The effect of electron acceptors on the phytochrome-controlled germination of Paulownia tomentosa seeds

The effect of substances with different redox potentials in the phytochrome-controlled germination of Paulmtnia tomentosa seeds was examined. Up to 25% of water-imbibed seeds germinated upon irradiation with 5 min red light The seeds irradiated with 5 min red light and incubated in substances with redox potentials equal or higher than E'₀= 360 mV [potassium nitrate, potassium hexacyanoferrate (III) or potassium hexachloroiridate (IV)] and sodium nitroprusside germinated up to 80%. The optimal concentration was between 1 and 10 mM. Other electron acceptors such as 2.6-dichlorophenol-indoplhenol, phenazine methosulfate and methylene blue failed to produce and effect. The germination-promoting effect was obtained when the substances were supplied to the incubation medium from the onset of imbibition or at the onset of irradiation. Delay of application of these chemicals until after the red light treatment diminished their effectiveness and the effect was lost after 48 h. The escape from far-red reversibility was evident in the presence of substances which stimulated germination. The results presented support the view that phytochrome-broken dormancy of Paulownia tomentosa seeds is closely connected with redox changes.     

Phylogenetic relationships of Cyrtandromoea and Wightia revisited: A new tribe in Phrymaceae and a new family in Lamiales

The familial placements of Cyrtandromoea Zoll. and Wightia Wall., two small and enigmatic South‐East Asian genera, have long been controversial in Lamiales. Here we adopt a two‐step approach to resolve their phylogenetic relationships. We initially reconstructed a large‐scale phylogeny of Lamiales using six chloroplast markers (atpB, matK, ndhF, psbBTNH, rbcL, and rps4). The results showed that both Cyrtandromoea and Wightia emerged in the LMPO clade, including Lamiaceae, Mazaceae, Phrymaceae, Paulowniaceae, and Orobanchaceae. Based on the second set of six chloroplast markers (atpB, matK, ndhF, rbcL, rps16, and trnL‐F) and two nuclear ribosomal regions (external transcribed spacer and internal transcribed spacer) for the analyses focusing on the LMPO clade, our results revealed that Cyrtandromoea was consistently nested within Phrymaceae, whereas Wightia was supported as sister to Phrymaceae by the chloroplast DNA dataset or sister to Paulowniaceae by the nuclear ribosomal DNA dataset. Morphological and anatomical evidence fully supports the inclusion of Cyrtandromoea in Phrymaceae, and an updated tribal classification is done for Phrymaceae with five tribes, that is, Cyrtandromoeeae Bo Li, Bing Liu, Su Liu & Y. H. Tan, trib. nov., Diplaceae Bo Li, Bing Liu, Su Liu & Y. H. Tan, trib. nov., Leucocarpeae, Mimuleae, and Phrymeae. The conflicting phylogenetic position of Wightia indicated by different genome markers results in difficulty placing the genus in either Phrymaceae or Paulowniaceae. Considering the distinct morphological differences between Wightia and other families in the LMPO clade, we here propose a new family, Wightiaceae Bo Li, Bing Liu, Su Liu & Y. H. Tan, fam. nov., to accommodate it, which is the 26th family recognized in Lamiales.     

Anti-herbivore structures of Paulownia tomentosa: morphology, distribution, chemical constituents and changes during shoot and leaf development

