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1.
Secondary embryogenesis from rapeseed microspore-derived embryos (MDEs) was studied in three Brassica napus L. cultivars Global, PF704 and Option. The best results in terms of secondary embryogenesis percentage obtained in cultures of Global and PF704 MDEs (75.88 and 65.97 %, respectively) and PF704 produced the highest number of secondary embryos per each primary embryo (14.91 ± 2.18). After optimization of physical parameters,
rapeseed hypocotyls of MDEs were bombarded with microcarriers coated with a plasmid containing GUS reporter gene. The highest
levels of transient GUS expression were obtained using bombardment with gold particles of 1.6 μm, at helium pressure of 9.3
MPa, a bombardment distance of 9 cm, chamber vacuum pressure of 7.1 × 10−6 kPa and single bombardment in bombardment medium containing 0.4 M mannitol. 相似文献
2.
Plant regeneration through somatic embryogenesis was achieved using immature zygotic embryos (ZE) of Sorbus pohuashanensis as explants. Over 50% of immature ZEs from immature seed collected at 30 days after pollination produced direct somatic embryos
(SEs) on Murashige and Skoog (MS) medium supplemented with 0–0.44 μM 6-benzyladenine (BA) in combination with 5.73 μM naphthaleneacetic
acid (NAA) or with 0.91–2.26 μM 2,4-dichlorophenoxyacetic acid (2,4-D) alone. Fourteen to 23 SEs per explant were regenerated
on MS medium supplemented with BA 0.44 μM in combination with NAA 5.73 μM. SE formation decreased when sucrose concentrations
were higher than 40 g L−1. Repetitive embryogenesis occurred following culture on solid MS medium containing 12 μM abscisic acid, 75 g L−1 polyethylene glycol, and 20 g L−1 sucrose at 25 ± 1°C under a 16-h photoperiod with a light intensity of 40 μmol m−2 s−1. Over 40% of the mature SEs germinated on solid MS medium under light condition described previously. Up to 40% of the regenerated
plantlets were successfully acclimatized under greenhouse conditions. Plantlets derived from SEs grew vigorously with similar
morphology as those germinated from ZEs. Histological studies of explants at various developmental stages of somatic embryogenesis
revealed that SEs passed through globular, heart, torpedo, and mature stages. Similar to ZE suspensors, similar structures
of SE degenerated in later stages of embryo development. ZE and SE are a effective means of regenerating tissue culture plantlets
for S. pohuashanesis. 相似文献
3.
Ai Hua Chen Jing Li Yang Yu Da Niu Chuan Ping Yang Gui Feng Liu Chang Yeon Yu Cheng Hao Li 《Plant Cell, Tissue and Organ Culture》2010,102(3):357-364
We developed a new protocol for highly efficient somatic embryogenesis and plantlet conversion of Schisandra chinensis. Friable embryogenic callus was induced from cotyledonary leaves and hypocotyls of germinated zygotic embryos on Murashige
and Skoog (MS) agar medium containing 2,4-dichlorophenoxyacetic acid (2,4-D). Preculture of zygotic embryos on 2,4-D-containing
medium increased embryogenic callus induction efficiency. The highest embryogenic callus induction frequency of 56.7% was
obtained from shoot apical meristem-containing hypocotyl explants from 1-week-old germinated embryos on MS medium containing
4.0 mg l−1 2,4-D. Embryogenic callus proliferation, somatic embryo (SE) formation, and subsequent plantlet conversion occurred under
optimal culture conditions. The effects of MS medium strength, sucrose, gibberellic acid (GA3), and 6-benzyladenine (BA) on SE formation and plantlet conversion were evaluated. Low MS medium strength (1/4 to 1/2) was
necessary for SE formation, and the optimal sucrose concentration was 2.0%. Supplementing medium with GA3 negatively impacted SE formation and subsequent development. BA significantly increased the number of SEs and the plantlet
conversion capacity. One-third-strength MS medium with 1.0% sucrose and 0.5 mg l−1 BA produced the highest number of SEs (309 embryos from 9 mg embryogenic callus) and the highest frequency of plantlet conversion
from germinated SEs (52.6%). When transplanted to soil, 90% of the regenerated plants developed into normal plants. 相似文献
4.
