水分胁迫对龙眼幼苗叶片膜脂过氧化及内源保护体系的影响

对龙眼（ＤｉｍｏｃａｒｐｕｓｌｏｎｇａｎａＬｏｕｒ．）实生幼苗进行人工水分胁迫,检测其抗氧化酶和抗氧化剂的变化,研究了干旱对叶片膜脂过氧化及内源保护体系的影响,结果表明,在水分胁迫下,龙眼叶片ＲＷＣ下降,电解质渗漏上升,ＲＷＣ的下降和电解质渗漏的上升呈极显著负相关;叶片中ＳＯＤ和ＰＯＤ活性及ＭＤＡ含量明显上升,且与电解质渗漏的增加呈极显著正相关;叶片中可溶性蛋白质,ＧＳＨ含量和ＡｓＡ－ＰＯＤ活性显     

表油菜素内酯对月季切花保鲜作用的研究

本文初步探讨了表油菜素内酯（epiBR）对瓶插月季切花的保鲜作用。与对照（蒸馏水）和基本液（2％蔗糖＋500mgL-1柠檬酸＋250mgL-8-羟基喹啉＋25mgAgNO3）相比,经epiBR处理（基本液＋0．1mgL-1epiBR）的月季切花花枝坚挺,蓝变延迟,瓶插寿命延长1-1.5倍。测定有关生理指标表明,epiBR处理对月季切花瓶插花枝前期鲜重的增加及后期的保持有明显作用。并显著延缓花瓣和叶片质膜相对透性的增加,还能使瓶插前期花瓣还原糖含量增加。epiBR处理对花瓣蛋白质和叶片叶绿素含量变化无明显影响,而对花瓣花青素水平下降有轻微的促进作用。     

膜脂过氧化作为扁桃品种抗寒性鉴定指标研究

研究不同低温胁迫下（３℃,一２℃和一ｌ０℃下分别处理０．５、３、６、９、ｌ２ｈ）扁桃离体叶片中ＭＤＡ含量、ＣＡＴ活性和类胡罗Ｌ素含量以及反映组织受伤害程度的膜透性变化和叶绿素降解间的关系,以探明膜脂过氧化在扁桃叶片低温伤害中的作用。３℃处理初期,ＣＡＴ活性、类胡罗卜素含量显著增加,叶片无明显伤害症状（水渍、黄化等）;一２Ｃ和一ｌ０℃下随处理时间的延长,叶片膜透性增大、叶绿素含量下降、ＭＤＡ积累增多;同时ＣＡＴ活性、类胡罗Ｌ素含量显著下降。ＭＤＡ含量的增加与组织受伤害程度（膜透性增加及叶绿素降解）及抗氧化系统（ＣＡＴ和类胡罗Ｌ素）水平下降之间具有极显著的相关性。以７个扁桃品种的田间越冬伤害指数及冬季所测枝条的ＬＴ５０代表植株的冬季抗寒性,以一５℃下处理４ｈ和８ｈ后所测叶片ＭＤＡ相对含量代表叶片的抗寒性,发现２者呈显著的相关性,表明ＭＤＡ可以作为鉴定扁桃品种抗寒性的指标。     

小麦叶片亚精胺含量对乙烯产生速率及蛋白酶活性间的影响

用外源ＳＰＤ处理根系可以显著提高小麦叶内ＳＰＤ的含量,抑制乙烯的产生和蛋白酶的活性,提高蛋白质的含量并降低细胞膜的相对透性。ＰＣＭＢ处理根系可以显著降低小麦叶片ＳＰＤ的含量,促进乙烯的产生,增加蛋白酶的活性和细胞膜的相对透性,降低蛋白质和叶绿素的含量。可见小麦叶片ＳＰＤ含量可能与乙烯产生间存在负的相关性。较高的亚精胺含量及较低的乙烯产生速率可能对叶片的衰老过程具有阻抑作用。反之则可能表现为促进衰老的作用。     

保鲜剂对夏季香石竹切花衰老的延缓作用

香石竹切花瓶插期间花瓣中ＳＯＤ和蛋白质在前期上升,然后比处理组提前３天呈下降趋势。采后花瓣中ＣＡＴ、可溶性总糖和蔗糖均为下降。经由蔗糖、８－羟基喹啉和植物生长调节剂或钴镍盐组成的保鲜剂能延缓切花花瓣中ＳＯＤ、ＣＡＴ活性的下降,阻碍蛋白质、可溶性总糖和蔗糖的降解速度,同时使切花的瓶插寿命延长、含水量增加。     

