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1.
Summary

Meristems of ginger with or without leaf primordia were induced to form shoots on three-quarter strength Murashige-Skoog’s (MS) medium containing sucrose 6%, coconut milk (CM) 20%, ascorbic acid (AA) 100 mg l?1, glutamine (GL) 400 mg l?1, activated charcoal (AC) 250 mg l?1, 6-benzylaminopurine (BAP) 0.5 mg l?1, indolebutyric acid (IBA) 0.4 mg l?1 and agar 0.8%. Meristem-derived shoots exhibited consistent multiplication on three-quarter strength MS medium containing sucrose (3%), AA (100 mg l?1), AC (100 mg l?1), BAP (4–5 mg l?1) and agar (0.8%). Liquid media (agitated or static) were less effective than a solid (agar-gelled) medium for micropropagation. Kinetin and naphthalene acetic acid (NAA) incorporated at various levels (0.01–0.8 mg l?1) with or without added BAP and IBA neither improved plantlet formation nor enhanced shoot multiplication. The in vitro plants were successfully established in vivo and the rhizome yield was comparable with that of plants grown by conventional methods.  相似文献   

2.
Summary

The influence of partial substitution of agar by galactomannans in culture media supplemented with different concentrations of indole-3-butyric acid (IBA) was studied on in vitro rooting of pear (Pyrus communis L.) cultivar ‘Durondeau’ and apple rootstock (Malus prunifolia Borkh.) cultivar ‘Marubakaido’. The galactomannans applied were obtained from Cassia fastuosa (cassia) and Cyamopsis tetragonolobus (guar gum) seeds. The results obtained with mixtures of agar and galactomannan (3 g l–1 each) were compared with those from media solidified with a standard concentration of agar (6 g l–1). The rooting of pear shoots was enhanced significantly in the presence of a mixture of agar plus cassia galactomannan compared to medium solidified with agar only. The modified media promoted a higher number of roots than the control, and increased the percentage of rooted shoots. A maximum of 84.8% rooting was obtained on half-strength MS medium (1?2MS) supplemented with 0.49 µM IBA and solidified with a blend of agar plus cassia galactomannan. For the apple rootstock, only the number of roots per shoot was influenced significantly by the addition of galactomannan to the rooting medium. The highest number of roots per shoot was 16.67 on 1?2MS medium gelled with a mixture of agar plus guar galactomannan supplemented with 4.90 µM IBA. The behaviour of the agar-galactomannan gel and the possibility of reduced costs when compared with systems containing only agar, suggest new biological and commercial applications for galactomannans.  相似文献   

3.
Summary

To optimise conditions for micropropagating Galanthus species, a basal medium (G) was developed based on mineral analyses of G. nivalis, G. nivalis ‘Flore Pleno’ and G. elwesii bulbs. Compared with Murashige and Skoog (MS) medium, the main features of G medium were increased concentrations of Cu ( 30.4), P ( 3.6), Ca ( 1.9), Mg ( 1.3) and S ( 1.2) and reduced levels of Mn ( 0.07), Zn ( 0.59) and K ( 0.65). The efficacy of G medium in supporting bulblet initiation on bulb chip explants, bulblet multiplication (on media supplemented with 30 g l–1 sucrose, 1.0 mg l–1 6-benzylaminopurine and 0.1 mg l–1 naphthalene acetic acid), and bulblet growth (on plant growth regulator-free media with 60 g l–1 sucrose and 5 g l–1 activated charcoal) was compared with MS medium over a range of dilutions (full-, 1?2-, 1?4-, and 1?8-strength). Bulblet initiation was superior on G medium for G. nivalis and G. nivalis ‘Flore Pleno’, but inferior for G. elwesii. The choice of basal medium did not influence bulblet multiplication, although multiplication was reduced on both media diluted to 1?8-strength. G medium supported bulblet growth and rooting better than MS medium, while dilution of either medium reduced bulblet growth and rooting. Using G medium in place of MS medium during bulblet multiplication greatly reduced hyperhydration with G. elwesii, as did dilution of either of the basal media.  相似文献   

