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1.
C. E. Aragón C. Sánchez J. Gonzalez-Olmedo M. Escalona L. Carvalho S. Amâncio 《Biologia Plantarum》2014,58(1):29-38
The current work compared the physiological characteristics of plantain (Musa AAB) plantlets micropropagated in temporary immersion bioreactors (TIB) and on a gelled medium (GM). The plantlets were evaluated during in vitro growth (in the shoot elongation phase) and at the end of ex vitro acclimatization. TIB improved rooting and gave rise to longer shoots and higher dry mass. Respiration rate was the highest at the beginning of shoot elongation in both the TIB and GM plantlets. Photosynthetic rate in TIB was significantly higher than in GM from the midpoint of acclimatization, whereas a pyruvate kinase (PK) activity was lower. Starch accumulation was ca. two fold higher in corms than in leaves and always higher in the TIB than GM plantlets. The higher expression of genes coding for carbon metabolism enzymes PK and phosphoenolpyruvate carboxylase (PEPC) in TIB than in PM indicates a more important role of an autotrophic metabolism in the TIB plantlets when compared to the GM ones. The accumulated reserves were used during the first days of acclimatization leading to the higher survival rates and to the better plant quality of the TIB plantlets. 相似文献
2.
Masmoudi Raja Rival Alain Nato Aimé Lavergne Danièle Drira Nourredine Ducreux Georges 《Plant Cell, Tissue and Organ Culture》1999,57(2):139-143
While describing major trends of carbon metabolism during the initiation and expression of somatic embryogenesis in date palm
(Phoenix dactylifera L., cv. Deglet Nour), we have investigated the role of two carboxylases, namely PEPC (Phosphoenolpyruvate
carboxylase, EC 4.1.1.31) and RubisCO (Ribulose 1,5-bisphosphate carboxylase/oxygenase, EC 4.1.1.39), in embryogenic and non-embryogenic
cultures. The detection of PEPC activity on polyacrylamide native gels after electrophoresis revealed the presence of 3 active
isoforms in crude extracts from the embryogenic (E) callus strain, whereas only a single band was present in the non-embryogenic
(NE) one. The level of PEPC specific capacity was of the same order (3.9 ± 1.2 μmol CO2 h−1 mg−1 TSP) in both types of cultures. Further changes in carboxylase (PEPC and RubisCO) activities during the growth and development
of somatic embryo–derived plantlets were also analysed. The PEPC/RubisCO ratio was found to progressively decrease (from 17.7
to 0.2) throughout the in vitro development of plantlets, due to a substantial depletion of PEPC activity, which decreased
from 5.3 to 1.2 μmol CO2 h−1 mg−1 TSP. Concomitantly, RubisCO assumed greater importance (from 0.3 to 5.3 μmol CO2 h−1 mg−1
TSP
) and became the main route for inorganic carbon fixation. Western blot analysis using polyclonal antibodies raised against
PEPC and RubisCO purified from tobacco leaves confirmed this trend in terms of relative enzyme abundance.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
S. Roels C. Noceda M. Escalona J. Sandoval M.J. Canal R. Rodriguez P. Debergh 《Plant Cell, Tissue and Organ Culture》2006,84(2):100138-100146
The positive effect of ventilation of the culture container on in vitro shoot proliferation and quality was already proven for different species. Hereafter we report on the evolution of the headspace
during in vitro culture of plantain in a Temporary Immersion Bioreactor (TIB) on the one hand, and culture on semi-solid medium on the other
hand. The CO2 and C2H4 concentration reached a maximum of 12% and 0.45 μl l−1, respectively in the control treatment on semi-solid medium, compared to 5.7% CO2 and 0.06 μl l−1 C2H4 in TIB. The minimal O2-concentration on semi-solid medium was 15.1%, compared to 19.3% in TIB. The multiplication rate was best in TIB, 6.4 compared
to 4.3 in semi-solid conditions, and this was also the case for shoot height (4.3 cm compared to 3.3 cm), and leaf number
(2.6 compared to 1.6). Moreover shoots produced on semi-solid medium showed distorted leaves. A typical day-night pattern
in CO2 and O2 concentration was observed in TIB, as well as on semi-solid medium; this is illustrative for the photosynthetic capacity
of the plant material produced in both systems. 相似文献
4.