涝渍逆境下玉米叶片中谷胱甘肽的含量变化及其作用

涝渍逆境下玉米叶片ＧＳＨ含量和ＧＳＨ还原酶活性都明显下降,但前者的降幅小于后者,两者的变化均与叶片质膜透性以及ＭＤＡ的积累呈显著性负相关。施加外源ＧＳＨ明显减少ＭＤＡ和Ｈ２Ｏ２含量,降低Ｏ＾－２产生速率。而叶面喷施８－羟基喹啉和抗坏血酸等活性氧清除剂则减缓因涝渍而引起的ＧＳＨ含量下降。     

杀菌剂和低温贮藏对芍药切花保鲜及其生理变化的影响

利用杀菌剂及低温贮藏对切花芍药‘婴粟子’的抑菌效果、瓶插寿命、开花率及其生理变化进行了研究。结果表明,不同浓度杀菌剂均有一定的抑菌作用,并且处理Ⅲ（1000mg／kg甲基托布津＋1000mg／kg多菌灵）效果最好。预冷处理可以降低切花的呼吸速率,延长瓶插寿命和贮藏保鲜期。随着低温贮藏时间的延长,切花鲜重和开花率下降,花瓣的细胞膜透性和MDA含量增加,蛋白质含量下降,呼吸速率呈跃变型变化。     

渗透胁迫下稻苗中游离脯氨酸累积与膜脂过氧化的关系

杂交稻幼苗经聚乙二醇（ＰＧＥ４０００）渗透胁迫（－０．９５ＭＰａ）处理,幼苗含水量及相对含水量下降,游离脯氨酸和膜脂过氧化产物丙二醛（ＭＤＡ）含量上升,质膜透性增大。随ＰＥＧ渗透胁迫时间延长,幼苗膜脂饱和脂肪酸含量逐渐增加,不饱和脂肪酸含量降低,不饱和脂肪酸指数（ＩＵＦＡ）减少。脯氨酸累积与ＭＤＡ增长及膜透性加大呈正相关性,与膜脂脂肪酸不饱和度呈负相关性。讨论了游离脯氨酸累积与细胞透性的相关性,以     

热激锻炼诱导菊花耐热性研究

以菊花(Chrysanthemum morifolium)叶片和花瓣为试验材料,在38℃下对其进行5 h的热激锻炼,再于50℃下分别进行0、0.5、1.0、1.5、3.0 h的高温胁迫,然后对其细胞膜透性、叶绿素、丙二醛(MDA)和蛋白质含量动态变化及5′-核苷酸酶的活性进行了测定.结果表明,热锻炼的菊花叶片电解质渗漏率相对较小,叶片叶绿素含量比对照下降的慢,5′-核苷酸酶活性比对照高,MDA含量也相对较低,而且花瓣中可溶性蛋白质保持了相对较高的含量,说明热锻炼诱导菊花获得了一定的耐热性.     

不同保鲜剂对非洲菊切花的保鲜效应

探讨不同保鲜剂对非洲菊切花的瓶插寿命、观赏品质以及生理生化指标的影响。结果表明,在供试7组保鲜剂中,以处理7(T₇):20g/L Suc+200mg/L 8-HQC+150mg/L CA+75 mg/L KH₂PO₄·3H₂O+1g/L CaCl₂的保鲜效果最佳,可显著延长非洲菊切花瓶插寿命;T₇处理有利于减缓花瓣组织pH上升、花青素含量下降及花瓣细胞膜相对透性的上升,从而延长瓶插寿命。     

多胺对月季切花衰老过程中生理生化和瓶插寿命的影响

精胺处理可保持月季切花瓶插前期花瓣还原糖和蛋白质的较高水平、减缓花瓣和叶片细胞膜稼性的增加,减少共 积累以及降低乙烯释放速率,这与精胺处理后月季切花瓶插寿命提高相一致;但亚精胺处理对季切花瓶插寿命和改善观赏品质无明显影响。     

