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1.
Irina Kovalchuk Yelena Lyudvikova Mariam Volgina Barbara M. Reed 《Plant Cell, Tissue and Organ Culture》2009,96(2):127-136
The goal of this study was to evaluate the in vitro storage of apple germplasm by screening a range of genotypes followed
by more comprehensive testing of multiple parameters on two genotypes of differing species, Malus domestica cultivar Grushovka Vernenskaya and wild Malus sieversii selection TM-6. Stored plants were rated on a 6 point scale (0 low to 5 high) for plant appearance at 3 month intervals after
storage at 4°C. Combinations of carbon source (sucrose and/or mannitol), nitrate nitrogen content (25, 50 or 100%) and plant
growth regulators (ABA, BAP, IBA) were studied in three types of containers (tissue culture bags, test tubes or jars). An
initial screen of 16 genotypes stored in tissue culture bags indicated that plantlets could be stored at 4°C for 9–14 months
without subculture on standard 3% sucrose Murashige and Skoog (1962) (MS) medium with no plant growth regulators (PGRs). In subsequent in-depth studies on the two genotypes, ANOVA indicated
highly significant interactions of medium, container and genotype. ‘Grushovka Vernenskaya’ shoots with no PGRs and 3% sucrose
remained viable (ratings of ≥1) for 21 months of storage in bags. Storage on reduced nitrogen (MS with 25% nitrogen), PGRs,
and 3% sucrose kept ‘Grushovka Vernenskaya’ shoot condition rated >2 at 21 months. Addition of 0.5 or 1 mg−1 abscisic acid (ABA) also improved plant ratings at 21 months. The longest storage for ‘Grushovka Vernenskaya’ was 33–39 months
with PGRs and 3% sucrose in either tubes or jars. Addition of abscisic acid (ABA) to the medium did not improve storage of
plantlets in jars and tubes at 15 months. TM-6 stored best in tubes on 3% sucrose with PGRs or in jars on 2% mannitol and
2% sucrose. Overall it appears that cold storage of apple shoot cultures can be successful for 21 months in tissue culture
bags with 25% MS nitrate nitrogen, 3% sucrose, and no PGRs or for 33 months in jars or tubes on MS with 3% sucrose and PGRs.
Preliminary RAPD analysis found no significant differences between plants stored for 39 months and non-stored controls. 相似文献
2.
The effects of reducing sucrose level on tuber formation (% of cultures with microtubers), development (length and fresh weight
of microtubers) and sprouting in yam Dioscorea cayenensis–D. rotundata complex in vitro were investigated. Only 29% of the explants showed tuber formation after 3 weeks in the presence of 1% sucrose
in contrast to 100% with 3%. After 120 days of culture, the length and the weight of the tubers obtained in the presence of
1% sucrose were less than with 3% sucrose. Addition of sorbitol to keep osmolarity at the same level did not restore normal
rate of tuber formation. Similar results were obtained with the use of reduced fructose or glucose level. Microtuber sprouting
was also affected by sucrose level incorporated into the tuberisation medium. Tubers obtained on reduced sucrose level sprouted
later and the increase of osmolarity with sorbitol did not restore normal sprouting. The bigger tubers obtained on high sucrose
media could contain more carbohydrate reserves that could partially explain a higher sprouting rate. These results can be
used for optimising in vitro conditions for mass production of microtubers in yam and especially in Dioscorea cayenensis–D. rotundata complex, a very important species in West Africa. They specially showed the importance of tuberisation conditions on precocity
of tuberisation, on tuber length and weight and on their further sprouting. 相似文献
3.
The effects of photoperiod (8, 12 or 16 h), mineral medium strength (dilutions of a tuberization medium, the T medium), sucrose
(0, 2, 4, 8% w/v) and kinetin (0, 2.5μM) on the development of roots, shoots and microtubers in shoot cultures of Dioscorea alata L. and D. bulbifera L. yams were evaluated. All of the factors were found to have substantial effects on microtuber induction in these two species.