4.
Capsicum spp. is a commercially important crop of the Solanaceae family, well-known for its multipurpose use as a vegetable, spice, medicinal and ornamental plants. The genus Capsicum is a recalcitrant species in terms of in vitro morphogenesis and plant regeneration. An efficient method was developed for multiple shoot regeneration in 10 cultivars of Capsicum collected from diverse geographical regions of India and Mexico. Seeds germinated in vitro on a half-strength Murashige and Skoog (MS) medium supplemented with 3.0 % sucrose. Nodes of the in vitro germinated seedlings were used as explant for micropropagation. The combination of the 6-benzylaminopurine, indole-3-acetic acid, and spermidine was found to be the best for multiple shoot induction. However, the optimum responcse varied accompanied by different cultivers with maximum 8.9 ± 0.52 (Capsi-10) to 15.3 ± 0.69 (Capsi-5) multiple shoot per explant. Depending on the cultivar, multiplied shoots were successfully rooted with maximum 18.4 ± 0.20 (highest for Capsi-9) to 36.8 ± 0.29 (highest for Capsi-5) roots per shoot on half-strength MS medium supplemented with 2.0 mg l?1 indole-3-butyric acid, 1.0 mg l?1 α-naphthalene acetic acid, and 1.5 mM spermidine. Finally, the micropropagated plantlets were acclimatized with 40.0–86.7 % survival rate, depending on different cultivars.  相似文献   

5.
Summary

Giant reed (Arundo donax L.), a promising energy crop, is vegetatively-propagated from fragments of stems and rhizomes. This may limit large-scale cultivation, since it is time-consuming and involves considerable cost and effort. Tissue culture is an alternative to conventional methods of vegetative propagation and may represent a useful tool for large-scale propagation of plants for biomass production programmes. This report describes a protocol for the large-scale in vitro propagation of giant reed by adventitious bud formation. Stem nodes with dormant buds proved to be the most effective to initiate in vitro cultures giving the highest percentage of differentiated shoots (77%) compared to the other plant fractions tested. A sterilisation procedure using 5 g l–1 HgCl2 enabled the production of sterile explants. Moreover, early results indicated that late Autumn excision dates not only gave a higher percentage of well-developed shoots ( > 80%), but also a lower level of bacterial contamination (15 – 20%). 6-Benzylaminopurine (BAP) at 3.0 mg l–1 was most effective in promoting shoot multiplication when added to a basal medium containing Murashige and Skoog (MS) macro- and micro-nutrients, Morel’s vitamins, 30 g l–1 sucrose, and 7.0 g l–1 bacteriological agar supplemented with 1.0 mg l–1 indole-3-acetic acid (IAA) and 0.05 mg l–1 gibberellic acid (GA3). Rooting was successfully induced on the same basal medium used for proliferation, modified by halving the MS macro-nutrients and replacing BAP and the other growth regulators with 2.0 mg l–1 1-naphthaleneacetic acid (NAA). Successful acclimatisation (> 95% survival) of plantlets was carried out, even in late Winter, in a cold greenhouse or under simpler facilities such as shade nets.  相似文献   

6.
An effective protocol was developed for in vitro regeneration of Psoralea corylifolia through enriched cotton moistened-liquid (CML) and solid culture systems. Prolific adventitious shoot buds were achieved from hypocotyl explants of 2-week-old cultures on enriched CML Phillips and Collins (L2) medium supplemented with different concentrations and combinations of thidiazuron (TDZ), benzyladenine (BA), kinetin (KIN), naphthalene acetic acid (NAA), indole-3-acetic acid (IAA) and bavistin (BVN). Combination of 2 μM TDZ, 0.5 μM BA, 100 mg l−1 BVN and 2 μM NAA produced a greater number of adventitious shoots per explant (93.5) when transferred to half-strength enriched solid L2 medium. Regenerated shoots (40–50 mm in length) were exposed simultaneously for rooting as well as hardening in moistened (1/8-L2 basal salt solution with 5 μM IBA and 100 mg l−1 BVN) soil mixture and vermiculite (3:1, v/v). The plants were subsequently established in the field. The survival percentage differed with seasonal variations.  相似文献   

