using of Biotechnology rechniques in Plant Improvement atuf RapidPropagation

Abstract

his study was carried out in the Plant Biotechnology Lab, Bioengineering and Plant Analysis Labs, Fac. of Agric., Univ. of Cairo, and Anatomy Lab., Fac. of Science, Ain Shams Univ. Egypt, during the study period (2002-2005).Two banana cultivars (Grande -Naine and Williams cvs)were used to study th effect of six levels of water deficit stress induced by PEG ( MW 6000) (0,2.5,5,10,15 and 20 %) in vitro. Ex vitro acclimatized plants were subjected to five levels of PEG (0,2.5,5,10 and l5%).Putrescme at 0, 2 and 4 ppm was added into MS culture medium, and at 0 and 2 ppm was used as foliar application under greenhouse conditions. Data were calculated in vitro and ex vitro. The obtained data reveal that the increase of PEG concentrations induced negative response in all growth characters (survival percentage, shoot height, and leaves number). Root number root weight, plant dry weight were increased as PEG level increased. Anatomical parameters of leaf (leaf blade, midrib, mesophyll, and vascular bundles thickness), and root (root and vascular cylinder diameter) as well as plant pigments, N,P,K,Ca and Mg concentrations were I decreased with the mcreasing of PEG level either in vitro or ex vitro. I! Positive responses of organic components (total sugars, free amino acids

,proline ,phenols)and Na concentrations, anatomical parameters ( air cavities of leaf, cortex width and number of vessels of root) were observed as PEG levels increased . On the other hand, the data indicate that the putrescine treatment significantly prevented all above morphological, chemicals and anatomical parameters from the inhibition resulted by water stress conditions.Stomata frequenc)' was significantly decreased by the increasing of PEG concentration. The activity of superoxide dismutase (SOD) and glutathione reductase ( GR) enzymes were mcreased under the increasing of PEG. Positive response of this enzymes was detected by application of putrescine at 2 ppm. New low ,molecular weight protein . It was found that the using of gene gun is effective method for msert new genes into apical menstem of banana . also it was found that the I acceleration pressure 1100 psi gave the highest transient expression followed by pAB6 plasmid. Histochemical GUS assay in transformed 1l plants revealed GUS expression. Gene integration was assessed by subjecting plants to PCR analysis using specific primers for bar and GUS genes.