The effects of high and low inorganic ammonium containing media on microtuberization of yam shoot cultures indicated that
ammonium ions inhibited microtuber induction in D. alata but not in D. bulbifera. Microtubers of D. alata were only formed on shoot cultures if these were held under 8-h days. D. bulbifera cultures on the other hand produced microtubers under this photoperiod treatment as well as under 16-h photoperiods provided
that kinetin was present in media at 2.5μM. Most microtuberization in D. alata shoot cultures occurred on full-strength T medium supplemented with 2% sucrose, 2.5μM kinetin held under 8-h photoperiod
at 25°C, whereas most microtuberization in D. bulbifera shoot cultures occurred on full-strength MS medium supplemented with 4% sucrose, 2.5μM kinetin held under 8-h photoperiods
at 25°C. Under these two sets of conditions, yam shoot cultures consistently produced microtubers with individual weights
in excess of 100 mg which were large enough to be capable of direct planting and subsequent growth in unsterilized soils. 相似文献
4.
Kouadio A. Olivier Koffi N. Konan Felicia N. Anike Georges N. Agbo Hortense W. Dodo 《Plant Cell, Tissue and Organ Culture》2012,109(1):179-189
Two methods were used to produce yam minitubers from two different yam cultivars (cv. Krengle and cv. Kponan) using in vitro
culture techniques. Method 1: Yam microtubers were first initiated in vitro and then transplanted to soil to generate plants
from which minitubers were produced. Yam plants were obtained either by directly planting the microtubers to soil, or by inducing
the germination of the microtubers using various chemical and physical treatments, before their transfer to soil. Method 2:
Yam plantlets were first produced in vitro and then transplanted to soil for further development and tuber production. In
both methods, the presence of jasmonic acid (JA) in the culture medium was found to be essential for yam tuberization, as
well as for the germination of yam microtubers. In vitro production of yam microtubers was variety dependant. Compared to
cv. Krengle, cv. Kponan responded better to microtuberization, and 2.5 μM JA was the optimum concentration resulting in 70
and 90% explants producing microtubers in the MS medium and the Tuberization medium (T-medium), respectively. Germination
of the microtubers required treatment of JA at concentrations ranging from 1.0 to 2.5 μM. The overall length of the process
to produce minitubers from microtubers took 32 weeks. In contrast, minitubers were obtained within 20 weeks when plantlets
were directly transferred to soil. In this case, plantlets were first grown for 8 weeks on medium containing JA (0.1–1.0 μM)
and 8% sucrose to initiate plant growth and rooting. 相似文献
5.
Effects of kinetin,paclobutrazol and their interactions on the microtuberization of potato stem segments cultured in vitro in the light 总被引:1,自引:0,他引:1
I. Šimko 《Plant Growth Regulation》1993,12(1-2):23-27
Single-nodal cuttings of Solanum tuberosum (four cultivars) and Solanum chacoense were induced to produce in vitro microtubers on Murashige & Skoog (MS) medium supplemented with 8 g l–1 sucrose and various concentrations of kinetin and paclobutrazol. The cultures were kept 10 days in darkness and then transferred to a 14 h daylength with 100 µE m–2 sec–1 light intensity at 21 °C. Kinetin (2.5 mg l–1) had no significant influence on tuber formation. However, its addition together with paclobutrazol (0.001 mg l–1) significantly enhanced tuberization. Paclobutrazol alone stimulated early tuber initiation and inhibited stem growth. Despite some genotype × treatment interactions, all genotypes (from very early to late and wild type) formed the maximum proportion of explants bearing microtubers on the media containing both plant growth regulators. 相似文献
6.
Mahmoud Otroshy Farhad Nazarian Paul C. Struik 《Plant Cell, Tissue and Organ Culture》2009,98(2):213-218
An experiment, including potato cultivars Gloria (very early), Marfona (mid-early) and Agria (late), was carried out to assess
the effects of different temperatures during two phases of the day on in vitro potato microtuber production. Temperature significantly
(P < 0.01) affected the percentage of cuttings that produced microtubers. The highest temperatures in either phase resulted
in the lowest percentage of cuttings that produced microtubers. With lower temperature during either phase, we found more
microtubers per cutting and larger microtuber sizes. The effects of temperature on individual microtuber weight were not statistically
significant. However, increasing the temperature during different thermophases increased both length and weight of sprouts
formed on the microtubers. Moreover, the highest temperatures resulted in the lowest levels of tuberization (as shown by bud
status) and the largest sprout growth. The temperature amplitude had a significant effect as well: very large temperature
amplitudes resulted in poorer tuber formation compared with smaller temperature amplitudes with the same average temperature.
