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1.
Development of two endomycorrhizal symbioses on soybean and comparison with phosphorus fertilization
Summary Soybean (Glycine max L. Merr. cv. Amsoy 71) plants were grown in a greenhouse in a soil very low in plant-available P, and plants were harvested
5 times over a 21-week growth period. Soybeans were inoculated with one of two species of VAM fungi or received daily one
of three nutrient solutions of different P concentrations (0.0, 0.2, or 1.0mMP). Until week 9, the dry weights, leaf areas and developmental stage of soybeans inoculated withG. fasciculatum orG. mosseae were similar to the 1.0 or 0.2mMP-treated plants, respectively. Phosphorus concentrations were significantly lower in VAM plants at weeks 6 and 9 as compared
to non-VAM soybeans given 1.0mMP, suggesting P input in VAM plants was immediately used for new growth. Total P input for VAM plants was linear over 21 weeks,
and the average rate of P uptake for these plants was 0.19mg P d−1. Estimated specific P uptake rates (SPUR) for the mycorrhizae (VAM roots) were twice that of the control (0.0mMP) roots. The calculated SPURs forG. fasciculatum andG. mosseae hyphae were 95 and 120μg P g−1 VAM d−1 respectively, a 4 to 5 fold increase over non-inoculated roots, indicating more attention must be paid to P assimilation
by VAM fungi in P-fixing substrates.
Contribution from the Western Regional Research Center, USDA-ARS (CRIS No. 5325-20580-003). 相似文献
2.
Understanding of the mechanisms of Mn supply from the soil and uptake by the plants can be improved by using simulation models
that are based on basic principles. For this, a pot culture experiment was conducted with a sandy clay loam soil to measure
Mn uptake by summer wheat (Triticum aestivum L. cv. Planet), maize (Zea mays L. cv. Pirat) and sugar beet (Beta vulgaris L. cv. Orbis) and to simulate Mn dynamics in the rhizosphere by means of a mechanistic model. Seeds of three crops were sown
in pots containing 2.9 kg soil in a controlled growth chamber. Root and shoot weight, Mn content of plants, root length and
root radius were determined 8 (13 days in case of sugar beet) and 20 days after germination. Soil and plant parameters were
determined to run nutrient uptake model calculations. Manganese content of the shoot varied from 25 mg kg-1 for sugar beet to 34 mg kg-1 for maize. Sugar beet had the lowest root length/shoot weight ratio but the highest relative shoot growth rate, resulting
in the highest shoot demand on the root. This is reflected by the Mn influx which was 0.9 × 10-7, 1.7 × 10-7 and 2.5 × 10-7 nmol cm-1 s-1 for wheat, maize and sugar beet, respectively. Nutrient uptake model calculations predicted similar influx values. Initial
Mn concentration of 0.2 μM in the soil solution decreased to only 0.16 μM for wheat, 0.13 μM for maize and 0.11 μM for sugar beet at the root surface. This shows that manganese transport to the root was not a limiting step. This was confirmed
by the fact that an assumed 20 times increase in maximum influx (Imax) increased the calculated Mn influx by 3.7 times. Sensitivity analysis demonstrated that for controlling Mn uptake the initial
soil solution concentration (C
Li), the root radius (r0), Imax and the Michaelis constant (K
m) were the most sensitive factors in the listed order.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
The effects of low concentrations of aluminium on the growth and uptake of nitrate-N by white clover 总被引:1,自引:0,他引:1
Summary The effects of aluminium (Al3+) at concentrations of 0, 25, 50 and 100 μM on the growth of white clover, dependent upon N supplied as NO
3
−
, were examined in flowing solution culture. Plants were established with a normal nutrient supply for 7 weeks and then grown
with carefully controlled pH (at 4.5) and P concentrations, and with 0, 25, 50 or 100 μM Al3+ for a further three weeks. There were rapid visual effects (i.e. symptoms of P deficiency and reduction in root extension) and the dry weights of shoots and roots were reduced at 50 and
100 μM. Less than 10% of Al absorbed from solution was transported to the shoots. The uptake of P, and its transport between roots
and shoots, were reduced in plants grown with Al. The uptake of NO
3
−
stopped immediately after the introduction of 50 or 100 μM Al, and was significantly reduced at 25 μM after three weeks.
