多胺在果实生长发育中的作用研究进展

多胺是广泛存在于植物体内的具有生物学活性的低分子量脂肪族含氮碱。它在植物的胚胎发育、花和果实的发育等生长发育过程具有重要的调控作用,同时在延缓植物衰老和抗逆境等方面也具有重要意义。近几年的研究表明多胺代谢同植物开花坐果、果实发育甚至果实品质特性密切相关。概述了多胺对果实坐果,膨大与衰老等果实发育生理过程的影响,并对多胺在果实逆境发育中的作用进行了探讨,对多胺在果实发育过程中可能的调控作用机理以及外源多胺在植物开花坐果上的应用潜力进行了讨论,并展望了多胺作用分子机理的研究前景。     

大豆新型营养因子亚精胺的研究进展

亚精胺是在大豆中发现的又一功能性营养因子,作为一种无毒的天然物质,可通过诱导自噬作用发挥抗衰老和延长寿命的功能,同时对神经变性还具有抗氧化和消炎作用。大豆种子中亚精胺含量水平较一般谷类、蔬菜、块根农作物等植物高,研究表明大豆食品中亚精胺含量更高,说明大豆品种亚精胺含量对大豆食品保健功能起着重要作用。本文从亚精胺的营养保健作用、亚精胺含量检测方法、亚精胺在植物抗逆中的生理作用和大豆及其制品中亚精胺的研究进展4个方面进行了综述,以期为高亚精胺含量大豆材料的筛选、开展大豆亚精胺基因挖掘、选育高亚精胺含量大豆品种及开发大豆保健食品提供参考。     

水稻籽粒中内源多胺及其与籽粒充实和粒重的关系

以８个水稻品种（含杂交稻组合）为材料，研究了籽粒发育期内源多胺的含量及其与籽粒充实和粒重的关系。结果表明：籽粒中Ｐｕｔ（腐胺）、Ｓｐｄ（亚精胺）和Ｓｐｍ（精胺）的含量，强势粒高于弱势糕卫粒充实好的品种（组合）高于籽粒充实差的品种（组合），尤以Ｓｐｄ和Ｓｐｍ更明显；籽闰中Ｓｐｄ和Ｓｐｍ的含量或浓度，以及Ｓｐｄ／Ｐｕｔ和Ｓｐｍ／Ｐｕｔ的比值与谷粒充实率和千粒軎于极显著正相关在花后３天喷施外源多胺（１ｍ     

Inhibition of mycelial growth and sporidial formation in the wheat pathogenNeovossia indica by a polyamine biosynthetic inhibitor

DL-α-Difluoromethylornithine (DFMO), a specific suicide inhibitor of the polyamine biosynthetic enzyme ornithine decarboxylase (EC 4.1.1.17), strongly inhibited mycelial growth and sporidial formation of the wheat pathogen,Neovossia indica, in vitro, while DL-α-difluoromethylarginine (DFMA), the analogous suicide inhibitor of arginine decarboxylase (EC 4.1.1.19), did not. The inhibited mycelial growth and sporidial formation were not only restored by putrescine (polyamine) addition, but were actually enhanced in the putrescine + DFMO cultures. Besides altering mycelial growth and morphology, DFMO also reduced the cell size drastically. The inhibition of fungal polyamine biosynthesis is discussed in relation to selective control of plant disease.     

外源多胺对苹果花粉管伸长及胚珠寿命的影响

研究了多胺对苹果花粉管伸长及胚珠寿命的影响。结果表明,多胺能促进花粉管伸长,延缓胚珠衰老;多胺浓度以１×１０－５ｍｏｌ／Ｌ较１×１０－３ｍｏｌ／Ｌ效果为好。     

Polyamines enhance chilling tolerance of cucumber (Cucumis sativus L.) through modulating antioxidative system

