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1.
The estimation of practical radial oxygen loss (ROL) of wetland plant roots was attempted in this study. We have devised a
new method to measure ROL of wetland plant roots. The whole root system was bathed in an anoxic nutrient solution. Oxygen
released from the root was removed immediately by introducing oxygen-free nitrogen gas (O2 < 4 nmol L−1) to mimic natural habitats where released oxygen is consumed rapidly due to chemical and biological oxidation processes.
Oxygen removed from the root-bathing chamber was simultaneously detected colorimetrically by use of the highly oxygen-sensitive
anthraquinone radical anion (AQ·−) in a cell outside the root-bathing chamber, which decolorized by a rapid reaction with oxygen. An emergent macrophyte Typha latifolia L. was incubated, and its ROL was measured by both the new method and one of the conventional methods, the closed chamber/electrode
method, by which the ROL of Typha latifolia L. had not yet been measured. The new method succeeded in detecting the ROL, whereas the conventional method was not able
to detect oxygen, due to the level being below the detection limit of the oxygen electrode. The oxygen supply via the seedlings
of Typha latifolia L. was ca. 10 times higher compared with control measurements without plant. Light illumination significantly enhanced the
ROL of Typha latifolia L. (0.33 nmol O2 g−1 root dry weight s−1 under light and 0.18 nmol O2 g−1 root dry weight s−1 in the dark). Theses values fall between those previously reported by the closed chamber/titanium citrate method and the
open chamber/electrode method. 相似文献
2.
Sieved agricultural soil samples were treated with the anti-knock agent tetraethyl lead (Et4Pb), and the resulting effects were analyzed by microcalorimetry. Et4Pb additions resulted in an increase of the heat production rate, provided that oxygen was present and that the soil was not
autoclaved. The increased heat production rate was accompanied by degradation of Et4Pb, as verified by speciation analysis (GC-MS) of the remaining Et4Pb and its ionic degradation products (triethyl lead and diethyl lead cations). Conclusive evidence was obtained that these
transformations were mediated mainly by microbes. At an initial Et4Pb concentration of 2 g Pb/kg dry weight the biodegradation rate was about 780 μmol day−1 kg dry weight−1, whilst the chemical decomposition was only 50 μmol day−1 kg dry weight−1. A fivefold rise of the initial Et4Pb concentration resulted in a decrease of the biodegradation rate to 600 μmol day−1 kg dry weight−1 and an increase of the chemical decomposition to 200 μmol day−1 kg dry weight−1. The biodegradation rate was not influenced by the addition of glucose, which means that no indication for a cometabolic
attack of Et4Pb was found.
Received: 25 February 1997 / Received revision: 22 April 1997 / Accepted: 27 April 1997 相似文献
3.
Hemant Lata Suman Chandra Ikhlas Khan Mahmoud A. ElSohly 《In vitro cellular & developmental biology. Plant》2009,45(1):12-19
Induction of high-frequency shoot regeneration using nodal segments containing axillary buds from a 1-yr-old mother plants
of Cannabis sativa was achieved on Murashige and Skoog (MS) medium containing 0.05–5.0 μM thidiazuron. The quality and quantity of regenerants
were better with thidiazuron (0.5 μM thidiazuron) than with benzyladenine or kinetin. Adding 7.0 μM of gibberellic acid into
a medium containing 0.5 μM thidiazuron slightly increased shoot growth. Elongated shoots when transferred to half-strength
MS medium supplemented with 500 mg l−1 activated charcoal and 2.5 μM indole-3-butyric acid resulted in 95% rooting. The rooted plants were successfully acclimatized
in soil. Following acclimatization, growth performance of 4-mo-old in vitro propagated plants was compared with ex vitro vegetatively grown plants of the same age. The photosynthesis and transpiration characteristics were studied under different
light levels (0, 500, 1,000, 1,500, or 2,000 μmol m−2 s−1). An increase in photosynthesis was observed with increase in the light intensity up to 1,500 μmol m−2 s−1 and then decreased subsequently at higher light levels in both types of plants. However, the increase was more pronounced
at lower light intensities below 500 μmol m−2 s−1. Stomatal conductance and transpiration increased with light intensity up to highest level (2000 μmol m−2 s−1) tested. Intercellular CO2 concentration (C
i) and the ratio of intercellular CO2 concentration to ambient CO2 (C
i/C
a) decreased with the increase in light intensity in both in vitro as well as ex vitro raised plants. The results show that in vitro propagated and hardened plants were functionally comparable to ex vitro plants of same age in terms of gas and water vapor exchange characteristics, within the limits of this study. 相似文献
4.
