Polyamines can inhibit paraquat toxicity and translocation in the broadleaf weed Arctotheca calendula

Reduced paraquat transport from the site of application to the site of action in the chloroplast seems a likely mechanism for paraquat resistance in several weed species including Arctotheca calendula. Recently, it has been shown that paraquat translocation in A. calendula is correlated with paraquat-induced injury and is reduced in paraquat-resistant A. calendula. Studies with leaf slices have shown that some polyamines when applied concomitantly with paraquat can reduce the toxic effects of paraquat. This study examined the effects of three polyamines, putrescine, cadaverine, and spermidine, on paraquat translocation to examine the possibility that paraquat translocation in susceptible plants would be reduced in the presence of polyamines due to competition of the polyamines with cellular paraquat uptake. Two polyamines, spermidine and cadaverine were effective in reducing paraquat translocation in susceptible A. calendula inducing these plants to perform more like resistant A. calendula in terms of translocation. Quantification of the polyamine contents of resistant and susceptible A. calendula showed that resistant plants have higher constitutive spermidine levels than susceptible plants, which infers a possible role of either polyamines or a polyamine transporter in paraquat resistance.     

Effect of leaf scald (<Emphasis Type="Italic">Xanthomonas albilineans</Emphasis>) on polyamine and phenolic acid metabolism of two sugarcane cultivars

Polyamine and phenolic acid levels as well as activities of some enzymes of their biosynthetic metabolism were examined in two sugarcane (Saccharum officinarum) cultivars differing in susceptibility to leaf scald, a disease caused by the bacterium, Xanthomonas albilineans. Juice obtained from both infected cultivars showed significantly increased levels of free putrescine and ornithine decarboxylase activity. However, the pathogen induced different changes in the two cultivars in subsequent metabolic steps. Whereas acid insoluble conjugated spermidine completely disappeared from the highly susceptible cv. C 439-52, an increase in acid insoluble conjugated polyamines was observed in the moderately susceptible cv. L 55-5. Phenolic acid metabolism also differed in the two cultivars. Since total phenolic acid content and phenylalanine ammonium lyase activity was greater in both cultivars after infection, distribution of phenolic acids between free or conjugated forms diverted into different pathways. The level of susceptibility of the two cultivars is discussed in terms of changes in these compounds.     

低温胁迫下4种苹果砧木叶片多胺的变化

以山定子(Malus baccata Borkh)、新疆野苹果[M.sieversii(Ledeb)Roem]、烟台沙果[M.prunifoli(Willd)Borkh]和莱芜难咽(M.micromalus Makino)等4种苹果砧木为试材,测定了低温胁迫下不同砧木叶片的多胺含量。结果表明,胁迫6 h时叶片的MDA含量可反映4个砧木的耐寒性,从高到低依次为山定子>新疆野苹果>莱芜难咽>烟台沙果;低温胁迫能明显诱导多胺总量(PAs)、腐胺(Put)、亚精胺(Spd)和精胺(Spm)的合成,耐寒性强的山定子和新疆野苹果PAs、Put和Spd增加显著,而耐寒性较弱的莱芜难咽和烟台沙果多胺和3种胺的变化不大。低温胁迫6 h时,MDA变化量与叶片PAs、Put、Spd变化量以及Put/PAs比值呈极显著或显著负相关,而与(Spd+Spm)/Put、Spd/PAs、Spm/PAs呈显著正相关,与Spm变化量无相关关系,表明当低温胁迫下叶片PAs、Put、Spd增加量较大时,苹果砧木耐低温胁迫的能力比较强,PAs、Put及Spd在胁迫条件下的增加量可作为苹果砧木耐低温胁迫能力高低的鉴定指标。     

油菜细胞质雄性不育系及其保持系花蕾发育过程中的多胺代谢

在花蕾发育过程中,不育系花蕾的多胺代谢不同于其保持系。不育系花蕾中腐胺、亚精胺、精胺含量及三者之和均先略降后升高再降低,而其保持系则先降而后升高,在发育早期不育系明显低于其保持系。不育系的精氨酸脱羟酶活性一直下降,而其保持系的则先降后略升,不育系始终低于保持系。保持系的多胺氧化酶一直降低而不育系的先     