During a second phase of the experiment, plants previously grown at 0, 25, 50 and 100 μM Al, were grown for a further 2 weeks either with NO
3
−
(with and without 50 μM Al3+) or without NO
3
−
but with inoculation by Rhizobia (and with or without 50 μM Al3+). The effects of the previous treatments with Al on N uptake were small during the second phase, but uptake by all plants
was restricted when Al was present. Inoculation did not result in nodulation in the second phase when Al3+ was present in the solution, but Al already in the plant from the first phase did not prevent nodulation in the absence of
Al during the second phase. 相似文献
4.
The uptake of soluble phosphate by the green sulfur bacterium Chlorobium limicola UdG6040 was studied in batch culture and in continuous cultures operating at dilution rates of 0.042 or 0.064 h–1. At higher dilution rates, washout occurred at phosphate concentrations below 7.1 μM. This concentration was reduced to 5.1
μM when lower dilution rates were used. The saturation constant for growth on phosphate (K
μ) was between 2.8 and 3.7 μM. The specific rates of phosphate uptake in continuous culture were fitted to a hyperbolic saturation
model and yielded a maximum rate (Va
max) of 66 nmol P (mg protein)–1 h–1 and a saturation constant for transport (K
t) of 1.6 μM. In batch cultures specific rates of phosphate uptake up to 144 nmol P (mg protein)–1 h–1 were measured. This indicates a difference between the potential transport of cells and the utilization of soluble phosphate
for growth, which results in a significant change in the specific phosphorus content. The phosphorus accumulated within the
cells ranged from 0.4 to 1.1 μmol P (mg protein)–1 depending on the growth conditions and the availability of external phosphate. Transport rates of phosphate increased in
response to sudden increases in soluble phosphate, even in exponentially growing cultures. This is interpreted as an advantage
that enables Chl. limicola to thrive in changing environments.
Received: 9 February 1998 / Accepted: June 1998 相似文献
5.
Preferential utilization of organic and inorganic sources of phosphorus by wheat plant 总被引:3,自引:0,他引:3
On soils of low P supply organic P (Po) makes up a similar or even larger part in soil solution than inorganic P (Pi). The
ability of wheat (Triticum aestivum L., cv. Star) plants to hydrolyze and absorb this Po in comparison to similar concentrations of Pi was studied. Four concentration
levels of Pi and Po were obtained by extracting two soils with deionized water in a ratio of 1:1 and concentrating the resulting
filtrate by freeze drying to different degrees. The concentration of Pi varied between 5 and 36 μM and Po between 3 and 22 μM. Wheat seedlings were grown in these solutions for 12 and 24 h and acid and alkaline phosphatase activity determined. The
reduction of Po concentration in solution expressed on a root length basis gave the rate of Po hydrolysis and the reduction
in concentration of Pi and Po gave the P inflow into the roots. No alkaline phosphatase activity was detected. The activity
of wheat root acid phosphatase increased with Po concentration in solution. Phosphorus uptake was 2 to 6 fold higher from
Pi than from Po at similar concentrations of both. The rate of uptake from Pi, the inflow, as well as the rate of hydrolysis
of Po increased linearly with concentration but at similar concentration the inflow was 2 to 4 times higher than the rate
of Po hydrolysis. Results suggest that plants can utilize Po after hydrolysis by phosphatase, but Pi is more important and
preferentially used by plants; Po may be essential for plant nutrition especially in high P-fixing soils. 相似文献
6.
Increased levels of rhizospheric dissolved inorganic carbon have repeatedly been demonstrated to enhance plant growth by up
to 80%, although carbon from dark fixation accounts for only 1–3% of total plant carbon gain. This study, therefore, aimed
at investigating the effects of bicarbonate on nitrate uptake, assimilation and translocation to shoots. Clonal saplings of
poplar (Populus canescens(Ait.) Sm.) and elder (Sambucus nigraL.) were grown hydroponically for 35 days in a nutrient solution containing 0, 0.5 and 1 mM bicarbonate and 2 mM nitrate as the sole nitrogen source at pH 7.0. Net nitrate uptake, root nitrate accumulation and reduction, and export of
nitrogenous solutes to shoots were measured after incubating plants with 15N-labelled nitrate for 24 h. Net nitrate uptake increased non-significantly in plant species (19–61% compared to control plants)
in response to 1 mM bicarbonate. Root nitrate reduction and nitrogen export to shoots increased by 80 and 95% and 15 and 44% in poplar and elder,
respectively. With enhanced root zone bicarbonate, both species also exhibited a marked shift between the main nitrate utilising
processes. Poplar plants increasingly utilised nitrate via nitrate reduction (73–88% of net nitrate uptake), whereas the proportions
of export (20–9%) and storage in roots (7–3%) declined as plants were exposed to 1 mM external bicarbonate. On the other hand, elder plants exhibited a significant increase of root nitrate reduction (44–66%)
and root nitrate accumulation (6–25%). Nitrate translocation to elder shoots decreased from 50 to 8% of net nitrate uptake.
