Study On Cytology Basic Of Rice Anthesis And Lodicule Programmed Cell Death

On the basic of having observed flowering habits and the parts that compose the spikelet between male_sterile rice (ZhenShan97A,80078A) and maintenance line( Zhenshan97B,80078B,Minghui63,Shanyou63) , the study investigated in male_sterile and male_fertile rice (Oryza sativa subsp.indica)., used structural botany method and electron microscope technology, studied lodicules structure changes during blooming stage, discussed cytology basis of lodicules programmed cell death.The results were shown as follows:1.Differences of flowering habits between male_sterile and male_fertile rice Compared with male_sterile, flowering period of male_fertile rice was earlier, and obvious flowering peak in a day. male_fertile rice all had big glume opening dimension, short glume opening time, short period of flowering days.2. Morphological character and structure changes of lodicules during flowering processMorphological character of lodicules: Both in male_sterile and male_fertile the sizes of lodicules were nearly 3 mm , living on the subapical region of rachilla, presenting cystoid inverse triangle. Compared with male_sterile, lodicules of male_fertile are thicker and wider. During flowering process, lodicules cubage increased by absorbing water. In closing process, lodicules shrink,wizened, cubage dwindle, Living on the basic of ovary ,assuming dry membranous. Male_sterile lodicules'Morphological character didn't had extensive changes.Structure of lodicules: On the transverse section of lodicule, 1 layer of epidermis (thicker outer cell wall,cuticle,non-stomatal apparatus),lots of parenchymas and approximated to2 rows of vascular were observed. During flowering process ,the goffered cell wall of parenchymas in the ground tissue became flat, the size of the cell increased obviously, organelles was vacuolating, nucleolus was disapeared, and finally the whole cell shrank.Vasculars in the lodicule are made up of several sieve tubes,annular vessels and vascular parenchymas. During flowering process, there were obvious changes occurred in the vascular parenchymas. At the beginning, there are large nucleus,thick cytoloasm,abundance of mitochondria. In the end, these components entirely disappeared.3. process and character of PCD during flowering processFrom 5 to 20 minutes after flowering, the conformation of nucleus had degree changes.5 to 10 minutes later, nucleoplasm condensated into floccules.10 to 20 minutes later, by irregular contracting or extending of nucleus, the nucleus outline was amoeba-shaped. Nucleolus gradually faded and various forms and different sizes chromosome clump appeared. Nuclear membrane shrank or invaginated, salienting itself like pseudopodia.Dictyosome vesicles increased. Endoplasmic reticulum besieged to assimilate enchylema,mitochondrial and plastid, and maked them vacuolization, formed multi-ply membrance(Mpm).30 to 40 minutes later, chromosome clump hanged to karyotheca. Electronic density was declined in mitochondrial matrix. Vacuoles syncretized with others ,or cytosis vesicle , assimilated enchylema to form multi-ply membrance. Along with karyotheca disorganization the nucleolus disappear.40 to 50 minutes later, mitochondrial degenerated, more Mpm emergencing. In the end, the whole cell death.4. Ca2+ changes in the process of lodicule programmed cell deathPotassium pyroantimonate precipitation was used to show loosely bound calcium distributions in different time and space, which changes during programmed cell death of lodicules. Before or at the beginning of programmed cell death, Ca2+ largely accumulated in intercellular space.20 minutes later, there were evidence Ca2+ localized in karyotheca,nucleolus and karyoplasm of nucleolus. 30 minutes, Ca2+ notability localized in mitochondrial membrane and plasma membrane.40 minutes, surface of vesicle ,which was surround by endoplasm sediment in evidence. This process indicated that the cytology basis of lodicule expansion and shrinkage was programmed cell death.