小麦幼苗根系核蛋白体上结合态多胺与渗透胁迫关系

检测了渗透胁迫下, 小麦幼苗根系核蛋白体(deoxyribonucleic acid-protein, DNP)上的非共价结合态多胺(noncovalently conjugated polyamines, NCC-PAs)和共价结合态多胺(conjugated polyamines, CC-PAs)的含量. 两个品种的NCC-Spm(精胺)含量都因渗透胁迫而上升, 而且抗旱性强的豫麦18上升幅度明显大于抗旱性弱的扬麦9号; 豫麦18的NCC-Spd(亚精胺)含量因胁迫明显上升, 而扬麦9号的NCC-Spd变化不明显; 在两个品种中未检测到NCC-Put(腐胺). 外源Spm处理明显促进了渗透胁迫下扬麦9号核蛋白体上NCC-Spm和NCC-Spd含量的上升, 也提高了扬麦9号幼苗对渗透胁迫的抗性; 甲基乙二醛-双(鸟嘌呤腙)(即MGBG: Spd和Spm的生物合成的抑制剂)处理豫麦18的效应相反. 两品种小麦幼苗在渗透胁迫下根系核蛋白体上共价结合态腐胺(covalently conjugated, CC-Put)和CC-Spd水平上升, 抗旱性强的豫麦18的上升幅度明显大于抗旱性弱的扬麦9号. 菲咯啉(即o-Phen, CC -PAs合成酶, 转谷酰胺酶(TGase)的抑制剂)处理明显抑制了渗透胁迫下豫麦18小麦幼苗根系核蛋白体上CC-PAs的上升, 而且明显降低其幼苗的抗性. 这些结果表明: 渗透胁迫下小麦幼苗根系核蛋白体上NCC-Spm和NCC-Spd以及CC-Put和CC-Spd水平的上升有利于增强小麦幼苗适应渗透胁迫的能力.     

干旱胁迫与小麦幼苗亚精胺代谢变化的关系

通过对亚精胺（spermidine,Spd）在抗旱性不同的小麦品种幼苗中的作用的研究,发现抗旱品种周麦18号在渗透胁迫处理时,其叶片中的Spd含量明显大于不抗旱的豫麦51号。用Spd合成的抑制剂甲基乙二醛-双（鸟嘌呤腙MGBG）处理周麦18号,则导致Spd含量下降和抗性的降低,外源Spd又可逆转MGBG对周麦18号在渗透胁迫下的伤害。外源Spd可以明显提高豫麦51号的叶片内Spd含量,并相应提高其抗性。以上结果表明,Spd可以提高小麦幼苗的抗渗透胁迫能力。     

水分胁迫对小麦幼苗叶片多胺含量的影响

水分胁迫下小麦幼苗叶片多胺含量变化的研究表明,聚乙二醇(PEG)的渗透胁迫明显提高了抗旱性强的周麦系列幼苗叶片游离态Put、Spd和Spm的含量和抗旱性弱的温麦6号的Put含量。外源Spd显著提高了水分胁迫下温麦6号的Spd的含量,对其抗性也有所改善。外源MGBG(Spd和Spm生物合成抑制剂)可提高水分胁迫下周麦12号Put的含量,但降低了Spd和Spm的含量和幼苗的抗性。     

盐适应过程中香根草内源游离态、结合态、束缚态多胺含量的变化

研究了不同浓度NaCl胁迫下,香根草（Vetiteria zizanioides）根、叶中的游离态、结合态、束缚态多胺（PAs）[包括腐胺（Put）,尸胺（Cad）,亚精胺（Sod）和精胺（Spm）]含量的变化。在中度盐胁迫（100,200mmol L^-1NaCl）9天时,香根草基本能够正常生长,但在重度盐胁迫（300mmol L^-1NaCl）下,其生长受到严重抑制。在上述3个不同浓度的NaCl胁迫下,香根草根、叶中游离态Put,Cad,spd,Stma和总的游离态PAs含量明显下降,在高盐浓度下下降幅更大;结合态Put,Cad,Sod,Spm和总的结合态PAs含量显著上升,但在重度盐胁迫下升幅较小或与对照相当;束缚态Put,Cad和总的束缚态PAs含量均减少,而束缚态Spd和Spm含量在叶中是下降的,在根中则增加,且在中度盐胁迫下更明显。对根和叶片而言,除游离态（Spd＋Spm）,Put比值在重度盐胁迫下较对照显著下降外,其它游离态、结合态、束缚态和总的（Spd＋Spm）／Put比值在不同盐胁迫下均上升,在中度盐胁迫下更明显。这表明,维持多胺总量的稳态和较高的（Spd＋Spm）／Put比值是香根草适应中度盐胁迫的一个重要机制。     