Age-related changes in petal membranes from attached and detached rose flowers

Changes in petal membrane properties during aging were studied in cut and in attached rose flowers (Rosa hybrida L., cv Mercedes). Both cut and attached flowers exhibited a growth phase characterized by an increase in fresh weight and an accumulation of membrane components. The growth phase, which was more pronounced in the attached than in the cut flowers, was followed by a senescence phase, characterized by a decrease in fresh weight and a decline in membrane components. In cut flowers, both the growth and the senescence phases were accompanied by a decrease in membrane fluidity and in the ratio of unsaturated to saturated fatty acids, but the ratio of sterol to phospholipid increased. In attached flowers, while both the membrane fluidity and the sterol-to-phospholipid ratio remained unchanged during the growth phase, the senescence phase was accompanied (as in cut flowers) by a decrease in membrane fluidity and an increase in the sterol-to-phospholipid ratio. Unlike in cut flowers, however, the age-related changes in the ratio of unsaturation of fatty acids were not correlated with those of fluidity. Changes in the saturation of phospholipid acyl chains are commonly thought to influence membrane fluidity. Our observations question this view and suggest instead that the ratio of sterol to phospholipid may play the major role in maintaining membrane lipid fluidity.     

Nitrogen metabolism and senescence-associated changes during growth of carnation flowers

Nitrogen metabolism including nitrate reductase (EC 1.6.6.1), glutamate dehydroge-nase (EC 1.4.1.2) and glutamate-oxalacetate aminotransferase (EC 2.6.1.1) activities were studied during growth of petals taken from carnation flowers ( Dianthus caryophyllus L. cv. Sir Arthur) together with senescence parameters (lipid hydroper-oxides, soluble amino acids and permeability). A slight decline in nitrogen percentage on a dry weight basis was found together with a sharp decrease in nitrate reduct-ase, glutamate-oxalacetate aminotransferase and glutamate dehydrogenase activities during the maximum growth phase, which was characterized by increase in respiration, dry weight, length, organic nitrogen and DNA per petal. Changes generally associated with senescence, like lipid hydroperoxide and soluble ammo nitrogen accumulation and increases in permeability began to appear already during early growth. The results indicate that permeability and proteolysis may be closely related. The possible significance of the decrease in nitrogen percentage and enzyme activities during growth of petals is discussed.     

Calcium regulation of senescence in rose petals

Rose plants grown at high relative humidity (RH) produce flowers with a shorter vase life than those grown at low RH. The calcium content of the former is lower than that of the latter. The present study was conducted to examine the possible involvement of calcium in the regulation of rose flower senescence. In whole cut flowers and in detached petals of cvs Mercedes and Baroness, CaCl₂ treatment promoted bud-opening and delayed senescence. The treated flowers stayed turgid and continued their initial postharvest growth for longer periods of time. The membrane protein content in detached petals decreased with time, in parallel to the decline in membrane phospholipids (PLs). Calcium treatment delayed the decrease in both membrane proteins and PL and increased ATPase activity in the aging petals. Electrolyte leakage, which is a reliable indicator of petal-membrane senescence, was postponed in calcium-treated flowers. Calcium treatments also sukppressed ethylene production with age. We suggest that the calcium-induced delay in rose petal senescence involves the protection of membrane proteins and PLs from degradation, thus preserving the integrity of the membranes, reducing ethylene production, and hence maintaining solute transport and tissue vitality.     

月季切花衰老过程中多胺与膜脂过氧化的关系

以月季切花为材料,研究了月季切花瓶插过程中多胺含量的变化,外源多胺处理对月季药花体内多胺含量的影响以及多胺与膜脂过氧化的关系。结果表明,月季切花瓶插衰老过程中腐胺在前2d略有增加,亚精胺和精胺均呈下降趋势;外源亚精胺和精胺处理均能增加切花体内多胺含量,并能延缓切花衰老和改善切花品质;且亚精胺和精胺处理降低了MDA含量的积累和膜相对透性的上升趋势。     

Activities of Various Peptidases in the Senescing Petals of Tulip

The hydrolysis of seven peptidase substrates by petal extracts of tulip (Tulipa sp. cv. Guillaume Tell) was assayed at four stages in the life cycle of the petals. During senescence pronounced increases from three- to sixfold took place in all the activities. At the same time the amount of soluble protein decreased about 75% and there was a simultaneous increase in free amino acids. The activity levels (on a dry weight basis) in the petals at the beginning of withering were rather similar to those present in normal leaves. Despite their different pH-optima (5-9), all the peptidases probably act in the mobilization of protein amino acids in the senescing petals.     