The improved supply of nitrogen to shoots did not translate into a significant stimulation of growth, relative growth rates
increased by only 16% in poplar saplings and by 7% in elder plants.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
The modelling of ion uptake by plants requires the measurement of kinetic and growth parameters under specific conditions.
The objective of this study was to evaluate the effect of nine NH
inf4
sup+
:NO
inf3
sup−
ratios on onions (Allium cepa L.). Twenty-eight to 84 day-old onion plants were treated with NH
inf4
sup+
:NOf3/sup− ratios ranging from 0 to 100% of each ionic species in one mM solutions in a growth chamber. Maximum N influx (Imax) was assessed using the N depletion method. Except at an early stage, ionic species did not influence significantly Imax, the Michaelis constant (Km) and the minimum concentration for net uptake (Cmin). Imax for ammonium decreased from 101 to 59 pmole cm-2 s-1 while Imax for nitrate increased from 26 to 54 pmole cm-2 s-1 as the plant matured. On average, Km and Cmin values were 14.29 μM, and 5.06 μM for ammonium, and 11.90 μM and 4.54 μM for nitrate, respectively. In general, the effect of NH4
+:NO3
- ratios on root weight, shoot weight and total weight depended on plant age. At an early stage, maximum plant growth and N
uptake were obtained with ammonium as the sole source of N. At later stages, maximum plant growth and N uptake were obtained
as the proportion of nitrate increased in the nutrient solution. The was no apparent nutrient deficiency whatever NH4
+:NO3
- ratio was applied, although ammonium reduced the uptake of cations and increased the uptake of phosphorus.
The research was supported by the Natural Sciences and Engineering Research Council of Canada. 相似文献
8.
Pradeep K. Agarwal Rajinder S. Ranu 《In vitro cellular & developmental biology. Plant》2000,36(5):392-397
Summary The in vitro plant regeneration potential of vegetatively propagated geraniums (Pelargonium x hortorum) has been investigated. Using various combinations of growth regulators and a choice of different explants, a regeneration
protocol has been developed to raise in vitro plantlets from young petiole and leaf explants from three different cultivars of geraniums. In all three cultivars, very
young petiole explants exhibited a higher regeneration potential as compared with leaf explants. Regeneration efficiencies
were found to be highly dependent on the cultivar, with cv. Samba showing the highest regeneration potential, followed by
cvs. Yours Truly and then Sincerity. Samba also showed the highest number of shoots from both the petiole [57 shoot buds per
petiole explant in the presence of 3 μM zeatin and 1 μM indole-3-acetic acid (IAA) and leaf explants (43 shoots per leaf explant with 10 μM zeatin and 2 μM IAA). Shoot buds transferred to Murashige and Skoog (MS) medium supplemented with 0.44 μM N6-benzyladenine and 0.11 μM IAA grew vigorously and attained 1–2 cm in length in 3–4 wk. These shoots rooted with 100% efficiency on MS basal medium,
and plants developed that showed normal growth and flowering under greenhouse conditions. 相似文献
9.
Summary The generation of transgenic Cucumis sativus cv. Greenlong plants resistant to phosphinothricin (PPT) was obtained using Agrobacterium tumefaciens-mediated gene transfer. The protocol relied on the regeneration of shoots from cotyledon explants. Transformed shoots were
obtained on Murashige and Skoog medium supplemented with 4.4 μM 6-benzylaminopurine 3.8 μM abscisic acid, 108.5 μM adenine sulfate, and 2 mg l−1 phosphinothricin. Cotyledons were inoculated with the strain EHA105 harboring the neomycin phosphotransferase II (npt II), and phosphinothricin resistance (bar) genes conferring resistance to kanamycin and PPT. Transformants were selected by using increasing concentrations of PPT
(2–6 mg l−1). Elongation and rooting of putative transformants were performed on PPT-containing (2 mg l−1) medium with 1.4 μM gibberellic acid and 4.9 μM indolebutyric acid, respectively. Putative transformants were confirmed for transgene insertion through PCR and Southern
analysis. Expression of the bar gene in transformed plants was demonstrated using a leaf painting test with the herbicide Basta. Pre-culture of explants
followed by pricking, addition of 50 μM acetosyringone during infection, and selection using PPT rather than kanamycin were found to enhance transformation frequency
as evidenced by transient β-glucuronidase assay. Out of 431 co-cultivated explants, 7.2% produced shoots that rooted and grew
on PPT, and five different plants (1.1%) were demonstrated to be transgenic following Southern hybridization. 相似文献
10.
