Ontogenetic shifts in resource allocation and potential defense syndromes of a tropical medicinal treelet

Bhadra, Sreetama; Cai, Zheng

doi:10.1016/j.indcrop.2019.06.013

Cited by 5 publications

(4 citation statements)

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“…3 a). The incensement of the internal N availability contributed to the initiation of new axes and the functional biomass partition between woody tissues and/or the enhanced N uptake from soils increased N contents in plant tissues [ 2 , 7 , 37 , 38 ]. Thus, C limitation, but not N remobilization, is a source-driven growth process in P. volubilis plants [cf.…”

Section: Discussionmentioning

confidence: 99%

Source–sink manipulations differentially affect carbon and nitrogen dynamics, fruit metabolites and yield of Sacha Inchi plants

Cai

Xie

2021

BMC Plant Biol

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Background Being a promising tropical woody oilseed crop, the evergreen and recurrent plants of Sacha Inchi (Plukenetia volubilis L.) has complex phenology and source–sink interactions. Carbon source–sink manipulations with control and two treatments (reduce source, ca. 10% mature leaf pruning; reduce sink, 10% fruitlet thinning) were conducted on 2.5-year-old field-grown P. volubilis plantation during the early-wet season in a seasonal tropical area. Results Leaf photosynthetic rate and specific leaf area largely remained unchanged in response to defoliation or defloration. Compared with control, higher N contents on average were observed in both remaining leaves and branches of the defoliated plants, suggesting that N-mobilization was mainly due to the enhanced N uptake from soil. Carbon, but not N, is a source-driven growth process of P. volubilis plants, as defoliation reduced the contents of non-structural carbohydrates (especially sugar) in branches, although temporally, whereas defloration increased available C reserve. The seasonal dynamic pattern of fruit ripening was altered by source–sink regulations. Total seed yield throughout the growing season, which depends on fruit set and retention (i.e., number of matured fruit) rather than individual fruit development (size), was slightly increased by defloration but was significantly decreased by defoliation. Compared with control, defloration did not enrich the KEGG pathway, but defoliation downregulated the TCA cycle and carbohydrate and lipid metabolisms in fruitlets after 24 days of the applications of source–sink manipulation. Conclusion Carbohydrate reserves serve to buffer sink–source imbalances that may result from temporary adjustment in demand for assimilates (e.g., defloration) or shortfalls in carbon assimilation (e.g., defoliation). Defoliation is disadvantageous for the yield and also for carbohydrate and lipid accumulation in fruits of P. volubilis plants. Although more studies are needed, these results provide new insights to the further improvement in seed yield of the strong source-limited P. volubilis plants by source/sink manipulations.

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Section: Discussionmentioning

confidence: 99%

Source–sink manipulations differentially affect carbon and nitrogen dynamics, fruit metabolites and yield of Sacha Inchi plants

Cai

Xie

2021

BMC Plant Biol

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“…Not surprisingly, this can impact growth‐RNA‐P coupling. For example, although nutrient contents are often coupled with growth in certain plant tissues (i.e., leaves; Rivas‐Ubach et al, 2012 ), P‐allocation and growth rates of other plant tissues may differ throughout ontogeny, making whole organismal growth/nutrient relationships challenging both to quantify and interpret within the context of the GRH (Bhadra & Cai, 2019 ; Jing et al, 2017 ). When P‐allocation differs in this way, a variety of patterns could be observed, such as a stronger coupling during juvenile stages (Figure 3a or e ), a weaker coupling at adult stages (Figure 3c ), or even no coupling at the organismal level (Figure 3c ).…”

Section: How Do We Test the Grh ?mentioning

confidence: 99%

Revisiting the growth rate hypothesis: Towards a holistic stoichiometric understanding of growth

et al. 2022

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The growth rate hypothesis (GRH) posits that variation in organismal stoichiometry (C:P and N:P ratios) is driven by growth‐dependent allocation of P to ribosomal RNA. The GRH has found broad but not uniform support in studies across diverse biota and habitats. We synthesise information on how and why the tripartite growth‐RNA‐P relationship predicted by the GRH may be uncoupled and outline paths for both theoretical and empirical work needed to broaden the working domain of the GRH. We found strong support for growth to RNA (r2 = 0.59) and RNA‐P to P (r2 = 0.63) relationships across taxa, but growth to P relationships were relatively weaker (r2 = 0.09). Together, the GRH was supported in ~50% of studies. Mechanisms behind GRH uncoupling were diverse but could generally be attributed to physiological (P accumulation in non‐RNA pools, inactive ribosomes, translation elongation rates and protein turnover rates), ecological (limitation by resources other than P), and evolutionary (adaptation to different nutrient supply regimes) causes. These factors should be accounted for in empirical tests of the GRH and formalised mathematically to facilitate a predictive understanding of growth.

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“…It has been documented that the turnover times of leaf pools across these biomes exhibit an inverse relationship to growth (“grow fast, die fast” hypothesis) (108). Some theories suggest that this trade-off happens in agreement with the plant investment strategies, adjusting carbon allocation to balance early growth against defenses (108,109). Plants in the tropics do not necessarily experience strong selective pressure to evolve higher levels of chemical defense against biotic threats (110).…”

Section: Discussionmentioning

confidence: 99%

Exploring biodiversity dynamics and taxonomy of Rubiaceae fungal endophytes in tropical regions

Castillo-González,

Slot,

Yarwood

et al. 2024

Preprint

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Fungal endophytes play a pivotal role in tropical forest dynamics, influencing plant fitness through growth stimulation, disease suppression, stress tolerance, and nutrient mobilization. This study investigates the effects of region, leaf developmental stage, and tissue type on endophyte communities in tropical Rubiaceae. Our hypotheses, centered on the influence of these factors, were tested using targeted amplicon sequencing. Leaves and sapwood samples were collected from old-growth forests in Golfito and Guanacaste, Costa Rica, and fungal diversity was assessed through metabarcoding of the ITS2 nrDNA region. Most identified ASVs belonged to the phylum Ascomycota. The orders Botryosphaeriales and Glomerellales significantly contributed to endophytic assemblages, without detection of host-specific communities. We observed significant differences in species richness across locations, confirming distinct compositions through beta diversity. No statistically significant variances were found between mature and juvenile leaf tissues. In contrast, leaves exhibited richer and more diverse assemblages than sapwood. As plants experienced diverse environments over time and space, our results may be influenced by changing structural and chemical properties through ontogeny. Given the potential impact of these fungi on agricultural and forest ecosystems, ongoing research is crucial to discern the roles of hosts, endophytes, and other ecological mechanisms in apparent colonization patterns.

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Ontogenetic shifts in resource allocation and potential defense syndromes of a tropical medicinal treelet

Cited by 5 publications

References 50 publications

Source–sink manipulations differentially affect carbon and nitrogen dynamics, fruit metabolites and yield of Sacha Inchi plants

Source–sink manipulations differentially affect carbon and nitrogen dynamics, fruit metabolites and yield of Sacha Inchi plants

Revisiting the growth rate hypothesis: Towards a holistic stoichiometric understanding of growth

Exploring biodiversity dynamics and taxonomy of Rubiaceae fungal endophytes in tropical regions

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