植物生长调节剂对黑木相思优树腋芽增殖及生根的影响

为建立黑木相思(Acacia melanoxylon)快繁技术体系,以含1个腋芽的无菌茎段为材料,研究了植物生长调节剂对其增殖和生根的影响。结果表明,6-BA 极易诱导黑木相思愈伤组织形成,但芽长势较差,不利于腋芽增殖体系的建立。而生长素既能诱导黑木相思生根,又能诱导腋芽增殖;将无菌茎段接入MS+IAA 0.5 mg L^-1+IBA 0.5 mg L^-1培养基中培养20 d的生根率为98.41%,培养40 d的腋芽增殖倍数为2.36,单株繁殖系数为6.57。这是首次成功建立高效、简便的生根和增殖同步发生的黑木相思直接器官发生途径的组培技术体系。     

Regeneration from Leaf Squares of Peperomia sandersii A .DC: a Relationship between Rooting and Budding

Evidence is presented to show that in leaf squares of Peperomiasandersii bud initiation does not occur independently of rooting.Buds were formed close to the point of origin of roots and,in treatments where rooting was delayed, budding was affectedsimilarly. Promotion of root formation by pretreatment of squareswith 3-indolylbutyric acid was accompanied by increases in thenumber of buds initiated. Kinetin and N⁶-benzyladenine whichinhibited the initiation of roots also inhibited the initiationof buds. This was in contrast to the effect of these two compoundson leaf squares of Begonia rex where rooting was similarly inhibitedbut bud initiation was markedly promoted. When leaf squaresof Peperomia were grown in contact with relatively high concentrationsof kinetin buds were occasionally formed in the absence of roots.Removal of roots from leaf squares of Peperomia by excisionprevented the formation of buds.     

Effects of IAA, Zeatin, Ammonium Nitrate and Sucrose on the Initiation and Development of Floral Buds in Torenia Stem Segments Cultured In Vitro

In Torenia stem segments cultured on a defined medium from whichammonium nitrate and growth regulators were omitted, adventitiousbuds were readily formed from epidermal tissue, with subsequentdifferentiation of floral buds. Using this plant material, thecorrelation between the time of application of various chemicalsand the time-course of floral bud differentiation was investigated.Histological examination showed that adventitious buds werevegetative during the first two weeks of the culture, and floralprimordia appeared after about three to four weeks of culture.We divided the flowering process in Torenia stem segments intothe following 3 phases: the first phase (first 2 weeks) duringwhich adventitious buds are formed, the second phase (3rd and4th weeks) during which floral buds are initiated and the thirdphase (5th to 12th weeks) during which floral buds develop.Then we added IAA, zeatin, ammonium nitrate or a high concentrationof sucrose to the medium during one, two or three of these phases.Ammonium nitrate added during the third phase suppressed floralbud development, but the high concentration of sucrose givenduring this phase stimulated it. These two chemicals influencedonly the development of floral buds previously initiated. Theapplication of IAA during the first phase promoted both theinitiation and development of floral buds. However, its applicationafter 2 weeks of culture failed to promote floral bud formation.Zeatin inhibited floral bud formation in a manner similar toammonium nitrate, but if it was added to the medium only duringthe first phase, it slightly promoted the initiation and developmentof floral buds. (Received July 7, 1981; Accepted October 12, 1981)     

Effect of Cutting During Reproductive Development on the Regrowth and Regenerative Capacity of the Perennial Grass, Phalaris aquatica L., in a Controlled Environment

Two cultivars of phalaris (Phalaris aquatica L.), Australianand Sirolan, were cut at four stages of development in a controlledenvironment to study factors involved in the sensitivity ofphalaris to grazing during spring. Effects on tillering, regrowthafter cutting and regenerative capacity after an artificiallyimposed summer dormant period were observed. Compared with Australian,Sirolan cut after the commencement of stem elongation was characterizedby a higher degree of decapitation due to more synchronous elevationof its apices, and displayed a more severe reduction in regrowth,size of tiller bases and dormant buds and levels of carbohydratereserves in summer relative to plants cut before stem elongation.Suppressed bud activity in tillers of Sirolan decapitated atearly stem elongation, and the potential for profuse tilleringassociated with low bud dormancy after cutting at the earlyboot stage, could reduce persistence under field conditions. Relative to plants cut before stem elongation, regenerationgrowth after 'summer' by plants cut during reproductive developmentwas depressed more severely for Sirolan (56-70%; P 0·05)than Australian (28%; n.s), a result more closely related toregenerating tiller size than number. Regeneration growth didnot differ significantly with stage reproductive developmentat cutting in either cultivar. Regenerative capacity of phalariscut during reproductive development can be considered to dependon an increasing contribution from buds on bases of tillersdecapitated when cut and a contribution from buds on intacttiller bases which declines as the stage of cutting becomeslater. The balance between these source will depend on the environment.Copyright1993, 1999 Academic Press Phalaris aquatica L., phalaris, regrowth, persistence, defoliation, cutting, perennial grass, tillering     

