Why do tomato plants have hairs? What you never knew!


2 red ripe tomatoes

Tomato plants have hairs, also known as trichomes. The word trichome originates from the Greek term “trichomes,” which means hair. They are tiny outgrowths that emerge from the tomato dermis. These features found on the leaves and stems of TOMATOES are usually a few centimeters long.

The tomato plant hair or the trichome is the natural defense system of tomato plants; just like humans, our immune system is our defense system. These tiny trichomes also secrete essential oils, which give tomato plants their wonderful scent.

Generally, trichomes are unicellular or multicellular; however, they are multicellular epidermal cells resembling hair in TOMATOES. These organs are meant for protecting the plant against harm from weather and animals.

Types of trichomes

There are two types of trichomes: Glandular and Non-glandular.

Non-glandular trichomes

Non-glandular trichomes are like feelers, and they come to a point. They can sense when an insect or herbivore is walking by or on the plant surface. Once they perceive, a message is sent to the plant to activate its defense mechanism against herbivore attack.

Additionally, these trichomes protect the plant from damage by rainwater by keeping it off the leaf surface. They allow the water to roll off the leaf surface without touching the delicate dermal cells underneath.

Glandular trichomes

Glandular trichomes are similar to non-glandular, and they come to a point and beyond. At the tip of these trichomes, you will see a rounded gland resembling a dewdrop. Glandular trichomes can also sense when an animal walks on the plant surface or nearby.

When this happens, the gland at the tip raptures letting out a mixture of alkaloids, acyl sugars, terpenes, and other defense-like proteins. The fluid works by putting off herbivores through small, and it can also be toxic to insects. The liquid from tomato trichomes may also trap the insect, causing it to stick to the plant.

To sum up, the non-glandular trichomes provide a physical barrier from biotic and abiotic stressors. The glandular trichomes, on the other hand, produce a rich repertoire of secondary metabolites.

Genetics

Studies suggest that TOMATO HAIRS density is due to genetic factors as well as environmental conditions. These features are dependent on several genes.

The wooly gene (Wo) makes the trichomes on the tomato plant surface appear angora-like or fuzzy; it also brings about more and longer trichomes.

Secondly, we have another partial dominant gene- the Hirsute (Hr) gene. It causes the upper surface of tomato leaves to bear more and long trichomes. The Hr gene also causes the plant to bear fruit with trichomes on the surface. This gene type is more common in wild tomato varieties.

Finally, we have the third gene type, the hairless (hl) –this gene type suppresses the growth of trichomes. It, however, causes the surface of the leaves to appear curled or gnarled. Without these protective TOMATO HAIRS, the leaf surface is left vulnerable and becomes brittle. As a result, the leaf surface cracks easily, becoming susceptible to infections.

Purpose of TOMATO HAIRS

The purpose of tomato trichomes is dependent on their location. Some are above and others beneath the ground.

Tomato hair helps absorption of water and nutrients

When buried in the ground, TOMATO HAIRS develop into roots that help absorb water and nutrients, which can boost the plant’s health. It also improves the plant’s chances of survival and yield. For this reason, you are advised to plant TOMATOES with only one-third of the plant above the surface. As we will see later, this feature could be an adaptation for survival.

Trichomes harden the tomato plant skin

tomato plant hairs

Tomato hair makes the skin of the leaves and stems tougher by adding another layer. As a result, the fragile plant is safer from injury by animals and other plants that brush against it. It becomes more difficult for pests that feed on plant juices to penetrate the stem and leaves with this extra layer.

Moreover, tomato plants have weak and wobbly stems. Tomato stem and leaves would hardly survive certain weather conditions such as wind and heavy downpours without this extra layer of epidermal cells.

Tomato hair help repel herbivores

As we saw above, TOMATO HAIRS produce an oily substance that works for plant protection. This substance which originates from a particular type of trichrome is meant for protection against predation.

It is sticky, and insects that land on the plant can get trapped, thus stopping them from feeding on the tomato plant or leaves. Suppose you have ever touched the surface of a tomato plant or leaves during gardening. In that case, you can attest to the yellowish-colored substance stuck on the hands.

The compound also produces a specific type of unpleasant smell. The plant uses the scent to put off predators from taking a bite. As we saw above, tomato plants can sense predators or any other animal passing by producing this compound.

Finally, the TOMATO HAIRS deter animals from eating the plants. This is because the hairy appearance of the surface puts off animals. As a result, not many herbivores eat tomato plants as well as other plants with trichomes.

Tomato hair prevents attack by diseases

Tomato plants are susceptible to insect, viral, bacterial, and fungal attacks that destroy the plant and reduce yield. The oily substance produced by TOMATOES also prevents certain harmful organisms such as broad mites from laying eggs and multiplying on the leaf surface. It also deters the formation of caterpillars that destroy plants and, at the same time, impedes these caterpillars from searching for food in the plant.

Studies show that tomato trichomes also prevent the tomato from viruses and other disease attacks. The oily compound produced by tomato trichomes is antibacterial, antiviral, and antifungal. However, even with its secretion, tomato plants are still affected by diseases. All in all, it would be impossible for the plant to survive without the production of these oils.

