Fruit Development And Oil Accumulation Of Two Early Walnut Varieties

Oil accumulation in the fruit has been identified to be closely related to the fruit development. Consequently, J. regia‘xinwen 185? and J. regia ‘xinxin2’of South Xinjiang basin was chosen as research object in this study. From the start of flower budding, weight longitudial diameter, transverse diameter, horizontal diameter, mass of weight, nut fresh weight, nut dry weight was deeply mestured. Meanwhile, the development of pericarp and embryo were detected and studied for further steps. The time and locations of oil accumulation in the fruit were also observed by using the method of histochemistry and ultra-microscopically technology. It is intended to clarify the development rules of walnut and the formation process of oil, then to provide theoretical basis for breeding of high oil varieties.The results were as follows: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(30-70DAF), slow growth(within 70 d after florescence, DAF). Oil deposition during seed development exhibited“slow-fast-slow”accumulation pattern, single “S” shape.The tissue structure of the pericarp of J.regiu L. may he divided into three parts, i. e. exocarp, mesocarpand endocarp. The development stake can he divided into the early stake and late stake. The boundary lines between exocarp, mesocarp and endocarp are not clear in the early stake, but, it is clear in the late stake. J. regia embryonic developmental stages and the corresponding time period were Original embryo(within 10 d after florescence, DAF), globular embryo(10-20, WAF), pear-shaped embryo(20-30, WAF), heart-shaped embryo(30-40, DAF), torpedo-shaped embryos(40-50, WAF), mature embryos(after 50 d after florescence, WAF).Oil bodies were identified to be synthesized in endoplasmic reticulum. The time of oil appeared in embryos earlier than cotyledons. Oils bodies were firstly detected in 60 DAF after florescence, after that it has increased; Protein were firstly detected in 60 DAF after florescence, after that it has increased,when mature stage it has decreased. The results showed that starch grain increased gradually before 50 DAF and then decreased gradually. During seed development, the accumulation of sugar exhibitied the opposite accumulation pattern in contrast to oil, the accumulation of protein the same accumulation pattern in contrast to oil.High oil varieties J. regia ‘xinwen 185’walnut seed oil body inside than low oil varieties J. regia ‘xinxin2’tightly arranged,small voids. In the embryos, the diameter of oil and the rate sum of oil areas of J. regia ‘xinwen 185’ were significant higher than J. regia ‘xinxin2’,but, the number of oil were significant less than J. regia ‘xinxin2’(P<0.01); In the cotyledon, the number of oil and the rate sum of oil areas of J. regia ‘xinwen 185’ were significant higher than J. regia ‘xinxin2’,but, the diameter of oil were significant less than J. regia ‘xinxin2’(P<0.01). In the same spiecies, the diameter of oil and the rate sum of oil areas in cotyledon were significant higher than in the embeyos, but, the number of oil were significant less than in the embeyos(P<0.01).The number of oil was decrease of increase with the diameter of the oil(increase of decrease). Total sum of areas of oil bodies correlate well with the oil content of walnut.