ABSTRACT
The protoplast fusion was induced between Astragalus adsurgens Pall and Agrobacterium rhizogenes-transformed cell line of Medicago Sativa L. by use of PEG method. Putative somatic hybrid cells were selected based on the observation that only intergeneric hybrid cells continued to divide on the DPD medium without any phytohormone while the cells and clusters derived from parental cells did not survive further. After being cultured, the somatic hybrid calli were obtained. Although both of the parental calli were not capable of regenerating , one of the hydrid cell lines recovered the differentiation ability and produced small shoots. Characterizations of the hybrid calli were carried out by examination of chromsome number, opine synthetase assay, isoenzyme and RAPD analyses.
Subject(s)
Astragalus Plant/physiology , Hybridization, Genetic/physiology , Medicago sativa/physiology , Astragalus Plant/cytology , Astragalus Plant/genetics , Astragalus Plant/growth & development , Chromosomes, Plant/genetics , Hybrid Cells/cytology , Hybrid Cells/metabolism , Hybridization, Genetic/genetics , Medicago sativa/cytology , Medicago sativa/genetics , Medicago sativa/growth & development , Protoplasts/cytology , Protoplasts/physiologyABSTRACT
This study carried out experiments to investigate changes of shape, inter-structures and cell microstructures of milk-vetch root under simulated Cu stress at non- or contaminated levels in a red soil using observation and bio-microscopic technique. It resulted that when Cu concentration ranged from 0 to 40 mg.kg-1 soil, the milk-vetch grew well and it had a whole root which worked normally. When Cu concentration reached 50 mg.kg-1 soil, the growth of milk-vetch began to get influence with decline of biomass, the taproot crooked and was less branched, root became short and hazel and had fewer shorter hairs, tubby appeared, epidermis began to shrink and cell wall cockled slightly and unevenly, the boundary between plasmalemma and organelle blurred as well. When treatment concentration reaching to 200 mg.kg-1 soil, milk-vetch roots became rotted and black, the cell wall broke and cytoplasm shrank so severely that plasmolysis happened and the plant died. So the critical Cu concentration in experimented soil was 50 mg.kg-1 soil, and the resistance of milk-vetch root to Cu contamination buildup with the growth of aboveground part, and cell wall was the main part to Cu tolerance.
