共查询到20条相似文献,搜索用时 15 毫秒
1.
Involvement of putrescine in the inductive rooting phase of poplar shoots raised in vitro 总被引:1,自引:0,他引:1
Micropropagated poplar shoots rooted 100% on a rooting medium (A) containing NAA, but they did not root in the absence of auxin (NA). Putrescine, but not spermidine and spermine, promoted rooting up to 42% when added to the NA medium. Cyclohexylamine (CHA), an inhibitor of spermine synthase, also promoted (up to 36%) rooting in the absence of auxin. The inhibitors of polyamine biosynthesis DFMA (α-difluoromethylarginine) and DFMO (α-difluoromethylomithine), aminoguanidine (AG) and methylglyoxal-bis-guanylhydrazone (MGBG), inhibited rooting when applied in the presence of auxin and had no effect in its absence.
The rooting inductive phase (in the presence of auxin) was determined by periodical transfer of shoots from A to NA medium, and by changes in peroxidase activity, to be 7 h. Putrescine (not spermidine and spermine) accumulated to a maximum during the inductive phase. Both putrescine and CHA promoted rooting on NA medium when applied during the first 7 h. In contrast DFMA and AG inhibited rooting during this period. The results point to the involvement of putrescine and its Δ1 -pyrroline pathway, in the inductive phase of rooting in poplar shoots. 相似文献
The rooting inductive phase (in the presence of auxin) was determined by periodical transfer of shoots from A to NA medium, and by changes in peroxidase activity, to be 7 h. Putrescine (not spermidine and spermine) accumulated to a maximum during the inductive phase. Both putrescine and CHA promoted rooting on NA medium when applied during the first 7 h. In contrast DFMA and AG inhibited rooting during this period. The results point to the involvement of putrescine and its Δ
2.
Falasca G Capitani F Della Rovere F Zaghi D Franchin C Biondi S Altamura MM 《Planta》2008,227(4):835-852
Long-sized oligogalacturonides (OGs) are cell wall fragments that induce defence and developmental responses. The Ca2+-dependent “egg-box” conformation is required for their activity, and polyamines may prevent them from adopting this conformation.
Although OGs are known to inhibit auxin-induced growth processes, their effect on cytokinin-induced ones requires investigation.
In the present work OGs were shown to promote cytokinin (benzyladenine, BA)-induced vegetative shoot formation from tobacco
leaf explants, independent of the presence of CaCl2 in the medium and of auxin (indoleacetic acid, IAA) supply. The effect of polyamines, putrescine (PU) and spermidine (SD)
supplied with/without their biosynthetic inhibitors (DFMO, CHA) was also investigated, and showed that spermidine enhanced
adventitious vegetative shoot formation, but only on medium containing Ca2+ and IAA. Treatments with inhibitors blocked this promotive effect. OGs did not alter free polyamine concentrations, but caused
a moderate increase of conjugated ones, and exhibited an early inhibitory effect on polyamine biosynthetic gene expression.
OGs, but not SD, caused long-term changes in calcium-associated epifluorescent signals in the cell walls, and, later, inside
the cells of specific tissues. Electron microscopy analysis (ESI system) demonstrated that calcium accumulated in the cell
walls and vacuoles of OG-cultured explants. The relationship between OGs, cytokinin, calcium, and polyamines in adventitious
vegetative shoot formation is discussed. 相似文献
3.
Polyamines promote root elongation and growth by increasing root cell division in regenerated Virginia pine (Pinus virginiana Mill.) plantlets 总被引:1,自引:0,他引:1
Polyamines have been demonstrated to play an important role in adventitious root formation and development in plants. Here,
we present a detailed analysis of influence of exogenously added polyamines on adventitious root development and its relationship
to cold tolerance in Virginia pine (Pinus virginia Mill.). Our results demonstrated that polyamines putrescine (Put), spermidine (Spd), and spermine (Spm) at 0.001 mM improve
rooting frequency and promote root elongation. Put, Spd, and Spm at 0.01–1 mM decrease rooting frequency and reduce root elongation
root elongation. Measurements of diamine oxidase (DAO, EC 1.4.3.6) and polyamine oxidase (PAO, EC 1.4.3.4) activities showed
that higher DAO and PAO enzyme activities were obtained when high concentrations of polyamines were applied and when plantlets
were treated for 5–7 week at 4°C and 16°C. Survival rate of plantlets increased with the treatment of polyamines at low temperature.