The effects of post harvest application of ethylene, abscisic acid (ABA), indole-3-butyric acid (IBA) treatments or dark storage
on root induction and continued growth of regenerated roots in Pelargonium cuttings were investigated using hydroponics in the greenhouse. Ethylene markedly increased rooting percentage in ‘Greco’
and ‘Surfing’, reduced the number of roots per cutting in ‘Surfing’ and had no effect on the total root lengths in the two
cultivars. Ethylene treatment reduced fresh root mass in ‘Surfing’, increased dry root mass and reduced root water content
in both cultivars. ABA (50 μM) enhanced rooting percentage in ‘Greco’, reduced the number of roots per cutting, reduced total
root lengths and fresh root mass in both cultivars. ABA increased dry root mass and reduced root water content in ‘Surfing’
but this effect was not apparent in ‘Greco’. Storing cuttings in the dark for 4 days had no effect on rooting percentage and
number of roots per cutting in ‘Greco’ and ‘Surfing’. However, dark storage reduced total root lengths in ‘Surfing’ and reduced
fresh root mass in ‘Greco’. Dark storage had no effect on dry root mass and water content in both cultivars. Applying 4 μl l−1 IBA in the rooting solution induced maximum (100%) root induction in ‘Surfing’. However, IBA reduced the number of roots
per cutting in ‘Greco’, reduced total root lengths and fresh root mass in the two cultivars. IBA treatment profoundly increased
and reduced dry root mass and root water content, respectively, in ‘Greco’ and ‘Surfing’. The enhanced root induction observed
after IBA and ABA applications could be ascribed to their influence on ethylene biosynthesis, since ethylene treatment increased
rooting percentage in both cultivars. However, high ABA (100 μM) and IBA (12 μl l−1) levels or dark storage reduced the ability of induced roots to continue growth. We attribute our results to plant stress-response
mechanism and ethylene appears to play an important role in the process of root initiation and root growth in Pelargonium cuttings. 相似文献
5.
6.
K. Sorkheh B. Shiran M. Khodambshi V. Rouhi S. Ercisli 《Plant Cell, Tissue and Organ Culture》2011,105(3):395-404
Eight native Iranian almond species from three sections, ‘Euamygdalus’ (Prunus communis; Prunus eleagnifolia and Prunus orientalis); ‘Lycioides’ (Prunus lycioides and Prunus reuteri) and ‘Spartioides’ (Prunus arabica, Prunus glauca and Prunus scoparia) were in vitro screened for drought tolerance using sorbitol and polyethylene glycol (PEG) as an osmoticum. Different levels
of water stress were induced using five concentrations of either sorbitol or polyethylene glycol in Woody Plant Medium (WPM).
Water potential of various media ranged from −0.80 to −2.05 MPa and water stress in culture medium adversely affected plantlet
growth. Wild species from ‘Spartioides’ were less affected than ‘Lycioides’ and ‘Euamygdalus’. At the same level of water
potential, sorbitol had lower adverse effects than PEG; the latter being severe. Prunus × sorbitol and Prunus × PEG interactions were significant. At 0.2 M sorbitol and 0.003 M PEG, ‘Spartioides’ produced significantly more roots with
higher total root length and root volume, as well as root-dry weight than those of ‘Lycioides’ and ‘Euamygdalus.’ It is concluded
that in vitro screening of native Iranian almond species under specific and limited water-stress conditions may provide a
system for effectively differentiating the wild species of almond for their expected root mass production under field conditions. 相似文献
7.
