环切对苹果缺枝顶芽内源多胺水平的影响及其与成花的关系

研究了环切对６年生富士、金冠苹果缺枝内源多胺,包括腐胺、亚精胺和精胺的含量及其与成花的关系,发现内源多胺含量与成花作用显著相关。在花诱导阶段,Ｐｕｔ和Ｓｐｄ的含量呈下降趋势,主枝环切处理在促进成花的同时减缓了多胺下降的速率,Ｓｐｍ的含量呈下降趋势。表明Ｐｕｔ有助于分生组织的活化,而ＳｐｄＴ和Ｓｐｍ与花诱导的启动及促进有关。     

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.     

节瓜茎尖多胺含量和比值与花性别分化的关系

以4个不同基因型的节瓜为材料,通过两个发育时期（10、19片叶展平）茎尖取样,研究了多胺（PA）含量和比值与植株花性别分化的关系。结果表明,节瓜茎尖4种多胺含量差异显著,两个取样时期都是亚精胺（Spd）〉腐胺（Put）〉尸胺（Cad）〉精胺（Spm）。10片叶展平时期多胺含量与节瓜花性别分化之间没有明确的相关性;19片叶展平时期,节瓜茎尖Put、Spd和多胺总量与植株雌花分化比例呈极显著的正相关,而Cad则与雌花分化比例呈极显著的负相关。在两个取样时期,复合指标Spd/PA都与植株雌花分化比例呈显著的正相关,而（Put＋Cad）/（Spd＋Spm）均与之呈显著的负相关,可以较好地预测节瓜的花性别分化状况。     

‘神马’菊花花芽分化与内源多胺的关系

用薄层层析-荧光法测定菊花'神马'花芽分化期间顶芽和叶片中多胺的动态变化,分析了菊花花芽分化与多胺的关系.结果表明,花芽分化起始期顶芽中的腐胺(Put)含量急剧下降,此后在低水平上波动;叶片内Put则于总苞鳞片分化初期大幅上升,其后各阶段处于较低的水平.顶芽中精胺(Spm)与亚精胺(Spd)含量呈平行波动上升趋势,顶芽中Spin在小花原基分化初期直到花冠分化中期处于优势地位,而顶芽中Spd并无明显变化.顶芽、叶片中的Spin变化趋势相反,顶芽中Spm、Spd的含量变化趋势十分相似,但叶片中却呈交替性变化.结果显示,菊花花芽分化过程中,Put含量的降低有利于启动菊花花芽分化,后期Spm的增加有利于小花的分化,叶片可能向顶芽提供Spm,顶芽和叶片中的Spd与小花原基分化有密切关系.     

6-BA+B9对龙眼花芽生理分化期内源多胺含量变化的影响

在龙眼花芽生理分化期喷施6-BA 200 mg/L+B₉ 2000 mg/L,跟踪测定其内源多胺含量变化。研究结果表明,龙眼花芽生理分化期内源腐胺(Put)、亚精胺(Spd)和精胺(Spm)含量均出现积累,喷施6-BA+B₉能明显提高内源多胺含量,特别是Put和Spd的含量。内源多胺与花芽分化有一定的内在联系,生长调节剂对花芽分化的调控有可能通过多胺来实现或协同作用。     

多胺对菊花激素含量与花芽分化的影响

以切花菊（Dendranthema morifolium）品种‘神马’为试材,外源喷施0．1mmol·L-1的亚精胺（Spd）与多胺合成抑制剂D-精氨酸（D．Arg）,转入昼10h／夜14h的短日条件下进行开花诱导,测定不同花芽分化时期顶芽内源多胺[腐胺（Put）、亚精胺（Spd）、精胺（spm）]和几种激素[生长素（IAA）、玉米素核苷（ZR）、异戊烯基腺苷（iPA）、赤霉素（GA）]含量的动态变化,分析多胺对激素和花芽分化的作用关系。结果表明,外源多胺和多胺合成抑制剂能够显著影响顶芽内源多胺（Put、Spd、Spm）和激素（IAA、ZR、iPA、GA）的含量,顶芽内高水平多胺有利于菊花花芽分化的启动和保持;外源多胺及多胺合成抑制剂可能通过影响内源多胺含量从而影响内源激素或者直接影响内源激素和内源多胺,进而调控花芽分化：内源Put与IAA关系密切,高水平的内源Put不利于IAA的积累;ZR和iPA含量与内源多胺总量的变化趋势一致;外源多胺及多胺合成抑制剂对GA的影响主要在花序分化期和小花分化期,且高水平的内源Spd和Put不利于GA的积累。     