Romelio Rodriguez Carlos E. Aragon Maritza Escalona Justo L. Gonzalez-Olmedo Yves Desjardins 《In vitro cellular & developmental biology. Plant》2008,44(6):533-539
The activity of the main enzymes related to the sucrose metabolism, photosynthesis, and sucrose concentration were studied
in sugarcane (Saccharum spp hybrid) plantlets. Acclimatization was developed in two steps. (1) Light intensity of 1,000 μmol m−2 s−1 and 90% relative humidity during the first 21 d; followed by 2,000 μmol m−2 s−1 and approximately 80% of relative humidity. All measurements were carried out at the end of rooting phase concomitant with
day 0 of acclimatization and at 7-d intervals thereafter (0, 7, 14, 21, 28, 35, 42 d). As the in vitro plantlets were transferred to the acclimatization phase, photosynthesis increased significantly during the first 7 d. After
this period, the increase was constant with only a small but nonsignificant decline after being transferred to the uncontrolled
external conditions. The activity of the sucrose synthase began to show a decrease, starting from day 7, and was related to
the changes that began to happen in these plants from its adaptation to new ex vitro conditions. Due to the increase of fresh weight favored by the high light intensity and lower relative humidity, an increase
of the sucrose phosphate synthase activity was observed. The maximum activity of the acid and neutral invertases was reached
at 14 and 21 d, respectively, after 21 d of acclimatization period. There was a marked tendency for the activity of both enzymes
to decrease. The sucrose content was decreased only in the first 7 d. The metabolism of sugarcane plantlets seemed to be susceptible
to the environmental changes during the acclimatization phase but did not contribute to inhibitory factors for normal development. 相似文献
5.
6.
The effects of photosynthetic photon flux density (PPFD) on antioxidant metabolism and photosynthetic properties in leaves
during ex vitro establishment of micropropagated Rauvolfia tetraphylla plantlets were investigated. In vitro-propagated plantlets were acclimatized at either 50 (Low-light = LL) or 300 (High-light = HL)
μmol m−2s−1 photosynthetic PPFD for 4 weeks under controlled conditions. Increases in chlorophyll (Chl) a, b and carotenoid levels were observed in plantlets acclimatized at both light intensities. At transplantation, micropropagated
plantlets were not photosynthetically active, but the net photosynthetic rate increased in newly formed leaves over time during
acclimatization. The observed differences in pigment contents and photosynthetic rates suggested adaptation of plantlets from
heterotrophic to autotrophic mode of nutrition during acclimatization. Changes in activities of antioxidant enzymes were also
observed during acclimatization. Superoxide dismutase activity increased in plantlets acclimatized at HL intensities. Likewise,
changes in activity of catalase and ascorbate peroxidase were also detected. These observed changes reflected the ability
of plants in developing an antioxidant enzymatic defense system aiding in survival against oxidative stress and in reducing
release of free radicals. 相似文献
7.
Amâncio Sara Rebordão João Paulo Chaves Maria Manuela 《Plant Cell, Tissue and Organ Culture》1999,58(1):31-37
Grapevine plantlets multiplied in vitro were acclimatized at 40 or 90 μmol m−2 s−1 photon flux density for 12 or 16 h per day, respectively. In the high-light regime a decrease in total chlorophyll and an
increase in chlorophyll a/chlorophyll b ratio occurred. However, at high-light intensity lower photosynthetic capacities and higher apparent photosynthesis were
measured than at the low-light regime. In leaves expanded during acclimatization, the light compensation point was higher
in plantlets under high-light while quantum yield was higher in low-light conditions. High-light also gave rise to an increase
in carbohydrate concentration. As a whole, the results suggest that high-light increases carbon assimilation and growth although
with a low investment in the photosynthetic apparatus.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
In this article, the effects of increased light intensities on antioxidant metabolism during ex vitro establishment of Ulmus minor micropropagated plants are investigated. Three month old in vitro plants were acclimatized to ex vitro conditions in a climate chamber with two different light intensities, 200 μmol m−2 s−1 (high light, HL) and 100 μmol m−2 s−1 (low light, LL) during 40 days. Immediately after ex vitro transfer, the increase of both malondialdehyde (MDA) and electrolyte leakage in persistent leaves is indicative of oxidative
stress. As the acclimatization continues, an upregulation of the superoxide dismutase (SOD), catalase (CAT), and glutathione
reductase (GR) enzyme activities were also observed. Simultaneously, MDA content and membrane permeability stabilized, suggesting
that the antioxidant enzymes decrease the deleterious effects of reactive oxygen species (ROS) generation. Unexpectedly, newly
formed leaves presented a different pattern of antioxidative profile, with high levels of MDA and membrane leakage and low
antioxidant enzyme activity. Despite these differences, both leaf types looked healthy (e.g. greenish, with no necrotic spots) during the whole acclimatization period. The results indicate that micropropagated U. minor plantlets develop an antioxidant enzyme system after ex vitro transfer and that, in general, LL treatment leads to lower oxidative stress. Moreover, new leaves tolerate higher levels
of ROS without the need to activate the antioxidative pathway, which suggests that the environment at which leaves are exposed
during its formation determinate their ability to tolerate ROS. 相似文献
9.
