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为了解林窗大小对马尾松人工林林窗下更新过程中优势植物生态化学计量特征的影响,在长江上游低山丘陵区选取7种面积不等(100 m~2、225 m~2、400 m~2、625 m~2、900 m~2、1 225 m~2、1 600 m~2)的人为采伐形成的林窗,以林下为对照,分析更新优势植物油樟、芒萁、芒和皱叶狗尾草叶片化学计量特征.结果表明:4种植物化学计量特征对林窗大小响应不同,在各自林窗梯度中均有显著差异.4种植物C:N为17.0-37.7,C:P为152.5-748.0,N:P为6.4-21.5.随林窗面积增大,油樟、芒和皱叶狗尾草C:N均先升后降,C:P和N:P先降后升,芒萁变化不明显.油樟C、N、P元素分配最佳的林窗为625 m~2,芒萁为1 225 m~2,芒和皱叶狗尾草为1 600 m~2.4种植物在多数林窗中不受N、P限制,但900 m~2林窗中油樟和芒萁均处于缺P状态,400 m~2林窗中芒和皱叶狗尾草均受N限制.综上,更新油樟树种采用625 m~2林窗表现出较理想的效果,芒萁、芒和皱叶狗尾草的自然更新则在大面积林窗(1 225-1 600 m~2)中效果更好.
In order to understand the influence of gap size on ecological stoichiometry of dominant plants in the gap under Pinus massoniana plantations, seven different areas (100 m ~ 2,225 m ~ 2,400) were selected in the hilly area of the upper reaches of the Yangtze River m ~ 2,625 m ~ 2,900 m ~ 2,1 225 m ~ 2,1 600 m ~ 2), and under the forest as a control, And the chemical constituents of the leaves of Setaria viridis.The results showed that the four plant stoichiometry had different responses to the size of the gap, and there were significant differences in the gradient of the gaps.The C: N values of the four species were 17.0-37.7, C: P And the N: P values ranged from 6.4 to 21.5. With the increase of the area of forest window, the C: N and C: N of Setaria viridis increased firstly and then decreased, while C: P and N: P decreased first and then rose, The change of C, N and P in the camphor was 625 m ~ 2, 1 225 m ~ 2 in the mulberry leaves, and 1 600 m ~ 2.4 in the mulberry leaves in most forests The window was not limited by N and P. However, the oil camphor and mangosteen in 900 m ~ 2 canopy were all in a state of P deficiency, while the species of M. maculata and M. pubescens in the depth of 400 m ~ 2 were all restricted by N. In summary, 625 m ~ 2 kinds of forest window showed a more satisfactory results, Mount 萁, Crispa Setaria and natural regeneration of large gaps in the (1 225-1 600 m ~ 2) better results.