**2. Tropical plants: economic and nutritional importance**

Tropical plants are essential for providing food, fiber, and shelter, but they also have esthetic value because of their lovely hues, fragrances, and greens, which also have a cooling effect from evapotranspiration. They are crucial for people living not only in tropical areas but also in other parts of the world's economies, cultures, and spiritual life. For example, there are over 100 different varieties of the 400 different species of bananas that are grown in Africa alone, nearly 1 million hectares of coffee plantations in Brazil, 2 million hectares of sugarcane plantations in Hawaii, and over 3 million hectares of rice paddies in tropical regions of Asia. Compared with plants found in temperate climates, tropical plants are significantly different. They thrive in a variety of environments, but particularly in rainforests, and have evolved to

withstand extreme heat and heavy humidity. Additionally, as long as adequate water is available, many tropical plants may thrive on nutrient-deficient soils [1].

The economic value of tropical plants comes from their use in silviculture and timber production. Moreover, various species are used as sources of food, medicine, and raw materials (**Figure 1**). The esthetic value is derived from their beauty and usefulness in preserving the environment. On the other hand, they provide a vital service in maintaining soil fertility through their nutrient-rich soils and preventing erosion by providing habitats for microflora that act as decomposers of organic matter, root-dwellers, and rhizospheric antagonists [2]. Tropical plants also contribute to a variety of other services such as carbon sequestration (sequestering atmospheric carbon dioxide into biomass) by high photosynthetic rates, and water purification (through high evapotranspiration rates), and carbon capture and sequestration (through deposition of carbon on forest floors). In addition, they also provide a variety of amenities such as shade, food, and shelter for humans and animals; recreation opportunities for people; cultural heritage for indigenous civilizations; environmental education for children; protection from natural hazards such as floods and fires, and above all, biodiversity conservation.

Tropical plants contribute to the food supply, provide a source of nonfood raw materials, provide medicines, and are an essential part of human life in many cultures. They also have high nutritional content, making them an essential nutrition source for the tropics. Among nonfood products, tropical trees are rich in essential oils and resins used for cosmetics and medicines [3]. Medicinal plants such as the soapberry (*Sapindus mukorossi*) are used for treating skin ailments such as acne because it is rich in antimicrobial agents, which help to prevent bacterial or fungal infections. Other important medicinal plants include *Croton zaeus*, which has been used to treat diarrhea and other digestive disorders such as stomach aches; Passion vine (*Passiflora quadrangularis*), which contains compounds that suppress pain and Trumpet tree (*Cecropia peltata*), is known as a sort of cure-all in Caribbean folk medicine because of the long list of its uses.

#### **Figure 1.**

*Tropical plants, their sustainable cultivation, and value-added products are presented in the graphical abstract of the introductory chapter.*

#### *Introductory Chapter: Integrative Technologies for Sustainable Plant Improvement DOI: http://dx.doi.org/10.5772/intechopen.107104*

The edible plants are used to flavor foods as well as some bitter medicines and to make dyes, perfumes, medicines, and cosmetics. The medicinal plants provide relief from pain and suffering. The flowers of these plants are used to produce dyes for dying cloths or other materials. Some flowers contain potent alkaloids that can be extracted for use in therapeutics. The leaves of some tropical plants serve as fodder for animals, while others serve as fertilizer for agriculture. Being valuable food sources, some tropical plants have been grown worldwide for thousands of years including peanuts, potatoes, cocoa beans, and rice, and now have become essential crops owing to a source of nutrition because of richness in a wide range of vitamins and minerals in addition to having high amounts of protein, dietary fiber, and low-fat levels. Further, these plants help to prevent chronic diseases such as heart diseases and cancer by reducing free radicals that cause oxidative stress due to the presence of antioxidants in them. High fiber contents help in digestion and prevent constipation that reducing the risk of colon cancer by preventing inflammations of the digestive tract. High levels of vitamin C in many tropical fruits such as papaya, mangoes, mangosteen, etc., help to boost immunity against common infections. Vitamin C also protects against oxidative stress caused by free radicals, which may lead to cell damage or death if left unchecked [4].