盐胁迫下大麦幼苗多胺的种类和状态与多胺氧化酶活性的关系

200 mmol/L的NaCl胁迫8 d大麦幼苗叶片和根系中的三种形态多胺都有不同程度地下降,其中游离态多胺含量的下降幅度最大;高氯酸不溶性结合态多胺含量变化较小.根系中PAO的活性先上升后下降,而叶片中PAO的活性先下降后上升.游离态多胺中,亚精胺和精胺(Spd Spm)的含量变化与相应部位PAO的活性变化趋势相反,表明PAO在盐胁迫下可能调节了游离态多胺的含量从而影响高氯酸可溶结合态与高氯酸不溶结合态多胺的含量.     

氯化钠胁迫对嫁接黄瓜叶片多胺含量的影响

以日本耐盐品种‘帝王新土佐’南瓜为砧木,以’新泰密刺’黄瓜为接穗,在100 mmol·L^-1 NaCl胁迫下,对黄瓜嫁接和自根植株不同时期叶片中不同形态多胺含量的变化进行了研究.结果表明：NaCl胁迫下黄瓜嫁接植株游离态腐胺（Put）含量在胁迫2 d时与自根植株无显著差异,其余时间均显著高于自根植株;游离态亚精胺（Spd）和游离态精胺（Spm）含量在整个胁迫期间均显著高于自根植株;游离态多胺总量（PAs）在胁迫第4天出现峰值;嫁接植株游离态Put/PAs值在胁迫4 d时与自根植株无显著差异,其余胁迫时间均显著低于自根植株,而(Spd+Spm)/Put值在整个胁迫期间均显著高于自根植株;嫁接植株结合态和束缚态Put、Spd和Spm含量在整个胁迫期间均显著高于自根植株,结合态和束缚态PAs在胁迫第6天出现峰值;结合态多胺的Put/PAs值和(Spd+Spm)/Put值变化趋势与游离态多胺一致;嫁接植株束缚态Put/PAs值在胁迫6 d时与自根植株无显著差异,其余时间均显著低于自根植株,而(Spd+Spm)/Put值在整个胁迫期间均显著高于自根植株.表明黄瓜嫁接植株表现出较强的耐盐特征.     

外源亚精胺对盐胁迫下毕氏海蓬子体内多胺含量的影响

用含不同浓度(0、100、200、300、400和500 mmol·L 1)NaCl的Hoagland营养液及叶面喷施0.1 mmol·L-1外源亚精胺(Spd)处理毕氏海蓬子幼苗,研究外源Spd对NaCl胁迫下海蓬子体内游离态、结合态和束缚态3种形态多胺含量的影响,分析内源多胺含量的变化与植物耐盐性的关系.结果表明:(1)随盐胁迫浓度的升高,海蓬子幼苗叶片中3种形态腐胺(Put)含量均先降后升;同期的游离态Spd含量持续上升,结合态和束缚态Spd含量均先升后降;同期的游离和结合态精胺(Spm)含量均先升后降,而其束缚态Spm含量呈上升趋势;游离态和束缚态多胺(PAs)总量变化随盐浓度升高均呈上升趋势,而结合态PAs总量先升后降.(2)3种形态(Spd+ Spm) /Put比值均先升后降,而3种形态Put/PAs比值则均呈先降后升的相反趋势.(3)外源Spd处理提高了海蓬子幼苗叶片中结合态和束缚态PAs总量,也提高了游离态和束缚态(Spd+Spm)/Put比值.研究发现,外源Spd参与了NaCl胁迫下海蓬子内源PAs代谢的调节,可能通过促进盐胁迫植株中Put向Spd和Spm的转化,以及游离态多胺向结合态和束缚态多胺的转化来增强海蓬子耐盐性.     

外源亚精胺对盐胁迫下黄瓜幼苗游离态多胺含量和多胺合成酶基因表达的影响

以黄瓜品种‘津春2号’（Cucumis sativusL.cv.Jinchun No.2）为材料,采用营养液栽培,研究了外源亚精胺（Spd）对NaCl胁迫下黄瓜幼苗叶片游离态多胺含量和多胺合成酶基因表达的影响。结果表明,75 mmol/LNaCl胁迫下,幼苗株高、茎粗和干鲜重显著降低,外源喷施1 mmol/L Spd处理可明显缓解盐胁迫对幼苗生长的抑制。盐胁迫下叶片游离态多胺含量显著增加,外源Spd进一步促进了游离态Spd和精胺（Spm）的积累,降低了游离态腐胺（Put）的积累。多胺合成酶基因表达分析表明,盐胁迫上调了adc、odc、samdc和spds基因的表达,施用外源Spd后进一步上调了samdc基因,下调了adc、odc、spds基因的表达。表明外源Spd参与了黄瓜幼苗体内多胺代谢的调节,通过下调盐胁迫下adc、odc基因的表达,抑制游离态Put的积累,上调samdc基因的表达促进游离态Spd和Spm的积累,进而缓解盐胁迫对植物生长的抑制。     

