Effects of Photoradiation on the Growth and Potassium, Calcium, and Magnesium Uptake of Lettuce Cultivated by Hydroponics
Bibliographic record
Abstract
Photoradiation plays a major role in plant growth processes, especially photosynthesis and nutrient uptake. Light intensity and photoperiod affect temperature and caused more transpiration in plants, which influences nutrient uptake. This study aimed to examine the effects of photoradiation on the growth and K, Ca, and Mg uptake of lettuce (Lactuca sativa L.). Lettuce was hydroponically grown in a walk-in growth chamber, and the experiment was performed using eight treatments with eight replications. A combination of eight fluorescent lamps was used to provide a photon flux density of 128±20 umole m-2 s-1 for 15/15 minutes, 45/15 minutes, 345/15+15/15 minutes of black UV, and 345/15+15/45 minutes of black UV of light/dark periods. A combination of ten fluorescent lamps was used to provide a photon flux density of 194±28 umole m-2 s-1 for 30/30 minutes, 15/15 minutes, and 45/15 minutes of light/dark periods and 24 hours of light period. Continuous illumination with higher light intensity gave the greatest shoot fresh weight, plant height and number of leaves. Whereas a shorter photoperiod and lower light intensity gave the lowest shoot fresh weight. Shortened UV light radiation gave better result in lettuce growth performance such as shoot fresh weight, plant height and number of leaves. UV light also damaged the lettuce leaves. The leaves turned brown (brown spot) at the tip of the old leaves. Molar concentrations of K, Ca and Mg in the lettuce leaves were in the order of K > Ca > Mg for all of the treatments. The steep gradient and highest K accumulation at bottom leaves were found at lower light intensity and short photoperiod (15/15 minutes of light/dark). Extended photoperiod improved K and Ca movement and reduced K and Ca accumulation in the bottom leaves. High K in the leaves reduced Ca uptake. Continuous illumination with higher light intensity resulted in the lowest concentrations of K, Ca and Mg. The mole ratio of K/Ca decreased from the top to bottom leaves, whereas the mole ratio of K/Mg tended to be stable except in the treatment with lower light intensity and short photoperoid. The best growth performance was found in the treatment with consistent K/Ca ratio.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".