7.
Summary

An embryogenic protocol for plant regeneration of guava (Psidium guajava L.) was established using 10-week post-anthesis, zygotic embryo explants. Somatic embryogenesis was induced on Murashige and Skoog medium (MS) containing 3% (w/v) sucrose, 0.8% (w/v) agar and various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) by continuous treatment of the zygotic embryo explants. Somatic embryos appeared as globular structures at the end of the third week from culture initiation, and heart-shaped, cotyledonary-stage, and torpedo-stage embryos appeared within the next few weeks. The development of somatic embryos was asynchronous and showed five-to-seven discernible stages. Depending upon the response of the somatic embryos during their maturation, germination, acclimatisation, and encapsulation, they were grouped into one of three categories. The preferred type of somatic embryos (≥ 1.5 mm) were called the “elongated torpedo” (ET) category. The slightly less-preferred type of stomatic embryos (from 1.0 – 1.5 mm) were termed the “short torpedo” (ST) category. The least preferred types of somatic embryos, at the cotyledonary, heart-shaped, and/or globular stages of development (< 1.0 mm), were grouped into a third category designated “CHG”. The suitability and efficacy of various growth regulators and other treatments were assessed based on six different embryogenic parameters: (i) the frequency of embryogenesis; (ii) the intensity of embryogenesis, defined as the average number of somatic embryos produced per culture (“ANEPC”); (iii) the frequency of ET somatic embryos; (iv) the frequency of ST somatic embryos; (v) the frequency of CHG somatic embryos; and (vi) the overall efficiency of embryogenesis, defined as the potential of a treament to produce somatic embryos at the ET or ST stages, or at both stages of development, that could be converted into plantlets. In the present report, we found that 0.01 mg l–1 2,4-D gave the maximum frequency and intensity of embryogenesis. But the highest frequencies of ET and ST somatic embryos were produced on MS medium containing 3% (w/v) sucrose and 0.001 mg l–1 2,4-D, while CHG embryos were produced at the highest frequency on the same medium, but containing 0.5 mg l–1 2,4-D. It was difficult to calculate the most effective concentration of 2,4-D for somatic embryogenesis based on parameters (i) – (v) above. Hence, quantitative estimations of the efficiency of embryogenesis (sixth parameter) were imperative in order to analyse the potential of the different treatments. The highest efficiency of somatic embryogenesis was achieved by continuous treatment of 10-week post-anthesis, zygotic embryo explants with 0.01 mg l–1 2,4-D on full-strength MS agar medium containing 3% (w/v) sucrose. These somatic embryos matured normally on the same medium, and germinated well both on half-strength solid and in half-strength liquid MS medium containing 3% (w/v) sucrose. They grew in full-strength liquid MS medium with 3% (w/v) sucrose and showed maximum survival upon transfer to soil and hardening. Evaluations of the efficiency of somatic embryogenesis in guava, based on the six parameters defined above, have also helped us to understand and evaluate processes for high efficiency micropropagation in other species.  相似文献   

8.
The nucellus and globular adventitious proembryos were removed from 2-month-old fruits of mango (Mangifera indica L.) cultivars ‘Ono’ and ‘Chino’, and were cultured on sterile, solid Murashige and Skoog (MS) medium that had been modified as follows: half-strength major salts and chelated iron; 20% (v/v) coconut water (CW); 6% sucrose; 100 mg l?1 ascorbic acid and 400 mg l?1 glutamine. Embryogenic explants were sub-cultured after 4–6 weeks in liquid modified MS medium containing 2 mg l?1 2,4-dichlorophenoxyacetic acid (2,4-D) instead of CW. Rapidly growing cultures were established and were sub-cultured monthly. Somatic embryogenesis was induced following sub-culture from MS medium with 2,4-D to MS without growth regulators and with or without activated charcoal (0.5%). Germination of somatic embryos appeared to be enhanced by 1 mg l?1 benzyladenine (BA); however, most of the germinating embryos became embryogenic.  相似文献   

