油茶不同器官氮、磷、钾化学计量特征随年龄的变化

油茶Camellia oleifera为中国特有的食用油料树种，但关于油茶不同器官氮、磷、钾的生态化学计量特征的认识还不够充分。以浙江省常山县油茶人工林为对象，通过测定不同年龄油茶叶片、枝条、主干、根系和果实中氮、磷、钾质量分数，探讨了油茶不同年龄各器官氮、磷、钾化学计量特征及在各器官中的分配规律。结果表明:油茶氮质量分数从大到小依次为叶片、枝条、根系、果实、主干，磷质量分数从高到低依次为叶片、枝条、果实、根系、主干，钾质量分数从高到低依次为果实、叶片、根系、枝条、主干；随年龄的增加，枝条中的氮、磷质量分数逐渐增大，而其他器官中氮、磷质量分数先增大后减小，钾质量分数先增高而后降低。油茶各器官氮磷比（N:P）为3.91~10.68，氮钾比（N:K）为0.33~1.31，钾磷比（K:P）为3.71~19.08；随年龄的增长，油茶果实N:P逐渐增高，而其他器官N:P则先增高而后降低，叶片、枝条、根系和果实的N:K逐渐增大，叶片、主干和果实K:P先升高而后下降，枝条、根系的K:P逐渐降低。油茶叶片的氮、磷平均分配比例为31.4%和28.6%，钾在根系中具有最高的分配比例，平均占比达30.5%。影响油茶生长的限制元素是氮，在生产经营程中，可适当增施氮。

Ecological stoichiometry of N,P, and K with age in Camellia oleifera organs

To better understand the distribution of nitrogen (N), phosphorus (P), and potassium (K) over time in different organs of Camellia oleifera, a special edible oil tree species in China, samples of leaves, branches, stems, roots and fruits at different ages were collected from C. oleifera in Changshan County, Zhejiang Province. N, P and K content were measured to analyze the stoichiometry characteristics at different ages in the context of a distribution strategy. Results showed that average N content was leaf > branch > root > fruit > stem, average P content was leaf > branch > fruit > root > stem, and average K content was fruit > leaf > root > branch > stem. With an increase in age, in the branch the N and P content increased gradually; whereas, in the other organs, N and P content first increased and then decreased. For all organs, K content first increased and then decreased as time increased. The values for N:P were 3.91-10.68; for N:K were 0.33-1.31; and for K:P were 3.71-19.08. With increased age in fruits, N:P increased gradually, and in other organs N:P first increased and then decreased; in leaves, branches, roots, and fruits, N:K increased gradually; in leaves, stems, and fruits, K:P first increased and then decreased; and in branches and roots, K:P decreased gradually. In the leaves the average distribution ratio of N was 31.4%, and P was 28.6%. K had its highest proportion in the roots with an average ratio of 30.5%. Thus, the limiting element affecting the growth of C. oleifera was N; so in the process of production, N fertilizer should be properly added.