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1.
The anatomy of the adventitious roots of Musa acuminata cv.Gros Michel is described. Interesting anatomical features arethe occurrence of lysigenous lacunae in the cortex and the presenceof very large metaxylem vessels and internal phloem strandsin the stele. The organization of the root meristem is consideredin terms of present concepts. Histological preparations andautoradiographs suggest the existence of an area of relativequiescence in the meristem. The use of modified histogen terminologyin describing the apex is recommended. The development of thetissue systems is also described with emphasis on the differentiationof the vascular tissue.  相似文献   

2.
Embryogenic callus was established using immature male flower of Musa acuminata cv. Mas. After 5–6 months of culture, embryogenic callus was obtained at 21.75±11.9 from 750 immature male flower clusters with translucent somatic embryos proliferated from the whitish friable callus. It was observed that flower clusters ranging from 4 to 11 responded to form embryogenic callus and out of which 3–10 somatic embryos were formed per flower cluster. Embryogenic callus were obtained at a percentage of 10.00±0.3 on M1 medium initially supplemented with 18 M 2,4-dichlorophenoxyacetic acid (2,4-D) for 3 months and subsequently transferred to the same media with reduced 2,4-D (9 M) for the next 2–3 months. Embryos developed into translucent spheres and slightly torpedo shaped embryos in suspension cultures. Plantlets were obtained on medium M4 supplemented with 0.8M BA, at an average regeneration rate of 13.00±0.58.  相似文献   

3.
For Lolium perenne cv. Cropper, a system which resulted in 100%flowering comprised 90 short days (SD) at 4 ?C (vernalization)and 30 SD at 18 ?C followed by 8 long days (LD). The mitoticindex and G1 and G2 percentages were measured in the shoot androot apices of plants following 2, 5 or 8 LD and in SD controlssampled at the beginning and end of induction. Identical measurementswere made in plants given 48 SD at 18 ?C followed by 2, 5 or8 LD; plants remained vegetative in response to this treatmentlacking vernalization. Significant increases in both mitoticindex and meristem size occurred in the shoot apex in LD followingthe vernalizing, but not the non-vernalizing, treatment. A clusterof mitoses in the apical dome of the shoot apex was unique tothe vernalized plants given 5 or 8 LD. However, an increasein root meristem size occurred regardless of vernalization,but a significant increase in the mitotic index was limitedto vernalized plants given 5 or 8 LD. Whilst the vernalization-LDtreatment resulted in an increase in the G2 percentage in theshoot apex following 2, 5 or 8 LD, no such alteration was observedin the root meristem. Thus, the changes to the cell cycle whichcorrelated with flowering were increased mitotic indices andG2 percentages in the shoot apex at each sampling time and increasedmitotic indices in the root apex following 5 and 8 LD. Key words: Cell division, flowering, Lolium perenne L.  相似文献   

4.
Taylor CB 《The Plant cell》1997,9(7):981-988
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5.
Six-week-old Lolium temulentum cv. Ceres plants were inducedto flower by a single long day (Day 1). Cell proliferation wasanalysed in the apex during the period extending from Day 1to Day 3. A stimulation of mitotic and DNA synthetic activitieswas observed in the apical summit at 8 h of the photoextensionperiod of the LD, i.e. before any apparent movement of the floralstimulus out of the leaves and well in advance of apex evocation. Key words: Cell cycle, flowering, Lolium, shoot apex  相似文献   

6.
7.
A mathematical model is constructed to describe the morphopneticswitch that occurs when a vegetative plant apex becomes reproductive.The cusp equation from catastrophe theory is modified, and isused to relate primordial size at initiation to apex size. Theresulting equation may be viewed as an equation of state definingthe allowed organizational modes of the shoot apex. The modelsimulates the growth of the apex from the vetative stage toearly reproductive growth, and makes reasonable predictionsabout apex size and growth rate, primordial sizes, and the lengthsof the plastochron. flowering, mathematical model, catastrophe theory, shoot apex  相似文献   

8.
Musa acuminata Colla (Musaceae), the wild progenitor of thecultivated banana, is highly variable in Malaysia and presentsseveral unresolved nomenclatural problems. AFLP was employedto distinguish among three subspecies of Musa acuminata(subsp.truncata and subsp. malaccensis from peninsular Malaysia andsubsp. microcarpa from Borneo) and to examine whether subsp.truncata is a distinct taxon. Eight primer combinations revealedmolecular markers specific for each of the three taxa. UPGMAcluster analysis showed the three taxa were distinct. Subspeciesmalaccensis which is endemic in peninsular Malaysia and subsp.microcarpa which is endemic in Borneo were found to be moresimilar to each other in their DNA patterns than they are tosubsp. truncata, which is endemic to peninsular Malaysia. Sincesubsp. truncata is genetically separate from subsp. malaccensisand subsp.microcarpa , it cannot be regarded as synonymous witheither of these subspecies. This paper sheds light on the nomenclatureof the three subspecies of Musa acuminata. Copyright 2001 Annalsof Botany Company Musa acuminata Colla, truncata, malaccensis, microcarpa, Musaceae, wild banana, genetic diversity, AFLP, DNA fingerprinting  相似文献   

