| Oligostachyum scabriflorum was a species of bamboo belonging to Oligostachyum. Oligostachyum scabriflorum had the biggest distribution area and reclaimed area among all species of this genera. Oligostachyum scabriflorum forest in Fujian Yong'an county had been reclaimed for 10 years by cleaning the shrubs, digging in soil surface, etc. This thesis analyzed the relationship between genetic differentiation and environmental factors. This thesis also researched on ecological functions of Oligostachyum scabriflorum forest in order to enrich the theory of bamboo cultivating, such as bamboo growth rules, biomass allocation, productivity, biomass flux, energy, carbon storage, cycling of main nutrient and microelements in 5 plots, one of them reclaimed for 6 years (plot A), 3 of them reclaimed for 2 years located in down slope (plot B1) , middle slope (plot B2) , upper slope (plot B3) , and not reclaimed (plot C). The results showed as follows:(1) 24 Oligostachyum scabriflorum subpopulations from 3 geographic locations clustered to 4 groups. Ansha population had long genetic distance from Hongtian and Qingshui populations because of being separated by water system. Hongtian population differentiated to 2 subgroups. 6 environmental factors as altitude, slope position, slope degree, slope exposure, site situation and community type were selected to analyze the relationship between Oligostachyum scabriflorum genetic diversity and environmental factors. Altitude and slope exposure were closely related to Oligostachyum scabriflorum genetic diversity than other factors. Variance from subgroups corresponding to environmental subfactors had high percentage of total variance as 23．50-33．80%, meaning that environmental factors made a great selected pressure on genetic differentiation of Oligostachyum scabriflorum. Slope position and altitude were the main factors causing the genetic differentiation of Oligostachyum scabriflorum by analysis of main component.(2) Dividing shoot phrases of Oligostachyum scabriflorum with simplified Fisher method showed a weak phrase in which the number and production of bamboo shoot had higher percentage of total bamboo shoot number and production after the highest phrase. Reclaimation made obvious influence on the height growth of young bamboo, especially on height fast-growing phrase. The biomass accumulation in height growth phrase of young bamboo coincided with logarithm curves.(3) Reclaimation process changed intensely the bamboo's density, footpath, height and biomass allocation pattern. Bamboo's density, average footpath and average height of standing bamboos in plot reclaimed for longer years (6a) increased sharply, but that in plots reclaimed for shot time (2a) showed that reclaimation effects in down and middle slope were better than that in upper slope. Reclaimation had little effects on upright allocation patterns of biomass. Biomass allocated mainly to middle parts of bamboo, least to the top of bamboo. Biomass allocation percentage of 1a and 2a bamboos were higher than that of 3a or 4a bamboos. Reclaimation effects on bamboo culm were smaller than that on bamboo leaf and branch. The largest increasing degrees of leaf biomass among all organs after reclaimation were beneficial to high and stable productivity of Oligostachyum scabriflorum forest. Biomass net increments and flux were affected by reclaimation and slope position, so the net productivity of Oligostachyum scabriflorum forest were affected too. The flux route of biomass were very complicated. The rank of net productivity was :plot A>B1>C>B2>B3．The net productivity decreased obviously with lifting of slope position.(4) The ash concentrations of components in Oligostachyum scabriflorum forest were 1．22-24．55%. The highest ash concentrations was bamboo root's, and the minimum was culm's. The gross caloric values of components in Oligostachyum scabriflorum forest were 13796-21822 J·g-1 . The highest gross caloric value was shrub litterfall's, and the minimum was bamboo root's. The ash free caloric values of components in Oligostachyum scabriflorum forest were 17928-25343 J·g-1 . The highest ash free caloric value was bamboo litterfall's, and the minimum was bamboo root's.The energy storages of Oligostachyum scabriflorum forest were 21．451-75．033 MJ·m-2。The energy storages of 2a bamboo were higher than that of bamboos of other age-classes. The energy storage of underground parts of bamboos decreased sharply in the deeper soil layers.The energy return values of Oligostachyum scabriflorum forest were small, but the net energy increment were big, so the efficiency of energy accumulation were low and energy flowing speed were very high (41．22-67．22%).(5) The carbon concentrations of components of Oligostachyum scabriflorum forest were 421．35-533．21 g·kg-1 in plot C. The rank of carbon concentrations of alive parts was :bamboo stump > culm > bamboo shoot > shrub > branch > rhizome > young bamboo > dying bamboo shoot>bamboo root>leaf>shrub root, and the rank of dead parts was: shrub litterfall>bamboo litterfall>dead rhizome > dead bamboo root.The carbon concentrations of the same component of different age bamboos had little difference, meaning that reclaimation and slope position had little effects on carbon concentrations.The total carbon storage of vegetation of all the five plots were 6824．