All three cultivars showed different responses with regard to the percentage of explants that produced microtubers. After
45 days of incubation, the percentage of explants producing microtubers, the number of microtubers and the length of the sprouts
were significantly increased compared with 35 days of incubation. Nonetheless, the status of the microtubers (sprouted or
not-sprouted) and the microtuber size did not change beyond 35 days of incubation. Polynomial analysis of temperature effects
showed that almost all traits assessed showed a significant linear trend. 相似文献
7.
The Induction and Development of Potato Microtubers In Vitroon Media Free of Growth Regulating Substances 总被引:1,自引:0,他引:1
Reliable microtuber production has been obtained by culturingnodal explants of potato on Murashige and Skoog medium withoutthe addition of growth regulating substances. The use of sucroseat 8 %, as compared with 4 or 12%, advanced the initiation oftuberization and gave more and larger microtubers. A periodof 1 month under 16 h days, followed by transfer to 8 h photoperiodsgave most rapid microtuber development. A reduction in the totalnitrogen supply or an increase in the ratio of ammonium to nitratereduced the size and number of microtubers Potato, Solanum tubersum L;, microtubers, in vitro induction and development, sucrose, photoperiod, nitrogen nutrition 相似文献
8.
Summary Plant regeneration through direct somatic embryogenesis was achieved from root segments derived from in vitro shoots of Rauvolfia micrantha Hook. f. (Apocynaceae) grown for 6 wk in half-strength Murashige and Skoog (MS) medium with 3% sucrose, 100 mgl−1 myo-inositol, and 0.5 mgl−1 α-naphthaleneacetic acid (NAA). The effects of photoperiod and plant growth regulators (PGRs) in half-strength MS medium
were studied for the rapid and maximum induction of somatic embryos. The characteristic globular or heart-shaped stages of
somatic embryogenesis were not found and cotyledonary stage embryos occasionally appeared without the intervention of callus
in total darkness and 16-h photoperiod. Root segments cultured in the medium containing 0.1 mgl−1 NAA and 0.2 mgl−1 6-benzyladenine (BA) under 16-h photoperiod showed the maximum frequency (39%) of embryogenesis. The frequency of embryo
formation was increased to 63% when they were cultured in medium with 0.1 mgl−1 NAA and 0.2 mgl−1 BA in the dark for 4wk, then grown under the 16-h photoperiod. Explants with developing embryos developed into plants after
transfer to half-strength MS medium supplemented with 0.1 mgl−1 BA and 0.05 mgl−1 NAA. The well-developed plants were hardened and most plants (80%) survived and were phenotypically similar to the mother
plants. 相似文献
9.
Shamsudeen Varisai Mohamed Jih-Min Sung Toong-Long Jeng Chang-Sheng Wang 《Plant Cell, Tissue and Organ Culture》2006,86(2):187-199
A step-wise procedure for the regeneration of fertile plants by organogenesis from cultures of the economically important Phaseolus angularis L., cultivars: KS-6, KS-7 and KS-8 using etiolated seedlings was established. Pre-culture of 5-day old seedling explants with MS (Murashige and Skoog (1962) Physiol Plant 15:473–493) + B5-vitamins (Gamborg et al. (1968) Exp Cell Res 50:151–158) liquid medium containing either 5.0 μM TDZ or 5.0 μM BAP under dark condition was essential for organogenesis. Bud growth and shoot multiplication were stimulated by reducing the BAP concentrations from 5.0 to 2.5 μM after 3 weeks. The maximum frequency of shoot induction was 65.2% (33.8 ± 2.54 shoots/explant) in cultivar KS-8 followed by KS-7 34.6% (23.4 ± 1.91 shoots/explant) and KS-6 30.6% (21.2 ± 2.28 shoots/explant). The multiplied buds elongated after transferring to solid MSB5 medium supplemented with 4.0 μM GA3, 12.5 μM AgNO3 and 0.4 μM IBA. Up to 98% rooting efficiency of was obtained when the shoots were pulse-treated with liquid medium containing 4.5 μM IBA for 10 min. The rooted plantlets were transferred to pots in the greenhouse, where they grew, mature, flowered and bared pod normally. The efficient shoot bud induction capability was found to be cultivar dependent. All the three cultivars tested formed multiple shoots. This efficient and rapid regeneration system may also be helpful for Agrobacterium- or particle gun-mediated transformation for this important legume crop. 相似文献
10.