Dwarfism Caused by Floral-Bud Removal in Petunia and its Reversal by Gibberellin

The effect of floral-bud removal at different stages of developmenton the plant height and on the total number of buds of Petuniawas studied. Continuous removal of all the floral buds 2 d beforeanthesis caused a marked decrease in plant height and also increasedthe total number of floral buds formed thereafter. At otherstages of floral bud development, bud removal had a lesser effecton both phenomena. Moreover, the plants did not respond to budremoval at anthesis. GA₃ at 25 ppm applied to plants from which the buds had beenremoved, promoted stem elongation. The most pronounced effectwas on plants from which the buds were removed 2 d before anthesis,but it had no effect on plants from which the buds were removedat anthesis stage. The possible involvement of endogenous growth hormones in theresponse of Petunia plants to floral-bud removal and to applicationof GA₃ is discussed. Bud removal, bud number, dwarfness, GA₃, Petunia, plant height     

Influence of Position and Number of Nodal Roots on Outgrowth of Axillary Buds and Development of Branches in Trifolium repens (L.)

The implications of the presence of a root, either at the parentnode or at neighbour nodes, on branch formation of Trifoliumrepens (white clover) was investigated. Plants were freely rootedor rooting was restricted to every sixth or every twelfth nodealong the parent axis. The absence of a root at the parent nodehad little influence on the probability of the subtending axillarybud forming a branch but, on average, delayed the outgrowthof the bud. The probability that an axillary bud, emerging froma non-rooted parent node, developed to a lateral branch (branchwith elongated internodes) decreased with decreasing proximityof the parent node to a rooted node. Lateral branches emergingfrom non-rooted parent nodes which were two nodes distal toa rooted node had a higher rate of node appearance, a greatermean internode length and area per leaf, and were more branchedthan lateral branches emerging from other non-rooted parentnodes. The dry mass of each single root and of branches grownat rooted parent nodes were significantly higher in plants withrestricted rooting than in freely rooted plants. Restrictionin the number of rooted nodes per plant increased the numberof inflorescences. It is concluded that the whole plant responseto restricted root formation was continuous growth of the parentaxis and compensatory growth of the branch at the rooted node.In general, growth was slow for axillary buds whose developmentwas dependent on the basipetal movement or cross-transport withinthe stolons of resources exported from roots. Trifolium repens (L.); white clover; axillary bud outgrowth; branch development; clonal growth; nodal root     

红厚壳茎段丛生芽诱导与植株再生

红厚壳(Calophyllum inophyllum)为藤黄科红厚壳属多年生木本植物,有很高的药用价值。该研究以红厚壳带节茎段为外植体,探讨生长调节剂对腋芽萌发及丛生芽诱导、伸长和试管苗生根的影响。研究结果表明,外植体腋芽萌发和丛生芽诱导效果最好的培养基是MS+NAA1.0+TDZ0.5,在此条件下培养21天后,转入添加0.5 g·L–1活性炭且无生长调节剂的MS培养基,可有效促进不定芽的伸长。将带不定芽的外植体先在附加1.0 mg·L–1NAA的1/2MS培养基上进行生根诱导4周,之后转入附加1.0 g·L–1活性炭的无激素培养基进行根的伸长培养,这样的两步生根法能有效促进红厚壳生根。     

Whole plant regeneration from the shoot apex ofArachis hypogaea L.

