Biology, Chemical Composition, Cultivation and Applications of Cacti from the Opuntia Genus

In this review, we approached various aspects of Opuntia sp. that are a type of forage cacti. These
plants stand out for its energy potential and have peculiar morphological and physiological features
that allow tolerance for long periods of drought. In addition, Opuntia species has a cosmopolitan
distribution, found mainly in arid and semi-arid regions. Opuntia sp. presents phenotypic variations
related to weather conditions, like polyploidy occurring in a large number of populations and high
hybridization capacity. These plants have a shrub morphological characteristic with ramifications,
variable size, from creeping until arboreal; it can reach up to 4 m high and a series of fleshy stems
with, depending on time of year, flowers and fruits. Opuntia sp. have a typical physiology with the
photosynthetic process called crassulacean acid metabolism (CAM); stomata close during the day in
order to maintain hydration of tissues. The chemical composition of Opuntia sp. varies according to
species, age of reticule, and season. These cacti have excellent nutritional value with high water
content (about 90%), digestibility in vitro (about 75%) and vitamin A; in addition, they have organic
matter (67%), energy (2,61 Mcal.kg-1), crude fiber (4.3%), phosphorus (0.08 to 0.18%), calcium
(4.2%), potassium (2.3%) and magnesium (1.4%), but shows low protein content (about 5%). The
proper yield of the crop needs a climate with 400-800 mm annual rainfall, relative humidity above 40%
and day/night temperature from 25 to 15°C. The wide variety of applications demonstrates the
versatility of this plant species, being used in food and feed, agriculture, medicine, pharmaceutical
and cosmetic industries, in water and wastewater treatments, and even as insecticide agent. Opuntia
genus comprises about 1500 species and O. ficus indica is the most important as forage and human
uses.