Background and Aims: Recent studies have shown that small structures on plant surfacesserve ecological functions such as resistance against herbivores.The morphology, distribution, chemical composition and changesduring shoot and leaf development of such small structures wereexamined on Paulownia tomentosa. Methods: The morphology and distribution of the structures were studiedunder light microscopy, and their chemical composition was analysedusing thin-layer chromatography and high-performance liquidchromatography. To further investigate the function of thesestructures, several simple field experiments and observationswere also conducted. Key Results: Three types of small structures on P. tomentosa were investigated:bowl-shaped organs, glandular hairs and dendritic trichomes.The bowl-shaped organs were densely aggregated on the leavesnear flower buds and were determined to be extrafloral nectarines(EFNs) that secrete sugar and attract ants. Nectar productionof these organs was increased by artificial damage to the leaves,suggesting an anti-herbivore function through symbiosis withants. Glandular hairs were found on the surfaces of young and/orreproductive organs. Glandular hairs on leaves, stems and flowerssecreted mucilage containing glycerides and trapped small insects.Secretions from glandular hairs on flowers and immature fruitscontained flavonoids, which may provide protection against someherbivores. Yellow dendritic trichomes on the adaxial side ofleaves also contained flavonoids identical to those secretedby the glandular hairs on fruits and flowers. Three specialtypes of leaves, which differed from the standard leaves inshape, size and identity of small structures, developed nearyoung shoot tips or young flower buds. The density of smallstructures on these leaf types was higher than on standard leaves,suggesting that these leaf types may be specialized to protectyoung leaves or reproductive organs. Changes in the small structuresduring leaf development suggested that leaves of P. tomentosaare primarily protected by glandular hairs and dendritic trichomesat young stages and by the EFNs at mature stages. Conclusions: The results indicate that P. tomentosa protects young and/orreproductive organs from herbivores through the distributionand allocation of small structures, the nature of which dependson the developmental stage of leaves and shoots.     

泡桐属七种植物的RAPD分析

利用 1 3个 1 0 mer的随机引物对中国泡桐属的 7个种进行了 RAPD分析 ,对扩增形成的谱带进行了对比 ,发现 7个种间存在较丰富的多态性带纹。经用 UPGMA法聚类结果说明可把研究的 7个种分成 2个类群。其中白花泡桐与川泡桐亲缘关系最近 ,二者与揪叶泡桐、南方泡桐、山明泡桐归为 1个类群。毛泡桐与兰考泡桐亲缘关系也较近 ,二者在系统演化上比较原始 ,归为 1个类群。     

Geranylated flavanones from the secretion on the surface of the immature fruits of Paulownia tomentosa

Chemical investigation of the methanol extract of the viscous secretion on the surface of immature fruits of Paulownia tomentosa furnished nine geranylated flavanones, 6-geranyl-5,7-dihydroxy-3',4'-dimethoxyflavanone (1), 6-geranyl-3',5,7-trihydroxy-4'-methoxyflavanone (2), 6-geranyl-4',5,7-trihydroxy-3',5'-dimethoxyflavanone (3), 6-geranyl-4',5,5',7-tetrahydroxy-3'-methoxyflavanone (4), 6-geranyl-3,3',5,7-tetrahydroxy-4'-methoxyflavanone (5), 4',5,5',7-tetrahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]-3'-methoxyflavanone (6), 3,3',4',5,7-pentahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]flavanone (7), 3,3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone (8), and 3,4',5,5',7-pentahydroxy-3'-methoxy-6-(3-methyl-2-butenyl)flavanone (9), along with six known geranylated flavanones. Among these, compounds 4, 6-9 and the known 6-geranyl-3',4',5,7-tetraahydroxyflavanone (diplacone), 6-geranyl-3,3',4',5,7-pentahydroxyflavanone (diplacol) and 3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone showed potent radical scavenging effects towards DPPH radicals.     

泡桐叶片蛋白质提取方法的研究

２４个提取泡桐叶片蛋白质组合的试验结果表明,用ＵＫＣ（９．５ｍｏｌ／Ｌ尿素,５ｍｍｏｌ／ＬＫ２ＣＯ３,１．２５％ＣＴＡＢ,０．５％二硫苏糖醇,２％两性载体电解质ｐＨ３．５～１０,５％ＴｒｉｔｏｎＸ－１００）提取由１０％冷（－４０℃）三氯醋酸（丙酮配制,内含０．０７％的巯基乙醇）处理的泡桐叶片干粉提取出的蛋白质总量和种类最多。这表明该方法可用于泡桐叶片蛋白质的提取。     

山明桐小孢子败育及与小孢子囊壁发育异常的关系

作者研究了山明桐(Paulownia sp.)小孢子败育及小孢子囊壁异常发育的过程,并探讨了两者之间的关系。结果表明:小孢子败育发生在减数分裂至单核小孢子期间。在小孢子有丝分裂前小孢子已全部敗育拚辈惴⒂斐V饕硐衷诒3只疚唇到饣虬虢到庾刺敝脸墒旎ㄒ┦逼凇R┦夷诒谙赴┓只鎏踝丛龊裣赴凇P℃咦幽冶诜⒂械恼庑┮斐O窒蟮氖抵适瞧湔7⒂瘫恢型就V?而以幼态保持至花药最后干缩。观察表明小孢子囊壁发育异常不是小孢子败育的原因,而可能是其结果。     