精胺和甲基乙二醛-双(脒基腙)及D-精氨酸对水分胁迫下小麦幼苗内源多胺含量的影响

土壤自然干旱条件下叶面喷施精胺（Spm）、D-精氨酸（D-Arg）、甲基乙二醛-双（脒基腙）（MGBG）不改变小麦幼苗内源多胺含量变化趋势,只是不同程度地影响内源多腹水平。SPm处理提高内源腐胺（Put）和亚精胶（Spd）水平;D-Arg处理的内源Put和Spd水平也略有提高;MGBG提高内源Put水平,且MGBG作用前期降低Spd水平,后期则导致Spd水平增高。     

离体黄瓜子叶节花芽分化与内源激素及多胺的关系

用高效液相色谱法(HPLC)测定了黄瓜子叶节花芽分化期(0-6天)内源激素及多胺的变化。结果显示,子叶培养0-2天生长素(IAA)、赤霉素(GA_3)、玉米素(ZT)、脱落酸(ABA)等4种内源激素均明显下降,4-5天略有上升,表明0-2天IAA、GA_3和ABA的剧降有利于花原基形成,3-5天较高的ZT含量有利于花器官原基的形成。除腐胺(Put)外,精胺(Spm)、亚精胺(Spd)、尸胺(Cad)在0-1天均下降,1-4天上升,4-5天再下降,Put在0-1天急剧上升,而后持续下降,表明高水平的内源多胺总量和Put可能有利于花原基分化,2天后Spm含量上升有利于花器官原基分化,而Cad含量变化可能是区别花芽和营养芽分化的特征之一。     

离体黄瓜子叶节花芽分化与内源激素及多胺的关系

用高效液相色谱法(HPLC)测定了黄瓜子叶节花芽分化期(0—6天)内源激素及多胺的变化。结果显示,子叶培养0—2天生长素(IAA)、赤霉素(GA3)、玉米素(ZT)、脱落酸(ABA)等4种内源激素均明显下降,4—5天略有上升,表明0-2天IAA、GA3和ABA的剧降有利于花原基形成,3—5天较高的ZT含量有利于花器官原基的形成。除腐胺(Put)外,精胺(Spm)、亚精胺(Spd)、尸胺(Cad)在0—1天均下降,1—4天上升,4—5天再下降,Put在0—1天急剧上升,而后持续下降,表明高水平的内源多胺总量和Put可能有利于花原基分化,2天后Spm含量上升有利于花器官原基分化,而Cad含量变化可能是区别花芽和营养芽分化的特征之一。     

低氧胁迫下24-表油菜素内酯对黄瓜幼苗叶片光合特性及多胺含量的影响

采用1/2 Hoagland营养液培养,研究了低氧胁迫下24-表油菜素内酯(EBR)对黄瓜幼苗叶片光合特性及多胺含量的影响.结果表明：低氧胁迫下黄瓜幼苗的净光合速率(P_n)、气孔导度(g_s)、蒸腾速率(T_r)、胞间CO₂浓度(C_i)显著下降,而叶绿素含量显著提高,幼苗生长受抑;低氧胁迫显著提高了黄瓜幼苗叶片的腐胺(Put)、亚精胺(Spd)、精胺(Spm)、多胺(PAs)含量和Put/PAs,但降低了(Spd+Spm) /Put.低氧胁迫下,外源EBR不仅显著提高了黄瓜幼苗的P_n、g_s、T_r及叶绿素含量,也显著提高了黄瓜幼苗叶片的游离态Spm、结合态Spd、Spm及束缚态Put、Spd、Spm含量,促进了PAs的进一步积累,且降低了Put/PAs,提高了(Spd+Spm)/Put．可见,外源EBR调节了黄瓜幼苗内源多胺含量及形态的变化,维持了较高的光合性能,促进了叶面积和干物质量的显著增加,缓解了低氧胁迫对黄瓜幼苗的伤害.     

Changes in polyamine pattern are involved in floral initiation and development in Polianthes tuberosa

In the day-neutral plant Polianthes tuberosa (cv. Double) putrescine and spermine in corms at the early floral initiation stage decreased by 26 and 36%, respectively, compared with that in the vegetative stage. In contrast, a sharp increase in spermidine and cadaverine titers in corms was recorded at the early floral initiation stage. However, cadaverine in corms disappeared at the flower development stage. Polyamines in the roots were generally lower than those in the leaves and corms. In no case was the change in endogenous polyamine titers in the roots and leaves associated with floral initiation and flower development in P. tuberosa. Exogenous application of spermidine at 5, 25 or 150 microg per plant at the vegetative stage did not affect flower primordium counts. However, addition of a spermidine synthase inhibitor, cyclohexylamine, at 150 or 250 microg per plant (each dose was applied two times in total at an interval of 4 days) significantly reduced flower primordium counts, indicating that spermidine is involved in floral initiation and floral development in P. tuberosa. In P. tuberosa corms at the vegetative stage arginine decarboxylase activity rises and decreases at the early floral initiation stage. In contrast, ornithine decarboxylase activity reaches the highest level at the early floral initiation stage and declines significantly at the vegetative stage. Results indicate that an increase in spermidine and a transient increase in cadaverine titers in the corms seem characteristic of early floral initiation in P. tuberosa. It is also suggested that a significant reduction in putrescine and spermine in the corms is involved in the early floral initiation in P. tuberosa.     