Polyamines increased mitotic index of cells in root tips of regenerated plantlet cultured on medium containing 0.001 μM Put,
Spd, or Spm, but did not increase mitotic index in tissues of needle tips of the same plantlets. These results demonstrated
that polyamines promote root elongation and growth by increasing root cell division in regenerated Virginia pine plantlets. 相似文献
4.
Polyamines and ethylene in relation to adventitious root formation in Prunus avium shoot cultures 总被引:5,自引:0,他引:5
Stefania Biondi Teresa Diaz Isabel Iglesias Grazia Gamberini Nello Bagni 《Physiologia plantarum》1990,78(3):474-483
An attempt was made to identify some of the hormonal factors that control adventitious root formation in our Prunus avium micropropagation system in order to improve rooting in difficult-to-root genotypes. Changes in endogenous contents of free polyamines were determined at intervals during auxin-induced rooting of shoot cultures. Accumulation of putrescine and spermidine peaked between days 9 and 11. Spermine was only present in traces, Exogenously supplied putrescine or spermine (50-500 μM), in the presence of optimal or suboptimal levels of indolebutyric acid (IBA), had no effect on rooting percentage or root density, except for spermine at 500 μM. At this external concentration spermine caused a substantial accumulation in both free spermine and putrescine. The use of several inhibitors of polyamine biosynthesis, namely α-difluoromethylornithine (DFMO), α-difluoromethylarginine (DFMA), dicyclohexylammonium sulphate (DCHA) and methylglyoxal-bis-guanyl-hydrazone (MGBG) alone or in combination in the 0.1 to 5 μM range, resulted in an inhibition of rooting that was partially reversed by the addition of the corresponding polyamine. Cellular polyamine levels were significantly reduced by DFMO and DFMA but not by DCHA and MGBG, Labeled putrescine incorporation into spermidine increased somewhat in the presence of the ethylene synthesis inhibitor aminoethoxyvinylglycine (AVG). A system based on [3,4-14C]methionine incorporation was used to measure ethylene synthesis by the in vitro cultured shoots. Label incorporation was drastically reduced by 10 μM AVG and increased 3.5-fold in the presence of 50 μM IBA with respect to controls (no IBA). Labeled methionine incorporation into spermidine increased to some extent when ethylene synthesis was inhibited by AVG. Adding the ethylene precursor 1-aminocyclopropane-l-carboxylic acid (ACC) to the rooting medium significantly inhibited rooting percentage; AVG caused the formation of a greater number of roots per shoot but delayed their growth. Supplying the shoots with both compounds resulted in an intermediate rooting response, in which both rooting percentage and root density were affected. These results indicate that polyamines may play a significant role at least in some stages of root formation. The polyamine and ethylene biosynthetic pathways seem to be competitive but under our conditions, the enhancement of one pathway when the other was inhibited, was not dramatic. Although IBA promoted ethylene synthesis, AVG, which drastically reduced it, also promoted root formation. Thus, the auxin effect on root induction cannot be directly related to its ability to enhance ethylene synthesis. 相似文献
5.