The control of field tuber dormancy in the yam (Dioscorea cayenensis–D. rotundata complex) is poorly understood. Although studies have examined single environmental factors and chemical treatments that might prolong tuber dormancy and storage, only a few were focused on further tuber sprouting. The present study concerns microtubers obtained by in vitro culture. When microtubers were harvested (after 9 months of culture) and directly transferred on a new medium without hormones, the tubers rapidly sprouted in in vitro conditions. No dormancy was observed in this case. Harvested microtubers were also stored dry in jars in sterile conditions during 2 to 18 weeks before in vitro sprouting. In this case, microtubers stored during 18 weeks sprouted more rapidly than those stored 8 weeks. A constant “dormancy-like period” (storage duration + sprouting delay) was observed, between 20 and 28 weeks respectively for the more rapid and the slower microtubers. The size of the tubers used for the storage had great influence on further sprouting. The larger they were, the better they sprouted. Light during storage had no effect on the sprouting delay while a temperature of 25 °C permit a quicker sprouting than 18 °C. The medium used to obtain microtubers could also have an effect on sprouting rate. 相似文献
11.
Relative importance of maltose and sucrose supplied during a 2-step potato microtuberization process
A 2-stage in vitro tuberization process comprising first micropropagation via nodal explants and then tuber induction in the resultant in vitro plantlets was studied using 2 cultivars of potato, Iwa and Daeji. In particular, the effects on both plantlet growth and
subsequent in vitro tuberization of Murashige and Skoog (1962) basal medium containing either sucrose or maltose, each at 3 % (w/v), used for
micropropagation were investigated. Sucrose and maltose were found to be equally effective in supporting development of vigorous
plantlets from the nodal explants of both potato cultivars. Upon transfer to a medium with an optimised level of sucrose (i.e. 8 %, w/v) for in vitro tuberization, only the plantlets previously grown in the sucrose-containing medium were capable of forming more microtubers
of the larger size category (greater than 0.5 g). The relative importance of sucrose supply at the mircropropagation stage
was further confirmed when the resultant plantlets grown in the 3 % sucrose-containing medium were transferred to an in vitro tuberization medium containing either sucrose or maltose, each at 8 % (w/v). In this experiment, maltose and sucrose had
indistingushable effects on in vitro tuberization. 相似文献
12.
T. Kämäräinen-Karppinen E. Virtanen V.-M. Rokka A. M. Pirttilä 《Plant Cell, Tissue and Organ Culture》2010,101(2):245-249
Potato (Solanum tuberosum L. ssp. tuberosum) microtubers were produced in vitro with Liquid Lab™ Rocker system. A thin-layer liquid culture was applied together with
a regular pitch in autoclavable simple plastic vessels. All cultures were carried out at room temperature without contamination
problems. Each cultivar tested (Asterix, Timo, Van Gogh, Velox) formed microtubers in the Liquid Lab system. The mean number
of microtubers per vessel (50 explants) varied between 30 (cv. Asterix in 8 weeks tuber induction) and 75 microtubers (cv.
Velox in 11 weeks tuber induction). Majority (63%) of the microtubers was sufficient by size and weight (above 200 mg) for
further storage at dormancy (4°C). The cv. Velox yielded the highest number of microtubers with cultivation capacity. As a
result of prolonged microtuber induction of 2–3 weeks, more microtubers with competence for cultivation were obtained per
cultivar, except for cv. Van Gogh. Still, the mean weight of Van Gogh microtubers was significantly higher after prolonged
microtuber induction (0.67 g) than after short induction (0.51 g). In conclusion, Liquid Lab™ Rocker system is a novel, efficient
and rapid system for mass propagation of potato. 相似文献
13.
