根茎半灌木羊柴对光合同化物的克隆整合

羊柴为根茎半灌木，主要分布于我国北方半干旱区的沙地。该种的营养繁殖是由根茎的水平延伸使顶端分生组织与腋生分生组织序列化不断产生而进行的。本项研究采用^14C标记和去叶实验，探讨了母株、子株所组成的分株对内的光合同化物的整合。在24h的传输中，相当可观量的14C光合同化物自母株传输给子株、子株的根系和根茎，且它们的汇活度均超过了10%。在^14C-光合化物向基向传输（由子株向母株）中，传输率较小，且汇活度不足1%，但根茎在这一传输中的汇活度却超过2%。去叶影响着母株与子株之间的光合同化物整合。保持完整的母株增大向遭受去叶的子株传输光合产物；反之亦然。母相提并论和子株都向根茎传输一定量的同化物，表明根茎自分株获得光合同化物的支持。羊柴的相连分株间通过根茎而发生克隆整合，可能使其分株和基株在不利的沙地生境中都获得净收益。

The clonal integration of photosynthates in the rhizomatous half-shrub Hedysarum laeve

Hedysarum laeve, a rhizomatous clonal half-shrub, usually distributes in inland dune in semi-arid sandlands of northern part of China. This species propagates vegetatively by extension of horizontal rhizomes resulting in programmed reiteration of apical and/or axillary meristems. The rhizome connection is persistent after the new ramet establishment. In order to investigate the photosynthate translocation between the ortet and the daughter ramet through the rhizome in the species and the ecological significance of this translocation of the species, the ortet and the daughter ramet were labeled with 14CO 2 to detect the acropetal and basipetal translocation for the photosynthates within the ortet-daughter ramet pair, respectively. And either the ortet or the daughter ramet of the ramet pair was exposed to 14CO 2 while the other ramet was defoliated, in order to test the increase of photosynthate translocation from the intact ramet to the defoliated ramet within the pairs. A considerable amount of 14C-photosynthates acropetally transported from the ortet into the daughter ramet, roots of daughter ramet and the rhizome with approximate 5% translocation percentage and more than 10% sink activity during 24h translocation. In the basipetal translocation (from daughter ramet into ortet) of 14C-photosynthates, the proportions of 14C-photosynthates from the daughter ramet both into the ortet and the root of ortet were with a nearly 5% translocation percentage and a less than 1% sink activity, but sink activity of rhizome exceeded 2%. Defoliation had an influence on the photosynthate translocation between the ortet and daughter ramet. The intact ortet significantly increased its 14C-photosynthate translocation into the defoliated daughter ramet than it did under the circumstance that the daughter ramet was not defoliated. And the intact daughter ramet transported significantly more 14C-photosynthates to the defoliated ortet than it did in the situation that the ortet was not defoliated. Some portion of 14C-photosynthates was transported into the rhizome both from the ortet and the daughter ramet, indicating that the rhizome was supported by both ramets for photosynthates. The clonal integration between ramets of the species through the rhizome connection may confer a benefit both to the ramets and to the genet in the adverse environment of the sandlands. In addition, the ecological significance of photosynthate translocation both from the ortet and from the daughter ramet into the rhizome as discussed.