Polyamines and Adventitious Root Formation in the Juvenile and Mature Phase of English Ivy 总被引:3,自引:0,他引:3
The involvement of polyamines during adventitious root formationwas evaluated using a de-bladed petiole rooting assay for theeasy-to-root juvenile and difficult-to-root mature phase ofEnglish ivy (Hedera helix L.). Auxin (NAA 0.1 mM) stimulatedroot formation in juvenile phase cuttings, but failed to promoterooting in the mature phase. The addition of putrescine, spermineor spennidine (1.0 mM) with or without NAA (0.1 mM) did notaffect the rooting response in either the juvenile or maturephase cuttings. There was a significant increase in endogenouslevels of putrescine and spermidine in NAA-treated cuttings,but the only significant difference between the root formingjuvenile and the non-root forming mature phase cuttings wasan increase in putrescine levels. In NAA-treated juvenile cuttings,the polyamine biosynthesis inhibitor DFMA (1.0 mM) promotedroot formation from 9.2 to 14.5 roots per cutting, while DFMO(1.0 mM) reduced root formation from 9.1 to 1.4 roots per cutting.The promotion of rooting by DFMA was completely reversed byputrescine (1.0 mM), but putrescine, spermine or spermidine(1.0 mM) could not reverse the inhibitory effect of DFMO. NeitherDFMA nor DFMO promoted root formation in mature phase cuttings.DFMA was also added to NAA-treated juvenile petioles at variousstages during the root formation process. DFMA promoted rootingwhen applied during the early stages of root induction (03d), but became inhibitory to root formation when applied duringthe organization (69 d) or root elongation stages (912d). Key words: Hedera helix, organogenesis, root initiation, polyamines, DFMA, DFMO 相似文献
6.
7.
Yun-He Li Qi-Zhu Chen Jie-Ning Xiao Yun-Feng Chen Xiao-Ju Li Christian Staehelin Xue-Lin Huang 《Plant Growth Regulation》2008,54(2):165-177
Cotyledon segments derived from zygote embryos of mango (Mangifera indica L. cv. Zihua) were cultured on agar medium for 28 days. Depending on different pre-treatments with plant growth regulators,
two distinct patterns of adventitious roots were observed. A first pattern of adventitious roots was seen at the proximal
cut surface, whereas no roots were formed on the opposite, distal cut surface. The rooting ability depended on the segment
length and was significantly promoted by pre-treatment of embryos with indol-3-acetic acid (IAA) or indole-3-butyric acid
(IBA) for 1 h. A pre-treatment with the auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) completely inhibited adventitious
root formation on proximal cut surfaces. A second pattern of roots was observed on abaxial surfaces of cotyledon segments
when embryos were pre-treated with 2,700 μM 1-naphthalenacetic acid (NAA) for 1 h. Histological observations indicated that
both patterns of adventitious roots originated from parenchymal cells, but developmental directions of the root primordia
were different. A polar auxin transport assay was used to demonstrate transport of [3H] indole-3-acetic acid (IAA) in cotyledon segments from the distal to the proximal cut surface. In conclusion, we suggest
that polar auxin transport plays a role in adventitious root formation at the proximal cut surface, whereas NAA levels (influx
by diffusion; carrier mediated efflux) seem to control development of adventitious roots on the abaxial surface of cotyledon
segments. 相似文献
8.
The effect of fusicoccin (FC) on adventitious root formationwas investigated using in vitro shoot tip cultures of birch(Betula pendula ROTH) as test system. Treatment with 107105M FC hastened root appearance as well as 5 ? 106 M IAAdid. Optimal FC concentrations also promoted rooting by increasingthe root number per cutting. FC application during the first48 hours of culture was enough to obtain these effects. Usinginternode segments without any bud it was shown that FC couldnot replace the root inducing activity of endogenous auxin asapplied IAA did, but FC lowered the threshold concentrationof IAA for rooting response and stimulated adventitious rootformation if it was applied with IAA simultanously. Root growthwas enhanced in the early phase but inhibited later by continuoustreatment with FC. Some aspects of possible FC IAA interactionsare discussed. (Received September 4, 1986; Accepted November 24, 1987) 相似文献
9.