Microtubers of 13 cultivars, largely grown in Italy and other European countries, were induced. They were stored in the dark at 3°C for different periods (28, 56, 84 and 105 days), prior to being transferred to 20°C for between 4 and 17 weeks. Following removal to room temperature, sprouting was recorded and dormancy duration quantified. Dormancy decreased from 28.1 to 19.9, 11.1 and 7.8 days with reduced time of storage. Cvs Arsy, Nicola and Jaerla took consistently more time for dormancy release. The dormancy duration was linearly and inversely correlated with the length of storage. After sprouting, tubers were held at 20°C for various intervals and a range of physiological ages (0, 368, 720 and 1008 degree days) were accumulated. The field comparison of microtubers evidenced a plant growth response and tuber yield/plant affected by the cultivar and physiological age. In early cultivars (Jaerla), a better performance was shown by younger tubers; the opposite trend was noted in Alpha (a later cultivar) with an increase in stems/plant, tubers/plant and tuber yield/plant for tubers with greater physiological age. Like conventional seed tubers, microtubers showed differences in optimum physiological age associated with cultivar earliness. This study has provided some indications on how to enhance emergence and haulm development of plants from microtubers. 相似文献
14.
Embryogenic calli of Dioscorea bulbifera L. were successfully cryopreserved using an encapsulation-vitrification method. Embryogenic calli were cooled at 6°C for
5 days on solid MS medium (Murashige and Skoog 1962) containing 2 mg L−1 Kinetin (Kn), 0.5 mg L−1 α-naphthalene acetic acid (NAA) and 0.5 mg L−1 2,4-dichlorophenoxy-acetic acid (2,4-D). These were prior precultured on liquid basal MS medium enriched with 0.75 M sucrose
at 25 ± 1°C for 7 days. Embryogenic calli were osmoprotected with a mixture of 2 M glycerol and 1 M sucrose for 80 min at
25°C and dropped in a 0.1 M CaCl2 solution containing 0.4 M sucrose at 25 ± 1°C. After 15 min of polymerization, Ca-alginate beads (about 4 mm in diameter)
were dehydrated for 150 min at 0°C in a PVS2 solution [30% glycerol, 15% ethylene glycol, and 15% dimethyl sulfoxide (w/v)] containing 0.5 M sucrose. The encapsulated
embryogenic calli were then plunged directly into LN (liquid nitrogen) for 1 h. After rapid thawing in a water bath (37°C;
2 min), the beads were washed 3 times at 10-min intervals in liquid basal MS medium containing 1.2 M sucrose. Following thawing,
the embryogenic calli were transferred to fresh solid basal MS media supplemented with Kn 2 mg L−1, 0.09 M sucrose and 0.75% (w/v) agar (embryoid induction medium) and cultured under light conditions of 12-h photoperiod
with a light intensity of 36 μmol m−2 s−1 provided by white cool fluorescent tubes after a 2-day dark period at 25 ± 1°C. After 30 days, the embryoids developed from
embryogenic calli were transferred to fresh solid basal MS media supplemented with Kn 2 mg L−1, NAA 0.5 mg L−1, 3% (w/v) sucrose and 0.75% (w/v) agar (regeneration medium). After 60 days, the embryogenic calli developed normal shoots
and roots. No morphological abnormalities were observed after plating on the regeneration medium. The survival rate of encapsulated
vitrified embryogenic callus reached over 70%. This encapsulation-vitrification method appears promising as a routine and
simple method for the cryopreservation of Dioscorea bulbifera embryogenic callus. 相似文献
15.
Nodal cuttings of white yam were induced to produce microtubers on a MS-revised medium supplemented with various concentrations of sucrose, 20 mgl–1 L-cysteine, 0.5 mgl–1 kinetin and 0.7% agar. The frequency of tuberization was affected by the daylength, which is optimal at 12 and 16 h of light depending on the sucrose concentration. The microtubers were planted in a seed bed and grown to maturity. The importance of in vitro tuberization of yam as a means of international germplasm distribution or exchange as well as for the propagation of planting material is discussed. 相似文献
16.
