro-fusca）叶中的可溶性糖含量随着生长期的进程而增加;脯氨酸含量的变化因植物种类的不同而表现各异,其中在各生长期．垂穗披碱草的脯氨酸含量均高于矮嵩草和黑褐苔草,并在草盛中期表现出明显的差异;3种高寒植物叶片中的丙二醛（MDA）含量随着生长季和气温的变化而呈现不断增加的趋势;3种植物中的超氧化物歧化酶（SOD）和过氧化物酶（POD）活性表现出随生长期和气温变化而改变的趋势,但黑褐苔草的2种膜保护酶活性最高,垂穗披碱草的次之．矮嵩草最低。可见,在不同生长季,这3种高寒植物的抗寒生理反应或低温适应方式可能是多途径的．其中在抗寒物质代谢、膜脂过氧化能力和抗氧化酶系统等方面,有生理反应的共同规律和各自特有的生理抗寒特性．其适应性与抗逆性有所不同,这种差异和生理特性可能与高寒植物的遗传特性和极端高寒低温环境胁迫有关。     

Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities

Proline and betaine accumulate in plant cells under environmental stresses including salt stress. Here, we investigated effects of proline and betaine on the growth and activities of antioxidant enzymes in tobacco Bright Yellow-2 (BY-2) culture cells in suspension under salt stress. Both proline and betaine mitigated the inhibition of growth of BY-2 cells under salt stress and the mitigating effect of proline was more than that of betaine. Salt stress significantly decreased the activities of superoxide dismutase (SOD), catalase and peroxidase in BY-2 cells. Exogenous application of proline or betaine alleviated the reduction in catalase and peroxidase activities but not SOD activity under salt stress. In addition, proline was found to be effective in alleviating the inhibition of salt stress-induced catalase and peroxidase activities in BY-2 cells. Neither proline nor betaine directly scavenged superoxide (O(2)(-)) or hydrogen peroxide (H(2)O(2)). It is concluded that exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine because of its superior ability to increase the activities of antioxidant enzymes.     

Adaptability to drought in sugar beet cultivars

The effects of NaCl and polyethylene glycol (PEG) on superoxide dismutase (SOD) and peroxidase (P) activities, lipid peroxidation (LP) and proline content in seeds and leaves of drought tolerant (FC-506 and MS-100) and drought sensitive (MS-612 and MS-13) sugar beet cultivars were examined. After PEG and NaCl treatment in tolerant cultivars both in seeds and leaves SOD activity mainly increased, though P activity increased only in leaves of tolerant cultivars. In drought sensitive cultivars the decrease of SOD and P activity was mostly observed. LP increased in seeds and leaves of all examined cultivars. The proline content increased in the leaves of examined cultivars and was significantly higher in drought tolerant plants. On the other hand, in the seeds only slight increase in proline content was found. The results obtained indicated that drought tolerance could be correlated with high proline content and enzymatic defense against lipid peroxidation.     

低能离子注入短命植物多伞阿魏(Ferula ferulaeoides)抗性生理特征

以能量30 keV、不同剂量N 离子注入多伞阿魏(Ferula ferulaeoides)种子用以研究多伞阿魏抗性生理指标的变化,以期为保护短命植物多伞阿魏提供理论依据.试验结果表明:随离子注入剂量增大,多伞阿魏种子发芽率和发芽指数逐渐下降;超氧化物歧化酶(SOD)活性增加、过氧化物酶(POD)、和过氧化氢酶(CAT)活性逐渐升高.剂量过大时,SOD、POD和CAT活性下降;游离脯氨酸含量逐渐降低,但在6×1016N /cm2剂量时含量升高;可溶性蛋白质含量先升高再降低,6×1016 N / cm2剂量时为最高值.通过对发芽率、发芽指数的结果进行方差分析,得出低剂量N 离子注入可破除多伞阿魏种子休眠,促进种子萌发;适当剂量N 离子注入可激活保护酶、脯氨酸和可溶性蛋白的表达.     

Effect of inoculation with the endophyte Clavibacter sp. strain Enf12 on chilling tolerance in Chorispora bungeana

Endophytic bacteria have been shown to increase resistance against biotic stress and tolerance to abiotic stress in many plants. The objective of this study was to evaluate the effect of an endophytic bacterium, Clavibacter sp. strain Enf12, in regenerated plantlets of Chorispora bungeana subjected to chilling stress (0°C). Aerial biomass and physiological markers for chilling stress, such as electrolyte leakage, lipid peroxidation, reactive oxygen species (ROS) accumulation, proline content and activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), guaiacol peroxidase (EC 1.11.1.7) and ascorbate peroxidase (EC 1.11.1.11), were assessed. We demonstrated that Clavibacter sp. strain Enf12 was capable of colonizing internal tissues of regenerated plantlets of C. bungeana and maintained stable population densities under both normal (20°C) and chilling (0°C) conditions. Inoculation enhanced plantlet growth under both conditions and significantly attenuated the chilling-induced electrolyte leakage, lipid peroxidation and ROS accumulation. The endophyte significantly increased the activities of antioxidant enzymes and proline content in C. bungeana plantlets under chilling stress. These findings suggest that Clavibacter sp. strain Enf12 inoculation stimulates the growth of C. bungeana plantlets and improves their tolerance to chilling stress through enhancing the antioxidant defense system.     

短时间亚高温对蓖麻叶中几个与抗逆性有关生理指标的影响

检测了短时间亚高温胁迫下盆栽40片叶龄的蓖麻叶中几个与抗逆性有关生理指标变化的结果表明,温度低于38℃时,蓖麻的叶绿素含量缓慢下降,高于38℃时,呈快速下降趋势;随着温度的升高,游离脯氨酸、丙二醛（MDA）含量和相对膜透性呈上升趋势,46℃下达到最大值;超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性在低于43℃时与温度变化呈正相关,超过43℃则迅速下降。     

Effect of NaCl stress on dihaploid tobacco lines tolerant to Potato virus Y

Salinity is an important abiotic factor that limits plant growth and development. The influence of salt stress induced by sodium chloride on plant growth, proline content, level of lipid peroxidation and activities of antioxidative enzymes was studied in F1 hybrid DH10 and four dihaploid lines (207B, 238C, 239K, 244B) of tobacco (Nicotiana tabacum L.). Dihaploids were obtained from anther-derived haploids of hybrid DH10 and were previously proved to be tolerant to Potato virus Y (PVY). In our study, plants were grown in vitro and exposed to NaCl (100 and 200 mM) for 33 days. All dihaploids and hybrid DH10 showed reduced growth after NaCl treatment. They accumulated significant amounts of sodium and proline in response to salt stress as have already been observed in tobacco and other plant species. In tobacco exposed to NaCl the lipid peroxidation level did not increase and activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate peroxidase and catalase (CAT) mostly did not change significantly. The exception was line 239K where salt induced higher activities of SOD, CAT and POD. Two (238C and 244B) out of four dihaploids appeared more susceptible to salt stress as they showed weak growth in correlation with high proline and sodium content. Therefore, it seems that salt tolerance is not associated with tolerance to PVY. Variations in malondialdehyde and proline content as well as in enzymes activities observed among tobacco lines imply that dihaploids have different genetic properties which might result in different sensitivity to NaCl.