Summary Coconut (Cocos nucifera L.) plantlets grown in vitro often grow slowly when transferred to the field possibly, due to a limited photosynthetic capacity of in vitro-cultured plantlets, apparently caused by the sucrose added to growth medium causing negative feedback for photosynthesis.
In this paper, we tested the hypothesis that high exogenous sucrose will decrease ribulose 1,5-bisphosphate carboxylase (Rubisco)
activity and photosynthesis resulting in limited ex vitro growth. Plantlets grown with high exogenous sucrose (90 gl−1) had reduced photosynthetic activity that resulted in a poor photosynthetic response to high levels of light and CO2. These plantlets also had low amounts of Rubisco protein, low Rubisco activity, and reduced growth despite showing high survival
when transferred to the field. Decreasing the medium’s sucrose concentration from 90 to 22.5 gl−1 or 0 gl−1 resulted in increased photosynthetic response to light and CO2 along with increased Rubisco and phosphoenolpyruvate carboxylase (PEPC) activities and proteins. However, plantlets grown
in vitro without exogenous sucrose died when transferred ex vitro, whereas those grown with intermediate exogenous sucrose showed intermediate photosynthetic response, high survival, fast
growth, and ex vitro photosynthesis. Thus, exogenous sucrose at moderate concentration decreased photosynthesis but increased survival, suggesting
that both in vitro photosynthesis and exogenous sucrose reserves contribute to field establisment and growth of coconut plantlets cultured in vitro. 相似文献
10.
Pious Thomas 《In vitro cellular & developmental biology. Plant》1998,34(1):52-56
Summary
In vitro rooted grape (Vitis vinifera L.) plantlets (4 or 8 wk from culturing microcuttings) were plantedex vitro in polythene sachets (24×12 cm) filled to one-third their height with planting mixture. The sachets were misted, closed,
and incubated at ambient temperature (25–30°C) under 16 h photoperiod (40–50 μ E·m−2.·sec−1) for 1,2, or 3 wk before opening. Maximum establishment with no or minimum damage toin vitro formed leaves was obtained with 3 wk of closed sachet incubation in both age groups. Opening the sachet at 2 wk from planting
resulted in marginal scorching of lower leaves and some reduction in establishment and vigor. Opening at 1 wk led to severe
leaf scorching and significant reduction in establisment particularly in 4-wk-oldin vitro plantlets while growth was more affected in 8-wk-old ones. Relative humidity ofin vitro culture vessel was 68–75% while closed sachets had RH values of 45–77% depending on length of incubation and ambient RH.
Diurnal variation in RH of sachet in relation to ambient RH was the major factor that facilitated acclimatization rather than
the overall fall in RH during the period of closed incubation. Satisfactory acclimatization of plantlets to withstand the
open sachet RH (50–55%) by 3 wk and the ambient RH (30–40%) by 4 wk was achieved. Monitoring water loss from detached leaves
of plantlets showed a significant reduction between the date of planting and Week 3, and again between Weeks 3 and 4. Comparison
of growthin vitro andex vitro suggested that shifting toex vitro earlier was more beneficial. This observation was confirmed by transferring 3-, 4-, and 5-wk-old plantlets fromin vitro rooting medium toex vitro and recording the growth at 8 wk fromin vitro culturing when 3 wkin vitro plus 5 wkex vitro combination showed maximum vigor. The leftover stumps after subculturing of 1–4-mo.-old stock cultures could also be effectively
used forex vitro establishment. 相似文献
11.