J. E. Bourque J. C. Miller W. D. Park 《In vitro cellular & developmental biology. Plant》1987,23(5):381-386
Summary Nodal cuttings from micropropagated potato plantlets give rise to microtubers when placed on Murashige and Skoog medium containing
6% sucrose and 2.5 mg/liter kinetin and incubated in the dark at 19°C. Microtubers produced from the cultivar Superior were
shown to contain the same characteristic group of proteins as field-grown tubers. As with field-grown tubers, the 40 000-dalton
major tuber glycoprotein, patatin, accumulated to high levels in microtubers, reaching 3.7±0.2 mg/g fresh weight after 90
d. Also in agreement with field-grown plants, stems and leaves of micropropagated plantlets did not contain detectable levels
of patatin, but small amounts of an electrophoretically distinct form accumulated transiently in roots. Patatin mRNA is readily
detectable in developing microtubers 15 d after transfer of the cuttings to inductive medium. Patatin mRNA was also present
in roots, but as with field-grown plants, was 50- to 100-fold less abundant and could be distinguished from that in tubers
by primer extension. Microtuber development and patatin accumulation were inhibited by gibberellic acid.
This work was supported by grants 83-CRCR-1-1348 and 85-CRCR-I-1792 from the U.S. Department of Agriculture Competitive Grants
program and with funds from the Texas Agricultural Experiment Station. 相似文献
17.
ELLIS R. H.; QI A.; CRAUFURD P. Q.; SUMMERFIELD R. J.; ROBERTS E. H. 《Annals of botany》1997,79(2):169-178
The duration of the vegetative phase (i.e. days from sowingto panicle initiation) in sorghum [Sorghum bicolor (L.) Moench]is affected by photoperiod and temperature. Plants of severalcontrasting genotypes of sorghum were grown in controlled-environmentgrowth cabinets with either synchronous or asynchronous photoperiodsand thermoperiods. Apical development was recorded. Diurnalasynchrony between photoperiod and thermoperiod reduced durationsto panicle initiation when the temperature warmed after lightswent on and cooled after lights went off, but increased thesedurations when the temperature warmed before lights went onand cooled before lights went off. These effects were shownin the maturity lines 60M and SM100 and also in the USA cv.RS610 and the Sudanese landrace IS22365, but their magnitudevaried with genotype, photothermal regime, and the degree ofasynchrony. The greatest effect was detected in IS22365 grownat 30/21 °C (12 h/12 h) with a 12 h d-1photoperiod whenthe temperature warmed 2.5 h before lights went on and cooled2.5 h before lights went off, when the duration from sowingto panicle initiation was 69 d compared with 37 d in the control(synchronous photoperiod and thermoperiod in each diurnal cycle). Reciprocal transfers of plants of IS22365 between short andlong days revealed that asynchrony principally affected theduration of the photoperiod-insensitive pre-inductive phaseof development; i.e. asynchrony affected the time (age) at whichthe plants were first able to respond to photoperiod. In thatinvestigation in controlled-environment growth chambers, thesubsequent photoperiod-sensitive inductive phase continued untilpanicle initiation. Subsequent reciprocal transfer experimentsin controlled-environment glasshouses in four different alternatingtemperature regimes employed synchronous photoperiods and thermoperiodsin short (11 h) days with temperature warming 1.5 h after thebeginning of the day in long (12.5 h) days. In those investigations,photoperiod sensitivity ended some time before (2.58.1d, mean 5.7 d) panicle initiation in IS22365, Naga White andSeredo. Moreover, whereas the duration of the photoperiod-insensitivepre-inductive phase was affected by temperature, the durationsof the photoperiod-sensitive inductive and the photoperiod-insensitivepost-inductive phases were not. Sorghum bicolor (L.) Moench; sorghum; asynchrony; photoperiod; thermoperiod; vegetative phase; panicle initiation 相似文献
18.
