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1.
The lower part (4 cm) of the witloof chicory tap-root (15 cm) was immersed in a complete nutrient solution for 21 days, in the darkness at 18°C and at high RH. This process of forcing which leads to the emergence of an etiolated bud (chicon) was associated with a decrease in root dry weight. Although the amount of calcium in the root and the root cationic exchange capacity remained constant during forcing, the net uptake of calcium, negligible at the onset of forcing, progressively increased to a rate after ten days of 45 mol day–1. Absorption of 45Ca remained at a constant high rate, while the initially low upward migration of 45Ca within the root and the chicon accelerated markedly. This upward migration was associated with a progressive decline in the release of newly absorbed 45Ca. The data support the hypothesis that calcium acquisition by witloof chicory root is predominantly determined by calcium efflux. As the forcing progressed, the influx remained almost constant while a large decrease in the efflux led to a net uptake of calcium. Upward translocation was probably linked to the formation of new negative exchange sites within the growing chicon. The hypothesis that calcium movement occurred along a preferential pathway (xylem vessels) or involved a mass movement through the root is discussed. 相似文献
2.
3.
L.F.M. Rouws C.H.S.G. Meneses H.V. Guedes M.S. Vidal J.I. Baldani S. Schwab 《Letters in applied microbiology》2010,51(3):325-330
Aims: To evaluate the colonization process of sugarcane plantlets and hydroponically grown rice seedlings by Gluconacetobacter diazotrophicus strain PAL5 marked with the gusA and gfp reporter genes. Methods and Results: Sugarcane plantlets inoculated in vitro with PAL5 carrying the gfp::gusA plasmid pHRGFPGUS did not present green fluorescence, but β‐glucuronidase (GUS)‐stained bacteria could be observed inside sugarcane roots. To complement this existing inoculation methodology for micropropagated sugarcane with a more rapid colonization assay, we employed hydroponically grown gnotobiotic rice seedlings to study PAL5–plant interaction. PAL5 could be isolated from the root surface (108 CFU g?1) and from surface‐disinfected root and stem tissues (104 CFU g?1) of inoculated plants, suggesting that PAL5 colonized the internal plant tissues. Light microscopy confirmed the presence of bacteria inside the root tissue. After inoculation of rice plantlets with PAL5 marked with the gfp plasmid pHRGFPTC, bright green fluorescent bacteria could be seen colonizing the rice root surface, mainly at the sites of lateral root emergence, at root caps and on root hairs. Conclusion: The plasmids pHRGFPGUS and pHRGFPTC are valid tools to mark PAL5 and monitor the colonization of micropropagated sugarcane and hydroponic rice seedlings. Significance and Impact of the Study: These tools are of use to: (i) study PAL5 mutants affected in bacteria–plant interactions, (ii) monitor plant colonization in real time and (iii) distinguish PAL5 from other bacteria during the study of mixed inoculants. 相似文献
4.
Siri Caspersen Peter Sundin Mark Munro Sveinn Aðalsteinsson John E. Hooker Paul Jensén 《Plant and Soil》1999,210(1):115-126
Ferulic acid (FA) is released by living roots and by decaying plant material and is involved in chemical interactions between plants. Effects of FA on plant growth and root development of lettuce (Lactuca sativa L. cv. Grand Rapids) cultivated in axenic nutrient solution were studied in two factorial experiments. Root and shoot growth was impeded when 200 M trans-FA was added to the nutrient solution and the light intensity was in the range of 250–380 mol m-2 s-1. Root growth showed a stronger response to FA than did shoot growth. At 200 M, FA strongly inhibited root hair formation and reduced mean lengths of primary, secondary and tertiary roots, but stimulated primary and secondary root branching. Both isomerization to the cis isomer and the presence of the plant reduced the concentration of trans-FA in the nutrient solution during the two weeks exposure period. A third experiment was conducted to assess the influence of irradiance on the phytotoxicity of FA. At a light intensity of 489 mol m-2 s-1, or in the presence of microorganisms, the concentration of FA in the nutrient solution was lowered and the phytotoxic effects were reduced. 相似文献
5.
Bernhard?Schlesier Frédéric?Bréton Hans-Peter?MockEmail author 《Plant Molecular Biology Reporter》2003,21(4):449-456
We developed a hydroponic cultivation system for growingArabidopsis plantlets under sterile, controlled environmental conditions. The system consists of a piece of stainless-steel wire cloth
(125 μm mesh size) that is fixed between 2 flat rings and held in place by 3 legs, placed in a commercially-available glass
jar, and covered by the original glass lid or a sheet of sterilized cellophane. Sterilized seeds were distributed evenly across
the mesh piece, the size of which allowed root growth and kept the seeds in place. After 3 weeks of cultivation, shoot and
root tissues were easily harvested without mechanical damage. Proteome and metabolite analyses were performed on root and
shoot tissues and demonstrated excellent reproducibility, indicating that the system is advantageous when biological variation
is minimized. Induction experiments can be performed by transferring the apparatus (with plants) to a new jar containing a
different nutrient solution. The apparatus is reusable and can easily be sterilized by autoclaving or dry heat. The system
can be adapted to other small-seed plants by varying the mesh size. 相似文献
6.
