| Torreya grandis was an department of gymnosperms Taxaceae, Torreya, which were evergreen trees. Torreya grandis was a valuable economic species, but also for an excellent gardening tree species. The community and seedlings of Torreya grandis in Ningxiang County were the subject of this research. The community growth and floristic diversity of Torreya grandis growing in Ningxiang County, Hunan Province were investigated. The different kinds of seedling breeding technology of Torreya grandis, the growth law and photosynthetic characteristics of 1-year-old Torreya seedling were systematic carried out. The soil fertility characteristics of different stand origin of Torreya grandis were also comparative analyzed. Ultimately, these findings will be served as theoretical basis for the establishment of a scientific, effective and practical breeding technology system of Torreya grandis, At the same time as a technical support to promote the Hunan Torreya industry. The main conclusions of this study are as follows:1 There were 771 Torreya trees existing in Ningxiang County. The distribution curve of community growth according to DBH size was similar to a normal distribution. DBH of Torreya grandis were mainly concentrated in the range of 10?60cm. The floristic diversity of Torreya grandis was abundant. There were 51 kinds of species in 12 plots, among them,10 species such as Sundry bamboo, Discocleidion rufescens, Rubus corchorifolius, Vitex Negundo, Manyflower glorybower, Parthenocissus laetevirens, Polygonum flaccidum Meissn, Fern, mint, Rubus rosaefolius Smith were typical plants with high frequency.2 In the grafting experiments of Torreya grandis, the best grafting propogation method was split grafting using tender shoots as scions, one year seedlings as rootstocks, and the best period of grafting was April to June. In the cutting experiments, the best cuttings were intermediate shoots of trunk germination branches, more than 0.3cm thickness and 15-20cm length. The cutting survival rate was the highest while the cuttings were be quickly dipped by 6th ABT 1000 mg/Kg. In the seed multiplication experiment, the highest seed germination rate were seeds from No1. seed tree, using outdoor stratificaition variable temperature germination.3 The one year seedling growth rhythm of Torreya grandis was almost in line with Logistic equation. The seedling growth was relatively slow, the height of one-year seedling was between 13.16cm and 14.74cm, the ground diameter is between 3.04mm and 3.54mm, and the biomass of 5 single plant was between 1.78g and 2.67g respectively. In summary, the best growing performance was Ningxiang the 1st.4 The net photosynthetic rate (Pn) diurnal variation of Torreya grandis was rendered as "bimodal" curve. The maximum LCP, LSP, Pn, AQY and Rd values were all Ningxiang 1st in five families. Comprehensive considerated, the order of photosynthetic capacity was Ningxiang 1st>Ningxiang the 4th> Ningxiang the 5th> Ningxiang the 3rd> Ningxiang the 2nd.5 The average number of bacteria, actinomycetes, and fungi in natural forest land soil of Torreya grandis were 142.26×104 ind/g,1.00×104 ind/g and 145.70x104 ind/g, which were respectively 6.57,1.20 and 1.99 times of new afforestation land soil.The average content of enzyme, catalase and urease in natural forest land soil of Torreya grandis were 2.35mg·g-1·d-1,0.95mg·g-1·d-1 and 30.8mg·g-1·d-1, which were respectively 2.47,2.25 and 1.70 times of the new afforestation land soil. As Torreya stand growth, soil conditions, soil fertility and nutrient levels were all improved.6 The content of nitrogen, phosphorus and potassium in new afforestation land soil of Torreya grandis were 4.08g/Kg,0.436g/Kg,2.65g/Kg, while three macroelement content in natural land soil were respectively 7.73g/Kg,0.905g/Kg, 3.65g/Kg. The contents of N and K of Torreya grandis stand soil in Ningxiang County was considered to meet the minimum need of plant growth, but content of P was below the national average. |
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