K. Ohki 《Plant and Soil》1987,98(2):195-202
Summary Sorghum plants were grown in the greenhouse in modified Steinberg nutrient solution containing ten Al rates (0 to 297 μM) and harvested 28 days after transplanting. Top and root dry weight were not affected by added Al up to 74 μM; but decreased sharply at concentration of 148 μM and greater. Aluminum concentrations in blade 1 (recently matured blade) and plants remained constant from 0 to 297 μM added Al. Root Al concentration increased as added Al increased. No correlation existed between top dry weight and Al concentration
in blade 1 or in plant. Root Al concentration was related to top dry weight and root dry weight to estimate the Al critical
toxicity level. The Al critical toxicity levle in the root was 54 mmol kg−1 root dry weight basis for either top or root dry weight. In blade 1 Cu concentration negatively correlated with Al while
Fe and P were positively correlated. In roots Ca, Mg, Mn and Fe concentrations were negatively correlated with Al while Zn,
Cu, P, and K were positively correlated with Al concentration. 相似文献
11.
Summary Thidiazuron (TDZ) is a substituted phenylurea which has been shown to be an efficacious regulator of in vitro morphogenesis of many dicot plant species. However, information regarding the effect of TDZ on in vitro regeneration of monocot species is limited. We investigated the effects of TDZ on in vitro regeneration of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) and found that it promoted shoot regeneration from callus in these two important cereal species. Plant regeneration from
calluses derived from immature embryo culture of barley and wheat was observed in regeneration media with a wide range of
TDZ concentrations (0.045–45 μM). Shoot regeneration from barley calluses was the highest (38.3% for cv. Golden Promise) at 4.5 μM (1 mg l−1) TDZ, while the optimal TDZ level for wheat regeneration seemed to be 0.9 μM (0.2 mg l−1) (87% for cv. Bob White and 49.4% for cv. Hi Line). Roots developed normally when the regenerated wheat and barley shoots
from TDZ-containing media were transferred to the rooting medium. Comparison with other plant growth regulators commonly used
in wheat and barley regeneration media suggested that TDZ was among the best for in vitro regeneration of wheat and barley.
Both authors contributed equally 相似文献
12.
Deepak Prem Subhadra Singh Padam Prakash Gupta Jaivir Singh Gaurav Yadav 《In vitro cellular & developmental biology. Plant》2003,39(4):384-387
Summary Guar (Cyamopsis tetragonoloba L. Taub) is a drought-tolerant multipurpose cash crop. A rapid regeneration system has been developed for four Indian guar
genotypes. Investigations were carried out to assess the effect of different growth regulators and their combinations on a
variety of explants such as the embryo, cotyledons, and cotyledonary nodes for shoot morphogenesis. It was established that
Murashige and Skoog's culture medium containing 6-benzylaminopurine (13.3 μM or 3 mgl−1) in combination with indole-3-acetic acid (11.4 μM or 2mgl−1) with cotyledonary node explants gave the highest frequency of multiple shoot induction. In vitro rooting from cultured shoots was maximal on a half-salt concentration of Murashige and Skoog's culture medium fortified with
indole-3-butyric acid (4.9 μM or 1 mgl−1). In vitro-regenerated plants were grown to pod setting and subsequent maturity in greenhouse conditions. 相似文献
13.
