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1.
Direct plant regeneration, multiple shoot formation and callogenesis were induced from cocoyam shoot tips cultured in vitro. At different stages of culture, phenol content, peroxidase activity and acidic soluble isoperoxidase patterns were analysed in plantlets. Results showed that phenol content of plantlets cultured on auxin-free media decreased with time, while it increased in those cultured on media supplemented with an auxin. Each form of morphogenesis induced with a growth regulator was preceded by an increase in total peroxidase activity. On hormone-free medium, organogenesis occurred (single shoot development and rhizogenesis), but there was no increase in total peroxidase activity. The appearance of isoperoxidase A2 was associated with root initiation, while the disappearance of isoperoxidase A5 and the appearance of isoperoxidase A6 preceded multiple shoot formation. These results indicate that total peroxidase activity was not a proper marker for organogenesis in cocoyam. Each form of morphogenetic differentiation is associated with an alteration of the acidic isoperoxidase pattern. These enzymes can be used as biochemical markers for rooting and multiple shoot initiation in cocoyam. 相似文献
2.
Effect of gamma irradiation on growth, shoot organogenesis andenzyme activities and isoenzyme patterns of -amylase and peroxidaseduring differentiation in long-term calluses of Datura innoxiahave been investigated. Radiation in doses of 0.2 and 1.0 kRstimulated the shoot regeneration frequency as well as the numberof shoots per regenerating callus. The 0.2 kR dose could induceshoot organogenesis even in calluses incubated in the dark oncallusing medium, although with less frequency. Such cultures,however, showed profuse shoot regeneration when sub-culturedonto regeneration medium under light conditions. A higher radiationdose (5.0 kR) was lethal to both growth and shoot differentiation.Prior to shoot regeneration, -amylase and peroxidase specificactivities increased to four- to fivefold and 724-fold,respectively. While the amylase isoenzyme pattern remained unchanged,specific changes in the isoperoxidase pattern were observedduring shoot differentiation in callus cultures. The most significantchange was the appearance of fast-moving anodic bands priorto visible shoot differentiation. Thus, such isoperoxidasesprovide useful biochemical markers for shoot differentiation. Datura innoxia, shoot organogenesis, isoenzyme pattern, gamma-radiation, growth regulators 相似文献
3.
In vitro regeneration of plantlets and multiplication of Sesbania bispinosa (Jacq.) W.F. Wight plants from cultured callus tissue were demonstrated. Callus was established from both cotyledons and mature leaflets on Murashige and Skoog (MS) basal medium supplemented with BAP (0.5 mg/l) and 2,4-D (2 mg/l). Callus mediated shoot bud differentiation was studied under defined nutritional, hormonal and cultural conditions. Various concentrations of BAP or kinetin (Kn) with coconut milk (CM) in MS media induced different levels of shoot bud differentiation as well as multiplication. Multiple shoot bud differentiation occurred in most of the primary calli. The best medium for shoot bud differentiation from cotyledon derived callus, contained BAP (2 mg/l) and 15% CM (V/V). More efficient shoot bud organogenesis was recorded with BAP than Kn. Supplementation with CM in MS media accelerated shoot bud organogenesis in differentiating callus tissue. Rooting of differentiated shoots was achieved by a three step culture procedure involving (a) MS solid medium containing IBA (2 mg/l), (b) growth regulator free half strength MS medium with 1% charcoal, and (c) half strength MS liquid medium free of vitamins, growth regulators and charcoal.Abbreviations IAA
indoleacetic acid
- IBA
indole-3-butyric acid
- NAA
naphthaleneacetic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid
- BAP
6-benzylaminopurine
- Kn
kinetin
- CM
coconut milk
- MS
Murashige and Skoog's medium
- SBI
shoot bud inducing medium 相似文献
4.