A simple and efficient system was developed for rapid somatic embryogenesis from leaf explants of Merwilla plumbea, a traditional but threatened medicinal plant in South Africa. Friable embryogenic callus (FEC) was obtained from leaf explants
on embryogenic callus induction medium containing agar-solidified Murashige and Skoog (MS) salts and vitamins, 8.3 μM picloram,
2.3 μM thidiazuron (TDZ) and 20 μM glutamine. FEC was subsequently incubated in embryogenic callus proliferation medium containing
4.5 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.1 μM picloram for 7 days before it was transferred to liquid somatic embryo
medium (SEML) containing MS medium supplemented with 0.4 μM picloram and 0.9 μM TDZ. In SEML supplemented with 150 mg L−1 haemoglobin, 5.4–35.6 somatic embryos per settled cell volume of 500 mg FEC were obtained. These embryos were at globular
to cotyledonary developmental stages. Embryo maturation, germination and plant formation rate was 94.4% following transfer
of SEs to half-strength MS medium supplemented with 1.4 μM gibberellic acid. Plantlets transferred into soil acclimatized
in the misthouse and established successfully in the greenhouse (100%). This is the first report on induction of Merwilla plumbea somatic embryogenesis. The protocol developed offers controlled vegetative propagation by alleviating extinction threats,
ensures germplasm conservation and provides a system for physiological, biochemical, molecular and cellular studies of embryo
development. 相似文献
8.
Schuller Astrid Kirchner-Neß Robert Reuther Gerhard 《Plant Cell, Tissue and Organ Culture》2000,60(1):23-31
To promote SE maturation, the influence of different media components on different developmental stages was quantitatively evaluated. Advanced maturation was achieved with a sequence of culture media (prematuration medium and maturation medium) that contained various carbohydrates, organic nitrogen compounds and plant growth regulators. Application of lactose, BA, L-glutamine and casein hydrolysate in the prematuration medium enhanced the total number of SEs and promoted advanced differentiation. The highest number of late torpedo stage SEs was observed on maturation medium supplemented with 200 mM lactose and 29 mM sucrose. Lactose and sorbitol favoured SE maturation up to the early cotyledonary stage. With application of PEG and high ABA concentrations (20–40 M), only early torpedo stages were formed. The number of late torpedo stage SEs was significantly higher on hormone free media or with lower ABA concentrations (0–5 M). Formation of early and late cotyledonary SEs was significantly enhanced by adding BA in the maturation medium: neither Zeatin nor 2iP were effective. In addition, low sucrose concentrations in the proliferation medium (29 mM compared to 58 mM) also favoured the formation of cotyledonary SE in the maturation medium. 相似文献
9.
The effects of cytokinins, carbohydrates and amino acids were studied on maturation and regeneration of embryogenic callus
(EC) in kodo millet (Paspalum scorbiculatum Linn.) using a two-step culture procedure. The highest percentage (87.6%) of EC induction was obtained in the induction medium
containing Murashige and Skoog (MS) basal salts supplemented with 9.0 μM 2,4-dichlorophenoxy acetic acid and 2.25 μM kinetin.
This EC was subcultured in the maturation medium for somatic embryo (SE) maturation and plantlet formation. Addition of cytokinins,
carbohydrates and amino acids in the maturation medium promoted the SE maturation and plantlet formation. The maturation medium
containing MS basal salts amended with 4.50 μM thidiazuron, 120 mM maltose and 200 μM l-proline gave the maximum number of SEs (39.4) and plantlets (31.3). Plantlets were successfully grown to maturity after hardening
in the soil. 相似文献
10.
Joshua Otieno Ogweno Wen Hai Hu Xing Shun Song Kai Shi Wei Hua Mao Yan Hong Zhou Jing Quan Yu 《Plant Growth Regulation》2010,60(3):175-182
Detached leaves of tomato (Lycopersicon esculentum Mill.) experienced photoinhibition associated with sharp reductions in net photosynthetic rate (Pn), quantum efficiency of
PSII (ΦPSII) and photochemical quenching (qP) even though they were exposed to mild light intensity (400 μmol m−2 s−1 PPFD) at 28°C. Photoinhibition and the reduction in Pn, ΦPSII and qP, however, were significantly alleviated by 1 mg l−1 ABA, 0.1 mg l−1
N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) and 0.01 mg l−1 24-epibrassinolide (EBR). Higher concentrations, however, reduced the effects or even exacerbated the occurrence of photoinhibition.