Kaitlin J. Palla Paula M. Pijut 《In vitro cellular & developmental biology. Plant》2011,47(2):250-256
A plant regeneration protocol was developed for white ash (Fraxinus americana L.). Hypocotyls and cotyledons excised from embryos were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine
(BA) plus thidiazuron (TDZ), and compared for organogenic potential. Sixty-six percent of hypocotyl segments and 10.4% of
cotyledon segments produced adventitious shoots, with a mean number of adventitious shoots per explant of 3.5 ± 0.9 and 2.5 ± 1.5,
respectively. The best regeneration medium (52% shoot formation; 47% shoot elongation) for hypocotyls was MS basal medium
containing 22.2 μM BA plus 0.5 μM TDZ, producing a mean of 3.9 ± 0.4 adventitious shoots. Adventitious shoots were established
as proliferating shoot cultures following transfer to MS medium with Gamborg B5 vitamins supplemented with 10 μM BA plus 10 μM
TDZ. For in vitro rooting, woody plant medium with indole-3-acetic acid (IAA) at 0, 2.9, 5.7, or 8.6 μM in combination with 4.9 μM indole-3-butyric
acid (IBA) was tested for a 5- or 10-d dark culture period, followed by culture under a 16-h photoperiod. The best rooting
(78% to 81%) of in vitro shoots was obtained with a 5 d dark culture treatment on medium containing 2.9 or 5.7 μM IAA plus 4.9 μM IBA, with an average
of 2.6 ± 0.4 roots per shoot. Rooted plants were successfully acclimatized to the greenhouse. This adventitious shoot regeneration
and rooting protocol will be used as the basis for experimental studies to produce transgenic white ash with resistance to
the emerald ash borer. 相似文献
10.
Propagation by softwood canes and cuttings is preferred as a practical system for vegetative reproduction of many ornamental
plant species, despite the advances in tissue culture techniques. Dracaena purplecompacta L. is a species that has a high demand for exports. Conversely, coconut water (CW) is a rich supplement that naturally contains
plant growth regulators such as indole acetic acid (IAA). The objective of this work was to evaluate the potential of CW extracts
containing natural IAA, on adventitious root development in vegetative propagation of ornamental plant canes of D. purplecompacta L. Five different concentrations (28, 57, 143, 286, 571 μM of natural IAA) of CW extracts were tested. Another set of treatment
was carried out with the same concentrations of authentic IAA hormone for comparison purpose. The 143-μM IAA CW extract recorded
the best root induction and development. It was found that the root expression was faster (5 weeks) with the use of the novel
method. In the conventional method, the canes are propagated by quick dip application of commercial product containing artificial
hormone IAA and placing them on coir fiber dust beds. It takes up to 6 weeks for the canes to develop adventitious roots to
the desired level. Steeping canes in 143-μM IAA CW extract improved rooting in D. purplecompacta L., and it was comparable to the application of 143-μM authentic IAA. The study indicates that adventitious root development,
shoot development, and leaf emergence of D. purplecompacta L. is promoted by IAA CW extracts. 相似文献
11.
S. Naija N. Elloumi S. Ammar C. Kevers J. Dommes 《In vitro cellular & developmental biology. Plant》2009,45(1):83-91
Apple rootstock MM106 shoots, raised in vitro, rooted at 96.7% after culture on a medium supplemented with an auxin for 5 d in darkness followed by culture on a second
medium without growth regulators for 25 d in light. In control conditions (in absence of auxin in the first medium), these
shoots did not root. Putrescine (PUT), spermidine (SPD), cyclohexylamine (CHA), and aminoguanidine (AG) enhanced rooting when
applied during the first d of culture in the absence of IBA; on the contrary, α-difluoromethylornithine (DFMO) added to the
first medium with IBA inhibited rooting. The endogenous levels of indole 3-acetic acid (IAA) and indole 3-acetylaspartic acid
(IAAsp) increased up to a maximum concentration at days 2 and 3, respectively, in initial rooting conditions. PUT, when added
with IBA, did not affect the typical IAA and IAAsp increase; when applied alone, it provoked an increase of their levels.
Similar results were recorded with CHA. SPD, AG, and DFMO did not induce an increase of IAA and IAAsp in nonrooting conditions.
