源库关系改变对棉叶内源激素的影响

以中棉18号为材料,在大田条件下研究了摘蕾引起源库关系改变对主要源叶（对应的主茎叶和对位果枝叶）中内源激素的影响。结果表明;去蕾处理推迟了相应主茎叶和果枝叶中吲哚乙酸（IAA）峰出现,降低了玉米素及其核苷（Z ZR）含量,推迟了果枝叶中异戊烯基腺嘌呤及其核苷（iP iPA)的积累,提前了二氢玉米素及其核苷（DHZ DHZR）的积累,降低了脱落酸（ABA）含量。去除一个蕾对相应叶片内源激素的影响是短期的,随整株源库关系的协调,与对照趋同。激素的这种变化与叶片功能变化是一致的,表明棉花源库关系的协调不仅是物质上的关系,植物激素可能是其中重要的信息调控系统。     

Identification of abscisic acid glucose ester,indole-3-acetic acid,zeatin and zeatin riboside in receptacles of pear

The identity of abscisic acid glucose ester, indole acetic acid, zeatin, and its riboside in pear receptacles was revealed by use of chromatographic, ultraviolet and mass spectral analysis.     

Comparative Analysis of Endogenous Hormones in Leaves and Roots of Two Contrasting Malus Species in Response to Hypoxia Stress

Plant hormones play important roles in regulating developmental processes and signaling networks involved in plant responses to biotic and abiotic stresses. We comparatively studied the growth and endogenous hormonal levels in leaves and roots in two Malus species (M. sieversii and M. hupehensis) differing in hypoxia tolerance under normoxic and hypoxia stress. The results showed that hypoxia stress inhibited growth of seedlings of both Malus species, but with significant differences in intensity. Exposure to hypoxia altered the levels of endogenous hormones in leaves and roots in both Malus seedlings. Leaf and root abscisic acid (ABA) contents increased in response to hypoxia stress in both genotypes despite different extents. Compared with M. hupehensis, M. sieversii was more responsive to hypoxia stress, resulting in larger increases in leaf and root ABA contents. The changes in leaf and root ABA contents correlating with the different tolerance levels of the genotypes confirm the involvement of this hormone in plant responses to hypoxia stress. Gibberellins (GAs; GA₁ + GA₄) continuously increased in leaves and roots during the whole period of stress, whereas indole-3-acetic acid (IAA) showed a sharp increase at the early stage in both Malus seedlings. In addition, zeatin riboside (ZR), dihydrozeatin riboside (DHZR), and isopentenyl adenine (IPA) differed in their pattern of changes in both Malus seedlings under hypoxia stress. Based on variations in endogenous hormonal levels in both Malus species that differ in their ability to tolerate hypoxia, we conclude that not a single hormone but multiple hormones and their interplay are responsible for hypoxia tolerance.     

亚适宜温光下萘乙酸钠对番茄幼苗生长与生理特性的影响

以番茄“中杂105”为试材,研究亚适宜温光条件下根施10 mg·L^-1萘乙酸钠对番茄幼苗生长与生理特性的影响.结果表明： 亚适宜温光处理番茄幼苗生物量、壮苗指数、根系活力、光合速率、根系和叶片中全氮含量均显著下降,超氧化物歧化酶和过氧化物酶活性升高,过氧化氢酶活性降低,玉米素核苷含量显著下降,而脱落酸含量显著增加.亚适宜温光条件下,与对照相比,根施10 mg·L^-1萘乙酸钠可使番茄幼苗全株干质量、壮苗指数分别提高16.4%、22.9%,并使根、叶中全N含量及光合速率分别增加8.5%、28.5%、37.0%,提高根系活力和保护酶活性,增加吲哚乙酸和玉米素核苷含量,抑制脱落酸含量的增加.亚适宜温光处理下,根施10 mg·L^-1萘乙酸钠可以通过提高番茄幼苗根系活力、保护酶活性和光合速率,调控内源激素水平变化,促进番茄幼苗生长.     

