Asexual embryogenesis in plants
(2002)- Abstract
- The capacity of somatic cells and pollen grains or microspores to undergo embryogenesis is an important property used in improvement and regeneration of plants. Furthermore, somatic embryogenesis as well as pollen embryogenesis show many similarities with zygotic embryogenesis and are, thus, good model systems. Pollen suspensions of tobacco (Nicotiana tabacum L.) contain a mixture of embryogenic and normal pollen grains of different developmental stages. They could be fractionated due to different surface properties by using aqueous two-phase partition. Cold led to a general increase in specific isoperoxidase activity in pollen fractions enriched in embryogenic pollen, and also to changes of the isoperoxidase pattern towards more neutral... (More)
- The capacity of somatic cells and pollen grains or microspores to undergo embryogenesis is an important property used in improvement and regeneration of plants. Furthermore, somatic embryogenesis as well as pollen embryogenesis show many similarities with zygotic embryogenesis and are, thus, good model systems. Pollen suspensions of tobacco (Nicotiana tabacum L.) contain a mixture of embryogenic and normal pollen grains of different developmental stages. They could be fractionated due to different surface properties by using aqueous two-phase partition. Cold led to a general increase in specific isoperoxidase activity in pollen fractions enriched in embryogenic pollen, and also to changes of the isoperoxidase pattern towards more neutral and alkaline types. The total change of peroxidase activity obtained after cold-treatment was most pronounced in embryogenic pollen, and was probably both due to a general stress reaction in all pollen and to a switch into the sporophytic pathway of embryogenic pollen. There were also clear differences in peroxidase activities between embryogenic and non-embryogenic somatic carrot cells (Daucus carota L). The major part of the peroxidases was soluble with about three times lower specific activity in embryogenic cells as compared to non-embryogenic cells. The activity of membrane-bound peroxidases was enriched in the intracellular membrane fractions but, as opposed to the soluble peroxidases the activity was higher in embryogenic cells. The dominating Ca2+ transport system in both embryogenic and non-embryogenic carrot cells was a primary ATP-dependent Ca2+ transport located in the plasma membrane. The Ca2+ transport of plasma membrane vesicles was higher in non-embryogenic cells, although the uptake in vesicles from intracellular membranes was higher in preparations from embryogenic cells. Using a Spearman rank correlation test a negative correlation was found between plasma membrane-bound Ca2+ transport and intracellular membrane-bound peroxidases, which is in agreement with the fact that increased cytosolic Ca2+ activates the secretion and the activity of peroxidases. The alterations in peroxidase activity and Ca2+ transport thus appeared already before embryo development took place (the carrot cell suspensions did not contain any embryos), and probably reflected processes in the apoplast linked to cell wall formation and important with regard to cell shape determination. In pollen, specific peroxidases were linked to embryogenic pollen and it is possible that also in somatic cells the induction of embryogenesis involved specific peroxidases. Subcellular studies on enzyme activities give valuable contributions to the understanding of developmental processes during embryogenesis. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/464713
- author
- Mårtensson, Boel LU
- supervisor
- opponent
-
- Hakmn, Inger
- organization
- publishing date
- 2002
- type
- Thesis
- publication status
- published
- subject
- keywords
- Systematic botany, two-phase partitioning, somatic embryogenesis, pollen embryogenesis, plasma membrane, peroxidase, Daucus carota isoperoxidase, Nicotiana tabacum, Ca2+ transport, cell shape, calmodulin, taxonomy, morphology, phytogeography, chemotaxonomy. Physiology of nonvascular plants, Systematisk botanik, taxonomi, morfologi, kemotaxonomi. Växters fysiologi (inte kärlväxter).
- pages
- 134 pages
- publisher
- Animal Ecology
- defense location
- 13 june 2002 Växtfysiologen
- defense date
- 2002-06-13 10:15:00
- ISBN
- 91-628-5300-7
- language
- English
- LU publication?