The levels of endogenous PUT increased to a maximum at day 2 in rooting conditions; it was slightly affected by exogenous
PUT and CHA application but reduced by SPD, AG, and DFMO. In rooting conditions, if the first medium was supplemented with
SPD or AG, a small increase in peroxidase activity was observed, similar to that obtained with PUT treatment. The present
work indicates an involvement of polyamines in the control of rooting and an interaction with auxins during the physiological
phase of rooting. The consequence of this relationship was a different rooting expression, according especially to the content
of these regulators in the culture medium. 相似文献
12.
Annie Féray A. Hourmant M. Penot J. Caroff Christine Cann-Moisan 《Plant biology (Stuttgart, Germany)》1994,107(1):18-23
The effects of methylglyoxal-bis(guanylhydrazone) (MGBG), an inhibitor of polyamine biosynthesis were studied on tuberization and cellular polyamine content using in vitro Solanum tuberosum (cv Binjte) plants. When MGBG was added to the culture medium, it produced a partial inhibition of the growth of stems and leaves; it totally blocked rhizogenesis and strongly stimulated tuber formation. Morphogenetic effects of MGBG were correlated to a 40 % decrease in free putrescine, spermidine, spermine content of the leaves and to a 28 % decrease in spermidine titer of the stems. In the tubers, this inhibitor did not change the free polyamine titer but increased by up to 85 % the titer of conjugated putrescine, spermidine, spermine. When the plants were grown in the dark, MGBG produced, like benzyladenine, a stimulation of the rate of tuberization and enhanced the content of conjugated polyamines in the tuber. These results support the hypothesis that polyamines play an important role in the morphogenesis of potato plants. The role of polyamine conjugation in tuber development is discussed. 相似文献
13.
Summary The proliferative growth of thin cell layers ofNicotiana tabacum cultured on a rhizogenic medium was markedly disturbed when polyamine biosynthesis was inhibited. Treatments with polyamine inhibitors led to cell expansion, accompanied by thinning of the cell wall and inhibition of cell division, and frequent cases of nucleolar extrusion, mainly in the parenchymal layer in contact with the medium. Nucleolar extrusion was not correlated with cell expansion. The highest incidence of nucleolar extrusion occurred when the pathways of putrescine biosynthesis were inhibited and when spermidine synthesis, via S-adenosylmethionine decarboxylase, was blocked. The duration of the growth phase with nuclear amitotic divisions was prolonged in the presence of the inhibitors and root meristem formation delayed. When polyamines were added with the inhibitors, all reactions proceeded as in the controls.Abbreviations CHA
cyclohexylamine
- DFMA
DL--difluoromethyl-arginine
- DFMO
DL--difluoromethylornithine
- LS
longitudinal section
- MGBG
methylglyoxal-bis(guanylhydrazone)
- PA
polyamine
- Pu
putrescine
- RLS
radial longitudinal section
- S.E.
standard error
- Spd
spermidine 相似文献
14.
Geert-Jan De Klerk Huiyuan Guan Peter Huisman Svetla Marinova 《Plant Growth Regulation》2011,63(2):175-185
Stem slices (1-mm thick) cut from apple microshoots were cultured on a modified Murashige-Skoog medium with indole-3-acetic
acid (IAA) or α-naphthaleneacetic acid (NAA), and increasing concentrations of various phenolic compounds. Both auxins were
added at a concentration suboptimal for rooting. Indole-3-acetic acid is metabolized through oxidation and conjugation but
NAA through conjugation only; which might have affected the results. With IAA, all tested orthodiphenols, paradiphenols and
triphenols promoted adventitious root formation from the stem slices. Ferulic acid (FA, a methylated orthodiphenol) had the
largest effect and increased the number of adventitious roots from 0.9 to 5.8. With NAA there was little or no promotion after
addition of phenolics. Phloroglucinol (a triphenol) and FA were examined in detail. Their effects on the dose–response curve
of IAA and the timing of their action indicated that both acted as antioxidants protecting IAA from decarboxylation and the
tissue from oxidative stress. Experiments with carboxyl-labelled IAA showed that IAA was massively decarboxylated by the slices
and that decarboxylation was strongly reduced by phenolics. Decarboxylation was to a great extent attributable to the wound
response and did not occur to such an extent in non-wounded plant tissues. In shoots, FA promoted little rooting. Slices were
cultured on top of the medium and shoots were stuck into the medium. Possibly, the anaerobic conditions in the medium near
the basal part of the stem of shoots reduced the wound response and consequently decarboxylation of IAA. The monophenolic
compound salicylic acid (SA) promoted IAA decarboxylation. Accordingly, SA reduced rooting when added during the initial days
of the rooting process (the period during which auxin enhances rooting), and promoted outgrowth of root primordia later on
(the period during which auxin inhibits rooting). 相似文献
15.