Agrobacterium-mediated transformation of five wild Solanum species using in vitro microtubers

Summary A genetic transformation method, using in vitro microtubers and Agrobacterium-mediated transformation has been developed for five wild Solanum species: S. verrucosum, S. hjertingii, S. papita, S. stoloniferum, S. demissum, which range in ploidy from diploid to hexaploid. A disarmed A. tumefaciens strain, C58 harbouring the co-integrate vector pGV3580::pKU2 with the genes of neomycin phosphotransferase (NPTII) and hygromycin phosphotransferase (HPTII) as selectable markers, was used. Selection of putative transformants was based on their ability to grow and produce roots on a medium containing 150 mg/l kanamycin. The transgenic nature of the putative transformants was confirmed by Polymerase Chain Reaction analysis and by NPTII dotblot assay to show the expression of the NPTII gene. Additionally, the transmission of transgenes, NPTII and HPTII in selfed-sexual progeny of some transgenic plants was also determined.Abbreviations MS Murashige and Skoog - NPTII neomycin phosphotransferase - HPTII hygromycin phosphotransferase - PCR polymerase chain reaction - GA₃ gibberellic acid - CCC chlorocholine chloride - BAP benzylaminopurine - NAA naphthalene acetic acid - ZR zeatin riboside - IAA indole acetic acid - LB Luria Broth     

干旱胁迫对枳橙内源激素含量的影响

目的:研究干旱胁迫对枳橙内源激素含量的影响。方法:以一年生枳橙砧木苗为试验材料,采用盆栽试验,测定不同土壤失水率下枳橙叶片以及失水率为40%时枳橙根中内源激素含量的变化。结果:当土壤失水率为40%时,枳橙根和叶片中GA3和Z含量均降低、IAA含量增加,而根中ABA含量降低,叶片中ABA含量增加。不同土壤失水率下,叶片中ABA含量随失水率增加逐渐上升,IAA含量先上升后下降,当失水率为50%时达到最高,GA3和Z含量都呈先下降后上升再下降的变化趋势。结论:枳橙的内源激素受干旱胁迫影响。轻度胁迫下IAA等促进枳橙生长的内源激素含量增加,说明适度的干旱胁迫能促进枳橙的生长发育。     

T-DNA genes to study plant development: precocious tuberisation and enhanced cytokinins in A. tumefaciens transformed potato

Summary Potato Line Mb1501B is a derivative of the cultivar Maris Bard (Solanum tuberosum), transformed with T-DNA from A. tumefaciens strain LBA1501. In culture it grew as frequently branching stunted shoots with a basal callus, lacking roots. These shoots did not form tubers. When grafted, Mb1501B shoots gradually became morphologically more normal and aerial tubers formed readily. Cultured Mb1501B shoots contained 100–200-fold higher concentrations of the biologically-active cytokinins zeatin, zeatin riboside and their corresponding side-chain o-glucosides than untransformed Maris Bard shoots. Cultured Mb1501B shoots contained approximately a 3-fold lower concentration of indole acetic acid (IAA). In grafted Mb1501B plants a 3–10-fold higher concentration of the active cytokinins was found compared with untransformed plants and no difference in IAA concentration.     

Seasonal Changes in the Cytokinin Content of the Leaves of Salix babylonica

The young and old leaves of Salix babylonica contain at least four cell division-inducing compounds which coeluted with zeatin, zeatin riboside and their glucosylated derivatives. During the course of the growing season quantitative changes in the cytokinin content of the leaves were observed. The cytokinin glucosides increased as the leaves aged. The compounds which co-chromatographed with zeatin and zeatin riboside initially increased until early autumn and then decreased as the leaves senesced. It appears as though the cytokinins transported from the roots are metabolized in the leaves and are converted to their glucosides. Although it has been reported in the literature that Salix root exudate contains very small amounts of cytokinin in late summer and autumn, these compounds increase in the leaves for most of the growing season, suggesting that the leaves may not only obtain cytokinins from the roots but may well be an active site of cytokinin synthesis. It is, however, possible that cytokinins are also transported to the leaves via the phloem, thus accounting for their accumulation in these organs.     