盐胁迫下大麦根系多胺代谢与其耐盐性的关系

研究了0－300mmol/L NaCl对大麦（Hordeum vulgare L.)幼苗生长速率,根系游离和结合态多胺含量以及多胺生物合成关键酶活性的影响。结果表明,在0－200mmol/L NaCl处理下精氨酸脱羧酶（ADC）、多胺氧化酶（PAO）以及转谷酰胺酶（TGase)活性明显提高,而在300mol/L NaCl处理下活性下降,与之对应,游离腐胺（Put)含量随处理盐浓度的提高一直呈上升趋势。亚精胺（Spd)和在根系内检测到的未知多胺（PAx）在低浓度盐处理时含量上升,随盐浓度的提高含量下降,盐处理前后精胺（Spm)含量变化不明显,低浓度盐处理时游离态（Spd PAx)/Put上升,随盐浓度的提高比值明显下降,结合态Put,Spd和PAx含量以及结合态多胺总量均在低浓度盐处理时上升,随盐浓度的提高含量明显下降,统计分析显示,大麦相对生长速率与游离态（Spd PAx）／Put和结合态多胺含量间均呈极显著正相关关系,与游离态多胺和结合态多胺的比值间均呈显著负相关关系,上述结果说明盐胁迫下大麦体内游离态Spd,PAx与Put以及结合态形式之间的平衡与大麦耐盐性关系密切,游离态Put向Spd,PAx以及结合态形式转化均有利于大麦耐盐性的提高。     

盐胁迫下大麦根系多胺代谢与其耐盐性的关系

研究了0～300mmol/LNaCl对大麦(Hordeum-vulgare-L.)幼苗生长速率、根系游离和结合态多胺含量以及多胺生物合成关键酶活性的影响。结果表明,在0～200mmol/L NaCl处理下精氨酸脱羧酶（ADC）、多胺氧化酶(PAO)以及转谷酰胺酶(Tgase)活性明显提高,而在300 mmol/L NaCl处理下活性下降。与之对应,游离腐胺（Put）含量随处理盐浓度的提高一直呈上升趋势,亚精胺(Spd)和在根系内检测到的未知多胺(Pax)在低浓度盐处理时含量上升,随盐浓度的提高含量下降。盐处理前后精胺(Spm)含量变化不明显。低浓度盐处理时游离态（Spd+Pax）/Put上升,随盐浓度的提高比值明显下降。结合态Put、Spd和Pax含量以及结合态多胺总量均在低浓度盐处理时上升,随盐浓度的提高含量明显下降。统计分析显示,大麦相对生长速率与游离态（Spd+Pax）/Put和结合态多胺含量间均呈极显著正相关关系,与游离态多胺和结合态多胺的比值间均呈显著负相关关系,上述结果说明盐胁迫下大麦体内游离态Spd、Pax与Put以及结合态形式之间的平衡与大麦耐盐性关系密切,游离态Put向Spd 、Pax以及结合态形式转化均有利于大麦耐盐性的提高.     

Relationship between osmotic stress and polyamines conjugated to the deoxyribonucleic acid-protein in wheat seedling roots

Polyamines (PAs) are biologically ubiquitous aliphatic amines that are implicated in many aspects of growth, development, sex differentiation, ripeness and senescence of plants[1―6]. It has been well documented that PAs are closely associated with plant …     

Relationship between Polyamines and Anaerobic Respiration of Wheat Seedling Root under Water-Logging Stress