The concept of using higher plants to maintain a sustainable life support system for humans during long-duration space missions is dependent upon photosynthesis. The effects of extended exposure to microgravity on the development and functioning of photosynthesis at the leaf and stand levels were examined onboard the International Space Station (ISS). The PESTO (Photosynthesis Experiment Systems Testing and Operations) experiment was the first long-term replicated test to obtain direct measurements of canopy photosynthesis from space under well-controlled conditions. The PESTO experiment consisted of a series of 21–24 day growth cycles of Triticum aestivum L. cv. USU Apogee onboard ISS. Single leaf measurements showed no differences in photosynthetic activity at the moderate (up to 600 μmol m−2 s−1) light levels, but reductions in whole chain electron transport, PSII, and PSI activities were measured under saturating light (>2,000 μmol m−2 s−1) and CO2 (4000 μmol mol−1) conditions in the microgravity-grown plants. Canopy level photosynthetic rates of plants developing in microgravity at ∼280 μmol m−2 s−1 were not different from ground controls. The wheat canopy had apparently adapted to the microgravity environment since the CO2 compensation (121 vs. 118 μmol mol−1) and PPF compensation (85 vs. 81 μmol m−2 s−1) of the flight and ground treatments were similar. The reduction in whole chain electron transport (13%), PSII (13%), and PSI (16%) activities observed under saturating light conditions suggests that microgravity-induced responses at the canopy level may occur at higher PPF intensity. 相似文献
5.
Han Gil Choi Ki Hoon Lee Hyun Il Yoo Pil Jun Kang Young Sik Kim Ki Wan Nam 《Journal of applied phycology》2008,20(5):729-735
The effects of temperature, irradiance, and daylength on Sargassum horneri growth were examined at the germling and adult stages to discern their physiological differences. Temperature–irradiance
(10, 15, 20, 25, 30°C × 20, 40, 80 μmol photons m−2s−1) and daylength (8, 12, 16, 24 h) experiments were carried out. The germlings and blades of S. horneri grew over a wide range of temperatures (10–25°C), irradiances (20–80 μmol photons m−2s−1), and daylengths (8–24 h). At the optimal growth conditions, the relative growth rates (RGR) of the germlings were 21% day−1 (25°C, 20 μmol photons m−2s−1) and 13% day−1 (8 h daylength). In contrast, the RGRs of the blade weights were 4% day−1 (15°C, 20 μmol photons m−2s−1) and 5% day−1 (12 h daylength). Negative growth rates were found at 20 μmol photons m−2s−1 of 20°C and 25°C treatments after 12 days. This phenomenon coincides with the necrosis of S. horneri blades in field populations. In conclusion, we found physiological differences between S. horneri germlings and adults with respect to daylength and temperature optima. The growth of S. horneri germlings could be enhanced at 25°C, 20 μmol photons m−2s−1, and 8 h daylength for construction of Sargassum beds and restoration of barren areas. 相似文献
6.
