去除顶端优势对菊芋器官C、N、P化学计量特征的影响

以不同时期顶端优势去除处理的菊芋为研究对象,通过测定根、茎、叶、花和块茎等器官C、N、P含量,计算C∶N、C∶P和N∶P比值,探讨顶端优势去除对菊芋各器官C、N、P化学计量特征的影响规律。结果表明:各器官之间C含量高低顺序没有因去顶而改变,氮和磷含量高低顺序因去顶而表现出不同的大小关系;顶端优势去除提高了茎秆、块茎和分枝的C含量,除最后一次顶端优势去除提高了叶片C含量,其它顶端优势去除时间均降低了叶片含量;顶端优势去除降低了根系、茎秆和块茎N含量,提高了分枝和花的含N量;顶端优势去除提高了叶片和块茎的含P量;C∶N范围为24.15—153.75、C∶P范围为118.87—2265.72、N∶P范围为2.46—24.05,N∶P平均值为10.67,说明菊芋生长主要受N元素的限制。

Influence of apical dominance on the ecological stoichiometry of C,N,and P in Helianthus tuberosus

To better understand the influence of apical dominance on the ecological stoichiometry of C, N, and P in Helianthus tuberosus L., we removed the apical meristems of plants at different growth stages and measured the C, N, and P contents of different organs (root, stem, leaf, flower, and tuber), as well as the corresponding C:N, C:P, and N:P ratios. Removing the apical meristem had no effect on the C content of any of the organs but did affect the contents of N and P. The C content of the stems, tubers, and branches was improved by removing apical dominance, and the C content of the leaves was reduced expect the last removing apical dominance. Meanwhile, the N content of the roots, stems, and tubers was decreased, and the N content of the branches and flowers was increased, whereas the P content was only increased in the leaves and tubers. The C:N, C:P, and N:P ratios ranged from 24.15 to 153.75, from 118.87 to 2265.72, and from 2.46 to 24.05, respectively. The mean N:P (10.67) indicated that the growth of H. tuberosus was mainly limited by nitrogen availability.