宝天曼自然保护区两种优势藓类植物C、N、P生态化学计量特征研究

C,N and P ecological stoichiometry of two bryophyte plants in Baotianman Nature Reserve

该研究以宝天曼自然保护区两种优势藓类物种大羽藓(Thuidium cymbifolium)和无边提灯藓(Mnium immarginatum)为对象,测定和分析了不同海拔生境条件下苔藓植物绿色组织和土壤的C、N、P含量及其比值。结果表明:该区域内两种藓类植物绿色组织的C、N、P含量范围是46.81%~49.09%、0.21%~0.25%、0.02%~0.08%;不同元素在海拔间存在较大差异,具体表现为大羽藓的C、N含量在不同海拔间差异显著,无边提灯藓的N、P含量在不同海拔梯度间差异显著,但总体仅N元素随海拔的上升表现出显著下降的趋势;土壤的C、N、N∶P和C∶P比值总体上表现出随海拔升高而增加的变化趋势,而土壤P含量以及C∶N比值随海拔梯度的变化并未表现出一致的变化趋势;同时,随着土壤C含量增加,大羽藓C含量呈现上升趋势,无边提灯藓呈现下降趋势;随着土壤N元素含量的增加,两种藓类物种表现的趋势仍然与前者一致;随着土壤P元素含量的升高,大羽藓的N∶P显著下降,而无边提灯藓的N∶P则显著上升;此外,叶片N∶P均值为8.51,介于14和16之间,说明植物生长受N元素的限制。以上结果说明:两种藓类植物对土壤P元素利用上存在差异,导致两种藓类化学计量学特征的变化,且与全球尺度相比,该区域的藓类植物的生长共同受到了土壤N含量的限制作用。该研究结果为预测藓类植物营养元素的限制情况和生态适应机制提供了参考。

In order to explore adaptation mechanism on the bryophyte plants in Baotianman Nature Reserve,our research determined the ecological stoichiometry characteristics of Thuidium cymbifolium and Mnium immarginatum and revealed the relationships of these nutrient contents with soil nutrients along altitudinal gradients. Our results suggested that the contents of C,N and P in both species were ranged from 46.81% to 49.09% for C,0.21%-0.25% for N,0.02%-0.08% for P,re-spectively. There existed higher variability among different altitude gradients,Thuidium cymbifolium differed significantly for C and N contents,and Mnium immarginatum differed significantly in N and P,while only N exhibited a significant decreasing trend with increasing altitude. The C,N,N ∶ P and C ∶ P of soil exhibited an increasing trends with increasing elevation,which were different from soil P and C ∶ N. The content of C in Thuidium cymbifolium increased with the increase of soil C,while Mnium immarginatum decreased; the content of N in both species exhibited the same phenomenon with former; the N ∶ P showed different trends between two species,the N ∶ P significantly decreased with soil P in Thuidium cymbifolium,while Mnium immarginatum was opposite. Moreover,the mean of leaf N ∶ P was 8.51,which indicated that both of two species were limited by soil N content. These results suggested that two bryophyte species had different utilization ways on soil P element,and the growth of the bryophyte plants in Baotianman Nature Reserve were suffered from N limitation along the altitudinal gradients.