98-25516．00 kg·hm-2 , average 5150．04 kg·hm-2 . The conversion index between biomass and carbon storage were 0．5956-0．7076, average 0．6433, meaning high carbon conversion efficiency of Oligostachyum scabriflorum forest. Preliminary estimation of carbon balance in Oligostachyum scabriflorum forest showed that all the five plots were carbon sources, while plot A came near to carbon balance, but other plots had a long distances from carbon balance.(6) In all the five Oligostachyum scabriflorum forest plots, N concentrations of each component were 1．60-23．09 g·kg-1 , that of leaf were the highest and that of culm were the smallest; P concentrations of each component were 0．05-1．96 g·kg-1 , that of bamboo shoot were the highest and that of culm were the smallest; K concentrations of each component were 0．59-29．75 g·kg-1 , that of bamboo shoot were the highest and that of bamboo litterfall were the smallest; Ca concentrations of each component were 0．20-10．36 g·kg-1 , that of bamboo leaf were the highest and that of stump were the smallest; Mg concentrations of each component were 0．25-3．57 g·kg-1 , that of bamboo leaf were the highest and that of stump were the smallest, 1a and 2a bamboo's nutrient concentrations were higher than 3a and 4a bamboo's.Nutrient concentrations of each component in reclaimed plots were a little higher than that of not reclaimed plot, or the former were close to the later, meaning that reclaimation had little effects on nutrient concentrations. N and K concentrations of each component were higher than P and Ca except that N and Ca concentrations of bamboo litterfall were higher than other nutrients.Nutrient structure of reclaimed plots changed sharply. Nutrient storage of aboveground part in the reclaimed plot A took the percentage of 77．09 of the total nutrient storage, and the number was higher than that in not reclaimed plot C (60．79) . Nutrient storages of dead parts in Oligostachyum scabriflorian forest took up some higher percentage, 10．33 percent in not reclaimed plot, 7．67 percent in reclaimed plot.Utilizing index of Mg in all plots were the biggest than that of other nutrients, and that of Ca were the smallest. Nutrient utilizing index of reclaimed plot A (0．20) was higher than that of not reclaimed plot C (0．13) , meaning that the former nutrient utilizing efficiency was higher than the later. Cycling index of Ca and Mg in these two plots were bigger than that of other nutrient elements, and cycling index of P and K were smaller, cycling index of N ranked the third. Nutrient cycling intensity in plot A was smaller than that in plot C, and the former nutrient element turnover time was shorter than the latter.The nutrient concentrations of the same organ of the same age-class or the same soil layer in different slope position plots showed the certain stability, but there still had a little difference. The nutrient concentrations of the same organ decreased a little in higher slope, and the nutrient concentrations of rhizome and root decreased in deeper soil layer. These meant that the organ nutrient concentration depended on its own genetic property, but might changed a little because of the environmental effects. Nutrient storages ranked: down slope > middle slope > upper slope.The ecological system of Oligostachywn scabriflorian forest were divided into 6 components to simulate nutrient dynamics. Nutrient cycling amounts and cycling rate of the flux route were calculated respectively. The bamboo shoot component may be used to simulate the nutrient changes when percentage of bamboo shoot picked out was determinate. The changing simulating can provide reference for nutrient compensating.(7) The microelement concentrations of soil in Oligostachyun scabriflorian forest ranked as: Fe>Mn>Cu>Zn. The microelement concentrations decreased a little in deeper soil layers. The microelement storages in the five plots ranked as : plot A>C>B1>B2>B3．The storages were closely related to reclaimation and slope position. The microelement concentrations of different components were very different. The maximum values of microelement were : Cu-bamboo root, Mn-bamboo leaf, Fe-bamboo root and Zn-rhizome. The ranks of microelement in different organs were : Mn>Fe>Zn>Cu of culm, branch, leaf, rhizome and stump, but Fe>Mn>Zn> Cu of bamboo root.The total microelement storages of plot A and C were 25145．04 and 14952．48 g·hm respectively. The microelement storages allocated mainly to underground parts.The total microelement accumulation per year of plot A and C were 9492．3 and 4440．21 g·hm-2 respectively, and the return values were 1502．76 and 1564．78, g·hm-2 respectively. Absorption value and accumulation value of Fe were the largest, and Mn, Zn and Cu were next to Fe, but the rank of return value was Mn>Fe>Zn>Cu. Absorption index of Cu in plot A and C were the largest, and that of Fe were the smallest. Absorption intensity of microelement in plot A was far larger than that in plot C. The utilizing index of microelement in plot A and C had little difference. Cycling index of Mn was the largest, and that of Fe was the smallest. The retentian value of Mn was the smallest and Mn flowed fast, Fe in the reverse. |
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