Cllia Neves Helena Santos Luís Vilas-Boas Sara Amncio 《Plant Physiology and Biochemistry》2002,40(12):504
The recent advances in biotechnology have boosted interest in the differentiation processes, including adventitious rooting. Differentiation processes depend on endogenous factors, among which auxins and polyamines are believed to play a major role. A positive correlation between polyamine accumulation and the induction of adventitious rooting by auxin has been observed in numerous woody species, suggesting that polyamines could be used as markers of the rooting process. The aim of the present work is to investigate whether primary and secondary nitrogen metabolism is involved in adventitious root induction by auxin treatments in cork oak (Quercus suber L.) and grapevine (Vitis vinifera L.) shoots cultured in vitro. For this purpose, we followed the profile of free and conjugated polyamines, free amino acid pools and 15N-labelling profiles during root induction and expression. We have also observed the effects of cyclohexylamine (CHA), an inhibitor of spermidine synthase. Taking the results together, it is possible to conclude that: (a) glutamine is the most abundant free amino acid in grapevine, while in cork oak, asparagine and arginine are the major amino acids; (b) in grapevine, auxin did not significantly affect the glutamine levels, but changed the 15N-enrichment and labelling pattern of arginine; (c) auxin affected asparagine levels and 15N-labelling pattern of glutamine in cork oak; (d) in both cork oak and grapevine, free putrescine (Put) can be considered as a marker of in vitro root induction; (e) in both species, the presence of CHA resulted in the accumulation of free Put; (f) no Put catabolism was detected in the form of 15N-NMR products, namely 15N-γ-aminobutyric acid; (g) the CHA-induced accumulation of Put only increased grapevine rooting rate. 相似文献
16.
When bulb-scale segments of Lilium longiflorum were cultured on a medium containing auxin and cytokinin, the proportion of the expiants with newly-formed bulblets was significantly increased by the application of different polyamines. The most effective polyamine was spermine, where more than 90% of segments formed an average of 5 bulblets as compared to controls where less than 50% explants formed an average of 1.5 bulblets. Application of arginine one of the precursors putrescine biosynthesis, slightly promoted bulblet formation. The putrescine-stimulated bulblet formation was strongly inhibited by simultaneous addition of an inhibitor of the spermidine synthase, cyclohexylamine. The spermidine-promoted bulblet formation, however, could not be suppressed by this inhibitor. The promotive effect of spermidine on bulblet formation was reversed by an inhibitor of the spermine synthase, N-(3-aminopropyl)cyclohexylamine, but application of this inhibitor with spermine did not show any apparent effect on the bulblet formation. Endogenous level of spermine increased in common during bulblet formation that were stimulated by exogenous polyamines. Thus, spermine seemed to be the main stimulating chemical on bulblet formation in lily bulb-scale segments.Abbreviations APCHA
N-(3-aminopropyl)cyclohexylamine
- Arg
arginine
- BA
benzyladenine
- CHA
cyclohexylamine
- MS
Murashige and Skoog's
- NAA
naphthaleneacetic acid
- Orn
ornithine
- Put
putrescine
- Spd
spermidine
- Spm
spermine 相似文献
17.
