丛枝菌根真菌侵染率对喀斯特坡地坡位与灌木物种的响应

Responses of arbuscular mycorrhizal fungi colonization rate to slope position and shrub species in karst slopes

关键词:  喀斯特, 丛枝菌根真菌, 频度, 强度, 丰度

Key words:  karst, arbuscular mycorrhizal fungi, frequency, intensity, abundance

摘要:

明确丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)侵染率对喀斯特坡地坡位与物种的响应及其关键影响因子,是合理利用土壤AMF促进喀斯特植被恢复的前提。该研究在充分调查喀斯特峰丛洼地典型灌丛坡地环境背景信息的基础上,采用曲利苯蓝染色-镜检法检测并计算典型灌木黄荆(Vitex negundo)、红背山麻杆(Alchornea trewioides)和火棘(Pyracantha fortuneana)根系AMF侵染频度、侵染强度和丛枝丰度等侵染率参数。结果表明:(1)相同坡位火棘的侵染频度、侵染强度和丛枝丰度均显著低于红背山麻杆和黄荆; 下坡位黄荆和火棘的侵染强度均高于中、上坡位,而中坡位红背山麻杆的丛枝丰度显著高于上、下坡位(P<0.05)。(2)物种显著影响AMF侵染频度、侵染强度和丛枝丰度,坡位显著影响AMF侵染强度,物种与坡位的交互作用仅对AMF丛枝丰度有显著影响(P<0.05)。(3)影响AMF侵染率的关键土壤因子是土壤深度和全钾含量(P<0.05)。因此,合理利用土壤AMF促进喀斯特地区植被恢复需要考虑地形与物种的选择,并应注重兼顾喀斯特地区的水土保持。该研究结果为合理利用土壤AMF和植物的共生关系,促进喀斯特峰丛洼地生态恢复提供了科学依据。

Abstract:

The response of arbuscular mycorrhizal fungi(AMF)colonization rate to slope position and shrub species in karst slope and the key influencing factors were identified, which is the prerequisite for rational utilization of soil AMF to promote karst vegetation restoration. Based on field investigation of typical shrub communities and environmental variables on slopes of a karst peak cluster depression. The fine root samples of three typical shrub species(Vitex negundo, Alchornea trewioides and Pyracantha fortuneana)were collected from three positions(upper, middle and lower)along three slopes. The frequency, intensity and abundance of AMF colonization were detected and calculated by the Trypan blue-microscope method. The results were as follows:(1)The colonization frequency, colonization intensity and abundance of AMF for Vitex negundo and Alchornea trewioides were higher than those for Pyracantha fortuneana in the same slope. The colonization intensity for Vitex negundo and Pyracantha fortuneana in the lower slope was higher than that in the upper and middle slopes. The abundance of AMF for Alchornea trewioides in the middle slope was significantly higher than that in the upper and lower slopes(P<0.05).(2)Shrub species had significant effect on the colonization frequency, intensity and abundance of AMF, and slope position only had significant effect on the colonization intensity of AMF. Slope position and shrub species had significant interactive effect on the abundance of AMF(P<0.05).(3)Soil depth and total potassium content were identified as the two strongest explanatory factors on AMF colonization rate according to the redundancy analysis(P<0.05). Therefore, the rational use of soil AMF to promote vegetation restoration in karst areas needs to consider the choice of terrain and species, and should pay attention to the water and soil conservation. The results of this study provide a scientific basis for rational utilization of the symbiotic relationship between soil AMF and plants and promoting ecological restoration of karst peak cluster depression.