Renata Garcia Georgia Pacheco Erica Falcão Gabriela Borges Elisabeth Mansur 《Plant Cell, Tissue and Organ Culture》2011,106(1):47-54
Passiflora suberosa is used in popular medicine, improvement programs, and as an ornamental plant. The goal of this study was to establish efficient
protocols for plant regeneration and callus induction from nodal, internodal and leaf segments excised from in vitro-grown
plants. The different morphogenetic responses were modulated by the type and concentration of plant growth regulators, according
to the basal medium and light conditions. Shoot formation occurred through three pathways: (1) development of preexisting
meristems, (2) direct organogenesis, and (3) indirect organogenesis. Development of preexisting meristems was observed from
nodal segments (1 shoot/explant) in response to α-naphthaleneacetic acid (NAA), picloram (PIC), and 2,4-dichlorophenoxyacetic
acid (2,4-D), using two basal media (MS and MSM). Direct organogenesis in this species was obtained for the first time in
this work, through shoot development from internodal segments in the presence of 6-benzyladenine (BA). The highest regeneration
rates were achieved on MSM medium, regardless of the BA concentration. Indirect organogenesis was achieved from all explant
types on media supplemented with BA, used alone or in combination with NAA. The highest regeneration efficiency was obtained
from internodal segments cultured on MSM medium plus 44.4 μM BA. Compact, friable, or mucilaginous non-morphogenic calluses
were induced by thidiazuron, PIC, 2,4-D, and NAA. High-yielding friable calluses obtained on MSM medium supplemented with
28.9 μM PIC are being used for the establishment of suspension cultures and further analysis of the production of bioactive
compounds. 相似文献
5.
Diwakar Aggarwal Anil Kumar M. Sudhakara Reddy 《Plant Cell, Tissue and Organ Culture》2010,102(1):45-52
An efficient shoot organogenesis system has been developed from mature plants of selected elite clones of Eucalyptus tereticornis Sm. Cultures were established using nodal explants taken from freshly coppice shoots cultured on Murashige and Skoog medium
containing 58 mM sucrose, 0.7% (w/v) agar (MS medium) and supplemented with 2.5 μM benzyladenine (BA) and 0.5 μM α-naphthaleneacetic
acid (NAA). Shoot organogenesis was achieved from leaf segments taken from elongated microshoots on MS medium supplemented
with 5.0 μM BA and 1.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The addition of cefotaxime to the medium promoted shoot
differentiation, whereas carbenicillin and cephalexin inhibited shoot differentiation. Maximum shoot bud organogenesis (44.6%)
occurred in explants cultured on MS medium supplemented with 5.0 μM BA, 1.0 μM 2,4-D and 500 mg/l cefotaxime. Leaf maturity
influenced shoot regeneration, with maximum shoot organogeneisis (40.5%) occurring when the source of explants was the fifth
leaf (14–16 days old) from the top of microshoot. Shoot organogenic potential also varied amongst the different clones of
E. tereticornis. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) analyses indicated clonal uniformity of
the newly formed shoots/plants, and these were also found to be true-to-type. 相似文献
6.
The effect of media components and environmental factors on growth and organogenesis of protoplast-derived calli of curly kale and cabbage were tested. Optimal growth (fresh weight increase of calli, shoots and roots) was found at 60 mM sucrose. Lower sucrose concentrations (3–30 mM) were favourable for shoot formation. Nitrate concentrations from 23 to 100 mM in combination with 8 or 21 mM ammonium were optimal for shoot formation. However, growth was reduced by high (100 mM) nitrate concentration. The effects of various organic nitrogen compounds at 0.5 and 2 mM were tested. Glutamine did not influence shoot formation and barely growth. Proline at 0.5 mM stimulated growth of cabbage calli but decreased growth of curly kale calli, and at 2 mM, proline also inhibited shoot production. Adenine sulphate decreased growth of cabbage calli at 0.5 mM, and at 2 mM shoot production was also reduced. Spermidine and spermine inhibited both growth and differentiation. Putrescine resulted in about 50% higher fresh weights, and also increased the number of calli producing shoots by about 35%. More calli produced shoots in white light than in blue or red light or in darkness. The length of the photoperiod or intensity of light was not critical for shoot production. 相似文献
7.