多胺与玉米籽粒败育关系研究

以典型的顶端败育类型玉米杂交种为材料,在籽粒发育的早期,对果穗中部正常籽粒与上部败育籽粒内源精胺(Spm )、亚精胺(Spd)和腐胺((Put)的含量进行了比较研究。结果表明,败育籽粒在授粉后8~12天阶段三种多胺(PAs)含量明显低于正常籽粒。研究认为,果穗顶部籽粒较低的多胺含量与其籽粒败育密切相关。讨论了多胺、乙烯代谢的     

施氮对花生叶片多胺代谢及衰老的调控作用

以大田条件下两个花生品种为材料,研究了施氮后对叶片多胺含量、乙烯释放速率及其它一些生理生化指标的影响。结果表明：叶片多胺含量与衰老状况有关,随叶片衰老多胺含量下降;施氮提高了叶片内源多胺含量,降低了乙烯释放速率,延缓了叶绿素、蛋白质的降解,提高了活性氧清除酶类的活性,降低了膜脂过氧化程度。施氮延缓衰     

盐胁迫下大麦幼苗多胺与脯氨酸合成竞争前体L-Arg

200mmol/LNaCl处理结合14C-Arg叶面饲喂6日龄大麦幼苗,以L-Arg(精氨酸)为前体合成的Pro(脯氨酸)和PAs(多胺)含量显著上升.处理同时在心叶中滴加ADC(精氨酸脱羧酶)抑制剂D-Arg,游离Pro放射性明显上升,滴加精氨酸酶和鸟氨酸氨基转移酶抑制剂L-Lys,则游离Put(腐胺)和PAs总放射性明显上升.在心叶中滴加Put,游离Pro放射性明显提高,     

外源多胺、多胺合成前体及抑制剂对花生连体叶片衰老的影响

 对生长中后期大田花生连体叶片喷施外源多胺、多胺合成前体提高了叶片多胺含量 ,延缓了叶片衰老过程中叶绿素及蛋白质含量的下降 ,提高了活性氧清除酶类的活性 ,降低了膜脂过氧化产物丙二醛含量 ;喷施多胺合成抑制剂 MGBG[甲基乙二醛 -双 (脒基腙 ) ],对叶片多胺含量及衰老无显著影响。     

Polyamines as Modulators of Soybean Productivity

Polyamines have been shown to be involved in several aspects of plant growth and development. In soybean, increase in number of pods per plant, 100 seed weight, seed, biological and oil yield was highest with spray of spermine and lowest (but significantly higher than control) with putrescine. The soybean seed and oil yield increased by about 12.46 and 20.94% respectively with application of 10⁻³ m spermine at 50% flowering stage. Another spray of polyamines at pod initiation stage had little effect on different parameters.     

Exogenous putrescine reduces flooding-induced oxidative damage by increasing the antioxidant properties of Welsh onion

Soil flooding is an environmental factor of seasonal occurrence that negatively affects plant performance. Polyamines play an important role in the plant response to adverse environmental conditions including flooding stress. The objective of the present study was to assess the comparative oxidative damage to Welsh onion plants caused by flooding stress and to examine the role of putrescine (Put) in this response. Welsh onion plants were treated with Put prior to 10 d flooding. A positive effect was observed when treating with 2 mM Put. Exogenous application of Put resulted in alleviation of flooding-induced reduced relative water content, plant growth and chlorophyll fluorescence. Superoxide radical (O₂⁻) and hydrogen peroxide (H₂O₂) contents were also reduced in stressed plants after Put pre-treatment and thereby the oxidative stress in plant cells was lowered. The antioxidant system, as an important component of the waterlogging-stress-protective mechanism including α,α-diphenyl-β-picrylhydrazyl (DPPH)-radical scavenging activity, superoxide anion radical scavenging, metal chelating activities and reducing power, can be upgraded by Put, which is therefore able to moderate the radical scavenging system and to lessen oxidative stress. Under non-flooding conditions, the anti-oxidative activity of Welsh onion was regulated and elevated by Put pre-treatment. These results suggest that Put confers flooding tolerance to Welsh onion, probably through inducing the activities of various anti-oxidative systems. Thus, exogenous 2 mM per plant of Put 24 h prior to flooding could alleviate flooding stress.