Muhammad Iqbal Chaudhary Joseph J. Adu-Gyamfi Hirofumi Saneoka Nguyen Tran Nguyen Ryuichi Suwa Shynsuke Kanai Hany A. El-Shemy David A. Lightfoot Kounosuke Fujita 《Acta Physiologiae Plantarum》2008,30(4):537-544
Phosphorous (P) fertilization is the major mineral nutrient yield determinant among legume crops. However, legume crops vary
widely in the ability to take up and use P during deficiency. The aim here was to compare P uptake and translocation, biological
nitrogen fixing ability and photosynthetic rate among mashbean (Vigna aconitifolia cv. ‘Mash-88’), mungbean (Vigna
radiata cv. ‘Moong-6601’) and soybean (Glycine max L. cv. ‘Tamahomare’) during deficiency in hydroponics. Two treatments, the withdrawal of P from the solution (P-deprivation)
and continued P at 160 μM (P sufficient) were effected at the pod initiation stage. Plants were grown for 20 days. Short-term
labeling with 32P showed the uptake and distribution of P into plant parts. Withdrawal of P from the solution reduced biomass, photosynthetic
activity, and nitrogen fixing ability in mungbean, and mashbean more than in soybean. P deprivation decreased P accumulation
more than N accumulation. The decrease was more severe in mungbean and mashbean than soybean. More P was translocated and
distributed into leaves in soybean than in mungbean and mashbean. Leaf P amount was more correlated to leaf area than to photosynthetic
rate per unit leaf area among all three legume species. The results indicate that selection for increased efficiency of P
utilization and leaf area may be used to improve leguminous crops. 相似文献
14.
Rakhi Chaturvedi S. P. Bhatnagar 《In vitro cellular & developmental biology. Plant》2001,37(2):255-258
Summary A protocol for in vitro shoot regeneration from cotyledon explants of Citrullus lanatus (Thunb.) Matsum. & Nakai cv. Sugar Baby is described. The cotyledons excised from 7-d-old aseptic seedlings showed the highest
percentage of shoots on Murashige and Skoog (MS) + N6-benzyladenine (BA; 3.0 μM) + N6-[2-isopentenyl] adenine (2iP; 3.0 μM) and MS + BA (3.0 μM) + indole-3-acetic acid (IAA; 3.0 μM). Whereas the latter medium induced shoot regeneration after the callusing of the explant, the former stimulated direct shoot
formation. The regenerated shoots were rooted and the resulting plants were established in earthen pots with 55% success. 相似文献
15.
Kawahigashi H Hirose S Ozawa K Ido Y Kojima M Ohkawa H Ohkawa Y 《Transgenic research》2005,14(6):907-917
We introduced two novel types of pig (Sus scrofa) cytochrome P450, CYP2B22 and CYP2C49, into rice plants (Oryza sativa L. cv. ‘Nipponbare’) to produce herbicide-tolerant plants and to confirm the metabolic activities of the cytochrome P450
species. In germination tests, both types of transgenic plants showed tolerance to various herbicides with different modes
of action. CYP2B22 rice plants showed tolerance towards 12 herbicides including chlortoluron (100 μM), amiprofos-methyl (2.5 μM),
pendimethalin (10 μM), metolachlor (2.5 μM), and esprocarb (20 μM). CYP2C49 rice plants showed tolerance towards 13 herbicides,
including chlortoluron (100 μM), norflurazon (0.5 μM), amiprofos-methyl (2.5 μM), alachlor (0.8 μM), and isoxaben (1 μM).
The herbicide tolerance was considered to reflect the substrate specificity of the introduced P450 species. We used 14C-labeled metolachlor and norflurazon to confirm the P450 activity in the transgenic rice plants. The herbicides were metabolized
more quickly in the transgenic rice plants than in the nontransgenic rice plants. Therefore, CYP2B22 and CYP2C49 rice plants
became more tolerant to various herbicides than nontransgenic control plants because of accelerated metabolism of the herbicides
by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, these transgenic rice plants
may become useful tools for the breeding of herbicide-tolerant crops. 相似文献
16.
Summary Callus cultures were established from pith tissue of Coryphantha elephantidens (Lem.) Lem. on Murashige and Skoog (MS) basal medium supplemented with 9.05 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.3 μM kinetin. Highest shoot regeneration frequency was observed on a medium containing 6.9 μM kinetin and 2.3 μM 2,4-D under 30 μE m−2 s−1 light intensity with a 16-h photoperiod. Calluses retained organogenic potential throughout several passages of subculture
(18 mo.). Shoots were rooted on MS medium without plant growth regulators. All (100%) plantlets transplanted to soil survived
acclimatization. Regenerated plants showed good overall growth and were morphologically similar to the mother plants. 相似文献
17.
