Superior growth, N uptake and NH4+ tolerance in the giant bamboo <i>Phyllostachys edulis</i> over the broad-leaved tree <i>Castanopsis fargesii</i> at elevated NH4+ may underlie community succession and favor the expansion of bamboo
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The unbridled expansion of bamboo has imposed serious threats on ecosystem processes and functions. Considerable evidence indicates that bamboo invasions can alter plant-available soil nitrogen (N) pools and rates of N cycling, but the consequences of altered N availability for plant growth and community structure have thus far been poorly characterized. The primary soil-accessible N forms for most plants are ammonium (NH4+) and nitrate (NO3-), but plants differ in their ability to use the different N forms, and these differences can be related to their ecological characteristics and drive community structure. In this context, we evaluated the growth response, N uptake and interspecific competition in two subtropical species, Phyllostachys edulis (Carrière) J. Houzeau (Synonym Phyllostachys heterocycla Carrière) and Castanopsis fargesii Franch., dominant species of bamboo and secondary evergreen broad-leaved forests, respectively, under changing N availability in seedlings supplied with different N concentrations and NH4+/NO3- proportions, in vermiculite culture, in a controlled environment. The results show that (i) both species display an NH4+ preference at elevated N concentrations. The growth of P. edulis seedlings was strongly enhanced at increased ratios of NH4+ to NO3- especially at higher N concentrations, but to a much lesser extent in C. fargesii. (ii) NH4+ preference at the level of N uptake in both species was confirmed by the Non-invasive Micro-test Technology and by examining 15N signatures. Phyllostachys edulis had higher NH4+ net fluxes and N concentration under NH4+ treatments than C. fargesii. (iii) NH4+ at higher concentrations caused toxicity in both species as it inhibited root growth and even caused seedling death, but P. edulis had a higher NH4+-tolerance threshold (24 mM) than C. fargesii (16 mM). (iv) When mixed-species cultures were examined in an NH4+-rich medium, the growth of C. fargesii, but not P. edulis, was significantly inhibited compared with growth in monoculture. Therefore, P. edulis exhibited stronger plasticity and adaptation to changing N availability, whereas C. fargesii had low responsiveness and capacity to acclimate to soil N changes. Phyllostachys edulis displayed a significant competitive growth advantage compared with C. fargesii on NH4+-dominated substrates.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it