A rapid transformation method for Solanum tuberosum using binary Agrobacterium tumefaciens vectors

A tuber disc transformation and regeneration system was devised for potato (Solanum tuberosum). Tuber discs were found to be the most morphogenetic organ on a medium previously optimised for tomato regeneration. Shoot regeneration from tuber discs was rapid and transformed as shown by nopaline assays and Southern blot analysis. The ease and speed of the tuber disc method will allow for the increased use of this commercially important plant in transformation studies.Abbreviations MS Murashige and Skoog medium - IAA indole 3-acetic acid - BAP benzylaminopurine - NAA naphthalene acetic acid - ZR zeatin riboside     

Changes in the Content of Indole-3-Acetic Acid and Cytokinins in Spruce, Fir and Oak Trees after Herbicide Treatment

Treatment of spruce, fir and oak trees with herbicides, which may be one of the forest damage inducing agents, caused pronounced changes in the contents and distribution of indole-3-acetic acid (IAA) and cytokinins (CKs) one year after treatment, i.e. at the time of the first microscopically visible damage in treated trees. In Picea pungens IAA content increased in the terminal buds by about 105 % and in the apical buds of the first order branches by 220 %. The same was true for young sprouts of Abies nordmanniana, while in leaves of oak trees IAA content was decreased by 15 % after glyphosate treatment and by 30 % after 2,4-dichlorophenoxyacetic acid (2,4-D) treatment. Another striking feature was a significantly decreased content of IAA in the lower parts of roots in Picea pungens (50 % of the control), which is accompanied by an increase in IAA content in the middle part of the roots (130 %). On the other hand, the IAA content of both sprouts and roots of A. nordmanniana was significantly increased after herbicide treatment.In P. pungens, the content of free cytokinins (sum of zeatin, zeatin riboside, isopentenyladenine and isopentenyladenosine) decreased due to herbicide treatment. The strongest decrease was seen in roots, especially in their upper and middle parts (the average reduction of cytokinin content in roots was 63 %). In the above-ground organs the reduction was seen namely for isopentenyladenine and isopentenyladenosine, while the abundance of zeatin riboside was, on the other hand, higher in treated plants. In Quercus robur leaves, the total content of cytokinins also decreased, namely after glyphosate treatment. In consequence of these changes, CK/IAA ratio decreased pronouncedly in all organs of herbicide-treated trees, with the exception of oak leaves treated by 2,4-D.     

Use of High Performance Liquid Chromatography for the Determination of Endogenous Hormone Levels in Solanum tuberosum L. Subjected to Carbon Dioxide Enrichment of the Root Zone

Changes in cytokinin, auxin, and abscisic acid levels were determined by high performance liquid chromatography following CO₂ enrichment of the root zone. Both trans zeatin and zeatin riboside significantly decreased in the roots 6 days after treatment with CO₂. In the leaves zeatin riboside increased whereas trans zeatin showed no significant difference from the control. Indoleacetic acid in the leaves increased dramatically for 6 days following CO₂ treatment; however, indoleacetic acid levels in the roots increased slightly after 2 days and remained higher than the control. Abscisic acid increased shortly after CO₂ treatments; after 6 days this difference was no longer evident.     

Effect of the nitrogen-containing salt on the content of cytokinins in detached wheat leaves

The dynamics of the cytokinin content in detached leaves of wheat (Triticum durum, cv. Bezenchukskaya 139) seedlings moistened with ammonium nitrate or water (control) was studied by immunoenzyme analysis. Leaf treatment with water was accompanied by a transient accumulation of cytokinins, maybe due to their release from their O-glucosylated forms. An increase in the contents of zeatin and its riboside after their initial decrease in detached leaves treated with ammonium nitrate could not occur due to their release from stored forms (nucleotides or O-glucosides) because the contents of zeatin and its riboside increased simultaneously with the content of stored cytokinins. The accumulation of isopentenyladenosine and zeatin nucleotide, which occurred simultaneously with an increase in the content of zeatin and zeatin riboside, permits a supposition that cytokinins can be synthesized in detached wheat leaves treated with ammonium nitrate.     