Superoxide dismutase and ascorbate peroxidase activity in leaves increased with the increases in ABA concentration within
1–100 mg l−1, CPPU concentration within 0.1–10 mg l−1 and EBR concentration within 0.01–1.0 mg l−1. Catalase and guaiacol peroxidase activity also increased with the increase in EBR concentration but CPPU and ABA treatments
at higher concentrations caused a decrease. Malondialdehyde (MDA) content decreased with the increase in CPPU concentration.
ABA and EBR, however, decreased MDA concentration only at 1 and 0.01 mg l−1, respectively. In conclusion, detached leaves had increased sensitivity to PSII photoinhibition. Photoinhibition-induced
decrease in photosynthesis, however, was significantly alleviated by EBR, CPPU and ABA at a proper concentration. 相似文献
11.
Behzad Ahmadi Khoshnood Alizadeh Jaime A. Teixeira da Silva 《Plant Cell, Tissue and Organ Culture》2012,109(3):525-533
The effects of three periods of incubation (10, 20 and 30 min) at different levels of bleomycin (0, 0.1, 0.2, 0.3, 0.4 and
0.5 μg ml−1), as well as three periods of exposure (12, 24 and 48 h) to different levels of the anti-auxin p-chlorophenoxyisobutyric acid (PCIB), including 1, 2, 3, 4 and 5 mg l−1, on microspore embryogenesis of rapeseed cv. ‘Amica’ were investigated. Microspore embryogenesis was significantly enhanced
following 20 min treatment with 0.2 μg ml−1 bleomycin compared with untreated cultures. Highest embryo yield (163 embryos Petri dish−1) was observed with 24 h treatment of 4 mg l−1 PCIB. The highest percentage of secondary embryogenesis was observed on B5 medium containing 0.15 mg l−1 of gibberellic acid (GA3) and 0.2 mg l−1 6-benzyladenine (BA) in 4–6 mm microspore-derived embryos (MDEs). Most callus formed on B5 medium containing 0.15 mg l−1 GA3, 0.1 mg l−1 BA and 0.1 mg l−1 indole-3-acetic acid (IAA) when 4–6 mm embryos were used. Regeneration was highest on B5 medium containing 0.05 mg l−1 GA3 or 0.1 mg l−1 BA and 0.2 mg l−1 IAA with 2–4 mm embryos. Microspore embryogenesis and plant regeneration could be improved by both bleomycin and PCIB when
the appropriate MDE length and phytohormone level were selected. 相似文献
12.
Somatic embryogenesis (SE) was successfully induced from mature zygotic embryos of seven families of Picea likiangensis (Franch.) Pritz after 20 weeks culture on initiation medium. Three basal media (one-half strength LM medium, one-half strength
LP medium and improved LP medium) with different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzyladenine
(6-BA) were tested but only one-half strength LM medium supplemented with 2,4-D and 6-BA was successful for the embryogenic
cultures (EC) initiation. The initiation frequencies of EC varied greatly from different families when culturing on the same
initiation medium. The highest frequency (41.3%) was induced from one of the families on one-half strength LM medium supplemented
with 3 mg L−1 2,4-D and 1.5 mg L−1 6-BA and 16.83% on average for seven families. EC were subcultured and proliferated on the same medium as the initiation
one every 10 days. 3 lines of EC induced from the same family were applied in maturation experiment. Cotyledonary somatic
embryos were observed after EC were transferred to maturation media of one-half strength LM medium containing 20-80 mg L−1 abscisic acid and 7.5% polyethylene glycol (PEG-4000). However, one-half strength LM medium supplemented with 40 mg L−1 or 60 mg L−1 ABA and 7.5% PEG gave the best maturation and the 3 lines showed different ability in maturation. Over 80% cotyledonary somatic
embryos germinated normally on DCR medium containing 0.2% activated carbon. The success on SE induction of the species has
provided an effective clonal propagation method for this important tree’s genetic improvement. 相似文献
13.
