Carbohydrate storage in wood and bark of rubber trees submitted to different level of C demand induced by latex tapping
Carbohydrate storage in wood and bark of rubber trees submitted to different level of C demand induced by latex tapping
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DOI：
10.1093/treephys/tpp043
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发表时间：
2009-08-01
期刊：
影响因子：
4
通讯作者：
Thaler, P.
中科院分区：
文献类型：
--
作者：
Chantuma, P.;Lacointe, A.;Thaler, P.
当光合作用产生的碳水化合物的当前水平不足以满足维持、生长或新陈代谢的碳水化合物需求时，树木就会使用储存的碳水化合物。橡胶树(Vevea brasilisis Muell.)然而，先前的一项研究(Silpi U，A.Laco inte，P.Kasemsap，S.Thanisawanykura，P.Chantuma，E.Gohet，N.Musigamart，A.Clement，T.Ameglio和P.Thaler)。2007年。碳水化合物储备作为竞争下沉：来自采摘橡胶树的证据。树木生理学。27：881-889)表明，割胶所产生的额外库不会导致树干非结构性碳水化合物(NSC)储量的减少，而是增加了NSC的储量。为了更好地理解乳汁再生、生物量和贮藏之间的权衡，本研究进一步研究了NSC贮藏对胶乳割胶的响应。将三种割胶系统与未割胶对照进行了2年的比较。树干两侧距地面50~200 cm处的树皮和木材中均含有可溶性糖和淀粉。结果证实，在过去的两年里，割胶的树木比未割胶的对照储存了更多的NSC，主要是淀粉。此外，双割交替割胶系统比传统割胶系统产生更高的胶乳产量，导致NSC浓度更高。在所有割胶的树木中，贮存量的增加与树干径向生长的减少同时发生。这被解释为碳分配的转变，转向以牺牲增长为代价创造储量，以弥补割胶造成的风险增加(反复伤害和胶乳中碳的损失)。树皮中淀粉含量低于木材，而可溶性糖含量则相反。由此产生的NSC在树皮中的含量是木材中的两倍，变化也更小。虽然树皮中发生了乳胶再生，但与割胶相关的变化在木材中比在树皮中更明显。从季节动态和树干两侧对割胶反应的差异来看，木材中的淀粉在整个树干水平上表现为长期储备室，而树皮中的淀粉则是局部缓冲。可溶性糖在木材和树皮中的作用就像一个中间的、随时可以使用的隔间。最后，碳水化合物储备的动态似乎是评估胶乳割胶系统长期表现的一个相关参数。
When the current level of carbohydrates produced by photosynthesis is not enough to meet the C demand for maintenance, growth or metabolism, trees use stored carbohydrates. In rubber trees (Hevea brasiliensis Muell. Arg.), however, a previous study (Silpi U., A. Lacointe, P. Kasemsap, S. Thanisawanyangkura, P. Chantuma, E. Gohet, N. Musigamart, A. Clement, T. Ameglio and P. Thaler. 2007. Carbohydrate reserves as a competing sink: evidence from tapping the rubber tree. Tree Physiol. 27: 881-889) showed that the additional sink created by latex tapping results not in a decrease, but in an increase in the non-structural carbohydrate (NSC) storage in trunk wood. In this study, the response of NSC storage to latex tapping was further investigated to better understand the trade-off between latex regeneration, biomass and storage. Three tapping systems were compared to the untapped Control for 2 years. Soluble sugars and starch were analyzed in bark and wood on both sides of the trunk, from 50 to 200 cm from the ground. The results confirmed over the 2 years that tapped trees stored more NSC, mainly starch, than untapped Control. Moreover, a double cut alternative tapping system, which produced a higher latex yield than conventional systems, led to even higher NSC concentrations. In all tapped trees, the increase in storage occurred together with a reduction in trunk radial growth. This was interpreted as a shift in carbon allocation toward the creation of reserves, at the expense of growth, to cover the increased risk induced by tapping (repeated wounding and loss of C in latex). Starch was lower in bark than in wood, whereas it was the contrary for soluble sugars. The resulting NSC was twice as low and less variable in bark than in wood. Although latex regeneration occurs in the bark, changes related to latex tapping were more marked in wood than in bark. From seasonal dynamics and differences between the two sides of the trunk in response to tapping, we concluded that starch in wood behaved as the long-term reserve compartment at the whole trunk level, whereas starch in bark was a local buffer. Soluble sugars behaved like an intermediate, ready-to-use compartment in both wood and bark. Finally, the dynamics of carbohydrate reserves appears a relevant parameter to assess the long-term performance of latex tapping systems.