Summary Success has been achieved in developing a complete protocol for mass propagation of Anogeissus pendula and A. latifolia, two important forest species found in India. Seeds cultured on plant growth regulator-free, semisolid Murashige and Skoog
(MS) medium germinated within 5–6 wk and formed 4–6-cm long shoots. The shoots multiplied on MS+4.4 μM benzyladenine (BA)+5.7 μM indoleacetic acid (IAA) + casein hydrolysate (100 mgl−1) + ascorbic acid (50 mgl−1) + sucrose (3%) + agar (0.8%). A majority of the genotypes rooted with more than 90% efficiency when 5–6 cm individual shoots
were cultured on 1/2MS (only major salts reduced to half strength)+2.3 μM IAA+2.5 μM indolebutyric acid (IBA) + sucrose (3%)+agar (0.8%) for 15 d. Those 10% (approx.) genotypes that did not root well on the
above medium could be rooted with ease by increasing the concentration of IAA in the rooting media from 2.3 to 5.7 μM. The in vitro-raised plants were successfully transferred to the soil with a success rate of over 85%. Using this protocol, over 560 000
tissue-cultured plants of these two species have been produced and dispatched to various state forest departments for field
trials and routine plantations. 相似文献
18.
Root growth,macro-nutrient uptake dynamics and soil fertility requirements of a high-yielding winter oilseed rape crop 总被引:2,自引:0,他引:2
P. B. Barraclough 《Plant and Soil》1989,119(1):59-70
Shoot growth, root growth and macro-nutrient uptake by a high-yielding (5t/ha grain) winter oilseed rape crop have been measured.
Maximum rooting density in the top 20cm of soil was 9.4 cm cm−3 and roots reached a depth of at least 1.8 m. Maximum nutrient uptakes were 364 kg ha−1 for N, 43 kg ha−1 for P, 308 kg ha−1 for K, 287 kg ha−1 for Ca and 16 kg ha−1 for Mg. A 30-day drought coincided with the flowering period and root and shoot growth, as well as nutrient uptake rates,
were reduced. Nutrient concentrations in the soil solution necessary to sustain the nutrient fluxes into the root system by
diffusive supply have been calculated. Peak values were in the range 10 μM for P to 87 μM for N, lower than the observed concentrations, and it was concluded that nutrient transport to roots was not a limitation
to uptake by this rape crop. 相似文献
19.
The objective of this study was to determine if plant roots have to take up nitrate at their maximum rate for achieving maximum
yield. This was investigated in a flowing-solution system which kept nutrient concentrations at constant levels. Nitrate concentrations
were maintained in the range 20 to 1000 μM. Maximum uptake rate for both species was obtained at 100 μM.
Concentrations below 100 μM resulted in decreases in uptake rate per cm root (inflow) for both spinach and kohlrabi by 1/3 and 2/3, respectively. However,
only with kohlrabi this caused a reduction in N uptake and yield. Thus indicating that this crop has to take up nitrate at
the maximum inflow. Spinach, however, compensated for lower inflows by enhancing its root absorbing surface with more and
longer roots hairs. Both species increased their root length by 1/3 at low nitrate concentrations. 相似文献
20.
G. Vengadesan N. Selvaraj R. Prem Anand V. Gaba A. Ganapathi 《In vitro cellular & developmental biology. Plant》2005,41(6):789-793
Summary Suspension culture of cucumber (Cucumis sativus L.) has been an inefficient method for production of somatic embryos owing to problems with embryo maturation and conversion.
Embryogenic callus of cv. Green Long was induced on semisolid Murashige and Skoog (MS) medium containing 6.8 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.2 μM 6-benzylaminopurine (BA). A large number of globular somatic embryos were obtained on transfer of the callus to MS liquid
medium supplemented with 87.6 mM sucrose, 1.1 μM 2,4-D, and improved by the addition of 342.4 μM
l-glutamine. MS medium supplemented with 87.6 mM sucrose was more effective in somatic embryo production than other sugars. Subsequent development led to the formation of
heart-and torpedo-shaped embryos. Maturation of somatic embryos occurred on plant growth regulator-free MS semi-solid medium
containing 175.2 mM sucrose and 0.5 gl−1 activated charcoal. Conversion of embryos into plants was achieved on half-strength MS semi-solid medium containing 87.6
mM sucrose and 1.4 μM gibberellic acid (GA3) in a 16h photoperiod. Twenty-seven percent of embryos were converted into normal plants. 相似文献