Purpose

Benefits of clonal integration have been widely documented in clonal species, but quantitative tests of the translocation of resources in both directions between older and younger ramets (e.g., transport rate and partitioning pattern) are still scarce.

Methods

A control experiment, using a clonal species Alternanthera philoxeroides as plant material and the technique of ¹⁵N isotope, was conducted to quantify the transport rate of nitrogen (N) in two opposite directions (i.e., from younger to older ramets or the other way around) within a clone, and the partitioning proportion of N in recipient ramets.

Results

The amount of ¹⁵N transported toward the apical part was markedly reduced at the higher external N level, whereas the amount of ¹⁵N transported toward the basal part was unrelated to the external N levels. The rate of ¹⁵N acropetal transport basically averaged 20.9%, and the rate of ¹⁵N basipetal transport generally ranged between 0.2% and 6.3%, both being negatively dependent of ΔPNC (i.e., difference in plant N concentration [PNC] between apical and basal parts). The proportion of ¹⁵N in stems and leaves averaged 74.7% and 18.1%, respectively; the proportion of root ¹⁵N in the apical part significantly decreased from 7.6% to 0.4% when acropetal transport occurred.

Conclusion

These results suggest that N sharing between connected ramets tended to be acropetal and the partitioning pattern of N is organ-specific in A. philoxeroides, which potentially contributes to the early development of young ramets, and also to the spread of A. philoxeroides in limited N conditions.

中文翻译：

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均质环境中空心莲子草相连分株之间的氮共享

目的

克隆整合的好处已在克隆物种中得到广泛证明，但对较老和较年轻分株之间资源双向转移的定量测试（例如，运输速率和分区模式）仍然很少。

方法

使用克隆物种空心莲子草作为植物材料和¹⁵ N 同位素技术进行了一项对照实验，以量化氮 (N) 在两个相反方向（即从较年轻到较老的分株或相反方向）的运输速率) 在一个克隆中，以及 N 在受体分株中的划分比例。

结果

^{在较高的外部氮水平下，向顶端输送的15} N量显着减少，而向基部输送的^{15 N 量与外部氮水平无关。顶叶15} N 转运率基本平均为 20.9%，基部¹⁵ N 转运率一般在 0.2% 和 6.3% 之间，均与 ΔPNC 负相关（即顶端和基部之间的植物 N 浓度差异 [PNC]部分）。茎叶中¹⁵ N的比例平均分别为 74.7% 和 18.1%；发生顶叶转运时，根尖部分根¹⁵ N的比例由7.6%显着降低至0.4%。

结论

这些结果表明，连接的分株之间的 N 共享往往是顶瓣的，并且 N 的分配模式在空心莲子草中是器官特异性的，这可能有助于年轻分株的早期发育，也有助于空心莲子草在有限的范围内的传播。 N 个条件。