Attempts were made to study the effect of thidiazuron (TDZ) on adventitious shoot induction and plant development in Paulownia tomentosa explants derived from mature trees. Media with different concentrations of TDZ in combination with an auxin were used to
induce adventitious shoot-buds in two explant types: basal leaf halves with the petiole attached (leaf explant) and intact
petioles. Optimal shoot regeneration was obtained in leaf explants cultured on induction medium containing TDZ (22.7 or 27.3 μM)
in combination with 2.9 μM indole-3-acetic acid (IAA) for 2 weeks, and subsequent culture in TDZ-free shoot development medium
including 0.44 μM BA for a further 4-week period. The addition of IAA to the TDZ induction medium enhanced the shoot-forming
capacity of explants. The caulogenic response varied significantly with the position of the explant along the shoot axis.
The highest regeneration potential (85–87%) and shoot number (up to 17.6 shoots/explant) were obtained in leaf explants harvested
from the most apical node exhibiting unfolded leaves (node 1). An analogous trend was also observed in intact petiole explants,
although shoot regeneration ability was considerably lower, with values ranging from 15% for petioles isolated from node 1
to 5% for those of nodes 2 and 3. Shoot formation capacity was influenced by the genotype, with regeneration frequencies ranging
from 50% to 70%. It was possible to root elongated shoots (20 mm) in basal medium without growth regulators; however, rooting
frequency was significantly increased up to 90% by a 7-day treatment with 0.5 μM indole-3-butyric acid, regardless of the
previous culture period in shoot development medium (4 or 8 weeks). Shoot quality of rooted plantlets was improved not only
by IBA treatment but also by using material derived from the 4-week culture period. Regenerated plantlets were successfully
acclimatized in the greenhouse 8 weeks after transplanting. 相似文献
18.
Tagetes minuta is a source of secondary products which are used as pharmaceuticals, pesticides and as flavour components in
the food industry. Cotyledons and hypocotyls of T. minuta were cultured on MS medium with combinations of IAA or NAA and BA.
Hypocotyl-derived callus developed adventitious shoots which failed to develop further. Cotyledon-derived callus, cultured
on medium with IAA, regenerated adventitious shoots which developed into plantlets on MS medium or half-strength MS with 2.85
μM IAA. Cotyledons cultured on medium with 5.71 μM IAA + 44.4 μM BA and transferred to MS medium for shoot growth yielded
the highest number of shoots. Nodal segments from developing shoots were micropropagated on half-strength MS medium with 2.58
μM IAA and 95% of plantlets produced adapted successfully to greenhouse conditions. In vitro plants micropropagated from nodes
had many shoots whereas plants regenerated from shoot tips had only a single main stem. This difference in morphology was
retained after two months growth in a greenhouse. There were no significant differences in leaf and shoot fresh and dry weights
among the regenerated plants after two months growth. After six subcultures of cotyledon-derived callus on medium with IAA
and BA all explants lost their ability to regenerate except those cultured on medium with 17.23 μM IAA and 44.4 μM BA. The
methods of regeneration developed will facilitate selection of T. minuta plants more tolerant of environmental stress, their
micropropagation, and the in vitro production of secondary products.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
Seedling hypocotyls were used as explants to establish a regeneration protocol for Eucalyptus urophylla and N-phenyl-N′-[6-(2-chlorobenzothiazol)-yl] urea (PBU), one kind of di-substituted urea, was found useful growth regulator.
The hypocotyls incubated on a modified Murashige and Skoog medium (SPCa), supplemented with 6.6 μM PBU and 0.57 μM indole-3-acetic
acid (IAA) dedifferentiated and form calli (100 % after 7 d). Compared with other growth regulator combinations, PBU stimulated
more vigorous calli and restrained their darkening. In addition, the calli induced by PBU showed high frequency of adventitious
buds formation (57%). Shoot proliferation and elongation was then stimulated on SPCa medium containing 0.44 μM 6-benzyladenine
(BA), 0.54 μM naphthalene acetic acid (NAA) and 0.3 μM gibberellic acid (GA3). For rooting, shoots were cultivated on root
induction medium containing 2.5 μM indole-3-butyric acid (IBA). Plantlets were then successfully transplanted to greenhouse. 相似文献
20.