采后波莱叶片失水萎蔫时膜透性及膜脂过氧化作用的影响

本文分析了菠菜叶片失水萎蔫时叶绿索、相对含水量,膜透性及膜脂过氧化产物丙二醛的变化结果表明：叶片萎蔫衰老时随着相对含水量的降低,叶绿索含量减少,膜透性和丙二醛含量增大;并且随萎蔫程度加探,膜透性与丙二醛含量也明显增加。这说明菠菜叶片失水萎蔫与膜结构完整性的破坏有密切的关系。     

Retardation of Leaf Senescence by Triadimefon Treatment in Mung Bean Seedling

Treatment of triadimefon on detached leaves of mung bean (Phaseolus radiatus L. ) seedlings increased the levels of chlorophyll and soluble proteins. Declined activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate-peroxidase (AsA-POD) and contents of ascorbate (ASA) and glutathione (GSH) were observed during the senescence of detached young leaves. Triadimefon at concentration of 20 mg/L promoted the activities of POD, AsA-POD and levels of AsA and GSH, but had no effect on the activities of SOD and CAT. On the other hand, the levels of malondialdehyde (MDA) were increased and the increase of which was markedly negative correlated with the activities of POD, AsA-POD and with the contents of AsA and GSH during the senescence of leaves. MDA contents were decreased by triadimefon treatment. These resuits suggested that triadimefon retarded the senescence of leaves in mung bean seedlings in terms of enhancing the protective ability of plant tissues against membrane lipid peroxidation.     

低温胁迫对麻竹叶片和根系抗性生理指标的影响

采用室内人工低温处理,研究了麻竹(Dendrocalamus latiflorus)叶片及根部质膜透性、丙二醛、可溶性蛋白、可溶性糖含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)活性和膜脂脂肪酸组成的变化,寻找与竹类植物耐寒性关系最密切的抗性生理指标。结果表明:低温预处理(8℃)15d后,麻竹叶片中可溶性糖、可溶性蛋白含量、POD活性显著提高,根部可溶性糖含量、POD活性显著升高;低温胁迫处理(-2℃)72h后,经低温预处理的麻竹叶片可溶性糖、可溶性蛋白质含量、SOD、POD活性显著高于未经低温预处理,而质膜透性显著低于未经低温预处理,但膜脂过氧化程度显著高于-2℃处理前;经低温预处理的麻竹根部SOD、POD活性及膜脂不饱和脂肪酸相对含量显著高于未经低温预处理,而质膜透性、膜脂过氧化程度较-2℃处理前无显著差异。说明剧烈降温对麻竹生理特征造成严重影响,叶片通过提高可溶性蛋白、可溶性糖含量,维持较高的POD活性以减轻低温伤害;根系则通过维持较高的SOD、POD活性以减轻低温下膜脂过氧化水平,并通过提高膜脂不饱和脂肪酸比例降低质膜透性来抵御低温对膜的伤害。     

Physiological response of cut rose flowers to cold storage

The effects of low temperature storage on the physiology of cut rose flowers ( Rosa hybridaL. cv. Mercedes) were studied. Extension of cold storage or increase in temperature (from 3 to 8°C) was accompanied by shortening of vase life and advancement of petal senescence, as reflected in an advance in the timing of the rise in ethylene production and an increase in membrane permeability (ion leakage). Although storage at a relative humidity (RH) of 65% reduced petal water content by 20% in comparison with flowers stored at 95% RH, it did not shorten vase life. The progression of petal senescence was measured during storage at 3°C and during aging at 22°C. Both ethylene production rates and membrane microviscosity measured by fluorescence depolarization increased with time at 3°C and at 22°C, but more slowly at 3°C. At 3°C membrane permeability measured by ion leakage did not increase. Following cold storage the rate of ethylene production in the petals was increased by up to eight times the rate in unstored flowers. Silver thiosulphate extended the vase life of both stored and fresh flowers equally by 2 days, but did not increase the life of stored flowers to that of treated fresh flowers. It is concluded that the primary effect of cold storage on roses is to slow down senescence and that the continued slow senescence leads to shorter vase life. The possible occurrence of sequential processes during senescence and the effects of temperature on these processes is discussed.