- yes
- additional info
- Article: Mårtensson B, Widell S (1987). Separation of precultured pollen from Nicotiana tabacum by aqueous polymer two-phase partition. Plant Cell, Tissue and Organ Culture 8: 27-35Mårtensson B, Widell S (1993). Pollen from cold-treated Nicotiana tabacum buds: Embryogenic capacity, peroxidase activity and partitioning in aqueous two-phase systems. Plant Cell, Tissue and Organ Culture 35: 141-149Mårtensson B, Widell S. (1994) Separation of pollen from Nicotiana tabacum. Methods of Enzymology vol 228: 344-354Mårtensson B, Sommarin M, Widell S (1998) Peroxidase activity and ATP-dependent Ca2+ transport in subcellular fractions of embryogenic and non-embryogenic Daucus carota cell suspensions. Plant Physiol Biochem 36: 515-524 The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Animal Ecology (Closed 2011) (011012001)
- id
- f1f2635a-9adb-42ef-87e8-ee9a49daa35c (old id 464713)
- date added to LUP
- 2016-04-04 11:46:41
- date last changed
- 2018-11-21 21:07:09
@phdthesis{f1f2635a-9adb-42ef-87e8-ee9a49daa35c,
abstract = {{The capacity of somatic cells and pollen grains or microspores to undergo embryogenesis is an important property used in improvement and regeneration of plants. Furthermore, somatic embryogenesis as well as pollen embryogenesis show many similarities with zygotic embryogenesis and are, thus, good model systems. Pollen suspensions of tobacco (Nicotiana tabacum L.) contain a mixture of embryogenic and normal pollen grains of different developmental stages. They could be fractionated due to different surface properties by using aqueous two-phase partition. Cold led to a general increase in specific isoperoxidase activity in pollen fractions enriched in embryogenic pollen, and also to changes of the isoperoxidase pattern towards more neutral and alkaline types. The total change of peroxidase activity obtained after cold-treatment was most pronounced in embryogenic pollen, and was probably both due to a general stress reaction in all pollen and to a switch into the sporophytic pathway of embryogenic pollen. There were also clear differences in peroxidase activities between embryogenic and non-embryogenic somatic carrot cells (Daucus carota L). The major part of the peroxidases was soluble with about three times lower specific activity in embryogenic cells as compared to non-embryogenic cells. The activity of membrane-bound peroxidases was enriched in the intracellular membrane fractions but, as opposed to the soluble peroxidases the activity was higher in embryogenic cells. The dominating Ca2+ transport system in both embryogenic and non-embryogenic carrot cells was a primary ATP-dependent Ca2+ transport located in the plasma membrane. The Ca2+ transport of plasma membrane vesicles was higher in non-embryogenic cells, although the uptake in vesicles from intracellular membranes was higher in preparations from embryogenic cells. Using a Spearman rank correlation test a negative correlation was found between plasma membrane-bound Ca2+ transport and intracellular membrane-bound peroxidases, which is in agreement with the fact that increased cytosolic Ca2+ activates the secretion and the activity of peroxidases. The alterations in peroxidase activity and Ca2+ transport thus appeared already before embryo development took place (the carrot cell suspensions did not contain any embryos), and probably reflected processes in the apoplast linked to cell wall formation and important with regard to cell shape determination. In pollen, specific peroxidases were linked to embryogenic pollen and it is possible that also in somatic cells the induction of embryogenesis involved specific peroxidases. Subcellular studies on enzyme activities give valuable contributions to the understanding of developmental processes during embryogenesis.}},
author = {{Mårtensson, Boel}},
isbn = {{91-628-5300-7}},
keywords = {{Systematic botany; two-phase partitioning; somatic embryogenesis; pollen embryogenesis; plasma membrane; peroxidase; Daucus carota isoperoxidase; Nicotiana tabacum; Ca2+ transport; cell shape; calmodulin; taxonomy; morphology; phytogeography; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi (inte kärlväxter).}},
language = {{eng}},
publisher = {{Animal Ecology}},
school = {{Lund University}},
title = {{Asexual embryogenesis in plants}},
year = {{2002}},
}