Changes in cytokinin,auxin, and abscisic acid contents in wheat seedlings treated with the growth regulator Stifun

The growth regulator Stifun at all concentrations tested (0.033, 0.33, 3.3, and 33 mg/L) affected the hormonal status of wheat seedlings (Triticum aestivum L., cv. Zhnitsa) and stimulated plant growth. This was evident in activation of cell division and elongation, as well as in the increase in shoot and root length, water content, and dry weight. Effects of Stifun on roots and shoots depended on concentration. Application of Stifun at the optimal growth-stimulating concentration (0.033 mg/L) elevated the levels of zeatin, zeatin riboside, dihydrozeatin riboside, isopentenyladenosine, and IAA in roots of 2-day-old seedlings, but reduced the ABA content. The levels of ABA, IAA, dihydrozeatin, and dihydrozeatin riboside in shoots increased, while the levels of zeatin riboside, isopentenyl adenine, and isopentenyladenosine decreased. The results indicate that the hormonal system plays a part in the plant response to growth-stimulating action of Stifun.     

ENDOGENOUS CYTOKININS,AUXINS, AND ABSCISIC ACID IN RED ALGAE FROM BRAZIL1

Endogenous cytokinins, auxins, and abscisic acid (ABA) were identified and quantified in 11 red algae collected from the Brazilian coast. Field materials and two isolates cultured in the laboratory were extracted with various solvents and buffers containing a mixture of appropriate internal standards, purified by solid‐phase extraction followed by immunoaffinity chromatography, and analyzed by liquid chromatography–tandem mass spectrometry. Isoprenoid cytokinins (free and conjugated forms of isopentenyladenine [iP], cis‐zeatin [cZ], and trans‐zeatin [tZ]) were detected in all species with concentrations of cZ and iP forms being higher than tZ forms. Dihydrozeatin (DHZ) and its metabolites were only detected at very low levels in nine of the studied species. Aromatic cytokinins (6‐benzylaminopurine [BA], ortho‐ and meta‐topolin [oT and mT]) were not detected in any of the samples. The cytokinin profile of Chondracanthus teedei (Mert. ex Roth) Kütz. was distinct in comparison to other species with para‐topolin (pT) derivatives detected in low concentrations. The main auxins present in all species were free indole‐3‐acetic acid (IAA) and indole‐3‐acetamide (IAM). Indole‐3‐ethanol (IEt), indole‐3‐acetyl glutamic acid (IAGlu), and indole‐3‐acetyl leucine (IALeu) were detected in a few species at low concentrations. ABA was present in all species analyzed except for Hypnea nigrescens Grev. ex J. Agardh. No ABA conjugates were detected in any species. These results confirm that cytokinins, auxins, and ABA were common constituents in red seaweeds, with this being the first report of the occurrence of ABA in Rhodophyta. The complexity of the hormone profiles suggests that plant hormones play a role in regulating physiological processes in Rhodophyta.     