M. R. de la Peña 《Journal of applied phycology》2007,19(6):647-655
Two series of experiments were conducted to determine suitable growth factors for the mass propagation of the local algal
isolate Amphora sp. A higher growth rate of 0.2 doubling (μ) day−1 was attained at a lower photosynthetic photon flux density (PPFD; 11.4 μmol photon m−2s−1) compared to cultures exposed to higher levels of PPFD (16.1 μmol photon m−2s−1, −0.1 μ day −1; 31.3 μmol photon m−2s−1, 0.0 μ day−1). Cultures located inside the laboratory had a significantly higher cell density (133 × 104 cells cm−2) and growth rate (0.3 μ day−1) compared to those located outdoors (100 × 104 cells cm−2, 0.2 μ day−1). A comparison of nutrient medium across two locations showed that lipid content was significantly higher in cultures enriched
with F/2MTM (macronutrients + trace metals) and F/2MV (macronutrients + vitamins). Saturated fatty acids were also present
in high concentrations in cultures enriched with F/2M (macronutrients only). Significantly higher amounts of saturated fatty
acids were observed in cultures located outdoors (33.1%) compared to those located indoors (26.6%). The protein, carbohydrates
and n-6 fatty acid content of Amphora sp. were influenced by the location and enrichment of the cultures. This study has identified growth conditions for mass
culture of Amphora sp. and determined biochemical composition under those culture conditions.
Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines. 相似文献
7.
Mohammad K. Khalesi H. H. Beeftink R. H. Wijffels 《Marine biotechnology (New York, N.Y.)》2009,11(4):488-494
The branching zooxanthellate soft coral Sinularia flexibillis releases antimicrobial and toxic compounds with potential pharmaceutical importance. As photosynthesis by the symbiotic algae
is vital to the host, the light-dependency of the coral, including its specific growth rate (μ day−1) and the physiological response to a range of light intensities (10–1,000 μmol quanta m−2 s−1) was studied for 12 weeks. Although a range of irradiances from 100 to 400 μmol quanta m−2 s−1 was favorable for S. flexibilis, based on chlorophyll content, a light intensity around 100 μmol quanta m−2 s−1 was found to be optimal. The contents of both zooxanthellae and chlorophyll a were highest at 100 μmol quanta m−2 s−1. The specific budding rate showed almost the same pattern as the specific growth rate. The concentration of the terpene flexibilide,
produced by this species, increased at high light intensities (200–600 μmol quanta m−2 s−1). 相似文献
8.
This work describes the long-term acclimation of the halotolerant microalga Dunaliella viridis to different photon irradiance, ranging from darkness to 1500 μmol m−2 s−1. In order to assess the effects of long-term photoinhibition, changes in oxygen production rate, pigment composition, xanthophyll
cycle and in vivo chlorophyll fluorescence using the saturating pulse method were measured. Growth rate was maximal at intermediate irradiance
(250 and 700 μmol m−2 s−1). The increase in growth irradiance from 700 to 1500 μmol m−2 s−1 did not lead to further significant changes in pigment composition or EPS, indicating saturation in the pigment response
to high light. Changes in Photosystem II optimum quantum yield (Fv/Fm) evidenced photoinhibition at 700 and especially at 1500 μmol m−2 s−1. The relation between photosynthetic electron flow rate and photosyntetic O2 evolution was linear for cultures in darkness shifting to curvilinear as growth irradiance increased, suggesting the interference
of the energy dissipation processes in oxygen evolution. Carbon assimilation efficiencies were studied in relation to changes
in growth rate, internal carbon and nitrogen composition, and organic carbon released to the external medium. All illuminated
cultures showed a high capability to maintain a C:N ratio between 6 and 7. The percentage of organic carbon released to the
external medium increased to its maximum under high irradiance (1500 μmol m−2 s−1). These results suggest that the release of organic carbon could act as a secondary dissipation process when the xanthophyll
cycle is saturated.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
Juho So Krishna R. Pagilla Hyungjin Kim Benjamin C. Stark 《Biotechnology and Bioprocess Engineering》1999,4(3):176-180
The gene (vgb) encoding the hemoglobin (VHb) ofVitreoscilla sp. was cloned intoBurkholderia sp. and the effect of VHb on the growth characteristics of genetically engineeredBurkholderia (YV1) were compared with wild typeBurkholderia (R34) using continuous flow reactors (chemostat) at various dilution rates under aerobic conditions. Batch oxygen uptake
rate showed that YV1 has much higher oxygen uptake rate than R34 (i.e. 0.63 mg O2/g biomass/min vs. 1.43 mg O2/g biomass/min for R34 and YV1 respectively at a dilution rate of 1.2 day−1). Monod parameters, maximum growth rate (μmax) and half saturation coefficient (Ks) were found to be 7.03 day−1 and 691 mg/L for R34 respectively, compared to 5.49 day−1 and 404 mg/L for YV1 respectively. At low dilution rates (<2.5 day−1), when the substrate is present in low concentrations, the growth yield was much higher in YV1 (0.52) than in R34 (0.37).