Iyyakkannu Sivanesan Mi Young Lim Byoung Ryong Jeong 《Plant Cell, Tissue and Organ Culture》2011,107(2):365-369
A simple and efficient protocol was developed for somatic embryogenesis from leaf and petiole explants of Campanula punctata Lam. var. rubriflora Makino. Somatic embryos (SE) were obtained with greater frequency from petiole explants than from leaf explants when cultured
on Murashige and Skoog (MS) medium supplemented with 2.0 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 mg L−1 6-benzyladenine (BA). On this medium, a mean number of 19.5 and 31.2 SE were developed per leaf and petiole explants, respectively.
Embryos were induced both light and dark conditions but culturing the explants 2 weeks in the dark followed by 3 weeks under
light resulted in high frequency of embryo formation. Globular embryos germinated best on MS medium supplemented with 0.3%
(w/v) activated charcoal (AC) and 1.0 mg L−1 GA3. The germinated plantlets grew further on MS medium containing 0.3% AC. Plantlets were successfully acclimatized in the greenhouse
with 94% survival rate. This is the first report on induction of somatic embryogenesis in this genus and also has implications
for genetic transformation, and mass clonal propagation. 相似文献
14.
Lettuce (Lactuca sativa) transformation varies by genotype. Various culture parameters have been studied in order to improve the transformation efficiency
of lettuce cultivars. However, no improved transformation procedure for recalcitrant lettuce cultivars has yet been established.
Here, we demonstrate the effects of varying concentrations and distinct combinations of growth regulators on recalcitrant
lettuce transformation efficiency. More precisely, we assessed differences in the effects of several growth regulator combinations,
including N-6(2-isopentenyl)-adenine (2ip), on induction of callus and regeneration of shoots after co-cultivation with Agrobacterium. When two commercial recalcitrant cultivars, Red Romaine and Bibb, were cultured on a medium with 2ip 1 mg l−1, IAA 0.1 mg l−1, and subsequently transferred to a second medium with BA 0.4 mg l−1, NAA 0.05 mg l−1 for selection and shoot regeneration, transformation efficiencies reached 8 and 9%, respectively. Stable integration and
transmission of the transgene in T1 generation plants were confirmed by molecular analysis. This procedure represents a simple,
efficient, and general means of transforming various lettuce cultivars, including recalcitrant commercial cultivars. 相似文献
15.
Plant regeneration was achieved through direct and indirect somatic embryogenesis in Eucalyptus camaldulensis. Callus was induced from mature zygotic embryos and from cotyledon explants collected from 10, 15, 25, and 30-day-old seedlings
cultured on Murashige and Skoog (MS) basal medium supplemented with different concentrations of naphthaleneacetic acid (NAA).
Maximum callus induction from mature zygotic embryos was obtained on MS basal medium containing 1 mg l−1 NAA. The frequency of callus development varied based on the age of the cotyledon explants 10-day-old explants giving highest
percentage on MS basal medium supplemented with 1 mg l−1 NAA. Callus obtained from mature zygotic embryos gave highest frequency of somatic embryogenesis on MS basal medium containing
0.5 mg l−1 benzyladenine (BA) and 0.1 mg l−1 NAA. Separate age wise culture of the calli, obtained from cotyledons of different ages cultured separately, revealed high
somatic embryogenic potential on callus from 10-day-old cotyledons. Direct somatic embryogenesis too was obtained from hypocotyl
explants without an intervening callus phase on MS basal medium containing 0.5 mg l−1 BA. The effects of abscisic acid (ABA), sucrose, and different strengths of MS medium on somatic embryo maturation and germination
were also investigated. Number of mature somatic embryos increased with lower concentrations (0–1 mg l−1) of ABA while no significant differences were observed at higher concentrations (2–5 mg l−1) of ABA. Compared to basal medium containing lower concentrations of sucrose (1%), the MS medium supplemented with higher
levels of sucrose (4%) showed significantly lower frequency of mature somatic embryos. Basal medium without any dilution gave
the highest number of immature embryos. However, the number of mature embryos was high at higher medium dilutions. 相似文献
16.
