Phytotomy or plant anatomy has shown us the wonders of the botanical world. Every detail from the roots, stem, leaves, flowers, petals, sepals, fruits, and seeds has its substance. But the divinity of nature does not end here. Each of these parts is further complicated into a mesh of networks exclusive to it.
The root system of plants is one such example. Roots absorb water and minerals from the soil to nurture the entire plant while anchoring it sternly to the ground. The root system of plants is subdivided into 2 categories. These are; Fibrous Roots and Tap Roots. Fibrous roots have three types of modifications; Adventitious Roots, Prop Roots, and Stilt Roots.
A Fibrous Root is formed by intricate, thin, branching roots arising from the stem. A fibrous root system is exclusive to monocots/monocotyledons, the plants whose seeds consist of one embryonic leaf. The fibrous root system does not penetrate deep into the soil, however, some are entirely vertical and form deep anchoring roots. This enables the plant to eliminate the risk of erosion by harboring to the top layer of the soil.
A large variety of plants possess fibrous root systems.
The mighty Banyan tree that could not survive if it had a single root structure. It grows horizontally with hundreds of fibrous roots holding on to the soil and supporting its massive size. These trees live up to more than 1000 years and therefore, require a sturdy anchoring system.
The second fibrous plant is Sugarcane. Sugarcane belongs to the stilt root modification of the fibrous root system. These roots provide strength to those plants that attain a great height but have a thin stem. These roots appear from the basal nodes near the soil.
The all-time favorite Sweet Potato plant also possesses a fibrous root system. Here the modification that the roots take up is the adventitious type. Adventitious roots are fleshy and they swell up to preserve more water for the plant. Asparagus and Dahlia plants have tuberous types of adventitious roots that store starch in them.
Screw Pine (Pandanus), grown for its edible fruit has a stilt root system that helps it to achieve the tall height with added strength from the roots. One of the most widely distributed of the world's food crops, Corn (Zea Mays) also has stilt types of roots. Their stems are thin because of which they have to rely on the robust root system.
Grass has fine, thin roots and branches which resemble fibrous roots. These roots have a special name called 'surface feeders' because they do not penetrate deep into the soil. Orchids are eccentric plants with beautiful flowers. They have thickened adventitious roots and form finger-like projections due to this modification.
Basella, the common spinach, has beads like roots that are distended at equal distances. The perennial succulent, Portulaca is a flowering plant and also edible. These plants also have fibrous roots. Money Plant is a common household name. It has beautiful climbing roots that are often wound around furniture, walls, etc for beauty. These climbing roots are non-absorptive adventitious roots that help these climbers gain anchoring strength.
The 'tree of life'Coconut Palm has a root system that consists of an abundance of thin roots that grow outward from the plant near the surface. Rosemary plant also has a fibrous root system. In this case, the roots can penetrate much deeper into the soil to extract water by this drought-tolerant plant. A Banana Tree has a dense network of fibrous roots forming a 'Mat'. These roots can go as deep as 5 feet and their horizontal span can be up to 30 feet.
The customary vegetable, Onion has a fibrous root system consisting of 20 to 200 shining white thick roots. The horizontal spread of these roots is about 12 to 18 inches on all sides of the plant, whereas the depth can be up to 39 inches. The shallow root system makes it prone to drying out, therefore, watering should consist of thorough soaking of the soil up to 6 inches deep. The most common staple food Wheat also belongs to this category. Wheat is cultivated on larger land areas than any other food crop. There are two types of root systems in wheat. A seminal (seeds) roots system and a nodal (adventitious) root system.
The hefty Bamboo Trees also have fibrous root anatomy. Contrary to its towering height and enormous strength, its roots are very shallow. They only penetrate around 6 inches below the soil. However, there are some feeder roots as well that pierce the soil at a deeper level.
A rather unconventional example is that of Course Trees. Their root system begins as taproots to maximize stability. As the tree grows and its canopy spans around, the roots start to stretch too, ultimately forming a fibrous mat. Wildflowers such as Burr Medic possess the same network of roots. It is an annual legume plant with thin and weak stems. The roots are the main reinforcement source. Its roots grow from nodes.
What makes the fibrous roots so different from taproots that we needed an entire classification? Well, fibrous roots are found in monocots whereas taproots are found in dicots such as trees, most flowering plants, and shrubs. Fibrous roots are almost hair-like, very fine, and thin. Taproots, however, have a primary thick stem from which arise the lateral secondary or tertiary branches. Also, the taproots only develop from the embryonic root, whereas fibrous roots can originate from either stem or leaves.
Another important difference is the depth of roots in both systems. Fibrous roots, as evident from the above examples, are shallow and adhere only to the top layer of soil. They can be underground as well as aerial. In contrast, taproots are deep-rooted. They cannot be aerial. They are persistent underground anchoring roots. This depth of taproots allows them to withstand tough drought-like conditions as they can extract water much deeper from the soil. On the other hand, fibrous roots do not own this ability. They grow near the soil surface and cannot absorb water from deeper layers which makes them less drought-tolerant.
A single plant can have only one tap root whereas hundreds of fibrous roots can be present in a fibrous plant. The sturdiness makes plants with taproots difficult to pull out but the fibrous plants can be easily plucked from the soil for example onions.
The type of root system dictates how to treat a plant. Fibrous roots help prevent soil erosion and are excellent in their water and nutrient absorbing capability. Fibrous roots are nurtured by frequent watering but with less water each time. The shallow roots also require a good mix of fertilizer but again, in minimal quantities as we only have to enrich the top layers of soil. The fertilizer should be provided at regular close intervals as the thin roots can not hold much onto the nutrients they absorb. However, even a light rainfall is very beneficial for fibrous plants as the shallow roots can glean enough water from it.
It should be kept in mind that overwatering and excess fertilizer can harm the fine roots. Adequate harvesting seasons should be known and the plants must not be disturbed as the roots can shatter, leaving the plant decayed.