Although substrate utilization rates were similar between R34 and YV1, the latter showed much higher oxygen uptake rate than
did R34 at all dilution rates. When the stability of VHb was tested on agar plates containing 40 μg/L of kanamycin and 100
μg/L of ampicillin,vgb gene containing VHb plasmid in YV1 was stable over 82 days. When survivability under oxygen limited conditions was tested,
R34 survived only for 11 days whereas YV1 survived over 25 days in liquid media; in agar plate experiments, R34 did not survive
more than 40 days whereas more than 75% of YV1 survived over 110 days. 相似文献
10.
Photosynthetic Response of Carrots to Varying Irradiances 总被引:7,自引:3,他引:4
Response to irradiance of leaf net photosynthetic rates (P
N) of four carrot cultivars: Cascade, Caro Choice (CC), Oranza, and Red Core Chantenay (RCC) were examined in a controlled
environment. Gas exchange measurements were conducted at photosynthetic active radiation (PAR) from 100 to 1 000 μmol m−2 s−1 at 20 °C and 350 μmol (CO2) mol−1(air). The values of P
N were fitted to a rectangular hyperbolic nonlinear regression model. P
N for all cultivars increased similarly with increasing PAR but Cascade and Oranza generally had higher P
N than CC. None of the cultivars reached saturation at 1 000 μmol m−2 s−1. The predicted P
N at saturation (P
Nmax) for Cascade, CC, Oranza, and RCC were 19.78, 16.40, 19.79, and 18.11 μmol (CO2) m−2 s−1, respectively. The compensation irradiance (I
c) occurred at 54 μmol m−2 s−1 for Cascade, 36 μmol m−2 s−1 for CC, 45 μmol m−2 s−1 for Oranza, and 25 μmol m−2 s−1 for RCC. The quantum yield among the cultivars ranged between 0.057–0.033 mol(CO2) mol−1(PAR) and did not differ. Dark respiration varied from 2.66 μmol m−2 s−1 for Cascade to 0.85 μmol m−2 s−1 for RCC. As P
N increased with PAR, intercellular CO2 decreased in a non-linear manner. Increasing PAR increased stomatal conductance and transpiration rate to a peak between
600 and 800 μmol m−2 s−1 followed by a steep decline resulting in sharp increases in water use efficiency.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
Lubomír Adamec 《Ecological Research》2009,24(2):327-333
Aquatic carnivorous plants usually grow in shallow dystrophic waters poor in inorganic N and P. Utricularia australis was chosen as a model plant for its prolific distribution and great ecological plasticity. The photosynthetic CO2 compensation point and factors associated with investment in carnivory and capture of prey were measured in 17 U. australis micropopulations in Třeboň basin, Czech Republic, together with water chemistry factors at these sites differing greatly
in their trophic level, water hardness, and prey availability. Apical shoot growth rate was estimated at some oligotrophic
sites. The micropopulations differed greatly in the proportion of traps with animal prey (2.7–70%, mean 26%), trap proportion
to total biomass (1.4–42%, mean 26%), mean trap biomass (0.7–63 μg trap−1, mean 19 μg), and maximum trap size (1–3 mm, mean 2.0 mm). CO2 compensation points ranged from 0.7 to 6.1 μM (mean 2.6 μM). A weak HCO3
− use (compensation point 0.51 mM) was found in plants growing in alkaline water. Trap biomass proportion did not correlate
significantly with prey capture and CO2 compensation points with ambient [CO2]. A very rapid apical growth (2.5–4.2 new nodes day−1) occurred in sand pits. Thus, HCO3
− use in U. australis can be induced by growing at very high pH. CO2 compensation points resembled those known in other aquatic non-carnivorous plants. They did not reflect carnivory. In spite
of very rapid apical shoot growth, the relative growth rate of U. australis can be zero in oligotrophic habitats without prey. 相似文献
12.
