Studies On The Apomixis Property Of Early Bearing And Pellicle Walnut "LvLing"

In order to prove up the stability, occur period, ploidy and fruit character of apomixes ability in"LvLing"walnut., "LvLing" walnut was used as material in this experiment, " LvLing " walnut flowering phenology and female flowers opening process were studied with the method of microexamination, paraffin slice up and tissue culture techniques, fruit setting instance of walnut apomixis were investigated through 3 treatment of female flower baging, cutting stigma and envelop stigma with PVA. Ovule, embryo, embryonic development and fruit characters were also studied.The main results were as follows:The opening process of female stigma in"LvLing"walnut:Before blossom 2 d(from April 14th to April 15th in 2009), the female stigma was closed and no mucus;The female stigma opened slightly and secreted little mucus in the 1st day(April 16th); From the 3rd day (April 18th) to the 6th day (April 21st), there were abundant secretion when the female stigma puff and took on"Y"tape ; The secretion on the stigma began to dry and reduced in 7th day of blossom. with the appearance of stigma began drying obviously and parts of them withering in the 9th day (April 24th). Above all, It was need eight days during the development of stigma in"LvLing"walnut. The color change of stigma was peak green or pink, light Kelly, Kelly, yellow-white,and filemot in turn. It was concluded that ovary swollened of natural pollination was obvious earlier 4 ~ 5 d than that of the apomixis .The result showed that:"LvLing"walnut belong to single ovary and erection ovule in the female flower , the mature embryo sac was a typical eight-nuclei Polygonumembryo sac. Apomictic embryos of walnut came from egg cell or amalgamation with one of synergid. The endosperm cell was formed through amalgamation and division of two central polar nucleus.On March 21st, the ovule primordia formed when the female buds swollened; The integument primordium was appered gradually along with the female bud rending; On April 1st, the sporogenous cells carried through periclinal differentiated and differentiated archesporial cells which developed the megaspore mother cell when the tip of branch stretched out. From April 2nd to April 15th, the tip of branch continued elongation, light green or pink stigma exposed ovary gradually .At the same time, the stigma was closed and had no pollination ability, the embryo matured gradually; From blomming 1st day to 6th day, the stigma began to secret mucus and owned pollination ability but it was unable to accept pollen due to it by polyvinyl alcohol (pva) sealed or bagged, So that embryo sac had no significant changes. It is concluded that egg cell fusion with one of synergid and formed a cell when the stigma slightly dry On April 22nd. When the ovary swelled slowy and the stigma dried cleary , embryo sac egg cell or syncretic synergid began to mitosis, and formed two cell embryos, 4-cell embryos, 8-cell embryos, globular embryos, early heart-shaped embryos, late heart-shaped embryos, and further developed the apomictic embryo in turn.The apomixes fruit setting rate were 42.5%,26.7%,46.7% by way of bagging, cutting stigma and sealing stigma by polyvinyl alcohol. There had no significant difference between bagging and polyvinyl alcohol treatment,but both of them were significantly higher than that of the cutting stigma.The longitudinal diameter, side tracks, three tracks average, fruit weight, kernel weight, kernel percentage were 3.362 cm, 2.986 cm, 3.020 cm, 3.123 cm, 9.12 g, 5.64 g and 61.85% leave each other in apomixes nut, and that of natural pollination were 3.534 cm, 3.102 cm, 3.142 cm, 3.259 cm, 10.59 g, 6.76 g and 63.89%, there had no significant difference in the two treatment.The chromosome number of the radicle tip was 32 in"LvLing"wulnut through normal pollination ,wich was 93% in total cell. Thereby, somatic chromosome number were 2n = 32 in " LvLing " walnut. There had two kinds of chromosome wich was 16 and 32 in apomixes embryo. That was, apomictic " LvLing " walnut had both haploid and diploid embryos. The haploid accounted for 25.81% and the diploid embryos accounted for 74.19%. The germination of diploid tissue culture seedling was superior than that of haploid after inoculation.