HIGH‐THROUGHPUT SCREENING TECHNOLOGY FOR MONITORING PHYTOHORMONE PRODUCTION IN MICROALGAE1

New miniaturized techniques for multiplying microalgae and estimating their phytohormone production were developed; in these methods, the strains to be tested are cultivated in microtitre plates, and the phytohormones in suspensions of the cultures are measured by direct ELISAs. Specific and sensitive ELISAs for determining abscisic acid (ABA), indole‐3‐acetic acid (IAA), cis‐ and trans‐zeatin riboside, isopentenyladenosine (iPR), and other less common cytokinins were developed for this purpose. Polyclonal antibodies used in the ABA and IAA assays were raised against C1‐ and C1′‐ conjugates of the compounds with BSA, respectively, and thus were specific for the free acids and their respective C1‐derivatives. The use of cytokinin ribosides coupled via their sugar residues to BSA as haptens generally led to antibodies that bound free bases, 9‐glycosides and nucleotides, but with high specificity for the corresponding N⁶‐side chains. Using internal standards, dilution assays, and authentic [²H] and [³H] recovery markers, it was shown that the ELISAs could be used to estimate contents of the selected phytohormones in the cultures. The ELISAs provided reliable and very fast estimates of the selected phytohormones, at concentrations ranging from 0.01 to 10 pmol · mL^?1 in various microalgal strains. In addition, a recently developed HPLC selected ion monitoring mass spectrometry (HPLC‐SIM–MS) method was used to calibrate and validate the ELISA results and confirm the presence of the detected phytohormones in immunoaffinity‐purified extracts. Where independent validation of results is deemed necessary, the use of quantitative HPLC–MS is recommended for each new microalgal strain to be tested.     

Cytokinins and auxin communicate nitrogen availability as long-distance signal molecules in pineapple (Ananas comosus)

This work aimed at identifying a possible role of phytohormones in long-distance (root-shoot) signaling under nitrogen deficiency. Three-months old pineapple plants were transferred from Murashige and Skoog (MS) medium to nitrogen-free MS (-N). During the first 24h on -N, 20 plants were harvested every 4h. After 30 days in -N, the remaining plants were transferred back to regular MS (+N) and 20 plants harvested every 4h for the first 24h. Following the harvests, endogenous levels of nitrate (NO(3)(-)), indole-3-acetic acid (IAA), isopentenyladenine (iP), isopentenyladenine riboside (iPR), zeatin (Z) and zeatin riboside (ZR) were analyzed in roots and leaves. In N-starved plants, the NO(3)(-) level dropped by 20% in roots between the first (4h) and the second harvest (8h). In leaves a reduction of 20% was found 4h later. Accumulation of IAA peaked in leaves at 16h. In roots, the accumulation of IAA only started at 16h while the leaf content was already in decline, which suggests that the hormone might have traveled from the leaves to the roots, communicating N-shortage. The contents of the four cytokinins were generally low in both, shoot and roots, and remained almost unchanged during the 24h of analysis. After N re-supply, roots showed a NO(3)(-) peak at 8h whereas the foliar concentration increased 4h later. Hormone levels in roots climaxed at 8h, this coinciding with the highest NO(3)(-) concentration. In leaf tissue, a dramatic accumulation was only observed for Z and ZR, and the peak was seen 4h later than in roots, suggesting that Z-type cytokinins might have traveled from the roots to the leaves. These findings provide evidence that there is a signaling pathway for N availability in pineapple plants, communicated upwards through cytokinins (N-supplemented plants) and downwards through auxin (N-starved plants).     

Anatomy,microstructure, and endogenous hormone changes in Gnetum parvifolium during anthesis

The study of the sexual systems of plants is very important for understanding their evolutionary process. Gnetum is a pivotal species in comprehending the seed plant phylogeny. However, the sexual systems of this genus are not fully understood. To investigate the sexual system of Gnetum, the anatomical structure, microstructure, and endogenous hormones were investigated from the differentiation of flower buds to fertilization in the floral organs of female and male of G. parvifolium (Warb.) C.Y. Cheng, widely distributed in the north of China. After 2 years of field investigations, the staminate strobili were observed on female plants for the first time and the abortive ovules were also found on male plants. In addition, high levels of gibberellin A₃ and zeatin riboside led to masculinization, whereas a high level of indole‐3‐acetic acid favored feminization. A comprehensive analysis of the results indicates that G. parvifolium may not be completely dioecious on morphology, but female and male plants can only perform their own gender function, which would provide a better understanding of the diversity of sexual systems in Gnetum, and reproductive structures of seed plants.