APPROACH TO GROWTH AND PHYSIOLOGICAL CHARACTERS IN OCTAPLOID PANICUM MILIACEUM L. Cytological Studies of the Double Fertilization in Panicum miliaceum L. The Process and Timing of Embryo Development in Broomcorn Millet(Panicum Miliaceum L.) HISTOLOGICAL STUDY ON SOMATIC EMBRYOGENESIS OF PANICUM MILIACEUM IN VITRO Biochemical Mechanism of Synergistic Senescence between Root System and Flag Leaf in Broomcorn Millet(Panicum miliaceum L.)