M. E. Estrada-Zúñiga F. Cruz-Sosa M. Rodríguez-Monroy J. R. Verde-Calvo E. J. Vernon-Carter 《Plant Cell, Tissue and Organ Culture》2009,97(1):39-47
Plant tissue cultures represent a potential source for producing secondary metabolites. In this work, Buddleja cordata tissue cultures were established in order to produce phenylpropanoids (verbascoside, linarin and hydroxycinnamic acids),
as these metabolites are credited with therapeutic properties. Highest callus induction (76.4–84.3%) was obtained in five
treatments containing 2,4-Dichlorophenoxyacetic acid (2,4-d: 0.45–9.05 μM) with Kinetin (KIN: 2.32, 4.65 μM), whereas highest root induction (79.6%) corresponded to the α-Naphthaleneacetic
acid (9.05 μM) with KIN (2.32 μM) treatment. Verbascoside was the major phenylpropanoid produced in in vitro cultures (root,
white and green callus) [66.24–86.26 mg g−1 dry weight (DW)], while linarin and hydroxycinnamic acid production was low (0.95–3.01 mg g−1 DW). Verbascoside and linarin production were improved in cell suspension culture (116 mg g−1 DW and 8.12 mg g−1 DW, respectively). 相似文献
17.
Transgenic doubled haploid rapeseed (Brassica napus L. cvs. Global and PF704) plants were obtained from microspore-derived embryo (MDE) hypocotyls using the microprojectile bombardment. The binary vector
pCAMBIA3301 containing the gus and bar genes under control of CaMV 35S promoter was used for bombardment experiments. Transformed plantlets were selected and continuously
maintained on selective medium containing 10 mg l−1 phosphinothricin (PPT) and transgenic plants were obtained by selecting transformed secondary embryos. The presence, copy
numbers and expression of the transgenes were confirmed by PCR, Southern blot, RT-PCR and histochemical GUS analyses. In progeny
test, three out of four primary transformants for bar gene produced homozygous lines. The ploidy level of transformed plants was confirmed by flow cytometery analysis before colchicine
treatment. All of the regenerated plants were haploid except one that was spontaneous diploid. High frequency of transgenic
doubled haploid rapeseeds (about 15.55% for bar gene and 11.11% for gus gene) were considerably produced after colchicines treatment of the haploid plantlets. This result show a remarkable increase
in production of transgenic doubled haploid rapeseed plants compared to previous studies. 相似文献
18.
A correlation between protein kinase phosphorylation and ABA level was studied in Malus sieversii (Ledeb.) Roem. seedlings under water stress. The seedlings were treated with PEG 6000 for imitation of water stress, and
the MAPK activity and ABA content in each treatment were then determined. We demonstrated that the increase in the activities
of the total protein kinase (TPK) and mitogen-activated protein kinase (MAPK) after treatment with 20% PEG 6000 appeared to
result in a high level of ABA. MAPK activity accounted for 76.8% of TPK activity. The activity peaks of TPK and MAPK preceded
the highest level of ABA accumulation. It is interesting that the ABA level in roots and leaves of seedlings pretreated with
2 × 10−2 mM exogenous ABA for 20 min following treatment by 20% PEG 6000 was much higher than that of seedlings treated with exogenous
ABA only. We analyzed the influence of MAPK inhibitor ITU (5-iodotubercidin) on ABA accumulation in the seedlings of M. sieversii under water stress and showed that 1 μM ITU significantly decreased the ABA level induced by a water loss. However, the phosphoesterase
inhibitor PAO (phenylarisine oxide) enhanced ABA accumulation, indicating that the phosphorylated MAPK was correlated to ABA
synthesis. Together, these results suggest that MAPK phosphorylation played an important role in ABA accumulation under water
stress, and MAPK might mediate the signal transduction of ABA synthesis. 相似文献
19.