H. S. Chawla 《Plant Cell, Tissue and Organ Culture》1988,12(3):299-304
Callus cultures fron non-organogenic, young and one-year old, and morphogenic calli were used to assess the value of isozymes analysis for the prediction of morphogenic capacity by studying esterase, peroxidase and acid phosphatase. Basic isozyme patterns of each enzyme for the callus were retained in all the callus stages and in the callus which has differentiated into shoots. With the development of shoot and/or root some conspicuous isozymes appeared for esterase and acid phosphatase and some disappeared for peroxidase. As the isozyme changes became apparent only after shoot or root initiation these enzymes could not be used as markers to distinguish between morphogenic and non-morphogenic calli. 相似文献
8.
Changes in antioxidative enzymes activities during Tacitus bellus direct shoot organogenesis from leaf explants were examined. During the early stages of shoot organogenesis there was a decrease
in superoxide dismutase (SOD) and an increase in catalase (CAT) activity, and later during organogenesis there was an increase
in peroxidase (POD) and polyphenol oxidase (PPO) activity. Two highly regulated turning points may be distinguished regarding
activities and isoforms of antioxidative enzymes: the initiation of shoot organogenesis and the shoot bud formation. Our data
suggest the role of specific CAT, POD, SOD and PPO isoforms in separate processes during T. bellus direct shoot organogenesis. 相似文献
9.
Varsha Shriram Vinay Kumar Mahadeo G. Shitole 《In vitro cellular & developmental biology. Plant》2008,44(3):186-193
Abstract
Helicteres isora is a medicinal plant effective against asthma, diabetes, hypolipidemia, HIV, polio besides a good source of diosgenin. Seed
dormancy and low natural fruit production rate make this plant a perfect candidate for developing an in vitro regeneration
method. However, to date, no such work has been procured in this plant. An efficient method for plant regeneration via shoot
organogenesis from callus cultures has been developed using nodal explants in H. isora. Murashige and Skoog (MS) media counting 2,4-Dichlorophenoxyacetic acid (2,4-D, 2.26 to 13.57 μM), Indole-3-acetic acid (IAA,
2.85 to 17.13 μM), Indole-3-butyric acid (IBA, 2.46 to 14.70 μM), 6-Benzylaminopurine (BA, 2.22 to 13.32 μM) and Kinetin (Kin,
2.32 to 13.92 μM) either singly or in the following combinations (IAA + BA; IAA + Kin, and BA + Kin) produced granular callus
except BA + Kin which resulted in compact, hard, greenish-white (CHGW) callus. The optimum CHGW callus (2.62 g fresh weight/
explant) was produced on MS media with 13.32 μM BA + 2.32 μM Kin with over 93% callus induction frequency. Optimum shoot organogenesis
(67% frequency) was achieved in CHGW callus with lower level of BA (2.22 μM) and Kin (2.32 μM) and produced 3.2 shoots/0.5 g
callus within 35 d of culture. Microshoots were rooted successfully (62% frequency) after 35 d of culture on 1/2MS containing
4.90 μM IBA and hardened off. Antioxidant enzymes such as catalase, peroxidase, polyphenol oxidase, and biochemical parameters
viz. hydrogen peroxide, reducing and nonreducing sugars, starch, proteins, phenols, and proline contents were studied in regenerating
and nonregenerating CHGW calluses to establish a correlation between these parameters and shoot morphogenesis. All the enzyme
activities and biochemical parameters were found more in regenerating callus than in nonregenerating except phenols. 相似文献
10.
Jullien Frédéric Diemer Florence Colson Monique Faure Olivier 《Plant Cell, Tissue and Organ Culture》1998,54(3):153-159
An efficient protocol for plant regeneration from protoplasts of peppermint ‘Mitcham Digne 38’, ‘Mitcham Ribecourt 19’ and
‘Todd's#x2019; was developed by stepwise optimization of first cell division, microcalli formation and shoot differentiation.
