A method for fast plant regeneration via organogenesis directly from Lycium barbarum leaf explants has been developed. The key factor for shoot regeneration was the presence of benzyladenine (BA) in the medium. NAA could only induce root formation and explant callusing. Murashige and Skoog (MS) medium supplemented with 2mg/l BA and 0.5mg/l NAA is the most efficient condition for shoot formation, with up to 92.6% shoot regeneration and no callus formation. All adventitious shoots cultured on MS medium supplemented with 1mg/l IAA formed an extensive root system. Regenerated plants were morphologically normal and were also proved to be diploid (2n=24). Using the optimized regeneration system, the genetic transformation of L. barbarum was carried out mediated by Agrobacterium tumefaciens EHA101(pIG121Hm). 11.8% leaf explants produced kanamycin-resistant shoots after infection by A. tumefaciens. The putative transgenic nature of plants was confirmed by GUS assay and PCR analysis. Expression of the nptⅡ gene in the regenerated plants was also detected by observing the callus formation by leaf pieces on MS medium containing 0.2mg/l 2,4-D and 0-100mg/l kanamycin.

Pectinase activity was localized at the ultrastructural level in pollen mother cells of tobacco (Nicotiana tabacum L.) during meiotic prophaseⅠto elucidate its role in the biogenesis of secondary plasmodesma (sPD) and cytoplasmic channel (CC). At the leptotene stage the enzyme was mainly present in the cisternae of smooth endoplasmic reticulum (SER) and their derived vesicles, but absent in the Golgi body and Golgi vesicles. Later at the zygotene stage, when sPDs and CCs were actively formed, strong pectinase activity was observed not only in the SER cisternae and their derived vesicles but also in the cell wall, especially in the vicinity of or within both simple and branched plasmodesmata, notably along the middle lamellae, which also characterized the sites of CCs being formed. The presence of exocytotic vesicles containing reaction products suggests that pectinase shares the same excretive pathway as that used by cellulase for its delivery into the wall, i.e. in active form via smooth endoplasmic reticulum (ER) and its derived vesicles by exocytosis. In combination with cellulase, pectinase also promotes the secondary formation of plasmodesmata and CCs by specifically digesting the pectin in middle lamella.

Using apical and axillary nodes as explants, a rapid and efficient method for propagation of Amorphafruticosa L. has been developed. When grown on Murashige and Skoog (MS) medium supplemented with 8mg dm-3 benzyladenine, 100% explants responded with 4.94 shoots per explant after 6-weeks culture, and explants taken from the in vitro proliferated shoots subsequently produced multiple shoots when cultured on the same medium. The addition of casein hydrolysate (200mg dm"3) enhanced the number of shoots up to 8.77 per subculture, and coconut milk was found to promote the shoot elongation and make them grow more vigorously. 82.53% excised shoots were rooted on half-strength MS medium containing 2.0mg dm"3 indoleacetic acid after 3 weeks of incubation. After acclimatization, all of the rooted plantlets established in soil, exhibiting uniform morphological and growth characteristics.

In oogamous reproduction of multicellular organisms, a striking phenomenon is the prevailing synchronous development of male germ cells connected by wide intercellular bridges (IBs, 0.1-2mm), which is well conservedin both animal andplant species ranging from algae to human. In the literature, IBs are believed either to allow genetically segregated haploid spermatids to share diploid gene products after meiosis, or to mediate rapid transfer of some vital signals or nutrients. Although intercellular sharing of gene transcripts has experimental evidences, these hypotheses are still not satisfactory. To explore the unknown roles of IB, we assume that developing male germ cells may be especially sensitive to stochastic gene expression to become heterogeneous. To achieve best gamete quality, such heterogeneity must be eliminated so that relatively uniform gametes with normal functions can be produced. Development within a common syncytium may be the only way for this purpose. The process may require not only the intercellular exchange of a few molecular signals but also the mixing of protoplasm between the connectedcells so that they have similar levels/states of mRNAs, proteins andorganelles, which can be achievedonly through wide IBs. This hypothesis can explain some quite intriguing aspects of male gametogenesis and provide unique predictions that can be tested experimentally.