Changes in Polyamine Contents Development of the Frog, Microhyla ornata

Putrescine, spermidine and spermine levels were measured during development, metamorphosis and adult life of the frog, Microhyla ornata . Development of Microhyla was accompanied by high fluctuating levels of putrescine and spermidine with low and steady levels of spermine. Putrescine was the major polyamine during development from egg to mature tadpole. During metamorphosis both putrescine and spermidine decreased significantly; but the decrease in putrescine content was more rapid than that of spermidine. Thus, in the freshly metamorphosed frog, the concentration of spermidine exceeded that of putrescine. In most of the adult tissues also spermidine concentration was higher than putrescine and spermine. While the free form of putrescine and spermidine increased during early development of the fertilized egg to tadpole, the levels of protein conjugated polyamines decreased. In the free form, putrescine was the major polyamine while in the protein conjugated form spermidine concentration was higher than putrescine and spermine. Thus polyamine pattern is different in early development, during metamorphosis and in differentiated adult tissues of this frog. ∞-Difluoromethylornithine treatment at early blastula stage did not interfere with the normal development of Microhyla embryos.     

Polyamines are involved in the gynogenesis process in onion

Haploidization in onion ( Allium cepa L.) using immature flower buds simulates zygotic embryogenesis with no fecundation. In order to know the involvement of polyamines (PAs) in this process, we determined the concentration of endogenous PAs in flower buds and experimented the addition of various combinations of PA molecules in the medium. At the inoculation stage, high levels of free and conjugated spermidine and low putrescine + hydroxyputrescine/spermidine + spermine ratio characterized the highest responsive varieties. During in vitro culture, high levels of putrescine and its derivatives characterized the lowest responsive varieties, whereas high levels of spermidine and spermine characterized responsive varieties. The putrescine + hydroxyputrescine + homospermidine/spermidine + spermine ratio remained low in responsive varieties. The addition of spermidine or spermine (2 × 10⁻³  M ) to the culture medium improved significantly the embryo production. Our results suggest that the arginine decarboxylase pathway is involved in PA biosynthesis during the in vitro culture of flower buds. Our study showed that specific ratios of PAs are required for successful gynogenesis in onion.     

Changes in endogenous polyamines during flower development in two diverse species of rose

Changes in the concentrations of endogenous free, conjugated and bound polyamine were determined in petals of two different species of rose, viz. Rosa damascena and Rosa bourboniana, from small bud (stage 1) till full bloom (stage 8). High free putrescine and spermidine concentrations were associated with early stages of flower development and then decreased in R. damascena. At full bloom, the concentration of free putrescine was higher than rest of the polyamines measured. A steady increase in conjugated putrescine, spermidine and spermine was observed during entire period of flower development with predominance of conjugated putrescine at full bloom. In R. damascena the bound spermine was higher than rest of the polyamines during full bloom. In R. bourboniana, during the early stages of flower development, similar situation was observed, however, at full bloom, free spermidine concentration was higher than rest of the polyamines. In this species, the concentration of conjugated and bound spermine was higher than rest of the polyamines during full bloom. Polyamine concentrations were generally lower in the petals of R. bourboniana than R. damascena which may be due to genotypic differences. The possible roles of the observed polyamines are discussed in relation to flower development.IHBT Communication no, 0345.     

Polyamines,floral induction and floral development of strawberry (Fragaria ananassa Duch.)