Boubacar Dary Sima Yves Desjardins Le Van Quy 《In vitro cellular & developmental biology. Plant》2001,37(4):480-489
Summary The effect of sucrose on in vitro potato (ev. Kennebec) metabolism was evaluated. Plants were grown in three different media: Murashige and Skoog basal medium
containing high nitrogen concentration with 0 or 20 g l−1 sucrose; or modified medium containing reduced nitrogen amount and 20 g l−1 sucrose. Plants fed with 20 g l−1 sucrose and high N exhibited higher phosphoenolpyruvate carboxylase (PEPC) and pyruvate kinase activities and high PEPC protein
concentration at 7, 20 and 33 d of culture compared to those grown with 20 g l−1 sucrose and low N, or with 0 g l−1 sucrose and high nitrogen (control). The highest accumulation of starch and sucrose was found in plants grown with sucrose
and low nitrogen. This accumulation occurred concomitantly with a reduced enzyme activity resulting from a low utilization
of α-ketoglutarate by nitrogen assimilation, when plants were grown with reduced nitrogen. Our investigations on tricarboxylic
acid cycle activity showed that sucrose led to the reduction of organic acid amounts in both leaves and roots when high nitrogen
was supplied to plants. This was probably due to the intense exit of α-ketoglutarate, which was confirmed by measurements
of cytosolic isocitrate dehydrogenase activity. The low leaf glutamine/glutamate ratio observed in plants grown with 20 g
l−1 sucrose and high nitrogen compared to their counterparts cultivated with low nitrogen might be due to glutamine conversion
into proteins when nitrogen assimilation was intense. These results demonstrate that sucrose enhanced PEPC activity by increasing
protein synthesis. They also suggest that sucrose metabolism is involved in the replenishment of the tricarboxylic acid cycle
by providing carbon skeletons required to sustain phosphoenolpyruvate utilization during high nitrate assimilation. 相似文献
12.
S. M. A. Zobayed F. Afreen T. Kozai 《In vitro cellular & developmental biology. Plant》2001,37(6):807-813
Summary Nodal cuttings of Eucalyptus camaldulensis L. plantlets were cultured photoautotrophically (sugar-free nutrient medium and with enriched CO2 and high photosynthetic photon flux) in a scaled-up vessel (volume 4.0 liters) under forced ventilation (SV-treatment). After
28 d of culture, physiological aspects of the plantlets were compared with plantlets grown photomixotrophically (20 g l−1 sucrose in the medium) in a Magenta vessel (volume 0.4 liters) under natural ventilation (control). In the SV-treatment net
photosynthetic rates were enhanced, normal stomatal closing and opening were observed, and the epicuticular leaf-wax content
was significantly higher than the control. The anatomical study showed well-organized palisade and spongy mesophyll layers
of SV leaves. The SV-treatment also allowed in vitro acclimatization, and after transplanting ex vitro, the transpiration rate and the percent water loss was lower than those of the control and thus the SV plantlets acclimatized
easily ex vitro. 相似文献
13.
14.
Andrea Kodym Stefan Hollenthoner Francisco Javier Zapata-Arias 《In vitro cellular & developmental biology. Plant》2001,37(2):237-242
Summary Daylight instead of artificial light was exploited for the in vitro culture of banana. Tubular skylights rediverted natural light into an interior enelosed room whereby each skylight, available
for ca. US$600, could sufficiently illuminate an area of 3–5 m2. The maintenance-free system allowed only a minimum of heat transfer and no cooling was necessary. The culture room required
no electricity supply and under our conditions savings on costs for electricity of US$6 m−2 wk−1 were achieved, as compared to a standard growth room equipped with artificial lighting and controlled photoperiod and temperature
regimes. Under natural light conditions, micropropagated plantlets were well developed at mean photosynthetic photon flux
densities (PPFD) of 5–13 μmol m−2 s−1 and photoperiods of 9–14 h. Micropropagation rates were either the same or significantly higher than under artificial lighting.
Single shoots on rooting medium showed some symptoms of etiolation, yet acclimatization rates averaged 95%. A step-like culture
rack. rather than a vertical one, permitted uniform plant growth on all levels. This paper describes an established micropropagation
system of low cost and simplicity. 相似文献
15.