9.
BARKER  W. G. 《Annals of botany》1969,33(3):523-535
The banana leaf must pass through a prolonged growth periodwhile totally within the pseudostem and with the lamina in aninvolved double coil. During this time the blade makes mostof its growth, completing the last fourth of the expansion asit emerges. In this same latter period it accomplishes almosttwo-thirds of its elongating growth. The first few leaves of a single plant are essentially bladeless.Thereafter the size of the lamina increases in both dimensionswith each succeeding leaf tending to exceed its predecessor.A diurnal/nocturnal cycle is evident in both Costa Rica andHonduras and maximal elongation coincides with the highest temperaturein the daylight hours. Control of elongation is elegant witheach leaf developing at a rate governed by those ahead of it.An assessment is made of the stomatal occurrence over the surfaceof the blade.  相似文献   

10.
SUNDERLAND  N.; BROWN  R. 《Annals of botany》1976,40(2):199-211
This investigation was designed to show the nature of the developmentin terms of cell numbers and of rates of division that proceedsin the terminal region of the shoot during the vegetative phasein Lupinus albus. Data are assembled that show that with eachsuccessive plastochron in the dome the number of cells increasesand the rate of division decreases; in the first internode againthe number of cells increases and the rate of division decreases,and in the first primordium both the number of cells and therate of division decrease. The data also show that with thetransition from one plastochron to the next the rate of divisionin any particular intemnode or primordium decreases. It is asignificant feature that all the changes in the system can becharacterized through constant numerical factors. The significanceof the results is discussed.  相似文献   

11.
12.

Background

Banana (genus Musa) is a crop of major economic importance worldwide. It is a monocotyledonous member of the Zingiberales, a sister group of the widely studied Poales. Most cultivated bananas are natural Musa inter-(sub-)specific triploid hybrids. A Musa acuminata reference nuclear genome sequence was recently produced based on sequencing of genomic DNA enriched in nucleus.

Methodology/Principal Findings

The Musa acuminata chloroplast genome was assembled with chloroplast reads extracted from whole-genome-shotgun sequence data. The Musa chloroplast genome is a circular molecule of 169,972 bp with a quadripartite structure containing two single copy regions, a Large Single Copy region (LSC, 88,338 bp) and a Small Single Copy region (SSC, 10,768 bp) separated by Inverted Repeat regions (IRs, 35,433 bp). Two forms of the chloroplast genome relative to the orientation of SSC versus LSC were found. The Musa chloroplast genome shows an extreme IR expansion at the IR/SSC boundary relative to the most common structures found in angiosperms. This expansion consists of the integration of three additional complete genes (rps15, ndhH and ycf1) and part of the ndhA gene. No such expansion has been observed in monocots so far. Simple Sequence Repeats were identified in the Musa chloroplast genome and a new set of Musa chloroplastic markers was designed.

Conclusion

The complete sequence of M. acuminata ssp malaccensis chloroplast we reported here is the first one for the Zingiberales order. As such it provides new insight in the evolution of the chloroplast of monocotyledons. In particular, it reinforces that IR/SSC expansion has occurred independently several times within monocotyledons. The discovery of new polymorphic markers within Musa chloroplast opens new perspectives to better understand the origin of cultivated triploid bananas.  相似文献   

13.
A simple and efficient protocol has been developed for in vitro regeneration of M. acuminata ssp. burmannica (AA) plants. Somatic embryos were produced when immature and mature zygotic embryo explants were cultured on Murashige and Skoog medium supplemented with plant growth regulators 2,4-dichlorophenoxyacetic acid; (2,4-D), picloram or benzyl adenine and indole acetic acid. In general, immature embryos responded better than mature embryos. Callus proliferation was highest in medium supplemented with 2,4-D (4.5???M). Subsequent transfer of callus to fresh medium produced rapidly proliferating embryogenic calli. Embryogenic calli were maintained in complete darkness for 15?d followed by cycles of 8?h dark and 16?h light, under white fluorescent lamps with a light intensity of 3,000?lm/m2 and at temperature of 28?±?2°C. Regeneration of embryogenic calli into plantlets was higher for immature embryos (76.6%) than for mature embryos (50.6%). This plant regeneration protocol using mature or immature zygotic embryos, via somatic embryogenesis, has significant potential to improve germination efficiencies of hybrid progenies used in conventional breeding strategies. Furthermore, tests on seed storage showed that seed viability rapidly decline after harvesting and was negligible after 9?mo of storage. This indicates using freshly harvested seeds as explant material is necessary for maximizing the tissue culture response.  相似文献   