9.
An in vitro plant regeneration protocol for pansy (Viola wittrockiana) cultivar ‘Caidie’ from petioles was established as following: callus induction on a half-strength MS medium supplemented with 0.45 μmol l−1 2,4-d plus 8.9 μmol l−1 BA, callus subculture on medium F (1/2MS with 4.5 μmol l−1 2,4-d, 2.7 μmol l−1 NAA and 0.44 μmol l−1 BA) and then on medium T (1/2MS with 4.5 μmol l−1 2,4-d, 2.7 μmol l−1 NAA and 2.2 μmol l−1 BA), shoot regeneration on medium D3 (MS media supplemented with 2.9 μmol l−1GA3, 23.6 μmol l−1 AgNO3, 0.02% active charcoal and 4.5 μmol l−1 TDZ), shoot multiplication on medium M (half-strength MS medium containing NAA 1.1 μmol l−1, TDZ 9.1 μmol l−1 and GA3 8.7 μmol l−1), and then shoot elongation and rooting on medium R (MS medium supplemented with 1.1 μmol l−1 NAA and 1.1 μmol l−1 BA). Subculture on appropriate medium was found to be important for successful shoot regeneration.  相似文献   

10.
High-frequency somatic embryogenesis and shoot regeneration of broccoli (Brassica oleracea var. italica) were achieved. Cotyledon and hypocotyl explants from four varieties of broccoli were cultured on MS and modified MS media (mMS, supplemented with PG-96 organic components) with different combinations of growth regulator. The effects of genotypes, different explants, growth regulator combinations, organic components and AgNO3 on induction of calli and shoots were evaluated. The optimal media for inducting calli/shoots and roots were mMS medium containing 3% (w/v) sucrose and 0.8% (w/v) agar supplemented with NAA at 0.5 mg l−1, 6-BA at 3.0 mg l−1, AgNO3 at 4.0 mg l−1 and MS medium containing 3% sucrose and 0.8% (w/v) agar supplemented with NAA at 0.2 mg l−1, respectively. The callus induction percentages were over 90% in all four varieties; shoot induction percentage was 92.5% and the average number of shoot per explant was 4.1 from cotyledon explant in variety Bishan. In this study, we established high-efficient embryogenesis and shoot regeneration system of broccoli and analyzed genetic stability of regenerants at DNA level using RAPD molecular marker. Out of 62 arbitrary primers screened using PCR amplification, 79 polymorphic bands were amplified from 20 primers. The results demonstrated the genetic stability of regenerants from the same variety.  相似文献   

11.
Summary

We have developed a two-step procedure for rooting of tea microshoots in vitro. The effectiveness of different auxin treatments for root formation was found to differ. Among the auxins tested, 25 μM -naphthalene acetic acid (NAA) gave the best results, with 100% rooting, compared to 25 μM indole-3-butyric acid (IBA) or 25 μM indole-3-acetic acid (IAA), which induced 17% and 58% rooting, respectively. Incubation of tea microshoots on 0.33 Murashige and Skoog (MS) medium, supplemented with 25.0 μM NAA or 175.0 μM IBA for 10 d, followed by transfer to auxin-free 0.33 MS medium resulted in 100% rooting, whereas 50.0 μM IAA induced 91.7% rooting. Besides the different auxin treatments, the strength of the MS medium, the duration of incubation of microshoots in auxin-containing medium, the sucrose concentration, the gelling agent, the pH of the medium, the incubation temperature, the light intensity, and the quality of the shoots also played a significant role during in vitro rooting of micropropagated tea shoots. Among the combinations tested, the most effective results were obtained when green microshoots were incubated on 0.33 MS medium supplemented with 25.0 μM NAA, 50.0 mM sucrose, pH 5.5, gelled with 0.2% (w/v) PhytagelTM for 10 d at 25° – 30°C at a light intensity of 40 μmol m–2 s–1, followed by transfer of shoots to auxin-free 0.3 MS medium. This resulted in 100% rooting and, on average, 11 long roots were formed per shoot. Anatomical changes during adventitious rooting of micropropagated tea shoots in vitro were also studied to understand the process of rooting.  相似文献   

