2.6 KiB
Executable file
2.6 KiB
Executable file
As a leafy vegetable, lettuce is particularly vulnerable to stresses that affect turgor, growth, and nutrient uptake.
- Water Stress (Drought): Negatively affects growth and productivity, with low irrigation levels significantly reducing yield.
- Drought Effects on Biomass: Drought leads to lower dry aerial weight and dry root weight.
- Yield Reduction: Drought stress can decrease lettuce yield by up to 50%.
- Nutrient Stress: Nutrient unbalance or deficiency, particularly of nitrogen and phosphorus, can negatively affect crop productivity.
- Combined Water and Nutrient Stress: When combined, these stresses have a more significant negative impact than when applied individually.
- Cold Stress: Cold soil temperatures and frosts can cause cellular damage and increase disease pressure.
- Waterlogging: Can lead to anoxic conditions in the root zone, stressing the plant.
- Light Stress: Lettuce is sensitive to continuous light, especially at high intensities, which can induce oxidative stress.
- Biotic Stress (Fungal): Fungal diseases like Fusarium wilt can have a greater negative effect on lettuce than water or nutritional stress, reducing fresh weight by up to 69%.
- Phenolic Compounds: Stressed lettuce plants show a higher phenolic index, indicating an induced defense response.
- Anthocyanins: Biotic stress can lead to a significant increase in anthocyanin content.
- Nitrate Levels: Drought stress has been reported to decrease fresh biomass-related nitrate levels.
- Calcium Deficiency: Both overly humid and overly dry conditions can interrupt transpiration, leading to calcium deficiency, which manifests as tip burn or internal browning.
- Silicon Application: Foliar applications of silicon can strengthen plant cells, protecting the crop from cold stress, wind damage, and high humidity.
- Antioxidant Response: Lettuce plants have an antioxidant defense system to overcome oxidative stress from factors like continuous light.
- Root-to-Shoot Ratio: Under continuous light, lettuce plants may show a greater root-to-shoot ratio as an adaptive response.
- Chlorophyll Fluorescence: This parameter can be used to monitor the plant's response to light stress.
- Spectral Indices: Indices like the Pigment Specific Simple Ratio (PSSRa) can effectively detect biotic stress before visual symptoms appear.
- Combined Abiotic and Biotic Stress: The combination of stresses can lead to unique responses; for example, lettuce subjected to both water and biotic stress showed the highest phenolic index.