Plants allocate the acquired aboveground (leaf traits for light capture and carbon fixation) and below-ground (root traits for soil-resource exploration) resources for the vital functions of growth, resistance, defense and reproduction, to maximize their fitness in the environment.
However, little is known about how functional traits vary with plant size in woody species across their whole life cycles.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) conducted a study to reveal the functional trajectories throughout a woody plant’s life cycle under the conditions of no environmental interference.
The researchers examined plant functional traits in seven ontogenetic stages, following complete trajectories, of a tropical light-demanding evergreen medicinal treelet (Rauvolfia vomitoria) in a common garden experiment in the field.
Using the fully-exposed, sparsely cultivated plants, the researchers assessed the effect of real plant ontogeny.
They demonstrated that, at both plant-tissue and whole-plant levels, plant traits related to growth and potential defense syndromes of R. vomitoria plants were highly plastic throughout their life cycle (seedling, sapling, reproductive maturity, post-reproductive plants).
The pronounced non-linear ontogenetic trajectories, with a mostly well-defined transition at the reproductive onset, are due to real ontogeny-induced shifts in resource allocation.
At the whole-plant level, plant growth shifted from nitrogen- to phosphorous-limited conditions throughout the ontogenetic development.
There were overall trade-offs between leaf physical and chemical defenses across ontogeny of R. vomitoria plants, but phenotypic expression of potential defensive traits differed between above- and below-ground parts.
“The revealed variations of the growth traits and secondary metabolites of R. vomitoria plants at different developmental stages will be helpful for maximizing the reserpine yield through the suitable cultivation practices,” said Prof. CAI Zhiquan, correspondence author of the study.
The study entitled “Ontogenetic shifts in resource allocation and potential defense syndromes of a tropical medicinal treelet” has been published online in Industrial Crops and Products.
CAI Ziquan Ph.D
Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun 666303, Yunnan, China