Summary Arachis hypogaea L. peanut, has been a difficult species to manipulate in tissue culture. Lack of a reliable and quick regeneration method for peanuts has proven to be one of the hindrances in the application of transformation protocols to the crop. A protocol to initiate shoot apex elongation and rooting of these shoots is described. This protocol was successful with two peanut cultivars. Shoot apices were isolated from germinated seedlings and placed on Murashige and Skoog salts containing N⁶-benzyladenine for shoot initiation. Once shoot elongation occurred, the explant was transferred to a rooting medium containing Murashige and Skoog salts and only one plant growth regulator, α-naphthalene acetic acid. In as few as 3 weeks, the explants began to root and could be transferred to soil. Forty-five percent of explants isolated from germinating peanut seeds would root on this medium. Elongation and rooting of the shoot apices were not hindered by the addition of an antibiotic to the medium, indicating that the regeneration method could be useful inAgrobacterium tume-faciens-mediated transformation protocols.     

Root-to-shoot primordium conversion on Sesbania rostrata Brem. stem explants

The morphogenetic responses of cultured stem explants of Sesbaniarostrata Brem. from various positions along the stem axis wereanalysed after treatment with four growth regulators (BAP, NAA,kinetin, and GAJ. Internodal explants formed adventitious shootbuds when cultured on a Murashige and Skoog basal medium withoutadded growth regulators. Histological studies of regenerated shoot buds revealed thatapproximately 30% of the buds resulted from the conversion ofa preformed root primordium (characteristic of this species)into a shoot bud without a callogenesis phase. Each bud whichoriginated from a single root primordium grew into a leafy shoot.Preformed root primordia of stem explants of Sesbania rostratamay constitute an excellent model for physiological researchon plant differentiation. Key words: Organogenesis, adventitious bud, preformed root primordium, conversion, Sesbania rostrata     

The Effect of Rooting Space on Whole Plant and Leaf Growth in Brussels Sprouts (Brassica oleracea var. gemmifera)

Seedlings of Brassica oleracea var. gemmifera DC. (Brusselssprouts) were grown in four pot sizes over a 4-week period.Whole plant, stem, root and foliage d. wts and foliage area,together with specific leaf area, leaf area ratio and numberof leaves initiated were reduced by restricting rooting space.Individual leaves showed similar reductions in d. wt and area,with the effect being more pronounced in later-formed leaves.Cell counts and measurements on the epidermis and palisade mesophylllayers of the first four leaves showed that the reduction ingrowth was due to reduced cell division. Cell numbers in thefirst-formed leaf were halved over the range of pot sizes used,and there was a progressively greater reduction in cell numbersin later-formed leaves. There was some tendency for cell sizeto decrease with decreasing rooting space, but this was notgeneral and was most marked between plants grown in the twosmallest pot sizes. Brassica oleracea var. gemmifera, Brussels sprouts, rooting space, growth analysis, leaf growth, cell numbers, cell sizes     

Leaf Determination in the Fern Osmunda cinnamomea--A Reinvestigation

Earlier studies of leaf determination in the fern Osmunda cinnamomeaL., using the technique of excision and sterile culture, indicatedthat the apices of incompletely determined leaf primordia areconverted into shoot apices after isolation. Subsequently otherworkers questioned this interpretation, suggesting that a primordiumis determined as a leaf shortly after its inception and thatany shoot which arises from it is an adaxial adventitious bud.Because of the importance of this distinction in the interpretationof determination, the phenomenon has been reinvestigated byscanning electron microscopy and histological methods. Sincefixation for electron microscopy was inconsistence, the workwas performed on the primordia using resin models formed indental plastic moulds. Our data, on explanted P3, P4, and P5leaf primodia, provide strong confirmation for the interpretationthat the leaf apex is indeed converted to a shoot apex in incompletelydetermined primodia after explantation. This new evidence formsthe basis for interpreting leaf determination in this experimentalsystem.Copyright 1993, 1999 Academic Press Leaf determination, in vitro, surface replica, scanning electron microscopy, Osmunda cinnamomea L., cinnamon fern     

Morphological Analysis of Tillering in Agropyron spicatum and Agropyron desertorum