Cucumber chilling-resistant cultivar Changchun mici and -sensitive cultivar Beijing jietou were used in this study to investigate the effects of exogenous PAs on protection against chilling injury as well as on changes of physiological features, and the fluctuation of free PAs content in the leaves under chilling stress. Upon chilling treatment, free spermidine (Spd), spermine (Spm) and putrescine (Put) were remarkably induced in the leaves of cv. Changchun mici 1 day after treatment. The induction of Put declined thereafter, whereas Spd and Spm levels increased steadily. In the leaves of cv. Beijing jietou, Put content was increased only at 1 day after chilling while Spd content decreased significantly upon chilling treatment. Chilling reduced soluble protein content, and decreased the activities of antioxidant enzymes, including superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) only in Beijing jietou. However, these changes could be renovated by exogenous application of Put and Spd. It was also found that pretreatment with Put and Spd diminished the increased electrolyte leakage and malondialdehyde (MDA) content caused by chilling in the leaves of both cultivars. Pretreatment of methyglyoxal-bis-(guanylhydrazone) (MGBG), the PAs biosynthetic inhibitor cancelled the effects of PAs in most of the treatments. Moreover, histochemical staining and quantitative measurements showed that exogenous application of Put and Spd eliminated but MGBG exaggerated the hydrogen peroxide (H₂O₂) accumulation caused by chilling stress, especially in leaves of Beijing jietou. Interestingly, Changchun mici was found to contain higher endogenous free PAs contents compared to Beijing jietou. While no significant difference of SOD, POD and CAT activities was found between non-chilling Changchun mici and Beijing jietou seedlings, the former exhibited higher APX activity than the latter. These results suggest that PAs play important roles in the tolerance of cucumber against chilling stress, which is most likely achieved by acting as oxidative machinery against chilling injury.     

棉花S-腺苷蛋氨酸脱羧酶基因(GhSAMDC2/3/4)的克隆及其诱导表达分析

利用电子克隆结合RT-PCR技术克隆获得陆地棉(Gossypium hirsutum L.)S-腺苷蛋氨酸脱羧酶(S-adenosylmethionine decarboxylase,SAMDC)基因家族3个基因,分别命名为Gh SAMDC2、Gh SAMDC3和GhSAMDC4。序列分析显示,该基因c DNA包含的upstream ORF(u ORF)和main ORF(m ORF)为植物SAMDC基因特征ORF,其中m ORF长度分别为1068 bp、1110 bp和1032 bp,分别编码355、369和343个氨基酸。聚类分析表明,Gh SAMDC2/3蛋白与可可树(Theobroma cacao)SAMDC聚为一类,且Gh SAMDC2与GhSAMDC3蛋白亲缘关系最近;Gh SAMDC4与拟南芥At SAMDC4聚为一类。实时荧光定量PCR分析表明,Gh SAMDC2在茎中表达相对较高,随着纤维发育其表达量不断增加,在纤维发育后期其表达量达到最高;Gh SAMDC2/3/4在不同的胁迫条件下表现出不同的表达模式,Gh SAMDC2受低温和干旱胁迫诱导最强烈,Gh SAMDC3响应盐胁迫显著,Gh SAMDC4受ABA诱导强烈。上述结果为进一步研究棉花SAMDC基因功能奠定了一定基础。     

Influence of acid soil on nodule numbers in relation to polyamine and tannin concentrations in roots of Phaseolus vulgaris

The relationship between soil acidity and polyamine (putrescine, spermidine, spermine) concentrations in roots was evaluated and compared to (1) nodule numbers in common beans and (2) tannin concentrations in roots. Six Phaseolus vulgaris cultivars were grown in pots in a greenhouse in soil at pH 4.5 or 5.5 and inoculated with Rhizobium leguminosarum bv. phaseoli strains. At pH 4.5 nodule numbers were strongly reduced but polyamine concentrations were 50% higher than at pH 5.5. At both pH levels putrescine and spermidine were the dominant polyamines, while the concentration of spermine was less than half of the other two. There was also a cultivar effect on the polyamine concentration, but this was much less pronounced than the pH effect. By 22 days after planting the uninoculated control plants had about 13% lower levels of polyamines than the inoculated plants. The concentrations of putrescine, spermidine, and spermine were negatively correlated with nodule numbers, but positively correlated with the root tannin content. There were no significant correlations with either root or plant dry weight.     

甘薯抗疮痂病多胺与吲哚乙酸代谢的研究

研究不同抗性甘薯品种受疮痂病菌侵染前后多胺和吲哚乙酸代谢变化结果表明 ,感染疮痂病菌后抗病与感病品种甘薯叶片中吲哚乙酸含量和多胺氧化酶活性降低 ,多胺总量及腐胺含量增加 ,腐胺 / (精胺 亚精胺 )比值升高 ,感病品种变化幅度高于抗病品种。疮痂病菌侵入后感病品种甘薯叶片中绿原酸含量下降 ,吲哚乙酸氧化酶和过氧化物酶活性升高 ,而抗病品种则相反。     

多胺与园艺植物生长发育的关系

就多胺对园艺植物的花芽分化、花粉形成、果实发育、根系形成及营养生长的作用进行了综合评述，并就多胺与植物衰老的关系进行了分析。