The rate of first cell divisions was strongly dependent on the addition of 2,4-D to callus induction medium. Best results
were obtained with 1 μM 2,4-D in combination with NAA (2.5 μM) and BA (4 μM). Although liquid medium was more efficient to
support first protoplast divisions, solid medium was clearly more suitable to sustain subsequent cell divisions leading to
the formation of microcalli. Shoot organogenesis was induced from protoplast-derived calli by using reduced auxin concentration
(0.5 μM NAA) and high concentration of cytokinins. Addition of 2.3 μM thidiazuron increased bud formation, allowing a regeneration
frequency of more than 50% from calli of ‘Mitcham Digne 38’ and ‘Todd's’. Genotypic differences were noticed for regeneration
capability and the pathway of shoot regeneration.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
11.
P. Jha C. B. Yadav V. Anjaiah V. Bhat 《In vitro cellular & developmental biology. Plant》2009,45(2):145-154
An efficient in vitro plant regeneration protocol through somatic embryogenesis and direct shoot organogenesis has been developed for pearl millet
(Pennisetum glaucum). Efficient plant regeneration is a prerequisite for a complete genetic transformation protocol. Shoot tips, immature inflorescences,
and seeds of two genotypes (843B and 7042-DMR) of pearl millet formed callus when cultured on Murashige and Skoog (MS) medium
supplemented with varying levels of 2,4-dichlorophenoxyacetic acid (2,4-D; 4.5, 9, 13.5, and 18 μM). The level of 2,4-D, the
type of explant, and the genotype significantly effected callus induction. Calli from each of the three explant types developed
somatic embryos on MS medium containing 2.22 μM 6-benzyladenine (BA) and either 1.13, 2.25, or 4.5 μM of 2,4-D. Somatic embryos
developed from all three explants and generated shoots on MS medium containing high levels of BA (4.4, 8.8, or 13.2 μM) combined
with 0.56 μM 2,4-D. The calli from the immature inflorescences exhibited the highest percentage of somatic embryogenesis and
shoot regeneration. Moreover, these calli yielded the maximum number of differentiated shoots per callus. An efficient and
direct shoot organogenesis protocol, without a visible, intervening callus stage, was successfully developed from shoot tip
explants of both genotypes of pearl millet. Multiple shoots were induced on MS medium containing either BA or kinetin (4.4,
8.8, 17.6, or 26.4 μM). The number of shoots formed per shoot tip was significantly influenced by the level of cytokinin (BA/kinetin)
and genotype. Maximum rooting was induced in 1/2 strength MS with 0.8% activated charcoal. The regenerated plants were transferred
to soil in pots, where they exhibited normal growth. 相似文献
12.
T. Dennis Thomas 《In vitro cellular & developmental biology. Plant》2009,45(5):591-598
Protoplast culture and plant regeneration of an important medicinal plant Tylophora indica were achieved through callus regeneration. Protoplasts were isolated from leaf mesophyll cells and cultured at a density
of 5 × 105 protoplasts per gram fresh weight, which is required for the highest frequency of protoplast division (33.7%) and plating
efficiency (9.3%). The first division was observed 2 d after plating and the second division after 4 d. Culture medium consists
of Murashige and Skoog (MS) liquid medium with 4 μM 2,4-D, 0.4 M mannitol and 3% (w/v) sucrose with pH adjusted to 5.8. After 45 d of culture at 25°C in the dark, protoplasts formed colonies consisting of about
100 cells. The protoplast-derived microcalli were visible to the naked eye within 60 d of culture and reached a size of 0.2–0.4 mm
in diameter after 90 d. Calli of 0.2–0.4-mm size were transferred to MS medium supplemented with 2,4-D (4 μM), 3% (w/v) sucrose and 0.8% (w/v) agar, formed friable organogenic calli (7-8 mm size) after 8 wk under incubation in normal light period supplemented with
200 μmol m−2 S−1 of day light fluorescent illumination. The calli were transferred to MS medium supplemented with thidiazuron (TDZ) (1–7 μM)
and naphthalene acetic acid (NAA) (0.2–0.4 μM) for regeneration. The calli developed shoot buds after 3–4 wk, and the frequencies
of calli-forming shoots varied from 5% to 44%. Optimum shoot regeneration occurred on MS medium supplemented with 5 μM TDZ
and 0.4 μM NAA. On this medium, 44% cultures responded with an average number of 12 shoots per callus. Whole plants were recovered
following rooting of shoots in 1/2 MS medium supplemented with 3 μM indole 3-butyric acid. 相似文献
13.