The caespitose grasses Agropyron spicatum and Agropyron desertorumexhibit a striking difference in tillering response followingexperimental clipping treatment, with plants of A. desertorumproducing up to 18 times more tillers. The two species are similarin many aspects of their phenology and physiology. Previousexamination of current photosynthate production and levels ofstored carbohydrates indicate only slight differences betweenthe species. The possible role of three anatomical/morphologicalconstraints in controlling tillering was examined. No evidencefor such constraints was found. A basal cluster of buds is presenton the parent tillers. The mean bud number per tiller was similarfor both species and the range (3–9) was identical. Nearlyall of the bud apical meristems appeared anatomically viablethroughout the growing season and vascular development occurredto within 250 to 490 µm of the various bud apices of bothspecies. Both normal fall tillers and summer tillers producedunder clipping treatment originated from the largest, most distalbuds of the basal cluster of buds. However, precocious, morphologicallydistinctive, second-order tillers occasionally grew out fromthe smaller, most basal buds of some elongating fall tillers. Agropyron spicatum, Agropyron desertorum, bluebunch wheatgrass, crested wheatgrass, bud, tiller, tillering ability, meristematic potential, vascular development, regrowth     

'Vitrified' Dianthus--Teratomata in vitro due to Growth Factor Imbalance

Cultured shoot tips of Dianthus caryophyllus often develop asabnormal, ‘vitrified’ plants that have the characteristicsof teratomata: stable, unlimited development with fasciatedshoot apices, a bush habit, reduced stem elongation and succulentleaves. High concentrations of NAA in the culture medium increasedand benzylaminopurine decreased the proportion of shoot-tipsthat developed as abnormal plants. The requirements of abnormaland normal plants for continued development differed. Duringthe initial stages of development abnormal plants did not requireauxin and they were able to continue their growth in the absenceof roots. It is suggested that the abnormal plants are teratomata,similar to those induced by Crown Gall bacteria, and their inductionand abnormal traits could be due to imbalance of auxins andcytokinins. Dianthus caryophyllus L., carnation, abnormal plant growth, habituation, vitrification, teratoma (plant)     

Adventitious Bud Formation from Mature Embryos of Picea chihuahuana Martinez, an Endangered Mexican Spruce Tree

Zygotic embryos of Picea chihuahuana Martínez were cultivatedin vitro to determine the time of organogenic competence andto maximize adventitious bud induction. The induction mediumconsisted of modified B5 substrate supplemented with N⁶-benzyladenine(with or without naphthalene acetic acid) or kinetin (with orwithout 2-4, dichlorophenoxyacetic acid) at different concentrationsand induction times. The minimum induction time required forbud formation was 14 d with kinetin and 17 d with N⁶-benzyladenine.After induction embryos were transferred to the proliferationmedium (modified B5 substrate with 50% of its components andwithout growth regulators) for 30 d. The subsequent buds weretransferred every 15 d to Schenk and Hildebrandt medium at halfits concentration without growth regulators. The most effectivetreatments were 3 and 5 mg l^-1kinetin or N⁶-benzyladenine whichproduced five to seven buds per embryo. The largest shoots weresubjected to rooting trials with pulses of different concentrationsof indole butyric acid resulting in only one bud developinga root. Histological analysis revealed clusters of three tofour cells that became more evident as induction time increased.Kinetin promoted the development of an organized structure priorto adventitious buds formation sooner than N⁶-benzyladenine.Copyright 2000 Annals of Botany Company Competence, plant tissue culture, micropropagation, Picea chihuahuana, endangered species, spruce     

A tissue culture of the Ostrich fern Matteuccia struthiopteris (L.) Todaro

Multiple bud formation was induced from shoot apices of Matteuccia struthiopteris cultured on semi-solid Knudson's medium supplemented with 10^-5 and 10^-6 M kinetin. The effect of kinetin, naphthaleneacetic acid and gibberellic acid on shoot and root development is discussed and a three-part tissue culture system was devised for micropropagation and rooting.     

Lateral Bud Growth in Phaseolus vulgaris L. and the Levels of Ethylene in the Bud and Adjacent Tissue

Ethephon and the ethylene inhibitors Ag⁺ and aminoethoxyvinylglycine (AVG) inhibited outgrowth of the axillary bud of thefirst trifoliate leaf in decapitated plants of Phaseolus vulgaris.Endogenous ethylene levels decreased in the stem upon decapitationalthough it is not conclusive that a causal relationship existsbetween this decrease and the release of axillary buds frominhibition. The proposition that auxin-induced ethylene is responsiblefor the suppression of axillary bud growth in the decapitatedplant when the apical shoot is replaced by auxin is not borneout in this study. Application of IAA directly to the axillarybud of intact plants gave rise to a transient increase in budgrowth. This growth increment was annulled when AVG was suppliedwith IAA to the bud despite the fact that the dosage of AVGused did not affect the normal slow growth rate of the bud ofthe intact plant or bud outgrowth resulting from shoot decapitation.     

