AQA GCSE Biology 2 Views 1 Answers
What are some common signs that indicate a plant may be diseased?
What are some common signs that indicate a plant may be diseased?
Answer
Common signs that indicate a plant may be diseased include various visual symptoms and physical evidence of pathogens. Here are some key indicators to look for:
Visual Symptoms
- Color Changes
- Chlorosis: Yellowing of leaves, often indicating nutrient deficiencies or disease.
- Necrosis: Browning or death of tissue, which can appear as spots or entire leaves dying off.
- Wilting
- Plants may droop or wilt due to water stress, which can be caused by pathogens affecting water uptake, such as certain fungi and bacteria.
- Leaf Deformations
- Mosaic Patterns: Irregular light and dark green patches on leaves, typically associated with viral infections.
- Crinkling or Curling: Leaves may twist or curl due to various pathogens affecting growth.
- Stunted Growth
- Overall reduction in plant size and vigor, often seen in plants infected with viruses or certain fungal pathogens.
- Defoliation
- Loss of leaves as the disease progresses, which can lead to the plant dropping fruit as well.
Physical Signs
- Fungal Structures
- Visible signs of fungal infections such as molds, mildew, or fruiting bodies on leaves and stems.
- Bacterial Ooze
- A slimy exudate that can appear on stems or fruits, indicating bacterial infections like cankers.
- Spots and Lesions
- Leaf spots can vary in shape and color; some may have yellow halos indicating bacterial infections, while others might be dark and necrotic due to fungal diseases.
- Galls and Tumors
- Abnormal growths on stems or roots caused by specific pathogens, leading to swelling or deformation of plant tissues.
- Soft Rots
- Decay of plant tissues that may result in a mushy texture, often associated with bacterial infections
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