Somatic Embryogenesis Of Citrullus Lanatus And Cytological Observations

The paper summarized research progress on plant somaticembryogenesis ,studied the cultural conditions and influence factors in the process ofCitrullus lanatus somatic embryogenesis, mainly put up it's cytologyical observa-tions .Finding out the most suitable conditions for somatic embryo induction, theseresults provided foundations for the creation artificial seeds, the research resultswere as follows:1.Effects on different genotypes to induce the somatic embryo from Citrullus lanatuswere studied , research results indicated that the different genotype had the greatdifferent on the induction rates of somatic embryogenesis. In 10 different genotypes,heimi No.5 , heimiNo.2 and seedless zhengkang No.4 could induce somatic embryoeasier than others.2.The cotyledon was the best explants to induce the somatic embryo, the hypocotyls,radicals and root tips couldn'tinduce somatic embryo. There were direct and indirectpaths on somatic embryogenesis, but the indirect path was principle.3.Different influence factors were studied, Using 2,4-D alone or combinatin withBA couldn't induce somatic embryogenesis ,and non embryogenic callus(NEC)were indnced using them on different media. The functions of NAA were obviouslylarger than 2,4-D, NAA combined with BA could induce the somatic embryogenesis.Sugar of the 30 g·L-1 had the good effects to induce somatic embryo. It was necessaryfor the cotyledon explants to handle in the dark conditions in the earlier phase of 59somatic embroygenesis.4.This experiment showed MS was the best basic medium for the callus inductionand somatic embryogenesis, the suitable media for somatic embryogenesis on threedifferent genetypes of Citrullus lanatus were heimi No.5 MS+ BA3.0mg/ L+ NAA0.5mg/ L;heimiNo.2 MS+ BA3.0ｍｇ·Ｌ－１+ NAA0.1ｍｇ·Ｌ－１; seedless zhengkang No.4MS+ BA2.0ｍｇ·Ｌ－１+ KT1.0ｍｇ·Ｌ－１+ GA31.0ｍｇ·Ｌ－１, and thire inducation percentageof explants was respectively 26.3%,25.6% and 22.2%.5. Paraffin-wax sectioning showed that the somatic embryogenesis derived from theembryo cells, experiencing the early proembryo, globular embryo, heart-shapedembryo,torpedo-shaped embryo,and Cotyledonary embryo five phases. Theseprocesses were similar to zygotic embryo, and part of the mature cotyledonaryembryo could produce regeneration plants.