Study On Cytomorphology And Characteristics Of Physiology And Biochemistry In The New CMS Line Of Non-heading Chinese Cabbage

The new germplasm of non-heading Chinese cabbage synthesized through asymmetric electric fusion of protoplast cell and characterized by absence of degeneration of nectarines and seedling yellowing at low temperature of the primary OguCMS line, are identical to their maintainers in seed set ratio. At the same time, both the rate and the degree of male-sterility for the new CMS line reached 100%.The present study about male sterile mechanism of the new CMS line in theory was initiated, because main emphasis was paid on production utilization of this cytoplasm hybrid. The aim of our study was analysis of the physiological and biochemical characteristics of the new CMS line and its maintainer line and discussion of potential CMS mechanism through investigation of cytology, energy, substance, active oxygen and polyamine metabolism.Cotomorphological and histochemical studies indicated that the inhibition of CMS line anther development may occur at archesporia cell-sporogenous cell stage or at the tetrad-uninucleic pollen stage. As the sporogenous cell did not form or degenerated some anthers had no pollen sac at all, some had one. Tapetum of the male sterile line did not disappear even when the uninucleic microspores had degenerated. The CMS anther possessed little protein, polysaccharides and nucleic acids, while its maintainer anther stored rich polysaccharides, protein and nucleic acids during all development stages.In order to establish the correlation of physiological and biochemical characteristics with cytoplasmic male sterility, the rates of Vt, Valt, Pn and contents of Dw, pigment, free amino acids, proline, soluble sugar, soluble protein, MDA, H2O2, three poly amines including Put, Spd and Spm, in their different forms (free, perchioric acid soluble and insoluble conjugated), the production rate of O₂^- and the activities of SDH, α , β -amylase, SOD, POD, CAT and APX were examined in floral buds at different flower development stages and leaves in vegetable and flowering stages. The results were as follows:1. There were little differences in Dw, pigment contents and Pn between the new CMS line and its maintainer line. But much significant differences were in Vt, Valt and activities of SDH.2. A lower total free acid, proline and soluble protein in new CMS plants were observed compared to its maintainer plants. But little differences of soluble sugar contents lied in those tow plants. The α , β -amylase activities increased during flowering at first , then declined. All those above showed there were very close correlations with cytoplasmic male sterility.there were higher levels of MDA and H2O2 contents, higher O2- production rate and higher activities of SOD, POD and CAT in bud of the CMS lines than the maintainer lines, but activities of APX were different with the three enzymes above.3. During the flowering stage, all free polyamines and conjugates especially PCA insoluble conjugated examined were present at a much lower level in floral organs of CMS plants compared to maintainer plants.4. Although the abortion of pollen was the primary phenomenon of CMS. there were physiological and biochemical differences in leaves during vegetable and flowering stages at some extent, which may be aroused by the early expression of genes concerned CMS.In conclusion, the results indicated that there was some relativity between steriliy and the physiological and biochemical characters including overabundant accumulation of Of, H2O2, MDA, the severe deficiency of protein, free proline and total polyamines especially PCA insoluble conjugated, and the increasing of the activities of POD and CAT.