The purpose of this study was to clarify effects of anthocyanins on photosynthesis and photoinhibition in green and red leaves
of Oxalis triangularis. Gas analysis indicated that green plants had the highest apparent quantum yield for CO2 assimilation [0.051 vs. 0.031 μmol(CO2) μmol−1(photon)] and the highest maximum photosynthesis [10.07 vs. 7.24 μmol(CO2) m−2 s−1], while fluorescence measurements indicated that red plants had the highest PSII quantum yield [0.200 vs. 0.143 μmol(e−) μmol−1(photon)] and ETRmax [66.27 vs. 44.34 μmol(e−) m−2 s−1]. Red plants had high contents of anthocyanins [20.11 mg g−1(DM)], while green plants had low and undetectable levels of anthocyanin. Red plants also had statistically significantly
(0.05>p>0.01) lower contents of xanthophyll cycle components [0.63 vs. 0.76 mg g−1(DM)] and higher activities of the reactive oxygen scavenging enzyme ascorbate peroxidase [41.2 vs. 10.0 nkat g−1(DM)]. Anthocyanins act as a sunscreen, protecting the chloroplasts from high light intensities. This shading effect causes
a lower photosynthetic CO2 assimilation in red plants compared to green plants, but a higher quantum efficiency of photosystem II (PSII). Anthocyanins
contribute to photoprotection, compensating for lower xanthophyll content in red plants, and red plants are less photoinhibited
than green plants, as illustrated by the Fv/Fm ratio. 相似文献
13.
The role of gibberellins (GAs) in the regulation of shoot elongation is well established but the phytohormonal control of
dry-matter production is poorly understood. In the present study, shoot elongation and dry-matter production were resolved
by growing Brassica napus L. seedlings under five light intensities (photon flux densities) ranging from 25 to 500 μmol m−2 s−1. Under low light, plants were tall but produced little dry weight; as light intensity was increased, plants were progressively
shorter but had increasing dry weights. Endogenous GAs in stems of 16- and 17-d-old plants were analyzed by gas chromatography-selected
ion monitoring with [2H2] internal standards. The contents of GAs increased dramatically with decreasing light intensity: GA1, GA3, GA8 and GA20 were 62, 15, 16 and 32 times higher, respectively, under the lowest versus highest light intensities. Gibberellin A19 was not measured at 25 μmol m−2 s−1 but was 9␣times greater in the 75 compared to 500 μmol m−2 s−1 treatment. Shoot and hypocotyl lengths were closely positively correlated with (log) GA concentration (for example: r
2 = 0.93 for GA1 and hypocotyl length) but shoot dry matter was negatively correlated with GA concentration. The application of gibberellic
acid (GA3) produced elongation of plants grown under high light, indication that their low level of endogenous GA was limiting shoot
elongation. Although endogenous GA20 showed the greatest influence of light treatment, metabolism of [3H]GA20 and of [3H]GA1 was only slightly influenced by light intensity, suggesting that neither 2β- nor 3β-hydroxylation were points of metabolic
regulation. The results of this study indicate that GAs control shoot elongation but are not directly involved in the regulation
of shoot dry weight in Brassica. The study also suggests a role of GAs in photomorphogenesis, serving as an intermediate between light condition and shoot
elongation response.
Received: 18 June 1998 / Accepted: 29 July 1998 相似文献
14.
The reproductive phenology of Chondrus ocellatus and the effects of temperature and light on its growth were examined in Cheongsapo near Busan, Korea, from September 1994 to August 1995. The vegetative plants dominated over the year, with a peak occurrence in January. Gameto- and tetrasporophytes were most abundant in November and August. All vegetative and reproductive plants had a peak both in length and weight in October, when seawater temperature was highest (24°C). In laboratory culture, the maximum relative growth rate (RGR) of 2.94% day−1 was obtained at 20°C and 100 μmol photons m−2 s−1, whereas the lowest value was recorded at 25°C and 100 μmol photons m−2 s−1 in a 12: 12 h LD photoperiod regime. Among the three photoperiod regimes (8:16 h, 12:12 h, 16:8 h LD) tested, there was evidence of a higher RGR in the 12:12 h LD cycle. This result suggests that the growth and reproduction of C. ocellatus are correlated with the seawater temperature based on laboratory culture and field observations. 相似文献
15.
