Why Is Rot Important in Biology?
Rot is a type of plant disease caused by soil-borne bacteria, fungi. Rots meaning can be stated as any plant decomposition or putrefaction. The decay is usually hard, spongy, watery, or dry in any of the plant parts.
What is Rot?
To state the different types of rot, let us begin with the basal rot.
Basal Rot
It is a widespread plant disease caused by a variety of bacteria and fungi that can infect flower and crop bulbs. The necessary changes that can be seen in Basal rot are as follows:
Shoots are stunted or may fail to emerge.
Leaves discoloration varies from yellow to reddish or purplish.
Roots are discolored and decayed.
The rot starts at the root base, progressing upwards and outward.
Rot progresses when stored in warm humid places.
Fungal rots are dry to spongy or powdery and moldy.
Bacterial rots are moist, soft, mushy, and foul-smelling.
Gray Mold Rot
This disease usually affects flowers and buds, later infections on fruits, leaves, and stems can occur. The visible changes that can be seen here are:
Plants growing in humid areas are caused by fungi in the genus Botrytis.
Vegetables, fruits, flowers, and woody plants are susceptible.
Gray mold rot is characterized by tan to brown soft spots or blotches.
It is covered with dusty mold.
It causes seedling, young shoots, and leaves to wither and collapse.
Buds, flowers, and fruits become flecked and rotten.
Heart Rot
It is one of the plant rot diseases of trees, root crops, and celery. Heart rot usually does not affect the living sapwood but does cause structural weakness and lead to broken branches and trunks. This rot disease causes loss to the timber industry, as infected trees are unsuitable for timber.
To define rotten plants and their characteristics one should look for the following changes in the infected parts:
Heart rotting fungi produce discolored, lightweight, soft, spongy, stringy, crumbly, or powdery heart decay.
Conks or mushrooms appear at the wounds or trunk base.
Heart rot is also caused by certain nutrient deficiencies.
A brown to black internal rot of beets, carrots, and turnips are caused by a deficiency of boron.
Similar rot of celery, fennel, and parsley is induced by calcium deficiency.
This type of heart rot causes crop loss in poor soils.
Root Rot
Root rot is caused by fungi specially armillaria mellea, Clitocybe tabescens, and Fusarium. The following changes are noticed in root rot affected plants:
Plants lose vigor, become stunted, and yellow.
They wilt, or dieback and drop some leaves.
Plants do not respond to fertilizer and water.
Affected trees die gradually, roots decay and are covered with mold or black string-like strands.
Wood Rot
Wood rot is caused by fungi including species of Daedalea, Fomes, Lenzites, Poria, and Stereum. The following damage is noted in the affected trees:
Affected wood is discolored, stained, lightweight, soft, crumbly, or powdery.
Damage occurs slowly, usually over a period of many years.
Infection occurs through wounds.
Mushrooms may form at the trunk base.
A fruiting body also known as conks, or mushroom sightings indicates extensive decay.
Symptoms and Signs of Rot Disease
The symptoms of rot disease are similar to many plant infections and diseases. The following signs may include in the rot disease:
The symptoms hinder the uptake and transport of water and nutrients from the soil.
A thick, medium brown to the black crust of mycelium is found around the infected area.
The leaves of affected plants become wilt small or discolored.
Affected plants look stunted because of poor growth, develop cranks, or ooze sap.
Symptoms of Plant Disease
Most plant diseases are caused by fungal-like organisms whereas many others are caused by viral and bacterial infections. Plant diseases are non-infectious and include damage from air pollution, nutritional deficiencies, and may grow under less favorable conditions. The following symptoms may be noted while assessment of plant disease:
Detectable change in color.
Leaf wilting is a symptom of verticillium wilt.
Bacterial blight symptoms include brown, necrotic lesions at the leaf margin or the interior of the leaf.
Bird’s eyespot on berries.
Damping-off of seedlings.
Leaf spot
Fruit spot
Canker
Mosaic leaf pattern
Plant stunting
Crinkled leaves
The symptoms are caused by pathogens. Discussing the above symptoms, you are commonly not seeing the pathogen itself but rather symptoms caused by pathogens.
FAQs on Understanding Rot: Symptoms, Types, and Control
1. What does 'rot' mean in the context of biology?
In biology, rot refers to the decomposition or decay of organic tissue, primarily caused by microorganisms like bacteria and fungi. This process breaks down complex organic matter into simpler substances. In plants, it's a common disease that can affect roots, stems, leaves, and fruits, leading to tissue softening, discoloration, and eventual death of the affected part.
2. What are some common examples of rot found in plants?
There are many types of plant rot, often named after the part they affect or their appearance. Common examples include:
- Root Rot: Decay of the plant's root system, often caused by poor drainage and waterlogged soil.
- Stem Rot: Affects the base of the stem, causing it to become soft and weak, which can make the plant collapse.
- Leaf Rot: Appears as discoloured, mushy, or dead patches on leaves, hindering photosynthesis.
- Blossom End Rot: A physiological disorder common in tomatoes and peppers, causing the blossom end of the fruit to darken and decay.
- Brown Rot: A fungal disease that commonly affects stone fruits like peaches and cherries, causing them to rot quickly.
3. Why do plants often get root rot from too much water?
Too much water in the soil pushes out oxygen, creating an anaerobic (low-oxygen) environment. Plant roots need oxygen to function and survive. Without it, the roots begin to weaken and die. This makes them highly vulnerable to attack by water-loving fungi and bacteria, such as Pythium and Phytophthora, which thrive in these conditions and accelerate the rotting process.
4. How can you tell the difference between fungal and bacterial rot in a plant?
While a lab test is needed for a certain diagnosis, you can often spot visual differences. Fungal rot frequently produces visible signs like fuzzy mould, thread-like structures (mycelia), or tiny black dots which are fungal spores. In contrast, bacterial rot typically appears as water-soaked, slimy lesions and often has a distinct, foul smell.
5. Can a plant be saved once it starts showing signs of rot?
It depends on the severity and location of the rot. If caught early, especially with root rot, a plant can sometimes be saved. The process involves removing the plant from its container, carefully trimming away all the mushy and affected roots, and repotting it in fresh, well-draining soil. For rot affecting the main stem or crown of the plant, recovery is much more difficult.
6. What is the main difference in how leaf rot and root rot affect a plant?
The main difference is the part of the plant they attack and the primary function they disrupt. Leaf rot affects the foliage, which damages the plant's ability to perform photosynthesis and create energy. Root rot attacks the root system below the soil, which cuts off the plant's ability to absorb water and nutrients from the soil, effectively starving and dehydrating it.
