【摘要】 为了解不同人工林叶片C、N、P含量及其化学计量特征的季节变化规律,以福建三明格氏栲和杉木人工林为研究对象,分不同季节采集其新鲜成熟叶片进行分析.结果显示:(1)格氏栲叶片C、N、P及其计量比(C:N、C:P、N:P)分别为488.48 g/kg、15.67 g/kg、0.93 g/kg和31.87、537.16、17.32,杉木为501.99 g/kg、13.67 g/kg、1.00 g/kg和37.32、511.55、13.97,其中格氏栲叶片N含量、N:P显著高于杉木,C含量、C:N显著低于杉木,P含量和C:P与杉木无显著差异.(2)格氏栲和杉木叶片C含量均表现为从春季到冬季先升高后降低,秋季达到最大,格氏栲叶片N含量为秋季最低,而杉木叶片N含量为秋季最高,格氏栲叶片P含量为夏季最高、春季最低,杉木叶片P含量则为春夏季显著低于秋冬季.(3)格氏栲和杉木叶片C:N、C:P变化趋势与其N、P含量变化趋势相反,叶片N:P与其P含量变化趋势相反,说明叶片N、P含量对叶片C:N与C:P起主导作用,叶片N:P主要由P含量决定.(4)除叶片C含量和C:P外,其他指标均受季节和树种及其交互作用的显著影响;叶片C:P主要受季节的影响,其他各指标受树种的影响最大.本研究表明杉木人工林N的利用效率高,格氏栲人工林P的利用效率高;格氏栲在春冬季受P限制,秋季受N限制,夏季同时受N、P限制,杉木在秋冬季受N限制,春夏季同时受N、P限制.(图1表3参38)更多还原

【Abstract】 To investigate the seasonal variations in C, N, and P content and their stoichiometric characteristics in leaves of different plantations, fresh leaves of Castanopsis kawakamii and Cunninghamia lanceolata plantations were collected in different seasons in Sanming, Fujian and analyzed. The results showed that:(1) leaf C, N, and P content and stoichiometric ratios(C:N, C:P, N:P) of C. kawakamii were 488.48 g/kg, 15.67 g/kg, 0.93 g/kg and 31.87, 537.16 and 17.32, respectively, and the same parameters for C. lanceolata were 501.99 g/kg, 13.67 g/kg, 1.00 g/kg and 37.32, 511.55 and 13.97, respectively. The N content and N:P of leaves were significantly higher in C. kawakamii than in C. lanceolata, the C content and C:N of leaves were significantly lower in C. kawakamii than in C. lanceolata; there were no significant difference in P content and C:P between the two species.(2) The leaf C content of C. kawakamii and C. lanceolata increased first and then decreased from spring to winter, reaching the maximum in autumn; the leaf N content of C. kawakamii was lowest in autumn. However, the leaf N content of C. lanceolata leaves was highest in autumn, and the leaf P contents of C. kawakamii was highest in summer and lowest in spring, while the leaf P content in spring and summer were significantly lower than that in autumn and winter for C. lanceolata.(3) The trends of the changes in C:N and C:P in leaves of C. kawakamii and C. lanceolata were opposite to those observed for N and P content, while leaf N:P showed an opposite trend to P content, indicating that N and P content played a predominant role in determining C:N and C:P ratios. Meanwhile, the N:P ratio was controlled by P content.(4) Indicators other than C content and C:P in leaves were significantly affected by season and tree species and their interaction; C:P in leaves was mainly affected by season, and other indicators were most affected by tree species. The result indicated that the utilization efficiency of N was highest in the C. lanceolata plantation, and that of P was highest in the C. kawakamii plantation. As indicated by the content and stoichiometric ratio of N and P in leaves in different seasons, C. kawakamii was under P limitation in spring and winter, N limitation in autumn, and N and P co-limitation in summer; C. lanceolata was under N limitation in autumn and winter and N and P co-limitation in spring and summer.更多还原