We have demonstrated the presence of a Ca2+-dependent/calmodulin-stimulated protein kinase (PK) in chloronema cells of the mossFunaria hygrometrica. The kinase, with a molecular mass of 70,000 daltons (PK70), was purified to homogeneity using ammonium sulphate fractionation,
DEAE-cellulose chromatography, and calmodulin (CaM)-agarose affinity chromatography. The kinase activity was stimulated at
a concentration of 50 (AM free Ca2+, and was further enhanced 3–5-fold with exogenously added 3–1000 nm moss calmodulin (CaM). Autophosphorylation was also stimulated
with Ca2+ and CaM. Underin vitro conditions, PK70 phosphorylated preferentially lysine-rich substrates such as HIIIS and HVS. This PK shares epitopes with
the maize Ca2+-dependent/calmodulin-stimulated PK (CCaMK) and also exhibits biochemical properties similar to the maize, lily, and tobacco
CCaMK. We have characterized it as a moss CCaMK. 相似文献
16.
mRNA expression patterns of genes for metabolic key enzymes sucrose phosphate synthase (SPS), phosphoenolpyruvate carboxylase (PEPC), pyruvate kinase, ribulose 1,5-bisphosphate carboxylase/oxygenase, glutamine synthetase 1, and
glutamine synthetase 2 were investigated in leaves of rice plants grown at two nitrogen (N) supplies (N0.5, N3.0). The relative gene expression patterns were similar in all leaves except for 9th leaf, in which mRNA levels were generally depressed. Though increased N supply prolonged the expression period of each mRNA,
it did not affect the relative expression intensity of any mRNA in a given leaf. SPS Vmax, SPS limiting and PEPC activities, and carbon flow were examined. The ratio between PEPC activity and SPS Vmax was higher in leaves developed at the vegetative growth stage (vegetative leaves: 5th and 7th leaves) than in leaves developed after the ear primordia formation stage (reproductive leaves: 9th and flag leaves). PEPC activity and SPS Vmax decreased with declining leaf N content. After using 14CO2 the 14C photosynthate distribution in the amino acid fraction was higher in vegetative than in reproductive leaves when compared
for the same leaf N status. Thus, at high PEPC/SPS activities ratio, more 14C photosynthate was distributed to the amino acid pool, whereas at higher SPS activity more 14C was channelled into the saccharide fraction. Thus, leaf ontogeny was an important factor controlling photosynthate distribution
to the N- or C-pool, respectively, regardless of the leaf N status. 相似文献
17.
Klaus Martin Meiners S. Papadimitriou D. N. Thomas L. Norman G. S. Dieckmann 《Polar Biology》2009,32(7):1055-1065
Physical, biogeochemical and photosynthetic parameters were measured in sea ice brine and ice core bottom samples in the north-western
Weddell Sea during early spring 2006. Sea ice brines collected from sackholes were characterised by cold temperatures (range
−7.4 to −3.8°C), high salinities (range 61.4–118.0), and partly elevated dissolved oxygen concentrations (range 159–413 μmol kg−1) when compared to surface seawater. Nitrate (range 0.5–76.3 μmol kg−1), dissolved inorganic phosphate (range 0.2–7.0 μmol kg−1) and silicic acid (range 74–285 μmol kg−1) concentrations in sea ice brines were depleted when compared to surface seawater. In contrast, NH4
+ (range 0.3–23.0 μmol kg−1) and dissolved organic carbon (range 140–707 μmol kg−1) were enriched in the sea ice brines. Ice core bottom samples exhibited moderate temperatures and brine salinities, but high
algal biomass (4.9–435.5 μg Chl a l−1 brine) and silicic acid depletion. Pulse amplitude modulated fluorometry was used for the determination of the photosynthetic
parameters F
v/F
m, α, rETRmax and E
k. The maximum quantum yield of photosystem II, F
v/F
m, ranged from 0.101 to 0.500 (average 0.284 ± 0.132) and 0.235 to 0.595 (average 0.368 ± 0.127) in the sea ice internal and
bottom communities, respectively. The fluorometric measurements indicated medium ice algal photosynthetic activity both in
the internal and bottom communities of the sea ice. An observed lack of correlation between biogeochemical and photosynthetic
parameters was most likely due to temporally and spatially decoupled physical and biological processes in the sea ice brine
channel system, and was also influenced by the temporal and spatial resolution of applied sampling techniques. 相似文献
18.