This study analyzed changes of life history parameters of a Daphnia pulicaria clone in response to increasing (spring conditions) versus decreasing (fall conditions) photoperiod and low and high food
concentrations in maternal and offspring environments. One treatment increased the photoperiod from 12 to 16 h at a rate of
3 min per day, while the other treatment decreased the photoperiod from 16 to 12 h at the same rate. We also used two food
concentrations: low (0.2 mg C/l) and high (0.5 mg C/l). Maturation time, first clutch size, survivorship, and somatic growth
in offspring depended on the direction of photoperiodic changes for Daphnia grown under high food concentration. Natural-like changes of photoperiod on life history parameters and abrupt changes resulted
in similar effects on life history parameters of Daphnia (see Alekseev and Lampert 2004 Hydrobilogia 526:225–230). 相似文献
19.
Paul Ondo Ovono Claire Kevers Jacques Dommes 《Plant Cell, Tissue and Organ Culture》2007,91(2):107-114
Yams (Dioscorea spp) are tuber crops used as staple food in Africa because of their nutritional value. However agronomic constraints, phytosanitary
problems and the lack of good healthy planting material restrict their production. In contrast to the inefficiency of traditional
method of planting, tissue culture techniques allow to increase the multiplication and the rapid production of pathogen- free
plant material. This work was undertaken to provide farmers in African countries with healthy microplants and microtubers
as seeds. In vitro nodal segments of two varieties of local yams D. cayenensis–D. rotundata complex (cv. ‘Singo’, cv. ‘Singou’ and cv. ‘Gnidou’) were micropropagated on the modified medium of Murashige and Skoog.
The morphogenesis, the growth of microplants and microtuber formation have been found to be controlled by external factors
that act individually and synergistically. Addition of kinetin (2 mg l−1) to the culture media could reduce multiplication rate (node number) of some clones. An increase of the sucrose concentration
from 3% to 5% induced no change in the multiplication and tuberisation parameters. An important reduction of the multiplication
(shoot number, height and node number) and the tuberisation (tuber number and length) was observed with 8% sucrose. Multiplication
(shoot and node number) was increased in the presence of jasmonic acid (10 μM). JA also induced an increase of tuber number
in the absence of Kin. Multiplication of yam by in vitro growth of nodal segments is a way for rapid clonal multiplication
and could allow solving the problem of lack of seed material faced by farmers. This method could also be used for multiplication
of elite cultivars, independently of the growing season. 相似文献
20.
When cotyledonary explants, excised from in vitro germinated seedlings, of pomegranate (Punica granatum L.) were incubated on solid Murashige and Skoog (1962) medium supplemented with 21 μM naptheleneacetic acid (NAA) and 9 μM 6-benzyladenine (BA), 80% of explants developed callus.
A high frequency of shoot organogensis was obtained when explants were incubated on MS medium supplemented with 8 μM BA, 6 μM
NAA, and 6 μM giberrellic acid (GA3). However, adding 24 μM silver nitrate (AgNO3) to this medium markedly enhanced shoot regeneration frequency (63%) and mean number of shoots per explant (11.26) and length
of shoots (2.22 cm). Highest frequency of in vitro rooting, mean number of roots/shoot (4.32), and mean root length (2.71 cm)
were obtained when regenerated shoots were transferred to half-strength MS medium supplemented with 0.02% activated charcoal.
Well-rooted plantlets were acclimatized, and then transferred to soil medium. Moreover, when zygotic embryos of P. granatum, excised from seeds collected at 16 weeks following full bloom, were incubated on MS medium containing 30 g l−1 sucrose, 15% coconut water, 21 μM NAA, and 9 μM BA, they developed the highest frequency of embryogenic callus, clumps with
globular embryos, and mean number of both globular and heart-shaped embryos per callus clump. Subjecting zygotic embryo explants
to six-week dark incubation period was essential for embryogenic callus induction, and these were subsequently transferred
to 16 h photoperiod for further growth and development of somatic embryos. Germination of somatic embryos was observed when
these were transferred to MS medium was supplemented with 60 g l−1 sucrose. 相似文献