多胺对宁夏枸杞愈伤组织器官发生和体细胞胚发生的影响 总被引:7,自引:0,他引:7
利用已建立的宁夏枸杞(Lycium barbarumL.)愈伤组织器官发生和体细胞胚发生体系,对多胺在其离体形态发生中的作用进行研究。通过检测内源多胺含量发现,在所研究的三种多胺中,Put是器官发生途径的主要多胺,而在体细胞胚发生途径Spd含量占优势。Put含量变化在两条途径中相似:在愈伤组织分化的早期迅速积累不仅又下降,随着芽原基和球形胚的形成含量又进一步上升。器官发生中Spd最高含量仅在培养的第一天后,Spd含量才开始上升,到第十天时达到最高值。三种外源多胺的添加均有有效地促进两种离体分化途径的形态建成:Spd(100 μmol/L)能显著增加不定芽数,而体细胞胚发生中Spd(100μmol/L)而Put(100μmol/L)的单独处理能最好地促进体细胞胚形成和进一步发育成苗;尽管Spm在离体形态发生中含量较低,但添加外源Spm也促进了不定芽形成和体细胞胚形成然后成苗。多胺生物合成抑制剂CHA处理阻碍不定芽形成和和体细胞胚的进一步发育;但是MGBG对器官发生途径中的形态建成没有影响,即降低体细胞胚的发生频率及再生苗数。添加Spd(50μmol/L)能部分逆转CHA、MGBG的抑制效应。以上结果表明,多胺对宁夏枸杞器官发生和体细胞胚发生途径的离体形态建成有一定影响。 相似文献
14.
Kottackal Poulose Martin A. K. Pradeep Joseph Madassery 《Acta Physiologiae Plantarum》2011,33(4):1141-1148
Trichopus zeylanicus subsp. travancoricus (known as Arogyapacha), an endangered ethnomedicinal plant of the Western Ghats of South India, serves as the major source
of the commercial drug Jeevani. The present study established a long-term high frequency in vitro propagation protocol for Arogyapacha. Callus obtained from
the branch–petiole explants cultured on Murashige and Skoog (MS) medium with 4.5 μM 2,4-dichlorophenoxyacetic acid upon subculture
to medium with different concentrations of 6-benzyladenine (BA) either alone or in combination with an auxin favoured shoot
morphogenesis. Medium with 13.3 μM BA alone facilitated high frequency shoot bud (mean of 93.2) formation. Medium with lower
concentrations of BA (4.4, 6.6 and 8.8 μM) alone or in combination with lower concentration of α-naphthaleneacetic acid (NAA)
or indole-3-butyric acid (IBA) favoured better shoot growth than 13.3 μM BA containing medium, but with reduced number of
shoot buds. Subsequent cultures on medium with lower concentrations of BA and also on MS basal media facilitated shoot formation
as well as growth of shoots. The shoot regeneration potential showed no decline up to 5 years. Culture of the in vitro-derived
whole branch–leaf explants on MS basal medium developed shoots directly from the node. On medium with 19.6 μM IBA, the whole
branch–leaf explants induced nodular callus from the node, which developed shoots later. Subsequent cultures on medium with
BA exhibited high frequency shoot formation. The transfer of shoots after 10–15 days culture on half-strength MS medium containing
2.7 μM NAA to half-strength basal medium induced a mean of 11.3 roots. Field survival of plantlets relied on the soil mix:
a 1:4 ratio of sand and red-soil exhibited the highest plantlets survival (86.6%). RAPD profile of the source plant and plants
regenerated from calli after 4 years showed no polymorphism. The established plantlets with morpho-floral features similar
to that of the source plants flowered normally and set fruits. 相似文献
15.