Regulation of enzymes involved in C4 photosynthesis and the antioxidant metabolism by UV-B radiation in Egeria densa,a submersed aquatic species 总被引:2,自引:0,他引:2
Egeria densa, a submersed aquatic species, was exposed to different treatments under UV-B radiation, and the response of phosphoenolpyruvate
carboxylase (PEPC) and NADP-malic enzyme (NADP-ME) was determined. Exposure to UV-B radiation for 4 h per day over 7–16 days
caused an increase in both enzymes, together with an increase in the activity of some isoforms of several enzymes involved
in the antioxidant metabolism, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase
(POD). The content of chlorophylls and carotenoids was considerably decreased, suggesting that degradation or repression of
the synthesis of these molecules may be occurring after UV-B exposure. Reactive oxygen species (ROS) were also required for
UV-B induction of PEPC and NADP-ME, as the addition of ascorbic acid before UV-B treatment prevented the induction of these
enzymes, while salicylic acid was not effective in inducing NADP-ME but increased the expression of the lower molecular mass
isoform of PEPC. On the other hand, damage to the photosynthetic machinery may be occurring after exposure to UV-B radiation
for 8 per day over 1–2 days, as indicated by a decrease in the levels of Rubisco, PEPC and NADP-ME. Some of the enzymes involved
in the antioxidant metabolism, such as CAT and APX, were also sensitive to continuous exposure, evidenced by a decrease in
their activity. In this way, in E. densa, several enzymes involved in different metabolic pathways showed a distinct response, depending on the UV-B treatment.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
Cui Yong-Yi Hahn Eun-Joo Kozai Toyoki Paek Kee-Yoeup 《Plant Cell, Tissue and Organ Culture》2000,62(3):219-226
Rehmannia glutinosa plantlets were cultured for 4 weeks under different culture conditions to determine the optimum environment for in vitro growth and ex vitro survival. Plantlet growth increased with an increasing number of air exchanges of the culture vessel, exhibiting greatest
shoot weight, total fresh weight, leaf area, and chlorophyll content at 4.4 h−1 of air exchanges. High sucrose concentration (30 g l−1) increased root weight but reduced shoot growth. Net photosynthetic rates of the plantlets were greatest when sucrose was
not added to the medium. On the other hand, ex vitro survival of the plantlets was not influenced by sucrose concentration. In the experiment on difference in photoperiod and
dark period temperatures (DIF) and photosynthetic photon flux (PPF), plantlet growth increased as DIF and PPF levels increased.
Particularly, increasing PPF level had a more distinctive effect on plantlet growth than increasing DIF level. The interaction
of DIF × PPF was also significant, showing the greatest plantlet growth in positive DIF (+8 DIF) and a high PPF (210 μmol
m−2 s−1). In conclusion, the results of this experiment suggest that increased number of air exchanges of the culture vessel, decreased
sucrose concentration, and positive DIF in combination with high PPF level enhanced growth and acclimatization of Rehmannia glutinosa plantlets.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
Summary Explants of sugarcane, a C4 plant, were cultured in vitro for 18d on Floridalite (a solid cube consisting of vermiculite and cellulose fibers) used as supporting material with sugar-free
Murashige and Skoog liquid medium with double-strength KH2PO4, MgSO4, FeSO4, and Na2-EDTA in the vessel with enhanced natural ventilation. CO2 concentration in the culture room was kept at 1500 μmol mol−1 (four times the atmospheric CO2 concentration) during the photoperiod. A factorial experiment was designed with two levels of photosynthetic photon flux
(PPF) and three levels of N (number of air exchanges of the vessel). The results were compared with those in the control treatment (photomixotrophic
culture using sugar-containing agar medium under low PPF and low N). PPF and N showed significant positive effects on the growth of sugarcane plantlets in vitro. In the photoautotrophic (using sugar-free medium) treatments with relatively high PPF (200–400 μmol m−2 s−1) and high N (2–10 h−1), the growth of plantlets was four to seven times greater than that in the control. Also, the culture period for multiplication
and rooting was shortened from 30 d in the control to 18 d or less in the photoautotrophic, high PPF, and high N treatments. Use of porous supporting material in photoautotrophic treatments promoted rooting and plantlet growth significantly. 相似文献