The response of barley (Hordeum vulgare L. cv. Akcent) to various photosynthetic photon flux densities (PPFDs) and elevated [CO2] [700 μmol (CO2) mol−1; EC] was studied by gas exchange, chlorophyll (Chl) a fluorescence, and pigment analysis. In comparison with barley grown under ambient [CO2] [350 μmol (CO2) mol−1; AC] the EC acclimation resulted in a decrease in photosynthetic capacity, reduced stomatal conductance, and decreased total
Chl content. The extent of acclimation depression of photosynthesis, the most pronounced for the plants grown at 730 μmol
m−2 s−1 (PPFD730), may be related to the degree of sink-limitation. The increased non-radiative dissipation of absorbed photon energy for
all EC plants corresponded to the higher de-epoxidation state of xanthophylls only for PPFD730 barley. Further, a pronounced decrease in photosystem 2 (PS2) photochemical efficiency (given as FV/FM) for EC plants grown at 730 and 1 200 μmol m−2 s−1 in comparison with AC barley was related to the reduced epoxidation of antheraxanthin and zeaxanthin back to violaxanthin
in darkness. Thus the EC conditions sensitise the photosynthetic apparatus of high-irradiance acclimated barley plants (particularly
PPFD730) to the photoinactivation of PS2.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
The deposition and cycling of carbon and nitrogen in carbonate sediments located between coral reefs on the northern and central
sections of the Great Barrier Reef were examined. Rates of mass sediment accumulation ranged from 1.9 kg m−2 year−1 (inshore reefs) to 2.1–4.9 kg m−2 year−1 (between mid-shelf reefs); sedimentation was minimal off outer-shelf reefs. Rates of total organic carbon decomposition ranged
from 1.7 to 11.4 mol C m−2 year−1 and total nitrogen mineralization ranged from 77 to 438 mmol N m−2 year−1, declining significantly with distance from land. Sediment organic matter was highly reactive, with mineralization efficiencies
ranging from 81 to 99% for organic carbon and 64–100% for nitrogen, with little C and N burial. There was no evidence of carbonate
dissolution/precipitation in short-term incubation experiments. Rates of sulfate reduction (range 0–3.4 mmol S m−2 day−1) and methane release (range 0–12.8 μmol CH4 m−2 day−1) were minor or modest pathways of carbon decomposition. Aerobic respiration, estimated by difference between total O2 consumption and the sum of the other pathways, accounted for 55–98% of total carbon mineralization. Rates of ammonification
ranged from 150 to 1,725 μmol NH4 m−2 day−1, sufficient to support high rates of denitrification (range 30–2,235 μmol N2 m−2 day−1). N2O release was not detected and rates of NH4
+ and NO2
− + NO3
− efflux were low, indicating that most mineralized N was denitrified. The percentage of total N input removed via denitrification
averaged ≈75% (range 28–100%) with little regenerated N available for primary producers. Inter-reef environments are therefore
significant sites of energy and nutrient flow, especially in spatially complex reef matrices such as the Great Barrier Reef. 相似文献
17.
