Information on Cactus Plant

Cactus plants are native to Americas and belong to the family Cactaceae. They differ from the conventional plants, in several anatomical and physiological features. The unique feature of these plants is that they have fleshy stems, which perform the functions of the leaves and the spines, which are believed to be evolved from the leaves. The shape and size of the spines and the stems vary in different types of cactus plants. The stems of these plants can conserve water and so are adapted to arid environments. There are around 2000 species of cactus plants, with various shapes ranging from the tallest Pachycereus pringlei, which has a maximum recorded height of 19.2 meters, to the smallest Blossfeldia liliputana, which can grow up to a maximum diameter of one centimeter.

It is believed that these plants evolved in the Americas in the last 30 to 40 million years, after the continental drift, which separated the region from other continents. This explains the abundance of cactus plants in the Americas, as compared to other parts of the world. It is said that these plants were introduced to the arid environments in other continents by migratory birds, as seeds in their digestive tract. Later, people took up this task and introduced this plant across the globe.

Anatomy

Cactus plants grow as trees, shrubs and vines and some of them are epiphytic (a plant that grows upon another plant). Except the sub-family Pereskioideae, almost all cactus plants have no leaves or possess very small leaves. The spines are modified leaves, which protect the plant from being eaten by animals. Various species of cactus plants have different types of spines. The spines can be sharp or blunt, soft or hard, long or short, and with straight or hooked tips. They are found in groups, growing on mount-like structures called areolas. Generally, areolas are seen in regular patterns on the stem of these plants, but in some species, areolas merge to form ribs, which extends through the entire stem. Spines are of two types: the stronger, longer and more pigmented central ones, which sometimes possess hooked tips; and the straight, scattered radials.

The succulent and enlarged stems of the cactus plants carry out photosynthesis. The stems also perform the function of storing water. Most of the cacti possess a cylindrical or spherical shape, which reduces the surface area of the plant. This helps them to lessen water loss through evaporation. The stems have a thick, wax-like coating, which once again prevents water loss. Almost all cacti possess a shallow root system that grows close to the surface ground. For example, a very small saguaro cactus plant, with a height of 12 centimeters has a root system covering a diameter of 2 meters and none of the roots are more than 10 centimeters deep. In case of a fully grown saguaro, the root system can grow up to 15 meters in length. Taproots (long, straight roots that grows vertically downward) are found in large columnar cactus plants, mainly for the purpose of anchoring and for collecting water and nutrients.

Almost all cactus plants bloom and most of them have showy flowers with bright colors ranging from white to yellow, orange, red, or lavender. Flowers develop from the areolas and are generally, short-lived. Various species have flowers with different shapes and their size can be between 0.2 to thirty centimeters. In some plants, flowers bloom in the night. The short life of the flowers helps the plants in preventing water loss through the soft petals. These flowers are pollinated by pollinators like moths among other insects, small animals, and bats. The fruits of the plants are like berries, which can have a length of 0.4 to 12 mm. These fruits carry seeds and some species have around 3000 seeds in one fruit.

Reproduction

The flowers of the cactus plants possess both male and female parts. The pollen from the male part is transported to the female part by pollinators, thereby fertilizing the female egg cell. The fertilized egg cells produce fruits and these fruits are scattered by animals, birds, wind and rain. Some of the cactus plants can reproduce both sexually and asexually. In case of asexual reproduction, stems with weak joints fall off from the plant. Due to its water retention capacity, it can survive for long periods and if the conditions are right, it can grow roots and form a new plant by developing new stems. The growth rate is very slow in the cactus plants. In case of young plants, minimum one year is required to grow up to a height of 2.5 centimeters and older plants may grow 3 to 4 inches in the same period. The life span of these plants ranges from 25 years to 300 years, varying according to the species.

Cactus plants are used by human beings for a variety of purposes. While the fruits of some cactus plants are edible, the stems of some species are fried and eaten. Some cacti are of pharmaceutical importance, whereas some others are used as wood for construction. In some parts of the world, these plants are grown as fence to ward off animals from crops. Above all, some species of cacti are grown as exotic plants for ornamental purposes. You can also be the proud owner of one such beautiful plant and enhance the beauty of your garden.