12.
Summary

In Poncirus trifoliate, a highly efficient clonal propagation system for the culture of shoot primordia was devised. Shoot primordia were induced at the base of hypocotyl tissue cultured on MS medium supplemented with 44.4 µM BA, 3% sucrose and 0.8% agar. In MS liquid medium (44.4 µM BA, 3% sucrose) on a rotary shaker at two revolutions per minute, shoot primordia of Poncirus grew in size and number. Plant regeneration occurred on MS solid medium. Frequency of regeneration was highest on MS basal medium containing 3% sucrose and 0.8% agar. About 75 shoot buds regenerated from one shoot primordium. Histological observations showed that shoot buds arose from cells in the hypodermal layers of the shoot primordium. The shoot bud developed a vascular system, which became connected to the shoot primordium tissue. Regenerated shoots rooted on 1/2 MS basal medium or 1/2 MS medium supplemented with 0.5 or 5.0 µM IBA. These rooted shoots were acclimatized easily under intermittent mist.  相似文献   

13.
Sequential subculturing leads to a gradual physiological change in cells that may be termed ‘rejuvenation’. The effect of repetitive subculturing on callus induction and shoot regeneration from leaf explants of Punica granatum L. ‘Kandhari Kabuli’ were investigated. Surface-sterilised leaves were cultured on 1.0× Murashige and Skoog (MS) medium supplemented with 4.0 mg l1 α-naphthaleneacetic acid (NAA) and 2.0 mg l1 6-benzyladenine (BA) for callus induction. Shoots were regenerated from callus on 1.0× MS medium supplemented with 1.5 mg l1 BA, 0.5 mg l1 kinetin, and 0.25 mg l1 NAA. Subculturing of callus onto fresh medium maintained the rate of shoot formation and substantially increased the production of shoot buds up to the second subculture. Following further subculture passages, a lower shoot regeneration potential from callus was observed. A maximum shoot bud induction from callus of 63.9% was observed at the second subculture passage. The rate of multiplication of in vitro shoots increased until the fourth subculture, then became constant. Similarly, in vitro rooting of micro-shoots increased up to the third subculture, followed by a decline during further subculturing.  相似文献   

14.
Cost-effective tissue culture protocols have been established for the commercial multiplication of three banana varieties, ‘Rasthali’ (AAB – Silk), ‘Grand Naine’ (AAA – Cavendish), and ‘Udhayam’ (ABB – Pisang Awak). Reverse osmosis water and 3% (w/v) table sugar were used as the low-cost water and carbon source, respectively. Six different gelling agent treatments were tested: sago alone (T1), Isabgol alone (T2), sago + agar (T3), Isabgol + agar (T4), sago + Isabgol (T5), and agar alone as a control (T6). Full-strength Murashige and Skoog (MS) medium supplemented with 3 mg l1 6-benzylaminopurine (BAP) and 1 mg l1 indole-3-acetic acid (IAA) were used for culture initiation and subculturing. Rooting was accomplished on low-cost MS medium containing 1.0 mg l1 α-napthaleneacetic acid (NAA), 1.0 mg l1 indole-3-butyric acid (IBA), and 250 mg l1 activated charcoal. Statistical analysis indicated that sago + Isabgol (T5) produced the maximum number of shoots (10 per explant) in ‘Udhayam’ and ‘Rasthali’, while sago alone (T1) produced the maximum number of shoots (6 per explant) in ‘Grand Naine’. The genetic stability of tissue-cultured banana plantlets produced using these low-cost substitutes was assessed using inter-simple sequence repeat (ISSR) markers. The results indicated that the ISSR profiles of the five treatments and the control (T6) were similar, indicating genetic stability using these cost-effective tissue culture protocols. Reductions in cost over the control (l1 of MS medium) ranged from 65% to 86%, while the per plant production cost was reduced by 12.5%–20.0%. Adoption of these treatments (T1–T5) as low-cost tissue culture protocols for in vitro propagation would reduce production costs significantly, leading to an expansion of the area planted with tissue-cultured banana, thereby increasing productivity.  相似文献   

