红树林土壤因子对土壤微生物数量的影响

研究海南清澜港红树林土壤微生物数量和8个土壤因子对微生物数量的影响，结果表明，红树林5~20cm 土层细菌数量达1.0×10°~12.9×10cfu/g（cfu∶colonyforming units），放线菌数量达0.7×10'~19.0x 103cfu/g，真菌数量达0.5× 102~5.2×102cfu/g。逐步回归分析显示∶土壤pH、含水量、全磷量、全钾量明显影响土壤细菌的数量;土壤pH、有机质含量、有效钾含量明显影响放线菌的数量;土壤pH、全钾量明显影响真菌的数量。通过标准化回归系数分析（通径分析），仅有土壤pH是影响细菌、放线菌数量的主要因子，其直接通径系数分别为0.88和1.15，并且两者都达显著水平∶全氮、速效钾通过土壤pH对细菌和放线菌数量的间接作用也比较大，两者对细菌数量的作用系数都为0.4，对放线菌数量的作用系数都为0.58.土壤pH对细菌、放线菌数量的影响作用可能与红树林土壤普遍偏酸的现象有关，而多数细菌、放线菌类群生长的最适pH为6~8.真菌的线性回归模型未达显著水平，未能运用通径分析法来估计土壤因子的影响作用。这可能因为多数真菌类群嗜酸（pH5~6），而被调查的16个土样，有9个样品pH<5，有2个样品pH>6，土样pH的这种分布使其对真菌 数量的影响作用不能用线性模型来拟合。

Effects of Soil Factors on Microbe Distributions in Mangrove Soil

An experiment was conducted to reveal the microbe distribution in mangrove soil located on Qinglan Harbor,Hainan Province.The results showed that the volume of soil bacteria,actinomycetes and fungi was 1.0x10°～12.9×10°，0.7×103~19.0×103，and 0.5x102~5.2×102cfu（colony-foming units）/g respectively in the soil samples collected from the soil of 5~20 cm deep. Stepwise regression analysis suggested that silpH, water content, total phosphorus and total potassium significantly influenced the volume of bacteria. Soil pH,organic matter content and available potassium significantl influenced the volume of actinomycetes.And soilpH ad total potassum significantly influenced the volumeoffungi. Path analysisindicated that only oilpHsignificantly affected the volume of bacteria and actinomycetes since their path parameters were 0.88 and 1.15 respectively and both reached a significant level. The indirect ifluence of total nirogen and available poasum through soil pH on the volume of bacteria and actinomycetes was evident, and their indirect path cofients were 0.4 for bacteria and 0.58 for actinomycetes. This phenomenon was pehaps related to the fact that mangrove soil was geneally acidic and that the environment of pH6~8 was most suitable for most bactera and actinomycetes species.The model f linear regression applied to fungi volume did not reach a sigifiant lel, which howed that path analysis was not suitable for analyzing the effets of silfactors on fungi volume.This phenomenon was resultedperhaps from the fact that most fungi were acidophilic(pH5~6)while the silpH in9 out of 16smples investigaed were below 5 and the soil pH in 2 samples were above 6, which made lineregession modl unsutable oranalyzing the effect of pH on fungi volume.