In the short-day plant, strawberry (Fragaria ananassa Duch.), polyamines (putrescine, spermidine and spermine), conjugated spermidine (water-insoluble compounds) and bound amines (putrescine, spermidine, phenylethylamine, 3-hydroxy, 4-methoxyphenylethylamine) accumulated in the shoot tips during floral induction and before floral emergence. Different associations of free amines and conjugated amines were observed during floral induction, as compared with the reproductive phase. During the whole period of floral development, phenylethylamine (an aromatic amine) was the predominant amine, representing 80 to 90% of the total free amine pool. Phenylethylamine conjugates (water-insoluble compounds) were the predominant amides observed prior to fertilization. These substances decreased drastically after fertilization. In vegetative shoot tips from plants grown continously under long days, free polyamines (putrescine, spermidine) and bound polyamines (putrescine, spermidine) were low and no change was observed. Free amines (spermine and phenylethylamine), bound aromatic amines (phenylethylamine, 3-hydroxy, 4-methoxyphenylethylamine), conjugated spermidine and phenylethylamine did not appear. Male-sterile flowers were distinguished by their lack of conjugated spermidine and phenylethyalamine and by a decrease in free phenylethylamine. In normal and sterile strawberry plants -DL-difluoromethylornithine (DFMO), a specific irreversible inhibitor of ornithine decarboxylase (ODC), caused inhibition of flowering and free and polyamine conjugates. When putrescine was added, polyamine titers and flowering were restored. A similar treatment with -DL-difluoromethylarginine (DFMA), a specific, irreversible inhibitor of arginine decarboxylase (ADC), did not affect flowering and polyamine titers. These results suggest that ornithine decarboxylase (ODC) and polyamines are involved in regulating floral initiation in strawberry. The relationship between polyamines, aromatic amines, conjugates, floral initiation and male sterility is discussed.Abbreviations ADC arginine decarboxylase - ODC ornithine decarboxylase - DFMA -DL-difluoromethylarginine - DFMO -DL-difluoromethylornithine - Put putrescine - Spd spermidine - Spm spermine - Phen phenylethylamine - 3H4M Phen 3-hydroxy, 4-methoxyphenylethylamine     

Changes in endogenous polyamine levels are associated with differentiation in Dictyostelium discoideum.

This is the first report correlating levels of polyamines and its fractions with differentiation in Dictyostelium discoideum. Temporal changes in endogenous levels of free, conjugated and bound putrescine, spermidine and spermine were analysed at critical stages of morphogenesis in this organism. No spermine was found at any given stage and putrescine was the most abundant polyamine. There was a sharp increase in the levels of both free (and total) and conjugated forms of putrescine and spermidine at the slug stage as compared to the growth phase. The levels of putrescine and spermidine were found to be higher in isolated prespore cells as compared to the prestalk cells. Remarkably, the levels of polyamine decreased at the early culminant stage. Data suggest that a moderate level of polyamines is needed for growth but it is important to have high levels of polyamines at the time of differentiation.     

Profile of polyamines during sprouting and growth of saffron (Crocus sativus L.) Corms

The profile of free and conjugated polyamines putrescine, spermidine, and spermine was studied at the onset of sprouting and during various stages of vegetative growth in saffron (Crocus sativus L.) corms. Polyamines were extracted from the shoot meristems and estimated by high performance liquid chromatography. Free putrescine was not detected at the onset of sprouting, whereas free spermidine and spermine levels increased rapidly on sprouting and decreased during further stages of corm development. The levels of conjugated polyamines were several times higher than the free forms indicating their possible role in the developmental processes. A comparison of polyamine levels of vegetative and floral corms showed higher titers of free polyamines in vegetative and conjugated polyamines in floral corms.     

Free and conjugated polyamines during de novo floral and vegetative bud formation in thin cell layers of tobacco

The concentrations of three classes of polyamines, trichloroacetic acid-soluble (free), TCA-soluble conjugated (to small molecules) and TCA-insoluble conjugated (to macromolecules), was examined during de novo floral and vegetative bud formation in thin cell layers of Nicotiana tabacum L. cv. Samsun. Explants (consisting of 5–6 layers of epidermal, subepidermal and parenchyma cells) were excised either from floral pedicels or from stem internodes at the unripe fruit stage and cultured on the same medium. In the former, the first de novo formed flower buds appeared on day 8 of culture, while in the latter the first vegetative domes appeared on day 10. In both cases the number of floral and vegetative buds increased up to day 12 and 15, respectively. Changes in dry weight were determined throughout the culture period. Free and conjugated putrescine titer increased 5–60 times in both types of culture and in the three classes of polyamines examined; spermidine content also increased, while spermine, when present, did not show significant changes. TCA-soluble conjugated polyamines were most abundant, being about 2-fold the TCA-insoluble conjugated ones and 10-fold the free ones. The major increment in putrescine and spermidine content occurred in stem internode explants developing vegetative buds. In pedicel explants the maximum putrescine level was reached before or on day 8 in culture (emergence of the first flower buds with calyx initials), while in stem internode explants the maximum level was reached on day 12, at the emergence of the first vegetative buds with leaf primordia. While spermidine prevailed on day 0, putrescine was the most abundant polyamine during both differentiation processes. The putrescine content rapidly increased immediately after the onset of culture. Thus conjugated polyamines, especially putrescine, and not only the free ones, seem to be involved in both the reproductive and vegetative phases of tobacco growth and development.