Adrienn Guóth Dániel Benyó Jolán Csiszár Ágnes Gallé Ferenc Horváth László Cseuz László Erdei Irma Tari 《Acta Physiologiae Plantarum》2010,32(4):719-727
The effects of increasing osmotic stress induced by 100–400 mOsm (−0.976 MPa) polyethylene glycol (PEG 6000) were investigated
in a drought-tolerant (Triticum aestivum L. cv. Mv Emese) and drought-sensitive (cv. GK élet) wheat cultivar at the three-leaf stage. During osmotic stress, the decline
of the water potential (ψ
w) was more significant in the leaves, while the abscisic acid (ABA) levels of the roots increased earlier and remained higher
in the sensitive than in the tolerant variety. There was an increasing gradient of ABA content toward the youngest leaves
in the drought-sensitive GK élet, while more ABA accumulated in the fully developed, older leaves of the tolerant cultivar
Mv Emese. In accordance with the rapid and significant accumulation of ABA, the stomatal conductance decreased earlier in
the tolerant cultivar. The effect of water stress on the PSII photochemistry was pronounced only 1 week after the exposure
to PEG, as indicated by the earlier decrease of the net CO2 fixation, the effective quantum yield (ΦPSII) and the photochemical quenching (q
P) in light-adapted samples of the tolerant variety in 400 mOsm PEG 6000. The stress treatment caused more significant reductions
in these parameters toward the end of the experiment in the sensitive cultivar. In spite of small differences in the photosynthetic
characteristics, the net biomass production was not significantly altered by this osmotic stress. The accumulation of ABA
controlled the distribution of the biomass between the shoot and root systems under osmotic stress, and contributed to the
development of stronger and deeper roots in the drought-sensitive cultivar GK élet. However, the root elongation did not correlate
with the drought sensitivity of these cultivars on the basis of crop yield. 相似文献
20.
Yanmei Duan Na Li Chao Liu Huiting Liu Yaling Cui Han Wang Fashui Hong 《Biological trace element research》2010,136(3):302-313
In order to study the mechanisms underlying the effects of TiO2 nanoparticles on lactate dehydrogenase (LDH, EC1.1.1.27), Institute of Cancer Research region mice were injected with nanoparticulate
anatase TiO2 (5 nm) of various doses into the abdominal cavity daily for 14 days. We then examined LDH activity in vivo and in vitro and
direct evident for interaction between nanoparticulate anatase TiO2 and LDH using spectral methods. The results showed that nanoparticulate anatase TiO2 could significantly activate LDH in vivo and in vitro; the kinetics constant (Km) and Vmax were 0.006 μM and 1,149 unit mg−1 protein min−1, respectively, at a low concentration of nanoparticulate anatase TiO2, and 3.45 and 0.031 μM and 221 unit mg−1 protein min−1, respectively, at a high concentration of nanoparticulate anatase TiO2. By fluorescence spectral assays, the nanoparticulate anatase TiO2 was determined to be directly bound to LDH, and the binding constants of the binding site were 1.77 × 108 L mol−1 and 2.15 × 107 L mol−1, respectively, and the binding distance between nanoparticulate anatase TiO2 and the Trp residue of LDH was 4.18 nm, and nanoparticulate anatase TiO2 induced the protein unfolding. It was concluded that the binding of nanoparticulate anatase TiO2 altered LDH structure and function. 相似文献