Walnut (Juglans Regia) Embryo Development And The Dynamics Of Nutrient Metabolism

Walnut (Juglans regia) is the 21st century super food. The 9-year-old plants of precocious walnut cultivar'Xiangling'were employed in this study. We using the technique of paraffin sections and hemi-thin slices, Studied by optical microscope during the embryonic development; The developmental process of walnut fruit was investigated; meanwhile the dynamics of fat, protein and sugar content in the embryo and the activities of enzymes related with sugar metabolism were determined and analyzed; Embryo during its nutrient accumulation of fat, protein, sugar contents and spatial distribution of chemical analysis of the characteristics of the organization. Main results are as follows:1) The ovary is 1-loculus, and unitegmic, crassinucellar.Usually one arechesporium functions directly as megadpore mother cell.Cytokinesis in the megaspore mother cell usually accompanies meiosis, and the chalazal megaspore of a linear. Which chalazal megaspore megaspore direct development success can be, and the remaining three degradation, but not the law of degradation of the order, after which the female gametophyte through the development, after the formation of a mature embryo sac, followed by the original embryo stage of globular embryo maturity period of organ formation. The embryo sac is polygonum type.embryo development stage 4, the endosperm is gradually absorbed, the rapid development of embryo, cotyledon lobes rapid growth of apical meristem, ovary filled cavity, nutrient accumulation, seeds mature embryo development.2) The result showed that the developmental process of walnut fruit could be divided into four stages: slow growth (within 30 d after florescence, DAF), fast growth (30-60 DAF), fat accumulation (60-100 DAF) and fruit maturation (100-140 DAF).3) Fat content in walnut embryo increased continuously and the maximum increment occurred within 60-90 DAF. It amounted to 50.11% at 100 DAF and maximized with 63.13% at 140 DAF when the fruit ripened. The protein content during embryo development in walnut volatile, the overall presentation of a first increased and then decreased. Sucrose and glucose content showed similar trend. They were both low at earlier stage, then gradually increased and reached the peak at 90 DAF, followed by gradual descending. Fructose content topped at earlier stage and then gradually decreased. AI, NI, SS and SPS activities were higher during the earlier stage and then decreased until the minimum point at 80 DAF, thereafter these enzyme activities turned to ascend the crest value at 90-100 DAF, and then kept decreasing until the late maturity stage. Soluble sugar content had significant positive correlation with fructose and glucose content at P<0.05. Sucrose content positively correlated with glucose content at P<0.01, while with SS and SPS activities at P<0.05. Protein content negatively correlated with NI and AI content at P<0.01, while with fructose content at P<0.05.4) Sugar was dyed purple, protein was stained blue, fat was dyed black by PAS-Coomassie Brilliant Blue R, PAS-Sudan Black B. Histochemical localization showed that: During the nutrient accumulation of the walnut embryo, sugar distributed at the cell periphery or intercellular and the distribution of sugar and fat displayed spatial correlation. The fat accumulated in the cell periphery at the beginning period, and gradually accumulated to the cytoplasm and formed large clumps of fat which occupied the whole cell in the latter. The protein scattered in the cytoplasm in the form of protein particles, and the changes of its number were consistent with the results of chemical determination.