To elucidate the relationship between polyamines and anaerobic respiration of wheat (Triticum aestivum L.) seedling root under water-logging stress, the contents of polyamines (PAs), lactate and alcohol, and the activities of anaerobic respiration enzymes were investigated in seedling roots of two wheat cultivars, Yumai no. 18 and Yangmai no. 9. On the 5th day after water-logging treatment, spermidine (Spd) and spermine (Spm) contents increased significantly, pyruvate decarboxylase (PDC) activity increased and there was no difference between two cultivars. Alcohol dehydrogenase (ADH) activity and alcohol content in Yangmai no. 9 increased more markedly than Yumai no. 18, while lactate dehydrogenase (LDH) activity and the lactate content in the Yumai no. 18 increased more markedly than Yangmai no. 9. Treatments with exogenous Spd and Spm resulted in enhancing the increases in ADH activity, alcohol content, and the levels of Spd and Spm. This concomitantly inhibited the increases in LDH activity and lactate content in Yumai no. 18 under water-logging stress, alleviating stress-induced injury to the seedlings. Treatment with exogenous inhibitor methylglyoxyl-bis-guanylhydrazone (MGBG), resulted in reducing the increases in ADH activity, alcohol content, and Spd and Spm levels, promoting the increases in LDH activity and lactate content in Yangmai no. 9 under water-logging stress, and aggravating the stress-induced injury to the seedlings. The results suggested that under water-logging stress, increased Spd and Spm could facilitate the tolerance of wheat seedling to the stress by enhancing the increases in ADH activity and alcohol content, and inhibiting the increases in LDH activity and lactate content.     

NaCl胁迫对菜用大豆种子多胺代谢的影响

采用蛭石栽培,在100 mmol·L-1NaCl胁迫下,对耐盐性不同的两个品种菜用大豆种子的丙二醛(MDA)含量和多胺(PAs)代谢进行了研究.结果表明:NaCl胁迫显著增加了菜用大豆种子的MDA含量,但耐盐品种‘绿领特早’(LL)的增幅低于盐敏感品种‘理想高产95-1’(LX).与LX相比,LL种子在整个NaCl胁迫期间均维持了相对较高的游离态精胺(Spm)、结合态Spm、结合态亚精胺(Spd)、束缚态Spd和束缚态腐胺(Put)含量,较高的(Spd +Spm )/Put 和(cPAs+bPAs)/fPAs值及较低的Put/PAs值,在胁迫中、后期(9～15 d)维持了相对较高的游离态Spd含量;胁迫期间,LL的精胺酸脱羧酶(ADC)长时期(6～15 d)保持相对较高的活性,而多胺氧化酶(PAO)则长时期(6～15 d)维持相对较低的活性.综上,LL具有较强的多胺合成能力及较强的Put向Spd和Spm以及游离态多胺向结合态和束缚态多胺转化的能力,进而有效抑制了细胞的膜脂过氧化,这可能是其耐盐性较强的重要原因之一.     

Changes in content of free,conjugated and bound polyamines and osmotic adjustment in adaptation of vetiver grass to water deficit

Osmotic adjustment and alteration of polyamines (PAs) have been suggested to play roles in plant adaptation to water deficit/drought stress. In this study, the changes in cell intactness, photosynthesis, compatible solutes and PAs [including putrescine (Put), spermidine (Spd) and spermine (Spm) each in free, conjugated and bound forms] were investigated in leaves of vetiver grass exposed to different intensity of water deficit stress and subsequent rewatering. The results showed that, when vetiver grass was exposed to the moderate (20% and 40% PEG-6000 solutions) and severe (60% PEG solution) water deficit for 6 days, the plant injury degree (expressed as the parameters of plant growth, cell membrane integrity, water relations and photosynthesis) increased and contents of free and conjugated Put decreased with the rise of PEG concentration. Under the moderate water deficit, the plants could survive by the reduced osmotic potential (ψ_s), increased free and conjugated Spd and Spm in leaves. After subsequent rewatering, the osmotic balance was re-established, most of the above investigated physiological parameters were fully or partly recovered to the control levels. However, it was not the case for the severely-stressed and rewatering plants. It indicates that, vetiver grass can cope well with the moderate water deficit/drought stress by using the strategies of osmotic adjustment and maintenance of total contents of free, conjugated and bound PAs in leaves.     

Relationship between osmotic stress and polyamines conjugated to the deoxyribonucleic acid-protein in wheat seedling roots