Regulation of shoot branching patterns by the basal root system: towards a predictive model

This study aimed to underpin the development of a generic predictivemodel of the regulation of shoot branching by roots in nodallyrooting perennial prostrate-stemmed species using knowledgegained from physiological studies of Trifolium repens. Experiment1 demonstrated that the net stimulatory influence from the basalrooted region of the plant on growth of newly emerging axillarybuds on the primary stem decreased as their phytomeric distancefrom the basal root system increased. Experiment 2 found thatat any one time the distribution of net root stimulus (NRS)to the apical bud on the primary stem and all lateral brancheswas fairly uniform within a single plant. Thus, although NRSavailability was uniform throughout the shoot system at anypoint in time, it progressively decreased as shoot apical budsgrew away from the basal root system. Based on these findings,a preliminary predictive model of the physiological regulationof branching pattern was developed. This model can explain thedecline in growth rate of buds on a primary stem as it growsaway from its basal root system but not the rapid progressivedecline in secondary branch development on successive lateralbranches. Thus knowledge of NRS availability to emerging budsis not, by itself, a sufficient basis from which to constructa predictive model. In addition, it seems that the ability ofan emerging bud to become activated in response to its localNRS availability is, at least in part, directly influenced bythe activation level of its parent apical bud. The experimentaltesting of this hypothesis, required for continued developmentof the model, is proceeding. Key words: Axillary bud outgrowth, branch development, bud activation, intra-plant variation, nodal roots, prostrate clonal herbs, root signals, Trifolium repens Received 11 September 2007; Revised 25 November 2007 Accepted 18 January 2008     

The Rest Period of RhododendronFlower Buds I. EFFECT OF THE BUD SCALES ON THE ONSET AND DURATION OF REST

Shortly after flower differentiation, Rhododendron flower developmentis interrupted by a rest period. The results reported here showthat the onset and duration of rest depended upon the presenceof the flower bud scales. When the scales were removed beforethe onset of rest, the flowers continued to elongate and attainedanthesis. Intact buds stopped growing and remained in rest forat least four months. Scale removal after the onset of restterminated the rest period, though there was a lag phase beforethe flowers began to elongate. The duration of the lag phasewas related to the time of scale removal. The scales preventedflower development in situ, on detached stems and in vitro.Theresults further show that the rest period of each flower budwas independent of the rest period of adjacent flower buds andthat the resting terminal flower buds correlatively inhibitedthe growth of the lateral vegetative apices. The correlativeinhibition was eliminated by removing the terminal flower budor by breaking the rest period of the flower bud.     

Auxin and Ethylene-stimulated Adventitious Rooting in Relation to Tissue 9

We have previously shown that both endogenous auxin and ethylenepromote adventitious root formation in the hypocotyls of derootedsunflower (Helianthus annuus) seedlings. Experiments here showedthat promotive effects on rooting of the ethylene precursor,1-aminocyclopropane-l-carboxylic acid (ACC) and the ethylene-releasingcompound, ethephon (2-chloro-ethylphosphonic acid), dependedon the existence of cotyledons and apical bud (major sourcesof auxin) or the presence of exogenously applied indole-3-aceticacid (IAA). Ethephon, ACC, aminoethoxyvinylglycine (an inhibitorof ethylene biosynthesis), and silver thiosulphate (STS, aninhibitor of ethylene action), applied for a length of timethat significantly influenced adventitious rooting, showed noinhibitory effect on the basipetal transport of [³H]IAA. Theseregulators also had no effect on the metabolism of [³H]IAA andendogenous IAA levels measured by gas chromatography-mass spectrometry.ACC enhanced the rooting response of hypocotyls to exogenousIAA and decreased the inhibition of rooting by IAA transportinhibitor, N-1-naphthylphthalamic acid (NPA). STS reduced therooting response of hypocotyls to exogenous IAA and increasedthe inhibition of rooting by NPA. Exogenous auxins promotedethylene production in the rooting zone of the hypocotyls. Decapitationof the cuttings or application of NPA to the hypocotyl belowthe cotyledons did not alter ethylene production in the rootingzone, but greatly reduced the number of root primordia. We concludethat auxin is a primary controller of adventitious root formationin sunflower hypocotyls, while the effect of ethylene is mediatedby auxin. Key words: Auxin, ethylene, adventitious rooting, sunflower