Multiple shoot induction and callus regeneration in Sarcostemma brevistigma Wight & Arnott, a rare medicinal plant 总被引:1,自引:0,他引:1
An efficient micropropagation protocol based on multiple shoot induction and callus regeneration has been standardized in
Sarcostemma brevistigma, a rare medicinal plant. The nodal cuttings were cultured on MS medium supplemented with BA (0.5–8 μM) or Kn (0.5–8 μM) alone
or in combination with NAA (0.5–1.5 μM). Maximum multiple shoot induction was observed on MS medium supplemented with 4 μM
BA. On this medium, 100% cultures responded with an average number of 11.3 shoots per explant. However, the average shoot
length was limited to only 0.9 cm on this medium. The addition of 1 μM NAA along with 4 μM BA gave rise to an average number
of 10.9 shoots with an average shoot length of 1.8 cm. Luxuriantly growing callus was obtained on MS medium supplemented with
BA (5 μM) and 2,4-D (2 μM). The callus was subcultured on MS medium supplemented with BA (2–15 μM) or Kn (2–15 μM) alone or
in combination with NAA (0.5–2 μM) for shoot organogenesis. Optimum callus regeneration was obtained on MS medium supplemented
with 10 μM BA and 1 μM NAA. On this medium, 100% cultures responded with an average number of 13.4 shoots per culture. The
shoots obtained via multiple shoot induction and organogenesis were rooted on half-strength MS medium supplemented with NAA
(1–7 μM) or IBA (1–7 μM). IBA was better than NAA in terms of both the percentage of cultures that responded and the average
number of roots per explant. The rooted shoots were successfully transplanted to soil with 86% success. This standardized
protocol will help to conserve this rare medicinal plant. 相似文献
16.
I. V. Maksimov N. B. Troshina O. B. Surina E. A. Cherepanova L. G. Yarullina 《Applied Biochemistry and Microbiology》2010,46(5):530-535
The effect of Ca2+ on morphophysiological parameters of wheat calli (Triticum aestivum L.) infected by the bunt pathogen Tilletia caries, in particular on the level of active oxygen species, activity of oxalate oxidase, peroxidase, and catalase is investigated.
The concentration of O2−, H2O2, and activity of oxidoreductases (oxalate oxidase, peroxidase, and catalase) depended on the content of Ca2+ in the culture medium of calli. The increase of the concentration of Ca2+ ions in the culture medium led to forming of calli with high structure, induction of activity of oxalate oxidase and of some
isoperoxidase, and to accumulation of active oxygen species. These changes contributed to inhibition of development of the
fungus. So this dependence confirm the role of calcium as the intermediant in biochemical reactions related to the formation
of the protective response of plant cells to biotic stress. 相似文献
17.
High production costs due to low growth rate in vitro and high labour costs are among factors limiting commercial application
of micropropagation techniques. The low growth rate could be due to unfavourable or sub-optimal environmental and chemical
conditions of the cultures. The effects of temperature, photoperiod and culture vessel size were investigated on adventitious
shoot production of Huernia hystrix. There were significant increases in shoot proliferation with increased temperature in cultures maintained under a 16 h photoperiod.
Slow growth observed at low temperatures (15 and 20°C) offers a potential strategy for cost-effective in vitro storage of
H. hystrix germplasm. The maximum adventitious shoots produced per explant and percentage of explants producing shoots (4.2 ± 0.74 and
94% respectively) were observed in cultures maintained at 35°C, the optimum temperature for photosynthesis in plants possessing
crassulacean acid metabolism (CAM). The nocturnal accumulation of organic acids in cultures incubated under a 16 h photoperiod
further suggest the presence of CAM in this species. On the other hand, cultures kept under continuous light appear to shift
to a C-3 photosynthetic pathway. There was a significant decrease in fresh weight of adventitious shoots regenerated per explant
as temperature increased. The use of larger culture vessels further increased the shoot proliferation to 5.6 shoots per explant
with a potential production of 3,429 shoots per m2 in the growth room compared to 2,750 shoots per m2 using culture tubes. 相似文献
18.
