A soil-plant transfer study was performed using soil from a former uranium ore processing factory in South Bohemia. We present the results from greenhouse experiments which include estimates of the time required for phytoremediation. The accumulation of (226)Ra by different plant species from a mixture of garden soil and contaminated substrate was extremely variable, ranging from 0.03 to 2.20 Bq (226)Ra/g DW. We found differences in accumulation of (226)Ra between plants from the same genus and between cultivars of the same plant species. The results of (226)Ra accumulation showed a linear relation between concentration of (226)Ra in plants and concentration of (226)Ra in soil mixtures. On the basis of these results we estimated the time required for phytoremediation, but this appears to be too long for practical purposes.
Our study focused on the possible association between the cryotolerance of Norway spruce (Picea abies (L.) Karst.) embryogenic cultures and the anatomical structures of their embryogenic suspensor mass (ESM), their growth rate and their content of endogenous polyamines (PAs). The anatomical characteristics and PA content during cryopreservation and regrowth were studied in the ESMs of AFO 541 and C110 cultures, which have comparable ESM anatomy but diverse growth rates, PA content and regeneration abilities after cryopreservation. Different levels of tolerance to exogenous treatment were already apparent after transfer of the ESMs to liquid media. The endogenous free PAs were maintained at high levels, with spermidine being the predominant PA in the ESM of AFO 541, while in the ESM of C110 the content of putrescine and spermidine was almost identical and rather low, the content of spermidine being approximately one-third that in the ESM of AFO 541. Osmotic pretreatment, using a double application of sorbitol followed by an application of dimethyl sulfoxide (DMSO) resulted in the continual disintegration of polyembryogenic centers and suspensors in both cell lines. A continual decrease in the level of PAs was observed during the cell osmotic pretreatment. The cells that retained their viability and regrowth ability after cryopreservation were the meristematic cells inside the embryonal heads and the cells in the intermediate area between suspensor and meristems. Restoration of AFO 541 growth after cryopreservation was almost immediate; however, the C110 ESM culture regrew with difficulty, often exhibiting callogenesis. High levels of PA-soluble conjugates and an increase in the amount of PAs bound to high-molecular-mass substances was observed in cells of AFO 541 on Day 6 after thawing and also to some extent on Day 11. On Day 21 after thawing, the amount of free putrescine and spermidine in the AFO 541 cells reached the level observed in the suspension culture before the cryotreatment. The extremely low level of PAs determined in the ESM of C110 3 weeks after thawing agreed with the cell viability and rate of regrowth observed in this culture. The possible role of PAs in the process of cryopreservation of Norway spruce cultures is discussed.
- MeSH
- buněčné linie MeSH
- dimethylsulfoxid farmakologie MeSH
- kryoprezervace metody MeSH
- polyaminy metabolismus MeSH
- semena rostlinná anatomie a histologie cytologie účinky léků fyziologie MeSH
- smrk anatomie a histologie embryologie genetika růst a vývoj MeSH
- sorbitol farmakologie MeSH
- studené klima MeSH
- zmrazování MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Somatic embryogenesis in spruce is a process of high importance for biotechnology, yet it comprises of orchestrated series of events whose cellular and molecular details are not well understood. In this study, we examined the role of actin cytoskeleton during somatic embryogenesis in Norway spruce line AFO 541 by means of anti-actin drugs. RESULTS: Application of low doses (50-100 nM) of latrunculin B (Lat B) during the maturation of somatic embryos predominantly killed suspensor cells while leaving the cells in meristematic centres alive, indicating differential sensitivity of actin in the two cell types. The treatment resulted in faster development of more advanced embryos into mature somatic embryos and elimination of insufficiently developed ones. In searching for the cause of the differential actin sensitivity of the two cell types, we analysed the composition of actin isoforms in the culture and isolated four spruce actin genes. Analysis of their expression during embryo maturation revealed that one actin isoform was expressed constitutively in both cell types, whereas three actin isoforms were expressed predominantly in suspensor cells and their expression declined during the maturation. The expression decline was greatly enhanced by Lat B treatment. Sequence analysis revealed amino-acid substitutions in the Lat B-binding site in one of the suspensor-specific actin isoforms, which may result in a different binding affinity for Lat B. CONCLUSIONS: We show that manipulating actin in specific cell types in somatic embryos using Lat B treatment accelerated and even synchronized the development of somatic embryos and may be of practical use in biotechnology.
- MeSH
- aktiny antagonisté a inhibitory metabolismus MeSH
- bicyklické sloučeniny heterocyklické farmakologie MeSH
- cytoskelet účinky léků MeSH
- embryonální vývoj MeSH
- fylogeneze MeSH
- protein - isoformy metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- RNA rostlin genetika MeSH
- rostlinné geny MeSH
- sekvenční seřazení MeSH
- smrk embryologie růst a vývoj MeSH
- substituce aminokyselin MeSH
- techniky tkáňových kultur MeSH
- thiazolidiny farmakologie MeSH
- vazebná místa MeSH
- vývojová regulace genové exprese MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
