作 者 ：李敏,陈琳,肖燕,甘琳,胡秋香,安树青*
期 刊 ：生态学报 2009年 29卷 7期 页码：3960~3969
Keywords:arbuscular mycorrhizal fungi(AMF), Spartina alterniflora, Phragmites australis,
摘 要 ：互花米草（Spartina alterniflora Loisel.）是我国海滨盐沼的入侵植物，与土著种芦苇（Phragmites australis）形成了广泛的竞争；已知丛枝菌根（AMF）对不同植物的生长存在差异性影响；但其对互花米草与芦苇之间的种间关系，是否对互花米草入侵芦苇群体产生作用值得探讨。研究对两物种进行了丛枝菌根接种处理，种植模式处理和盐度处理的三因素实验。结果表明：盐度增加使得单种时芦苇、混种时互花米草的AMF侵染率显著下降（p<0.05），而混种时芦苇和单种时的互花米草AMF侵染率受盐度影响不显著（p>0.05）。混种时，两种植物的丛枝菌根形成均受对方影响，并且盐度升高使两种植物之间对AMF侵染率的影响发生变化，在淡水生境下混种时，芦苇的AMF侵染率比单种时降低40.5%，互花米草的AMF侵染率比单种时提高了869%，均差异显著（p<0.05）；在低盐度下混种时芦苇的AMF侵染率比单种时降低24.7%，差异显著（p<005），而对互花米草的影响不显著；在高盐度下混种对芦苇的AMF侵染率影响不显著，而使互花米草的AMF侵染率显著降低，降低率比例达787%。在淡水生境下，丛枝菌根对芦苇和互花米草的N、P吸收均有显著的促进作用；但是在咸水生境下生长时芦苇的N、P含量主要受盐度的显著影响（p<0.05），随盐度增加而增加；虽然在咸水生境下丛枝菌根仍旧促进芦苇的N、P吸收，但其影响远小于盐度的影响，并且促进效果受到盐度的抑制；但互花米草的N、P含量不受盐度影响。由此可见，接种AMF对这两种植物的氮磷吸收有着不同程度的促进，其作用大小与侵染程度有关，且受到盐度和种植模式的影响。
Abstract:Extensive competitions has been found between two species: the native plant, Phragmites australis, and the invasive plant, Spartina alterniflora, in the large areas of coastal China. Although their different influence on various species has been recognized, the impact of arbuscular mycorrhiza fungi (AMF) on the inter\|specific relationship between S. alterniflora and P. australis, especially their role in the invasion of S. alterniflora, still remain an open important topic. In this paper, a three\|factor experiment is designed to clear the impact. Two plant species are grown both separately and together in soil under mycorrhizal inoculation or un\|inoculation conditions, while fresh water or artificial seawater with two levels of concentrations are supplied, respectively. Experimental results indicated that the mycorrhizal colonization declined significantly as the salinity ascended in the mono\|cultured P. australis and mix\|cultured S. alterniflora, while was not affected by the salinity factor in the mix\|cultured P. australis and mono\|cultured S. alterniflora. In mix\|cultured cases, an inter\|reaction of the colonization rates of AMF between two species existed, which correlated with the salinity. Specifically, compared with mono\|cultured cases, the colonization rate on P. australis declined significantly with 40.5% and 24.7%, in fresh water and low salinity seawater respectively; the colonization rate on S. alterniflora increased dramatically with 86.9% in fresh water, in spite of a negligible change in low salinity seawater. In mix\|cultured case with high salinity seawater, however, the colonization rate on P. australis was unaffected, while that on S. alterniflora declined significantly with 78.7%. The N and P concentration of two plants were promoted by mycorrhizal inoculation with fresh water. However, the N and P concentration of P. australis were significantly affected by salinity, with a positive correlation. The effect of mycorrhizal inoculation on N and P concentration was overwhelmed and suppressed by the salinity in this case, implying the N and P concentrations of S. alterniflora were immune to the salinity. Thus, we conclude that, the AMF inoculation has different levels of promotion effects on the absorption of N and P of the two species, the effect is correlated with the infection degree, which is influenced by salinity and planting patterns.
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