This study was conducted to determine effects of nitrogen supply (75 and 150 kg(N) ha−1) and CO2 enrichment on partitioning of macro and micro nutrients in wheat (Triticum aestivum L. cv. HD-2285). Plants were grown from seedling emergence to maturity inside open top chambers under ambient CO2 (CA, 350 ± 50 μmol mol−1) and elevated CO2 (CE, 600 ± 50 μmol mol−1). Leaves, stems and roots of the same physiological age were analyzed for carbon, nitrogen, calcium, copper, iron, zinc and
manganese content at 40, 60 and 90 d after germination. C, Cu, Mn and Zn content was higher in the stem, leaves and roots
on dry mass basis under CE than CA. However, N and Fe contents decreased in CE grown plants. Ca content was unaffected due
to CE and variable N supplies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
Summary
In vitro banana (Musa spp.) shoots were cultured under photomixotrophic (30 gl−1 sucrose and 0.2 h−1 number of air exchanges of culture vessels) and photoautotrophic (0 gl−1 sucrose and 3.9 h−1 number of air exchanges) conditions for 28 d in 370 cm3 Magenta boxes (GA7-type) containing 70 ml of half-strength Murashige and Skoog (MS) medium with 22.2 μM N6-benzyladenine (BA). The effects of varying CO2 concentration (475 or 1340 μmol mol−1) and light intensity (photosynthetic photon flux (PPF) of 100 or 200 μmol m−2 s−1) were investigated. Fresh and dry weights of banana shoots grown photomixotrophically were significantly greater on day 28
than those grown photoautotrophically. Photoautorophic shoots had a larger number of unfolded leaves and greater leaf area
than photomixotrophic plants by days 14 and 28, regardless of CO2 concentration. The shoot fresh and dry weights on day 14 in photoautotrophic conditions were significantly greater at PPF
of 200 μmol m−2 s−1 than at 100 μmol m−2 s−1. The increase in net photosynthetic rate of photoautotrophic banana shoots was significant compared with photomixotrophic
shoots. The multiplication ratio of in vitro banana shoots grown photoautotrophically in a 28-d culture period was the greatest at 100 μmol m−2 s−1 PPF and 475 μmol mol−1 CO2. 相似文献
19.
Extracellular Matrix in Early Stages of Direct Somatic Embryogenesis in Leaves of Drosera spathulata
The growth and water relations of Paulownia fortunei in photoautotrophic cultures (nutrient medium lacking sucrose and growth regulator) with CO2 enrichment (PWAH) or without CO2 enrichment (PWAL) were compared with those in photomixotrophic shoot (PWC; 30 g dm−3 sucrose and 0.3 mg dm−3 N6-benzyladenine) and root cultures (PWR; 0.3 mg dm−3 indole-3-butyric acid). The photoautotrophic and photomixotrophic cultures were incubated under photosynthetic photon flux
125 and 60 μmol m−2 s−1, respectively. 100 % sprouting and significantly higher number of shoots (1.6) were obtained with PWAH as compared to PWAL
and PWC. PWAH and PWAL stimulated spontaneous rooting from the cut end of axillary shoots. In PWAH, 84 % of shoots rooted
with an average of 5.9 roots per shoot and 4.0 cm of root length in 21 d. Rooting of photomixotrophic shoot cultures were
stimulated by an auxin treatment. In this case, 98.3 % of shoots were rooted with an average of 4.6 roots per shoot and 1.9
cm length. A microscopic observation on leaf abaxial surface prints from photomixotrophic shoot and root cultures showed widely
open (6 – 8 μm) spherical stomata (12 – 14 μm) and from photoautotrophic cultures elliptical stomata (10 – 12 μm) with narrow
openings (3 – 4 μm). Leaves from photomixo-trophic cultures had higher stomatal index as compared to photoautotrophic cultures.
The rate of moisture loss from detached leaves was not varying significantly in different cultures.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Adam M. Dimech Rob Cross Rebecca Ford Paul W. J. Taylor 《Plant Cell, Tissue and Organ Culture》2007,88(2):157-165
The physiological effects of three auxins [indole-3-butyric acid (IBA), α-naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic
acid (2,4-d)] and two cytokinins [thidiazuron (TDZ) and N6-benzylaminopurine (NAA)] on in vitro morphogenesis of Doryanthes excelsa were measured. Longitudinal bud sections derived from immature inflorescences were used as a source of explants. Callus regeneration
was observed at the highest frequencies (46.2%) when grown on media containing 50 μmol L-1 NAA and 0.5 μmol L−1 TDZ. Adventitious shoot organogenesis was observed at the highest frequency (56.8%) when grown on media containing 0.5 μmol L−1 NAA and 50 μmol L−1 TDZ. Regenerated shoots were rooted ex vitro after 6 weeks when dipped in a solution of 50 μmol L−1 NAA or no plant growth regulators were applied. 相似文献