Nitrogen nutrition during ontogeny of hemiepiphytic Clusia species.
Nitrogen nutrition during ontogeny of hemiepiphytic Clusia species.
复制标题
DOI：
10.1071/pp01238
复制
发表时间：
2002-06
期刊：
影响因子：
--
通讯作者：
W. Wanek;S. Arndt;W. Huber;M. Popp
中科院分区：
文献类型：
--
作者：
W. Wanek;S. Arndt;W. Huber;M. Popp
本文源自 2001 年 8 月在澳大利亚昆士兰州苦难角举行的第三届景天酸代谢国际大会上的演讲。我们研究了哥斯达黎加低地热带森林中 Clusia osaensis、C. peninsulae 和 C. valerii 在幼苗期、附生期和半附生期的氮 (N) 营养，以阐明不同植物生长阶段对其栖息地的营养适应。尽管所有 Clusia 个体都是非菌根的，但切除的幼苗根部，以及附生和半附生阶段的根部，都表现出对甘氨酸吸收的明显偏好。尽管氮的有效性和有效氮库的组成发生了显着变化，但吸收率或偏好的变化并没有反映出主要生根部位从冠层土壤到陆地土壤的转变。高叶面氮浓度表明附生幼苗似乎通过母体种子资源和冠层土壤获得了充足的氮供应。随着发育，Clusia 的附生植物可能会面临氮限制，因为随着生长的增加和树冠资源的限制，氮需求量更高。 15N自然丰度数据表明，附生植物主要获取大气中的氮源，并在较小程度上获取冠层土壤氮源，并且在固定于陆地后，在半附生生命阶段利用了地面土壤的更大养分库。因此，Clusia 物种没有表现出对它们所经历的不同氮可用性情况的适应，无论是树冠还是地根。
This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. We investigated the nitrogen (N) nutrition of Clusia osaensis, C. peninsulae and C. valerii during the seedling, epiphytic and hemiepiphytic phase in a lowland tropical forest in Costa Rica in order to elucidate nutritional adaptations of different plant growth stages to their habitat. Although all Clusia individuals were non-mycorrhizal, excised roots of seedlings, but also of epiphytic and hemiepiphytic stages, showed a distinct preference for glycine uptake. The shift in main rooting site from canopy soil to terrestrial soil was not reflected by changes in uptake rate or preference, although N availability and the composition of the available N pool changed significantly. High foliar N concentrations indicated that epiphytic seedlings seemed to be sufficiently supplied with N by maternal seed resources and canopy soils. With development, the epiphytic plants of Clusia may face N limitation due to higher N demands with increasing growth and restricted resources in the tree crowns. 15N natural abundance data indicate that epiphytes mainly accessed atmospheric and, to a lesser extent, canopy soil N sources and, after becoming terrestrially anchored, in the hemiepiphytic life stage exploited the larger nutrient reservoir of the ground soil. In consequence, Clusia species did not show an adaptation to the different N availability situations that they experienced whether canopy or ground-rooted.