泡桐属植物染色体数目和形态的初步研究

本文报道了毛泡桐,白花泡桐和兰考泡桐的体细胞染色体数目均为2n=40。这与已报道的紫葳科大多数木本植物染色体数目是一致的,而与玄参科的大部分届不同。结合形态特征,认为将泡桐属归于紫葳科可能是更为合理的。并对白花泡桐和兰考泡桐的核型进行了初步分析。     

模拟酸雨和铜复合污染对白花泡桐生理特性的影响及其解毒机制

采用盆栽方法,研究了模拟酸雨(pH分别为4.0、5.0)和Cu(0～200mg·kg-1)复合污染对白花泡桐生理特性的影响及其解毒机制.结果表明:未加Cu处理时,不同酸雨处理间,白花泡桐的叶绿素、类胡萝卜素、超氧阴离子、过氧化氢和丙二醛含量均差异不显著;100和200mg·kg-1Cu处理时,pH4.0处理的叶绿素和类胡萝卜素含量显著低于,而超氧阴离子、过氧化氢和丙二醛含量显著高于pH5.0处理.Cu处理的叶绿素a/b值明显高于未加Cu处理.随着酸雨酸度增加,叶片铜含量明显减少,而根部铜含量明显增加.pH5.0时,随Cu浓度增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性均持续增强,植物络合素和谷胱甘肽(GSH)总量均明显增加;而在pH4.0时,SOD、POD、CAT和APX活性呈先升后降,而GSH总量在Cu浓度为200mg·kg-1时明显下降.模拟酸雨加剧了高浓度Cu对白花泡桐的氧化胁迫.     

Direct somatic embryogenesis and synthetic seed production from<Emphasis Type="Italic"> Paulownia elongata</Emphasis>

We have developed a reproducible system for efficient direct somatic embryogenesis from leaf and internodal explants of Paulownia elongata. The somatic embryos obtained were subsequently encapsulated as single embryos to produce synthetic seeds. Several plant growth regulators [6-benzylaminopurine, indole-3-acetic acid, -naphthaleneacetic acid, kinetin and thidiazuron (TDZ)] alone or in combination were tested for their capacity to induce somatic embryogenesis. The highest induction frequencies of somatic embryos were obtained on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 0.6% Phytagel, 500 mg l^-1 casein hydrolysate and 10 mg l^-1 TDZ (medium MS10). Somatic embryos were induced from leaf (69.8%) and internode (58.5%) explants on MS10 medium after 7 days. Subsequent withdrawal of TDZ from the induction medium resulted in the maturation and growth of the embryos into plantlets on MS basal media. The maturation frequency of somatic embryos from leaf and internodal explants was 50.8% and 45.8%, respectively. Subculturing of mature embryos led to their germination on the same medium with a germination frequency of 50.1% and 29.8% from leaf and internode explants, respectively. Somatic embryos obtained directly on leaf explants were used for encapsulation in liquid MS medium containing different concentrations of sodium alginate with a 30-min exposure to 50 mM CaCl₂. A 3% sodium alginate concentration provided a uniform encapsulation of the embryos with survival and germination frequencies of 73.7% and 53.3%, respectively. Storage at 4°C for 30 days or 60 days significantly reduced the survival and complete germination frequencies of both encapsulated and non-encapsulated embryos relative to those of non-stored somatic embryos. However, the survival and germination rates of encapsulated embryos increased following storage at 4°C. After 30 days or 60 days of storage, the survival rates of encapsulated embryos were 67.8% and 53.5% and the germination frequencies were 43.2% and 32.4%, respectively. These systems could be useful for the rapid clonal propagation and dissemination of synthetic seed material of Paulownia elongata.Abbreviations BAP 6-Benzylaminopurine - IAA Indole-3-acetic acid - NAA -Naphthaleneacetic acid - TDZ ThidiazuronCommunicated by H. Lörz