Preliminary Study On The Vertical Distribution Patterns Of Nematode-trapping Fungi In Northwest Yunnan

ObjectiveA survey of the nematode-trapping fungi was conducted in the northern part of Gaoligong Mountain in northwest Yunnan and the southern part of Cangshan Mountain in Yunling,to understand the vertical distribution pattern of nematode-trapping fungi and analyze the main factors affecting vertical distribution.Methods1.Gaoligongshan Sampling Strategy:The soil samples were collected from Derung-Nu Autonomous County Gongshan N'Mai River road,Set a sample point per1km along the new N'Mai River road,in the mountain streams set a total of five samples,the intersection of a sample point set in streams and roads,and this point as the center extends to both sides of every 30m set a sample,including in the old N'Mai River road,and set the N'Mai River tunnel entrance and exit and inside the tunnel of sample points,taking the tunnel as the dividing line,Gaoligong Mountains into east slope Nujiang River watershed and west slope N'Mai River watershed.A total of 116samples,580 samples of soil samples taken at an altitude of 1400-3400m.2.Cangshan Mountain Sampling Strategy:Soil samples from Dali Cangshan Mountain East and west slope of sunny,shady two slopes.Sample collection elevation in the range of 2100-3500m,the altitude increasing every 100m set a sampling point,East and West slopes were collected 150 soil samples,including shady,sunny slopes75 copies each,a total of 300 soil samples.3.Sample collection method:Collection of land samples:5 point diagonal sampling at each sampling point.The sampling depth is 5-30cm and mix thoroughly and take about 200g and put it on the sampling bag;collection of stream samples:in the Gaoligong Mountain streams like at each sampling point 5 diagonal point sampling,the stream sediment sampling in about 200g in the bag,and after the stream samples were collected after the land back to the laboratory cryogenic seal preservation,and within a week after treatment of the sample.4.Geography,environmental indicators record:including elevation,longitude,latitude,slope direction,collection time.5.Separation and purification of nematode-trapping fungi from collected soil samples,identification of species by combination of morphology identification and molecular identification.6.The species richness and detection rate of nematode-trapping fungi were calculated and plotted,and the factors such as altitude,slope direction and river basin were analyzed.ResultsThe species richness of nematode-trapping fungi at different altitudes in northwest Yunnan was investigated.3 genera and 17 species of 177nematode-trapping fungi were isolated and identified.15 species of 120nematode-trapping fungi were isolated and identified from Gaoligong Mountain.12species of 57 nematode-trapping fungi were isolated and identified in Cangshan Mountain,and the nematode-trapping fungi resources of Gaoligong Mountain in Northwest Yunnan were more abundant and diverse than Cangshan Mountain.Whether it is Gaoligong Mountain,Cangshan Mountain or the entire study area,the species richness of nematode-trapping fungi in the west slope is higher than that in east slope?east slope of Northwest Yunnan:14 species 70 strains;west slope of Northwest Yunnan:15 species 107 strains;east slope of Gaoligong Mountain:12species 46 strains;west slope of Gaoligong Mountain:13 species 74 strains;east slope of Cangshan Mountain:8 species 24 strains;west slope of Cangshan Mountain:11species 33 strains?.Among them,the sunny slope on the east and west slopes of Cangshan Mountain is richer in nematode-trapping fungi resources than on the shady slope.Lands of Gaoligong Mountain are more abundant than streams of nematode-trapping fungi resources.Northwest Yunnan nematode-trapping fungi presents the distribution features in the vertical gradient,with increasing altitudes,species richness of nematode-trapping fungi and detection rate was first increased and then decreased?Northwest Yunnan species richness:y₁=-1.64x₁²+9.76x₁-1.20,R₁²=0.902,P<0.05;Northwest Yunnan detection rate:y₂=-6.74x₂²+37.99x₂-19.87,R₂²=0.9283,P<0.05?.East and west slope of Northwest Yunnan,east and west slope of Gaoligong Mountain,land and stream of Gaoligong Mountain showed the same trend.Nematode-trapping fungi showed certain distribution characteristics on the vertical gradient of Cangshan Mountain.With the increase of altitude,the species richness and detection rate of nematode-trapping fungi decreased?Cangshan Mountain species richness:y₅=-1.20x₅+7.80,R₅²=0.63,P?27?0.05;Cangshan Mountain detection rate:y₆=-9.47x₆+48.42,R₆²=0.97,P?27?0.05?,and the east and west slopes and their sunny and shady slopes showed the same trend.Arthrobotrys oligospora is a dominant species throughout the Northwest Yunnan,where Arthrobotrys thaumasium is the dominant species of Gaoligong Mountain,Dactylellina ellipsosporum is the dominant species of Cangshan Mountain,and A.oligospora is the dominant species on the east slope and west slope of Northwest Yunnan.The dominant species in the east and west slopes of Gaoligong are all A.thaumasium.A.oligospora is the dominant species of east slope and its shady and sunny slopes of Cangshan Mountain.A.thaumasium is the dominant species of the west slope and its shady and sunny slopes of Cangshan Mountain.The dominant species of the Gaoligong Mountain land is A.thaumasium,and the dominant species of the stream is A.oligospora.ConclusionsTemperature,rainfall,and distribution of nematodes maybe the main factors affecting the vertical distribution of the nematode-trapping fungi in Gaoligong Mountain and Cangshan Mountain in Northwest Yunnan,The scale effect,sampling intensity and truncation effect may be the cause of the difference of vertical distribution patterns.