The contents of covalently conjugated polyamines (CC-PAs) and noncovalently conjugated polyamines (NCC-PAs) to deoxyribonucleic acid-protein (DNP) isolated from wheat (Triticum aestivum L.) seedling roots under osmotic stress were detected. Results showed that after osmotic stress treatment for 7 d, the levels in NCC-spermine (NCC-Spm) and NCC-spermidine (NCC-Spd) of drought-tolerant Yumai No. 18 cv. increased more markedly than that of drought-sensitive Yangmai No. 9 cv., while the NCC-putrescine (NCC-Put) could not be statistically detected in two cultivars. Exogenous Spm treatment alleviated osmotic stress injury to Yangmai No. 9 cv. seedlings, coupled with marked increases of NCC-Spm and NCC-Spd levels of this cultivar. Under PEG osmotic stress, the concomitant treatment of drought-tolerant Yumai No. 18 cv.seedlings with methylglyoxyl-bis (guanylhydrazone) (MGBG), an inhibitor of S-adenosylmethionine decarboxylase (SAMDC), aggravated osmotic stress injury to this cultivar, coupled with market decreases of the NCC-Spm and NCC-Spd levels. The levels in CC-Put and CC-Spd of drought-tolerant Yumai No. 18 cv. increased more markedly than that of drought-sensitive Yangmai No. 9 cv. Under osmotic stress. The treatment of drought-tolerant Yumai No. 18 cv. seedlings with phenanthrolin (o-Phen), an inhibitor of transglutaminase (TGase), aggravated osmotic stress injury to this cultivar, coupled with a reduction of sum contents of CC-Put+CC-Spd. These results suggested that NCC-Spm and NCC-Spd, together with CC-Put and CC-Spd, in DNP of roots could enhance tolerance of the wheat seedlings to osmotic stress.     

Organ-specific changes in the content of free and conjugated polyamines in <Emphasis Type="Italic">Mesembryanthemum crystallinum</Emphasis> plants under salinity

The content of free and conjugated polyamines (PA) was studied in the leaves of secondary shoots and in roots of the facultative halophyte Mesembryanthemum crystallinum L. under salinity. Plants were grown in water culture and at the age of 10 weeks were subjected to salinity stress by a single introduction of NaCl into nutrient medium to a final concentration of 400 mM. In 0, 6, 24, and 48 h, the content of free, HClO₄-soluble, and HClO₄-insoluble conjugates of PA were measured in leaves and roots. The levels of free and conjugated PA in the roots of control plants and plants subjected to salinity stress were higher than in the leaves. In response to salinity shock, the content of all forms of spermine (Spm), particularly its HClO₄-soluble conjugates, increased in roots and leaves. In contrast, the content of Spm precursors, putrescine (Put) and spermidine (Spd), as well as their HClO₄-soluble conjugates, decreased. Salinity treatment elevated the content of free cadaverine both in roots and leaves, whereas the content of its conjugated forms decreased, which might suggest transition of conjugated forms of cadaverine into the free form. The product of oxidative degradation of Spm and Spd, 1,3-diaminopropane (Dap), was absent in leaves, whereas the content of free and conjugated forms of this diamine in roots increased under salinity conditions. The obtained data indicate organ specificity for the content of free and conjugated forms of PA, as well as their active role in adaptation of Mesembryanthemum crystallinum to salinity shock.     

渗透胁迫和CO~(++)对小麦幼苗内源多胺含量和乙烯产生的影响

抗旱和不抗旱的小麦幼苗叶片与根系,在1MPaPEG渗透胁迫下释出乙烯和生成内源腐胺、亚精胺和精胺的数量增加。当增加2mmol钴离子处理6h和12h后,乙烯生成显著受到抑制,而亚精肢和精胺呈现进一步增加。表明钴离子阻遏了氨基环烷羧酸向乙烯转变的途径,并为多胺合成提供了更多的底物,从而有利于提高小麦抗衰老和抗旱的能力,抗旱品种表现更为明显。     

Association of polyamines in governing the chilling sensitivity of maize genotypes

Chilling stress is an important constraint of global production of maize. This study was undertaken to compare the chilling responses of different maize seedling tissues and to analyze changes in polyamines as a result of chilling stress. Reponses to chilling were characterized in two maize (Zea mays L.) inbred lines, ‘HuangC’ and ‘Mo17’, that putatively differ in chilling sensitivity. Seedlings were exposed to low temperature (5°C) and chilling injury was estimated by electrical conductivity (EC), malonaldehyde (MDA) concentration, and by changes in putrescine (Put), spermidine (Spd) and spermine (Spm) concentrations in root, mesocotyl, and coleoptile tissues. Membrane permeability (as measured by EC), MDA concentrations and Put concentrations in the three tissue of maize seedlings increased after chilling stress, except for the Put concentration in roots. Spd and Spm concentrations in the three tissues of seedlings decreased after chilling stress. The EC for cold stressed tissues were lower in HuangC than Mo17. Also, the EC of coleoptile tissues were lower than for mesocotyl in both inbred lines. We suggest that mesocotyl tissue can be used to evaluate cold tolerance in maize. Stepwise regression analyses showed that chilling injury in roots was generally correlated with Spd concentration while in the mesocotyl injury was mainly correlated with Put and Spd concentrations. Spermidine and Spm concentrations in the coleoptile were correlated with chilling injury. Characteristics changes of polyamines in chill-tolerant maize seedling combined with regression analysis are a reliable method for evaluating chill tolerance in maize lines.