Marta Medina Nieves Villalobos Pedro J. De La Cruz Ana Dorado Hilario Guerra 《Acta Physiologiae Plantarum》1998,20(4):383-392
Using 6 culture media (12, 12D, 12G, 11, A and B) made up of MS medium (Murashige-Skoog, 1962) supplemented or not with glycerine,
with different cytokinins, and/or 2,4-D, the morphological characteristics and contents in total carbohydrates, reducing sugars,
sucrose and starch were studied in calli induced from explants (cotyledon, petiole, hypocotyl and leaf) obtained from Medicago strasseri seedlings. Callus formation was induced under photoperiod (16h light/8h darkness) conditions or in the absence of light.
Considerable variability in the calli was observed, depending on the explants and media used. Under photoperiod conditions,
medium A with KIN (1 mg/l) and 2,4-D (3 mg/l) induced many calli with the highest contents in total carbohydrates (886.1–889.3
mg/g DW), sucrose (132.1–188.2 mg/g DW) and starch (125.2–247.6 mg/g DW) and the lowest contents in reducing sugars (118.4–173.3
mg/g DW). In media 11, A and B, under conditions of darkness, calli degenerated at the start of culture. Calli developed in
darkness generally had dry weights and total carbohydrate and starch contents lower than those cultured under photoperiod
conditions. However, sucrose contents were greater in calli formed in darkness.
At these cultures times, differentiation, in the form of organogenesis, was only seen using medium B with cotyledons, petioles
and leaves as explants. It was also observed when petioles were cultured in medium A but with a less pronounced organogenic
response. 相似文献
19.
The direct shoot organogenesis was achieved from leaf explant of two commercially important clones of Populus deltoides on MS medium enriched with 15 mg/l adenine sulphate, 5 mg/l Ascorbic acid, 250 mg/l (NH4)2SO4 (referred to as PD1 medium) supplemented with 2.5 µM each of 6-benzylaminopurine and indole-3-acetic acid. Higher shoot organogenic potential was recorded from the explants of clone ‘G48’ as compared to clone ‘L34’. The age of leaf explant also affected the shoot organogenic potential, and maximum shoot organogenesis was recorded in case of 5th leaf from the top of microshoot. Histological studies revealed altered cell division resulting in the formation of meristematic pockets after 5 days of culture, these meristematic pockets grew into dome protuberances by 10th day. Organized shoots were visible after 15 days of culture. A clear three phases of shoot organogenesis viz induction (0–4 days), initiation and organization (4–10 days) and growth (11–16 days onwards) were observed. Marked variation in the activity of enzymes such as catalase, peroxidase, polyphenol oxidase and acid phosphatase was observed during these phases. The activity of these enzymes was found to increase in cultures grown on the medium resulting in shoot organogenesis during shoot development (after 7 days of culture). 相似文献
20.
Summary
In vitro regeneration of plants from root culture of Melia azedarach seedlings was obtained. The origin and mode of development of the regenerated shoot buds were studied by means of histological
analysis and scanning electron microscopy (SEM). Maximum shoot bud regeneration was achieved when root segments were cultured
on Murashige and Skoog (MS) medium at quarter strength with 3% sucrose and 0.44 μM benzyladenine (BA) and kept under light (116 μmol m−2 s−1). Shoot bud elongation was achieved on MS with 0.44 μM BA, 0.46 μM kinetin (KIN), and 3.26 μM adenine sulphate (AD). Regenerated shoots were rooted on MS with 12.26 μM indole-3-butyric acid (IBA) for 4 d and subsequently in MS lacking plant growth regulators for 26 d. Plants were established
in a potting substrate. Histological analysis of roots from intact seedlings (without treatment) demonstrated that during
the early life of the roots, M. azedarach lacks preformed buds. In contrast, when the roots were excised and cultured in vitro, the histology and SEM observations revealed that buds originated from meristematic groups of cells, which had been formed
from the pericycle and several layers beneath. These meristematic groups of cells grew towards the periphery of the cortex
by crushing the outer layer of cortical cells. Further develoment led to the differentiation of leaf primordia and a shoot
apical meristem. 相似文献