The Embryo Development And The Change Pattern Of Biochemical Substances During The Stratification Of Torreya Grandis Seeds

Torreya grandis Fort. ex Lindl. is a unique rare tree species in China, Torreya genera.Taxaceae family, gymnosperms.Torreya grandis "Merrillii", is a general term that describes the excellent natural variation types of Torreya grandis, a cultivation group which through artificial breeding selection and grafting, also a rare specialty dried fruit in China. The seed of Torreya grandis "Merrillii" keeps a high price for a long time, because of the short of germplasm resources.In the production, the propagation of Torreya grandis "Merrillii" usually by grafting, which uses seedlings and rootstocks of Torreya grandis.In order to learn more about the change of embryo growth and development, the relationship between germination process of the seed and the change of storage substance content, corresponding enzyme activity in the stratification of Torreya grandis and Torreya grandis "Merrillii" seeds, then reveal the mechanism of seed germination and provide theoretical and practical basis for reasonable control ling the development of the embryo and the seed germination process, the development of the embryo was observed, and the main content of storage substances in endosperm and related enzyme activity were determined in the initial stage of germination in this study,which take Torreya grandis and Torreya grandis "Merrillii" as research objection.the main results were as follows:(1) The hundred seed weight and the hundred kernel weight of Torreya grandis "Merrillii" is lighter than the Torreya grandis, but with fairly yield. There is certain variation range on the length, diameter, and the quality.(2) After Torreya grandis seeds harvested, the embryo development is not mature, the top of the embryonic body casts a cone shaped, which is with twists and turns suspensor system.stratification for 30 d, the centre of the top of the embryonic body concaves down, form cotyledon,the shoot apex cells begin to form, with a semicircle bum; stratification for 50 d, with a bigger cotyledon, smaller shrinkage suspensor system, the shoot apex cells form a conical hill, the root cap cells present rib meristem forms, with plexus arrangement. stratification for 70 d, the cotyledon obviously elongates and bigger, with shorter suspensor, then the embryo breaks through the parcel of the endosperm and seed coat, seed germination, the radicle break through seed coat, withgeotropism bending growth. There is no obvious difference in morphological structure and in color and quality between Torreya grandis and Torreya grandis "Merrillii", but the time of embryo develops mature and breakthrough of Torreya grandis is 10 ~ 30 d later than Torreya grandis "Merrillii".(3) The embryo length of Torreya grandis "Merrillii" is radually increase in 0 ~ 70 d, slightly reduce in 80 ~ 100 d,and there no significant difference in 0~30d and 70~100d. The embryo length of Torreya grandis is radually increase in 0 ~ 100 d, and there no significant difference in30 d and40d, 40 d and 50 d,60d and 70 d, 80 d and 90 d.(4) The seed germination rate of Torreya grandis "Merrillii" is higher than Torreya grandis in90~ 110 d, but lower in 120~ 150 d, the germination rate of Torreya grandis is 16.55% higher than that of Torreya grandis "Merrillii" at the end of the stratification.(5)In the process of stratification, starch content of Torreya grandis "Merrillii" and Torreya grandis are gradually reduced, with a trend of first reduce then rise soluble sugar content. The total amylase activity and α-amylase activity of Torreya grandis "Merrillii" presents a trend of first rise then reduce, the β-amylase activity presents a trend of first rise then reduce, and rise again. The α-amylase activity is higher than β-amylase activity. The total amylase activity,α-amylase activity and β-amylase activity of Torreya grandis presents a trend of first rise then reduce, α-amylase activity is greater than the β-amylase activity.(7) In the process of stratification, the soluble protein content of Torreya grandis "Merrillii" and Torreya grandis are gradually reduced; the protease activity with a trend of first rise then reduce, the protease activity of Torreya grandis "Merrillii" reached the maximum on the 90 d, and that of Torreya grandis maximum on the 120 d.(8) In the process of stratification, the crude fat content of Torreya grandis "Merrillii" and T Torreya grandis are gradually reduced; the acid phosphoesterase activity with a trend of first rise then reduce, the acid phosphoesterase activity of Torreya grandis "Merrillii" reached the maximum on the 90 d, and that of Torreya grandis maximum on the 120 d.The acid phosphoesterase activity of Torreya grandis "Merrillii" were greater than Torreya grandis in the whole process of stratification.