Tomatoes are sensitive to a range of environmental stressors that can impact their growth, yield, and quality.

*   **Nutritional Stress:** Nitrogen deficiency, often combined with drought, can negatively affect the biological traits of pests like *Tuta absoluta* but is also unfavorable to the tomato plants themselves.
*   **Nitrate Overload:** Excessive use of nitrate-based fertilizers can cause oxidative stress, leading to stunted growth and cellular damage.
*   **Salt Stress:** Considered moderately salt-sensitive, with a saturated soil paste extract electrical conductivity (ECe) threshold value of 1.5 dS m−1.
*   **High Salinity:** Leads to a decrease in the green parts of the plant and reduces the mineral nutrient content of potassium and calcium in the leaves.
*   **Sodium and Chloride Content:** Salt stress can cause an increase in sodium (Na+) and chloride (Cl-) content, which can be toxic to the plant.
*   **Grafting:** Grafting tomato plants can enhance resistance to thermal stress.
*   **Drought Stress:** Reduces leaf water content, photosynthesis rates, and stomatal conductance, negatively impacting leaf growth.
*   **Combined Drought and Nutrient Stress:** This combination can lead to a significant reduction in leaf fresh weight, dry weight, and overall water content.
*   **Water Stress (General):** Affects the growth and development of tomato plants negatively.
*   **Leaf Area:** Plants under drought, salt, and water stress tend to have a smaller leaf area compared to control plants.
*   **Chlorophyll Content:** Can be higher in plants under drought, salt, and excessive water stress compared to plants not exposed to drought.
*   **Potassium Levels:** Salt stress can lead to higher potassium levels in the green parts of the plant compared to control plants.
*   **Calcium Levels:** Salt accumulation can cause an increase in calcium in the root region.
*   **Magnesium Levels:** The effect of moderate water reduction on magnesium (Mg2+) levels in leaves can vary depending on the cultivar.
*   **Heat Stress:** High temperatures negatively impact both vegetative growth and reproductive processes, leading to significant losses in yield and fruit quality.
*   **Reproductive Stage:** Heat stress during the reproductive stage is particularly damaging as it affects flower number, stigma exertion, pollen germination, and fruit set.
*   **Waterlogging:** Can reduce plant growth, degrade chlorophyll, and increase oxidative stress markers like malondialdehyde and hydrogen peroxide, which damages membrane integrity.
*   **Phenolic Compounds:** The concentration of phenolic compounds in leaves and fruits is a sensitive indicator of waterlogging stress.
*   **Wild vs. Cultivated Species:** Wild tomato species may exhibit different and sometimes more robust responses to stresses like varied temperatures and nitrogen deficiency compared to cultivated varieties.
*   **Combined Stresses:** The combination of abiotic (like drought and nutrient deficiency) and biotic (like herbivory) stresses can result in a "new stress state" with non-additive effects, which can be more harmful than single stressors.