Additionally, the oil keeps the leaf surface moist, preventing hardening and cracking, injuries that would pave the way for the entry of disease-causing organisms into the plant system.

Another way the plant can keep off virus and bacteria attacks is by putting off certain insects that transfer illnesses, such as whiteflies, from landing on its surface. Whiteflies cause a range of tomato diseases and are a significant menace to tomato farmers and gardeners. And this article covers dealing with whiteflies.

Other researchers suggest that animals and insects that feed on tomato plants get poisoned by the oils released by the trichomes. Insects, on the other hand, have s system of sensing poisonous plants to avoid them. For this reason, tomato leaves and stems are toxic to both animals and humans.

Tomato hairs not only help from attacks of diseases but sometimes they do suffer from them. in the video below I show you what tomatoes diseases they suffer from and how to deal with them.

Tomato hair help in temperature regulation

Trichomes in tomato plants are also helpful in regulating temperatures within the plant during hot and cold seasons. The plant trichomes protect it from extreme temperatures that would cause damage. During hot seasons, these features prevent excess heat from reaching the leaf surface, keeping it cool. TOMATO HAIRS also provides a larger surface area for the plant to lose heat to the environment cooling down.

In cold weather, when frost threatens in the spring or fall, the same features help keep the plant alive. They do so by acting as insulation and preventing the leaf surface from the effects of cold weather. However, trichomes cannot offer enough protection when the temperatures become extreme and the plant dies.

TOMATO HAIRS traps water within them, preventing the moisture from escaping to the immediate environment. This water helps cool the plant leaves during hot weather, giving it a more conducive internal environment.

The levels of humidity in the atmosphere also determine the amount of water the plant loses through transpiration. With high humidity, less water is lost. However, if the humidity is low, the plant is likely to lose more water. This is when trichomes become most beneficial to the tomato plant.

I recently wrote an article on how temperatures can affect tomato plants, If this is something you are unsure about being sure to check it out

Tomato hair offer resistance from drought

During dry seasons, tomato trichomes help keep the plant alive through a set of ways. First, the non-glandular trichomes under the ground develop into a more extensive root system, which allows the plant to absorb more moisture sustaining the plant’s survival.

This feature enables the plant to beat drought by preventing moisture loss through the leaves via evaporation in hot and sunny weather. These roots are less resistant to underground conditions. As a result, they die-off is very fast, becoming lignified and unable to function. However, as they die off, new cells start forming.

Also, during hot weather, the oil produced by TOMATO HAIRS keeps the leaf’s surface and stem moist and covered from direct sun and wind that dry up moisture. For this reason, they prolong the plant’s life during dry and hot seasons.

Moisture escaping from the leaf surface is also trapped in the TOMATO HAIRS preventing it from escaping to the environment. By so doing, these hairs reduce the rate at which water evaporates from the leaf surface through transpiration.

Tomato hair helps regulates light absorption

Studies show a need for plants to regulate the amount of light they absorb, just like water, air, and minerals. Tomato plants are affected by ultraviolet sun rays. For instance, the exposure of tomato fruit to intense sunlight causes sunscalds. However, the hairy surface helps them keep these harmful rays from reaching the leaf and stem surface.

TOMATOES, like other plants, need light to manufacture food through photosynthesis. Trichomes also help in photosynthesis; even with low light, these TOMATO HAIRS create a large surface area for trapping light.

Researchers have confirmed that tomato trichomes can synthesize and store foods for plants. Additionally, these plant organs secrete large amounts of different specialized metabolites. This means that despite being made of epidermal cells, they have structure and function as those of the plant leaves.

Protecting Tomato Trichomes during gardening

Since we are now aware of the function of tomato trichomes, you should be careful when handling tomato plants during gardening. Tomato plants can heal from minor damages; however, before recovering, the areas of injury act as entry points for viruses and other disease-causing organisms, which are likely to affect plant development and productivity. You should, therefore, avoid touching your tomato plants unless it is essential.

It’s crazy how many diseases that tomatoes can suffer from so I wrote a dedicated article on 13 of the most popular diseases and how to prevent them.

Summary

Different types of trichome cells perform various biological functions in the tomato plant. Not only do trichomes guard the plant against attack but also from other conditions such as damages by heat and cold. Trichomes increase the TOMATO plant’s resistance to drought and ultraviolet sunlight. The amount of trichomes on the plant surface directly affects the amount of heat reaching the leaf surface.

TOMATO HAIRS, therefore, affect not only the plant temperatures but also the rates of photosynthesis (production of energy) and transpiration (water loss through the plant leaves).

Additionally, trichomes help regulate the internal environment of the tomato plant by controlling the water levels in the plant. Excess water absorption can be damaging to the plant. Whenever the plant absorbs excess water from the soil, these glandular trichomes release it faster through their glands.

Tomatoes are great to grow especially if you follow the basic rules and growing methods. I wrote a detailed article on growing tomatoes at home to ensure perfect results every time. Read that here.

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Tony O'Neill

I am Tony O'Neill, A full-time firefighter, and professional gardener. I have spent most of my life gardening. From the age of 7 until the present day at 46. My goal is to use my love and knowledge of gardening to support you and to simplify the gardening process so you are more productive

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