14.
Recognition of a phenotypically distinct 'French-type' plantain(Musa AAB) designated 'Superplatano' (Superplantain) promptedevaluation of in vitro micropropagation as a means of generatingsufficient numbers of plants for field evaluation in three locationsin Puerto Rico. A multi-faceted study designed to evaluate relationshipsbetween different aseptic culture procedures and morphologicalorigins of primary explants was carried out. Vegetative budsfrom various positions relative to the mother corm (definedby cardinal points on the compass) and explants from the floralaxis of 'Maricongo' (the 'False-Horn', or florally determinatetype 'progenitor' of 'Superplatano'), and 'Superplatano' (a'French-type') were used as starting materials. Responses underfield conditions were studied using a number of parameters includingyield of commercially marketable fruits. We compared four populationsof shoots, each of which derived from at least three differentshoots from within one mat, shoots derived from vegetative andfloral material from the same mat for both 'Maricongo' and 'Superplatano',and shoots derived from a number of floral buds of the sameclone ('Maricongo') all of which were in culture for the samelength of time. 'Superplatano' was stable whether from vegetativecorm or floral bud apex. This shows conclusively that if thestarting point in the micropropagation process is a stable Musaclone, our tissue culture procedure is reliable. Considerablevariation in bunch phenotype was observed, however, in plantsregenerated from ten of 12 shoot and floral meristems startedfrom the 'False-Horn'-type 'Maricongo'. Change from 'False-Horn'-type(determinate) to 'French'-phenotype (indeterminate) was evidentin each of the three locations. Frequency of bunch reversionvaried from 0·4 to 100%, but was confined to individualoriginating stem tips rather than clones. The most dramaticbunch phenotypic change occurred in plants regenerated fromclone 3. All plants regenerated from shoot 3-North bore 100%'French-type' bunches. However, reversion in plants regeneratedfrom shoot 3-West was only 1·8%, and no bunch phenotypicchange was observed in plants from shoot 3-East. Plants regeneratedfrom both shoot and male floral axis tips in 'Maricongo' clone4 also bore 'French-type' bunches. Frequency of bunch reversionfrom shoot 4-East was 0·4% as compared to 2·6%from 4-floral. Bunch reversion occurred at the frequency of2·0% when plants were regenerated from clone 6-floral.No bunch reversion was observed in plants regenerated from asingle shoot tip in clones 1-West and 5-floral. No dwarfismwas encountered in any of the tissue culture-derived plants.We conclude that tissue culture per se plays a very small role,if any, in the direct induction of off-types. Pre-existing characteristicsof the primary explant determines whether products of a multiplicationshow fidelity or not. Our data suggest that 'Maricongo' is achimera and that 'Superplatano' is revertant off-type that resultswhen breakdown of the chimera occurs. Large numbers of stable'Superplatano' were produced from unstable 'Maricongo' and thisaffirms the value of micropropagation for generation of cloneswith desirable bunch phenotype.Copyright 1993, 1999 AcademicPress Musa, plantains, bananas, tissue culture, clonal multiplication, somaclonal variation, phenotype  相似文献   

15.
BOWES  B. G. 《Annals of botany》1963,27(2):358-364
The development of the vegetative shoot apex of Glechoma hederaceahas been followed through a double plastochron. During this period the apex grows from c. 20 to c. 260 µin height and c. 100 to c. 300 µ in width, whilst thepair of leaves inserted at the apex base increase from o toc. 600µ in height. The width of the apex and height ofthese leaves are directly related to apex height. Some variationoccurs in the average maximal dimensions of the apex with plastochronnumber but no regular increase or decrease in these dimensionsis apparent. Both a tunica-corpus organization and cytohistological zonationis visible within the apex throughout a double plastochron.The central initiation zone shows little change in size or appearanceduring this period but the rib and flank meristems grow considerablyand undergo some differentiation. The boundaries of these zonesare not sharply defined, but normally the rib meristem givesrise to the pith, and the flank meristem forms the epidermis,cortex, and provascular tissue. The provascular tissue differentiatesacropetally and in continuity with that in the axis below.  相似文献   

16.
In this paper, which is presented in two parts, the growth anddevelopment of the banana plant have been examined from thestandpoint of the origin of the inflorescence and the developmentof the flowers (Part A) and the structure and development ofthe fruit (Part B). First the main centres of growth in thesestructures are located and the manner of their development ispresented. Thereafter, attention is focused upon the salientevents which determine the alternative courses of developmentwith a view to designating the chemical and physiological stimulithat may be required.  相似文献   