Effects of NaCl Stress on the Structure,Pigment Complex Composition,and Photosynthetic Activity of Mangrove Bruguiera parviflora Chloroplasts 总被引:7,自引:1,他引:6
Exposure of two-month-old seedlings of Bruguiera parviflora to NaCl stress (0 to 400 mM) for 45 d under hydroponic culture caused notable disorganisation of the thylakoid structure
of chloroplasts in NaCl-treated leaves as revealed from transmission electron microscopy. The absorption spectra of treated
and control thylakoid samples were similar having a red peak at 680 nm and Soret peaks at 439 and 471 nm in the blue region
of the spectrum. The spectra of treated samples differed from control samples by gradual decrease in absorbance of 100, 200,
and 400 mM NaCl treated samples at 471 and 439 nm, which could be due to scattering of radiation in these samples. Thus, absorption
characteristics of thylakoid membranes indicated no major alterations in the structural integrity of the photosynthetic membranes
during salt stress in B. parviflora. Analysis of pigment protein complexes of thylakoids on non-denaturing gel showed that CP1 complex consisting of photosystem
(PS) 1 reaction centre decreased marginally by 19% and the CP47 constituting the core antenna of PS2 declined significantly
by 30% in 400 mM NaCl treated samples in respect to control. This decrease in structural core antenna might cause inefficient
photon harvesting capacity. However, CP43 content did not alter. An increase in CP2/CP1 ratio from 3.2 in control to 4.0 in
400 mM NaCl treated samples indicated significant structural changes in the thylakoids of salt treated plants. Haem staining
of thylakoids revealed significant losses in cytochrome (Cyt)f and Cyt b
6 contents by NaCl stress. However, Cyt b
559 content remained nearly constant in both control and NaCl treated samples. SDS-PAGE of thylakoid proteins showed that the
intensity of many of Coomassie stained polypeptide bands ranging from 15–22 and 28–66 kDa regions decreased significantly
in NaCl treated samples as compared to control. Electron transport activity of thylakoids, measured in terms of DCPIP photoreduction,
was 22% lower in 400 mM NaCl treated plants than in the control ones. Hence, NaCl induces oxidative stress in chloroplasts
causing structural alterations in thylakoids. These structural alterations might be responsible for declined efficiency of
photosystems and reduced electron transport activity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Hydroponic method for ramie and removal of nitrogen and phosphorus from livestock wastewater 总被引:1,自引:0,他引:1
Gang Gao Heping Xiong Jikang Chen Kunmei Chen Ping Chen 《International journal of phytoremediation》2018,20(6):545-551
By using a hydroponic culture system, the terrestrial fiber crop ramie can growth optimally in aquatic environment and enhance exponentially quantities of high quality seedlings for subsequent field cultivation. In this study, the survival rate of ramie seedling was more than 97% when cultured using the novel hydroponic method. Further physiological analysis of the hydroponic ramie to different concentration of livestock wastewater demonstrated that all of these ramies can survival in livestock wastewater, but the 4 times diluted livestock wastewater (total N: 100.9 mg L?1, total P: 2.69 mg L?1) was more appropriate for ramie growth. The nutrients N and P in livestock wastewater were significantly decreased by the growth of ramie, and the removal efficiency of total N and total P in the 4 times diluted livestock wastewater achieved 78.1% and 43.1% respectively within 5 weeks. In conclusion, our studies highlight that the combination of ramie and the hydroponic technology resulted to be effective in the phytoremediation of livestock wastewater. 相似文献
8.
Proteomics analysis of Medicago truncatula response to infection by the phytopathogenic bacterium Ralstonia solanacearum points to jasmonate and salicylate defence pathways 下载免费PDF全文
9.
In the Xinjiang province of western China, conventional methods of iodine (I) supplementation (i.e, goiter pills and iodinated
salt) used to mitigate I deficiencies were ineffectual. However, the recent addition of KIO3 to irrigation waters has proven effective. This study was conducted to determine the effects of I form and concentration
on rice (Oryza sativa L.) growth, I partitioning within the plant, and ultimately to assist in establishing guidelines for
incorporating I into the human food chain. We compared IO3
− vs. I− in order to determine how these chemical species differ in their biological effects. Rice was grown in 48 L aerated tubs
containing nutrient solution and IO3
− or I− at 0, 1, 10, or 100 μM concentrations (approximately 0, 0.1, 1, and 10 mg kg−1 I). The IO3
− at 1 and 10 μM had no effect on biomass yields, and the 100 μM treatment had a small negative effect. The I− at 10 and 100 μM was detrimental to biomass yields. The IO3
− treatments had more I partitioning to the roots (56%) on average than did the I− treatments (36%), suggesting differences in uptake or translocation between I forms. The data support the theory that IO3
− is electrochemically or biologically reduced to I− prior to plant uptake. None of the treatments provided sufficient I in the seed to meet human dietary requirements. The I
concentration found in straw at 100 μM IO3
− was several times greater than seed, and could provide an indirect source of dietary I via livestock feeding on the straw.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.