Introduction To Cactus
A member of the plant family Cactaceae, Cactus, plural cacti, derives from the ancient Greek name ‘Kaktos’. Cactaceae comprises of about 127 genera with approximately 1750 species of the order Caryophyllales. Cactus is present on earth in a vast variety of shapes and sizes.
Cactus is known to be found in the well-adapted dry regions but few species are also found in the tropical and subtropical regions. Their roots and stems are the reason for their survival in the great drought conditions. There are many species of Cactus which are even found in the Atacama Desert which is one of of the driest place known on the earth. Cactus has thickened fleshy parts which are adapted to store water.
Cactus is native to North and South America. Some species of genus Rhipsalis occur in East Africa, Madagascar, and Sri Lanka.
In this lesson, we will learn about the Cactus Root System along with its uses and some interesting facts about Cactus all over the world. Let us begin with
Genus – Nearly 100 genera including 1000-2000 species.
- Cactus belongs to the Cactaceae family.
- Cactus requires a very strong and good amount of light, especially during winters, for its survival.
- Most of the species of Catus have lost true leaves. The leaves are modified into the spines which can be observed on the stems. These spines help in storing water in the steams by reducing the amount of transpiration.
- Cactus is a part of the Succulent family because it has fleshy stems which store water. But for the succulent plants to be called Cactus, they need to have a special structure which is present in the Cactus family. We can distinguish cacti from other succulent plants by the presence of areoles.
- Areoles are cushionlike structures on the stem on which plant hair, better known as trichomes, and spines or barbed bristles grows. These Areoles are modified branches from which branches, leaves and flowers may also grow. They’re unique to the Cacti and often appear like wool because of the presence of the spines around it.
- Cactus is a perennial plant. Stems of Cactus are wide, thick and contains a good amount of Chlorophyll. Since the leaves of these plants are reduced to spines in order to decrease the surface area for the evaporation of water, the stems hold the responsibility for the photosynthesis.
- Some Cactus grows in the soil while others either grow on other plants (epiphytes), rocks or on the trees.
- Cactus in the wild grow up to 100 years while the Cactus grown indoors lives up to almost 10 years.
Based on their growth habits, Cacti have multiple categories out of which few are describes below,
- Arborescent Cacti
Those Cactus which are a tree-like that is they have a single more or less woody trunk topped by several to many branches. For example, Echinocactus platyacanthus, Stenocereus thurberi.
- Columnar cacti
These are the smaller cacti and are known as columnar because of the shape of their stem, that is, erect or cylindrical. For example, Cephalocereus senilis, Stenocereus eruca.
- Globular cacti
The cactus having smaller stems can be categorized as globular or globose. For example, Ferocactus latispinus.
Those Cactus which have few or even no spines and have their stem as typically flattened. These Cacti grow on other plants.
Cactus root system
Cacti generally have a kind of root system which spread widely but less deep. They have fibre like roots which are specialised to absorb the surrounding moisture more easily. They penetrate quite a short distance into the soil. For example, a young Saguaro has a root system with a diameter of 2m while having a height of 12cm but it 10cm of depth. This wide root system is the main factor behind its successful survival in the harsh weather conditions and scarcity of water.
Most Cacti have fibre-like root system which spread on in the vicinity of the plant, that is, not penetrate deep into the soil. But some species have Taproot system which has larger thicker roots penetrating into the ground.
Functions of roots in Cactus are that they absorb water and nutrients from the soil and also store food and water like the stems of succulent plants. Roots hold great importance for the Cactus plants as these plants tend to grow in drought areas where water is rarely present. So in order for the plant to survive, the roots system needs to stay strong. If the roots are destroyed either by disease or incests, the plant does not survive for long.
Different kinds of the root system which cacti possess are explained below:
A long, strong taproot is sent down by many cacti right after germinating. A taproot anchors a plant from washing away during storms and conducts deeper subsurfaces soil layers with more moisture. Taproots are mostly found in the genre Copiapoa.
For example, Mexican Cereus ( Pachycereus pringlei ) and Saguaro (Carnegiea gigantea) both of which are giant tree-like cacti of the Sonoran desert.
Lateral Roots are those roots which can branch repeatedly as they grow. Some Cacti which doesn’t have tap roots rely on Lateral Roots to harvest food and water and
to hold them in place
There are some cacti which can store water and food in succulent roots as well as in their stems. Succulent roots are enlarged roots which can weight from 5 to 60 pounds. Secondary wood or the xylem tissue is the part of the root that becomes enlarged.
Epiphytic Cacti that grow among tree branches posses aerial or adventitious roots. Orchid cacti ( Epiphyllum sp.) and night-blooming cereus (Hylocereus undatus) are some types of epiphytic cacti. The roots which emerge from the sides of the stems are fleshy and are there to anchor the climbing cactus stems to the trees or rocks supporting the plant
Uses Of Cactus
- Cactus protects brain cells and also fights cancer cells.
- Cacti are also used as ornamental plants.
- Cacti are known to possess psychoactive agents which can be helpful for people dealing with mental illness.
- Cacti are used for human food and after burning off their spines they can be used as fodder too.
- Living cactus fences are employed as barricades around buildings to prevent people from breaking in.
- Prickly Pear, an important variety of cactus is used for type 2 diabetes, high cholesterol, obesity, colitis, diarrhoea, benign prostatic hypertrophy etc
Interesting Facts about Cactus
- The highest Cactus ever recorded was almost 6 stories tall.
- Overwatering Cactus will kill them.
- Saguaro Cactus a very unique variety of cacti, It can take up to 10 years to grow an inch and 200 years to grow full size.
- Dragonfruits are a kind of Cactus,
- Bats Pollinates the organ pipe cactus (a type of Cactus).