17.
ARNEY  S. E. 《Annals of botany》1954,18(3):349-365
Changes in leaf size and in the number and size of the leafcells have been followed throughout the growing season and duringdrought and defoliation. The duration of the meristematic phaseof primordium growth is the major factor affecting leaf sizein all cases, and a hypothesis is developed to account for thechanges. A new index of shoot growth reflecting the rate ofcell production is used, together with the leaf initiation rate,to distinguish changes in growth rate at the time of runnerproduction and inflorescence initiation.  相似文献   

18.
In a comparative histopathological investigation, Poyo and Gros Michel cul-tivars of Musa acuminata (AAA triploid) were inoculated with Radopholus similis, Helicotylenchus multicinctus or Hoplolaimus pararobustus and were grown in a greenhouse under tropical conditions. R. similis infected all the cortical parenchyma layers of the roots, reaching the vascular cylinder, but it stayed more superficial in Gros Michel roots. Red-brown cytoplasmic globules appeared in the cortical parenchyma cells of Gros Michel only. H. multicinctus infected much of the outer cortical parenchyma in roots of both cultivars with a few phenolic cells occurring around the superficial lesions. H. pararobustus penetrated only the immediate sub-epidermal tissues in both cultivars. The differences observed between nématodes and cultivars reflect specific host-nematode interactions on bananas.  相似文献   

19.
The genomic DNA isolation from mature leaf midrib is a tough job, because of the abundance of polysaccharides and secondary metabolites, which interferes with DNA isolation as well as polymerase chain reaction (PCR) studies. The leaf midrib of 3rd leaf from 3-moths old, ex-vitro developing banana [AAA, Dwarf Cavendish-Basrai (Sindhri banana)] plants (healthy and BBTV infected) was grinded in liquid N2. Exact 0.3 g of leaf midrib powder was washed with washing buffer (100 mM Tris-Cl, 5 mM EDTA, 0.35 M sorbitol, 1% 2-mercaptoethanol) then homogenized in 0.8 ml of three different pre-heated (60°C) DNA isolation buffers. Supernatant was extracted through phenol: chloroform:isoamyl alcohol (25:24, v/v), chloroform: isoamyl alcohol (24:1, v/v) and finally with chloroform (100%) one by one. Maximum yields were ranged from 49.33 and 27.73 μg mg ?1 DNA with impurities 5.67 and 5.87 μg mg?1 through buffer I, while 45.77 and 25.53 μg mg?1 DNA with 6.13 and 6.16 μg mg?1 impurities through buffer III from healthy and infected plants respectively. Best one RAPD was observed in all the DNA samples isolated with different buffers, while viral amplification was good in DNA isolated with buffer I and II, when 10 (RAPD) and 25 ng DNA (C 1 gene) was used as a template in a reaction of 25 μl. Meanwhile, buffer II is limited for viral DNA isolation while buffer I (1M Tris-Cl, 5M NaCl, 2 % cTAB, 50mM EDTA, 1 % PVP, 0.2 % 2-mercaptoethanol) has dual capacity for plant and virus DNA isolation. This described protocol is economic in terms of times, labor and cost.  相似文献   

20.
Summary Suspensions of embryogenic cells of a triploid banana (Musa spp., cv. Bluggoe) were initiated from the uppermost part of meristematic buds, and used as protoplast source. After 20 weeks in culture, the suspension contained a mixture of globular structures or globules and embryogenic cell clusters, as well as single cells. Two types of protoplasts were obtained from embryogenic suspension culture: small (20–30 m) and larger (30–50 m) protoplasts with a dense cytoplasm and large starch grains respectively. The small protoplasts probably originated from embryogenic cell clusters, and also from pseudocambial cells of globules, while larger protoplasts were probably released from oval starchy cells and those of the globule peripheral area. In co-culture with a suitable feeder, consisting of suspensions of diploid banana cells, the protoplasts of triploid banana reformed the cell wall within 24 h and underwent sustained divisions leading to the formation of small clusters of 2–3 cells within 7 days. The latter developed directly into embryos without passing through an apparent callus phase. 10% of such embryos gave rise to plantlets when subcultured in 2.2 M 6-benzylaminopurine and 2 M 4 amino-3,5,6-trichloropicolinic acid for 1 week, before transfer to MS medium containing 10 M 6-benzylaminopurine. The rest of the embryos underwent intensive direct secondary embryogenesis which could lead to the formation of plantlets with a frequency of up to 50% upon further transfer to hormone-free medium.Abbreviations BAP 6-benzylaminopurine - MS Murashige and Skoog (1962) medium - 2,4-D dichlorophenoxyacetic acid - UV ultraviolet light - FDA fluorescein diacetate - MES 2-(N-morpholino)ethanesulfonic acid - Picloram 4 amino-3,5,6-trichloropicolinic acid  相似文献   

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