15.
Zingiber officinale, Rosc., one of the major tropical spices in the world, belongs to the family Zingiberaceae. Bacterial contamination is a major constraint on the cryopreservation of in vitro shoot tip explants. The main objective of this study was to identify the nature of this bacterial contamination and its response to various antimicrobial agents (e.g. the antibiotics cephotaxime and streptomycin sulphate, or copper sulphate) for more effective control. The bacteria isolated from ginger plantlets were identified by amplification and sequencing of their 16S ribosomal DNA, followed by partial sequence analysis. Luteibacter yeojuensis was found in all contaminated cultures. L. yeojuensis is found mainly in soil and as a human pathogen. We believe this is the first report of L. yeojuensis contaminating in vitro cultures of ginger. Among the antimicrobial agents tested in the shoot multiplication medium [i.e. 1.0× Murashige and Skoog salts + 2.5 mg ll 6-benzylaminopurine + 3% (w/v) sucrose + 0.45% (w/v) ClarigarTM], 100 mg l1 cephotaxime was most effective at reducing bacterial growth. It also gave the maximum number of shoots per shoot bud explant compared to the same medium supplemented with streptomycin sulphate, or CuSO4, or control medium. No further bacterial contamination was observed when 8-week-old cultures were then subcultured on the same medium without added antibiotic or CuSO4.  相似文献   

16.
Summary

Significant effects of seven basal media and three carbon sources (sucrose, glucose and fructose) on the induction of adventitious buds from embryos of Pinus sylvestris L. were observed. Moreover, hyperhydricity of expiants and shoot regenerants was observed on basal media containing fructose, especially with half-strength Murashige and Skoog (MS), MS, and woody plant medium (WPM). Expiants grown on a Gresshoff and Doy (GD) medium with sucrose produced the highest frequency of regeneration (81%) and with no hyperhydricity observed of developing adventitious shoots. Among three cytokinins tested including BA, BPA, and TDZ (at four concentrations each), 5 μM BA resulted in the highest regeneration frequency and mean number of adventitious shoots per embryo. Shoot régénérants were elongated after transfer to a GD medium containing 2 g-l–1 activated charcoal and no growth regulators. After one month, rooting was induced on 10% of expiants.  相似文献   

17.
This study has been conducted with the aim to determine the type of nutrient medium that can be used in micropropagation studies for ‘Öküzgözü’ and ‘Bo?azkere’ and to specify BAP concentrations. In the study where ejectors with a length of 0.7–0.8?cm that are obtained with single-node culture are used, it was focused on four different nutrient media such as MS, DKW, QL and WPM and on six different concentrations such as 0.2–0.4–0.6–0.8–1.0–1.5 mg l?1 BAP. Single-node suspension explants which will be used in initiating the culture, are taken into culture in MS nutrient medium and the nutrient medium is supported with 30?g l?1 sucrose, 6?g l?1 agar and 1?mg l?1 BAP. In the trial environment, parameters such as number of shoots, shoot length (cm), number of nodes and callus ratio have been investigated. For both grape varieties, the best outcome was obtained with MS nutrient medium with respect to number of shoots, shoot length, and number of nodes. These values were found as 4.66, 1.24 and 6.39 for ‘Öküzgözü’ variety respectively, whereas they are determined as 6.28, 1.15 and 6.81 for ‘Bo?azkere’ variety respectively. In both grape varieties in DKW nutrient medium, starting from the 2nd week of culture, obscuration began to appear on the shoots and after this stage no other development has taken place.  相似文献   

