Crop yields can decrease due to biotic and abiotic stresses in various conditions. Which of the following factors is/are classified as abiotic stress?

Appeared in: DSSSB 14 August 2024

Explanation

The question asks to identify an abiotic stress factor, which means a non-living environmental factor.
Frost is a meteorological event where water vapor freezes on surfaces, forming ice crystals. It is a non-living physical factor.
Exposure to frost can cause severe damage to plant tissues by forming ice crystals within the cells, leading to cell death and reduced crop yield.
Other abiotic factors include drought, extreme temperatures (heat and cold), high salinity, and heavy metal toxicity.

Option A: Insects are living organisms (animals) that feed on plants, causing direct damage. Therefore, they are a source of biotic, not abiotic, stress.
Option C: Nematodes are living microscopic roundworms that act as parasites on plants, primarily attacking the roots. This makes them a biotic stressor.
Option D: Diseases in plants are caused by other living organisms, such as bacteria, fungi, and viruses (pathogens). Stress caused by pathogens is classified as biotic stress.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Crop Stress Factors (Biotic vs. Abiotic) as background academic context rather than a clinical decision trigger.
Understanding the difference between biotic and abiotic stress is fundamental for developing effective crop management strategies and ensuring food security.
Management approaches differ significantly: biotic stresses are often managed with pesticides or biological control agents, while abiotic stresses require developing resilient crop varieties or modifying the growing environment (e.g., irrigation for drought, covers for frost).
What if? - If a farmer notices widespread yellowing of leaves but no visible pests, this would suggest an abiotic stressor, such as a nutrient deficiency in the soil or water stress, prompting soil and water testing rather than pesticide application.

How to Approach the Question

First, identify the key term in the question: 'abiotic stress'.
Define the term. 'A-' means 'not' or 'without', and 'bio' means 'life'. Therefore, 'abiotic' means non-living.
In contrast, 'biotic' refers to living organisms.
Evaluate each option to determine if it is a living organism or a non-living environmental factor.
Insects, Nematodes, and Diseases (caused by pathogens) are all related to living organisms.
Frost is a weather condition, which is a non-living physical factor.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) p. 112-114

E6 Comprehensive Textbook of Community Health NursingShyamala D part 1 (pp 26-389 of 389) p. 177-179

Practise the full DSSSB 14 August 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.