Analysis Of Organic Nutrition Metabolism And Anatomical Characteristics During Nuts Development And Dormancy Of Interspecific Hybrid F1 Between Corylus Heterophylla Fisch.and Corylus Avellana L.

In this project the nuts of line 82-7 and 'Dawei' were used as experimental materials,the dynamic changes of nut characters,physiological indices and anatomical structure during nut various development stages were systematically studied.In addition,the dynamic changes of nut kernel physiological indices and anatomical structure during different nut kernel lamination stages were researched.The results would provide technical support for hybrid hazelnut high quality cultivation,suitable storage of mature nut,and improving seed germination rate.Moreover,the result would offer reference foundation for exploring the mechanism of seed dormancy.The results were as follows.1.Hybrid hazelnut line 82-7 bore nuts in about May 18.And 'Dawei' bore nuts in about May 12.After nut set,2 hybrid hazelnut germplasms entered the shell expansion period first.This period lasted about 30d.At this stage,the shells of nuts were formed rapidly,and the whole nuts were expanded constantly the volume and fresh weight of which were increasing rapidly.Through observing the anatomy of shell,it was found that shells of line 82-7 and Dawei were divided into 5 layers:the exocarp layer,the dense lithocyte layer,the non-directional cell layer,the parenchyma cell layer,and the endocarp layer.The inner part of nut shell was filled with spongy tissue and contained plenty of nutrient substance.2.Through conducting continuous measurement of 2 years,it was found that nuts of line 82-7 entered kernel formation period in about June 28,and kernel formation period of Dawei was earlier a week than that of line 82-7 and was in June 21.At this stage,the nuts volume and weight no longer increased significantly,but the kernel three diameters and kernel weight entered a rapid growth period.Fat,protein and soluble sugar in kernel were accumulated in this period.The sponge filler material in the kernel which contained a lot of nutrients were exhausted and disintegrated rapidly for providing suitable substance that kernels could absorb and use during this period.The testa was divided into 4 layers:exotesta,mesosperm,fiber layer and indotesta.The testa became thinner at the nuts development stage.The seed embryo of nut which was between the top of the two cotyledons was formed initially.3.Line 82-7 entered the kernel-filling period in July 21,and Dawei entered this period in July 12.In this process,there is no obvious change in the size and weight of the kernel,and the transformation was produced between the inclusions.The fat in the kernel of 2 germplasms continued to accumulate,daily fat increment in the kernel of line 82-7 was 0.021 g/d,and daily increment in the kernel of Dawei was 0.0018g/d.The concentration of protein in the kernel of 2 germplasms was in a decline state.The soluble sugar content in the kernel of 82-7 continued to decline,the increasing amount of soluble sugar was-0.002 g/d or-0.003 g/d,on the contrast,the content of soluble sugar in the kernel of Dawei unchanged basically.The nuts of 82-7 was ripe in early August,Dawei nuts matured at the end of July.In this stage,the nut bract was easy to be separated from nut,and concentration of fat and soluble sugar in the kernel increased constantly.By observing the anatomical structure of kernels in the 2 variety or line,it was found that parenchyma cells in mesosperm disintegrated and fell off greatly from the kernel.The exotesta separated from kernel and structure of endotesta remained intact.The number of fatty granules in the cotyledon cells was increasing instantly and filled the whole cell.4.After harvest of the nut in 82-7 and 'Dawei',the contents of three substances such as fat were increasing at the beginning of the storage period.Then the contents of three nutrient substances tended to be stable after 30-40d.Observation of anatomical structures showed that the lipochondria in the cells continued to increase,and nuts was dried in the shade,seed coat became hard and fragile in this meantime and was colored deeply.5.The laminating treatment had gone through 150d.During the whole lamination,the fat content of line 82-7 seeds showed a downward trend while the soluble sugar content decreased first and then increased.The fat content in the seeds of Dawei which was in a declined trend during the lamination until germinating was higher than that of line 82-7.The soluble sugar content in the kernel of Dawei was lower than 82-7.Through observing seed anatomy structure,it was found that lipochondria in kernel cells of line 82-7 and Dawei decreased and was dyed lighter.The inclusion in the kernel central cells disappeared largely and cell disintegrated.Gaps were formed by cell walls that twisted and piled up.It was becoming lager gradually with the passage of time until February.6.During the germination of hybrid hazelnut seeds,fat content of kernel was decreasing while soluble sugar was increasing.Through dynamic observation of the seeds anatomical structure in germination,it was found that the radicle broke through the seed coat first and the germ grew at the opposite direction in the embryo.Then both of radicle and germ grew outside the nuts.The radicle and germ extended instantly outside the shell.The apical meristem of the radicle and germ cells were parenchyma cells which were large in the center while cells all round were small.They were arrayed in a radial shape state.By calculating germination rates of 4 hybrid hazelnut varieties or line which were Dawei,82-7,85-73 and Corylus heterophylla Fisch,it was showed that seed germination rate in pit lamination was significantly higher than that in cellar lamination.And seed germination rate of line 82-7 was significantly higher than those of other varieties or line.In summary,after harvest and dry storage,nuts were in dormant state.During this period,the fat contents of hazelnut kernels were high.Observation of anatomical structure was showed that there was a lot of liposomes in the kernel.Although the structure of embryo was complete,it did not have the conditions of germination.Through 150d lamination,liposomes of kernel in a long low temperature,breathe environment and water-saturated state gradually degraded and fat contents decreased.These changes in physiology and morphology laid the material foundation for the lifting of seed dormancy of hazelnut.In the later stage of the lamination,the radicle and germ gradually germinated,and the root cap was differentiated.The germination of the radicle and germ indicates that the dormancy of hazelnut seeds has been completely relieved after stratification.