18.
An unique procedure for the mass shoot propagation of Gerbera using receptacle transverse thin cell layer (tTCL) culture procedure was developed. Genotype, flower bud age, explant size, position of receptacle tTCLs and culture media were found to affect the success of culture. Ten interspecific crosses of Gerbera showed different shoot regeneration rates and callus induction via receptacle tTCL culture, all of which had shoot regeneration rates higher than 57%. Flower buds collected on the 10th day resulted in 91% shoot regeneration after 6 weeks of culture on basal MS medium [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassay with tobacco tissue cultures. Physiol. Plant. 15, 475–497] supplemented with 0.02 mg l−1 thidiazuron (TDZ), 0.8 mg l−1 adenine and 10% (v/v) coconut water (CW). This was significantly higher than those from flower buds on the 7th and 14th days (22% and 54%), respectively. Shoot regeneration rate was the highest (94–100%) in the middle layers of the receptacle. For mass shoot propagation, shoot clusters were subcultured on half-strength MS medium supplemented with 0.5 mg l−1 indole-3-butyric acid (IBA), 0.5 mg l−1 6-benzyladenine (BA) and 2.0 mg l−1 kinetin after every 4 weeks. Plantlets formed when single shoots were cultured on half-strength MS medium containing 1 mg l−1 IBA. All plantlets acclimatized well in the greenhouse.  相似文献   

19.
Summary

The in vitro multiplication of Galanthus nivalis ‘Flore Pleno’ bulblet clumps was evaluated through three 16-week sub-culture passages on media supplemented with either 1.0 mg l–1 6-benzylaminopurine (BA) and 0.1 mg l–1 naphthaleneacetic acid [NAA; the plant growth regulator (PGR) control], 0.5 mg l–1 BA and 0.05 mg l–1 NAA (PGR/2), or 0.1 mg l–1 BA and 0.01 mg l–1 NAA (PGR/10). At the end of the second sub-culture passage, clumps of bulblets from each of the three PGR treatments were also transferred to conditions to promote bulblet growth (G medium without PGRs) supplemented with 60 g l–1 sucrose and 5 g l–1 activated charcoal (AC). Lowering the PGR concentration during the initial multiplication phase reduced bulblet multiplication and overall culture growth, but did not influence bulblet size, as indicated by the diameter of the largest bulblet. Lowering the PGR concentration during the multiplication phase also reduced the multiplication of bulblets, overall tissue fresh weight, and the production of roots in tissues transferred to bulblet growth conditions. The reduced growth of tissues previously multiplied on PGR/10 medium was not, however, reflected in the growth of individual bulblets, since these were not significantly smaller than bulblets initially multiplied at the higher PGR concentrations. Bulblet sprouting and root growth on the bulblet growth medium were unaffected by prior PGR status in the multiplication phase. The results are discussed in terms of the mode of action of AC on the promotion of bulblet growth.  相似文献   

20.
《Scientia Horticulturae》2005,106(3):427-439
Cell suspension cultures were established from immature cotyledon derived calli from drought tolerant legume horsegram [Macrotyloma uniflorum (Lam.) Verdc.]. Embryogenic callus could be originated from cut slices of the immature cotyledons on MS solid medium [Murashige, T. Skoog, K., 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15, 473–497] augmented with 1.0 μM zeatin and 4.5 μM NAA. Numerous somatic embryoids (26.4%) appeared on MS liquid basal nutrient medium with 5.6 μM NAA and with absence of zeatin during 3 weeks culture. Sustained cell division resulted in the formation of cell aggregates, and then progressed to globular, heart and further if they differentiate properly to torpedo and cotyledonary stages within 5 weeks. Transfer of individual embryos on to a fresh MS basal medium with no plant growth regulators was able to achieve complete maturation. Only a relatively few number of embryos developed into root/shoot when transferred to 0.9 μM GA3, 15 g/l−1 sucrose and 2.4 g/l−1 gelrite containing medium. Substitution of sucrose associated with the use of l-glutamine gave, in the range of concentrations tested, the strongest enhancement of the embryo growth and development. About 5% of somatic embryos were converted into true-to-type fertile plants.  相似文献   

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