【作者】 陈美玲；

【导师】 上官周平；

【作者基本信息】 西北农林科技大学 ， 生态学， 2008， 硕士

【摘要】 本文对黄土高原子午岭林区七个天然次生植物群落:狼牙刺(Sophora viciifolia)群落、沙棘(Hippophae rhamnoides)群落、山杨(Populus davidiana)群落、白桦(Betula platyphylla )群落、油松( Pinus tabulaeformis )群落、柴松( Pinus tabulaeformisf.shekannesis)群落和辽东栎(Quercus liaotungensis)群落建群种以及优势伴生种大披针苔草(Carex lanceolata)的能量和养分特征进行了研究,结果表明:六种群落建群种的平均干质量热值分别为18.97、19.19、19.23、19.80、19.74和18.09 kJ?g-1,去灰分热值分别为19.59、20.62、19.82、20.54、20.17和18.37 kJ?g-1,无论是干质量热值还是去灰分热值,加权平均最低值均为辽东栎。建群种热值随着植被群落正向演替先升高后降低,表明随着植被群落的演替,建群种对光能的利用效率呈现先逐渐提高后降低的趋势。各个建群种不同组分热值波动较大,叶片是植物体生命活动最为旺盛的器官,它具有显著高于其他器官的干质量热值和去灰分热值。大披针苔草地上部分和地下部分干质量热值在不同群落内的波动明显;随着演替的进展,处于不同演替阶段群落的大披针苔草地上部分和地下部分去灰分热值呈下降趋势;狼牙刺群落的大披针苔草的地上部分去灰分热值最高,沙棘群落的最低;狼牙刺群落的大披针苔草的地下部分去灰分热值最高,辽东栎群落的最低;不同群落大披针苔草地上部分热值均明显高于地下部分。处于演替早期的各群落(狼牙刺、沙棘、山杨和白桦群落)内大披针苔草的热值差异较大,而演替后期的油松和辽东栎群落的大披针苔草的热值差异较小。各个群落地被物有机碳含量总体低于凋落物及活立木。沙棘群落地被物全氮含量总体高于其余五个群落,各群落凋落物和地被物全氮含量较高。各群落地被物均具有较高的灰分含量。地被物具有较高的能量回归速率,各群落地被物的热值总体低于活立木和凋落物。柴松以及处于演替后期的油松和辽东栎具有较高的地被物分解速率。较高的地被物分解速率和较高的光能利用效率以及群落优势伴生种大披针苔草热值和养分的聚类分析和比较,表明柴松群落在植被群落演替中处于演替的后期阶段,与油松群落处于相同的演替阶段,是演替的亚顶级阶段。更多还原

【Abstract】 Caloric value and nutrient contents of dominant plant species and dominant companion species of six natural secondary forests plant communities was studied. The six communities are Hippophae rhamnoides community, Populus davidiana community, Betula platyphylla community, Pinus tabulaeformis community, Pinus tabulaeformisf.shekannesis community and Quercus liaotungensis community, respectively. The results are as followed:The mean gross caloric values of the dominant plants in the six communities were 18.97、19.19、19.23、19.80、19.74 and 18.09 kJ?g-1, and the ash free caloric value were 19.59、20.62、19.82、20.54、20.17 and 18.37 kJ?g-1, respectively. No matter gross caloric value or ash free caloric value, the mean caloric value of the Quercus liaotungensis was the lowest. The caloric value of the dominant plant species was increasing with the community succession, and this indicated that the trend of the energy utilization efficiency of the dominant plant species was increasing first and then decreasing as the community succession progressing. The caloric value varied significantly in the different parts of the six dominant plant species. Foliage is the most active organ of the plant, and its gross caloric value and ash free caloric value of foliage were significantly higher than the other organs (P< 0.05).The gross caloric values of the aboveground and underground parts of the species varied within different communities. The ash free caloric values of the aboveground and underground parts of the species tended to decline in different communities that experienced different succesional stages. The aboveground part of Carex lanceolata had the highest ash free caloric value in Sophora viciifolia community and the lowest ash free caloric value in Hippophae rhamnoides community. The underground part of Carex lanceolata had the highest ash free caloric value in Sophora viciifolia community and the lowest ash free caloric value in Quercus liaotungensis community. Generally speaking, the aboveground part of Carex lanceolata had a remarkably higher caloric value than the underground part of the species did. The caloric values of Carex lanceolata greatly varied in the communities going through their early successional stages (Sophora viciifolia, Hippophae rhamnoides, Populus davidiana and Betula platyphylla communities) and less greatly in the communities experiencing their later successional stages (Pinus tabulaeformis and Quercus liaotungensis communities).The organic matter of groundlitter was lower than litter fall and fresh stumpage in different communities. The caloric value of the groundlitter was lower than that of the litter fall and fresh stumpage in each community. The total N content of groundlitter in Hippophae rhamnoides communities was higher than in other communities. The ash content of groundlitter was also higher than litter fall and fresh stumpage. The groundlitter had higher energy returning velocity, energy content of different communities was higher than litter fall and fresh stumpage.The decomposition rates of the groundlitter of Pinus tabulaeformisf.shekannesis community, Pinus tabulaeformis and Quercus liaotungensis community which in the later succession stage were all higher than that of the communities which were in the early successional stage. Both the mean gross caloric value and the ash free caloric value of Pinus tabulaeformisf.shekannesis were relative high, which suggested that it had high energy utilization efficiency. We could deduce that the Pinus tabulaeformisf.shekannesis community may be in the middle or in the later succession stage through higher energy utilization and the result of the cluster analysis of caloric value and nutrient contents.更多还原