**3. Tropical ecosystem**

Tropical plants grow in a wide range of habitats, from the equator to the tropics. They thrive in warm weather and grow in rainforests, deserts, and even on mountainsides. The problems of deforestation, soil degradation, and changing climate pose serious threats to tropical ecosystems including forestry and agriculture sectors. This resulted in an average decline of 15.8 million hectares of tropical trees since 2017. If the issue remains unattended, it will erode social-ecological resilience in the tropics and will ultimately result in self-propagating feedback and regime shifts. Various factors including climate change and soil erosion pose a negative impact on the stability of natural ecosystems. Moreover, the seasonal, interannual, and decennial climatic fluctuations badly affect the vegetation dynamics in these areas. Land degradation is also more noticeable in the tropics, and it affects biodiversity and soil characteristics. The major causes of land degradation are anthropogenic [5]. Hence, sustainable management of natural ecosystems has been recommended as the only way to control factors affecting the stability and preservation of tropical ecosystems. Sustainable use encompasses the management and use of natural resources including tropical natural resources. They can sustain their natural biodiversity, yield, renewal capacity, vitality, and capacity to satisfy the relevant ecological, economic, and social functions at local, national, and global levels, and that they do not cause damage to other ecosystems. This reflects contemporary discourse in sustainable development and governance, which emphasizes the importance of public-private and civil society partnerships, with the potential to bridge multilateral norms and local action by drawing on a diverse number of actors in civil society, government, and business [6].

### **4. Evolution and diversification**

The tropics comprise the geographic regions of the earth centered on the equator. They exhibit substantially variable landscapes ranging from deserts to rainforests and from hot lowlands to snow-capped mountains. Hence, we can find a variety of ecosystems in tropical regions with extreme climatic conditions along with a rich diversity of living organisms including plants, animals, and microbes.

Tropical plants are proposed to be originated 93–115 million years ago yet the rate of diversification increased dramatically during the last 15 million years. Hence, the tropics are considered a diverse rich region with a huge number of crop plants including cereals such as maize, rice, sorghum, and millet; tuberous crops such as potato, sweet potato, and cassava; vegetables such as tomato, peppers, many cucurbits; cash crops such as cocoa, rubber, tobacco, cotton; fruits such as banana, pineapple, mango, papaya; and other crops such as peanut, common beans, oil palm, coconut, sugarcane, and coffee. It is estimated that two-thirds of all angiosperms including crop as well as non-crop plant species are found within the tropics. Moreover, rich biodiversity of plants other than angiosperms such as Ferns [7], bryophytes, and liverworts are found highly concentrated in the tropics. The dispersal of plant species in tropical areas is not uniform. The Neotropical areas and the region of Asia Pacific are the most biodiverse while Africa and oceanic islands contain the least biodiversity. The tropical hyper-diversity is not well understood, and it has variously been attributed to be a *museum of diversity*, showing constant speciation and low extinction [8], or a *cradle of diversity*, referring to more recent and rapid speciation [9].

#### **5. Tropical plant species—as an ornament**

Tropical plants, with unique colors, shapes, and fragrances, have a great esthetic value and hence are very popular among culturists, collectors, hobbyists, and even enthusiasts. They not only lift the spirit of the room and indoor environment, uniquely and refreshingly but also make us feel alive, lively, and fresh. The craze for growing these housing plants has accelerated to multifold during the COVID pandemic particularly. Tropical flowering plants have enchanting colors and are key elements in the beautification of any landscape. The most popular tropical flowers are Amaryllis, Paper flower, Garden cosmos, Flamingo flower, Bush lily, and Ohe naupaka, etc. Though, most of the indoor plants available in nurseries are either grown by cuttings or seeds. However, these conventional techniques are slow and the resultant plants are susceptible to diseases. A valuable alternative is the use of tissue culture techniques for the mass production of disease-free plants [10]. The plants developed through tissue culture have uniform growth, hence providing rapid mass production of disease-free plants, off-season propagation, mass production in limited space, and can overcome the challenges of cultivating plants by traditional propagation techniques.

Researchers have worked out different protocols for the mass multiplication of these flowering plants. Different combinations of growth hormones and culture conditions were optimized for the establishment of *in vitro* regeneration and micropropagation. Different explants (leaf disc, mature embryos, and bulb scale) were tested in Amaryllis and other tropical flowers. Different varieties of hardy ornamental tropical plants have been explored, i.e., Bamboo (Goldstripe, Ghost bamboo, Slender weavers, and Chinese dwarf), Colocasia (Pink china), Hibiscus (Berry awesome, Perfect storm, and Cranberry crush), Bird of Paradise (Mexican bird of paradise), Palms (Dwarf Palmetto, Kumaon, Chusan, Miniature Chusan palm and Windmill), Canna (Peach, Stuttgart, Gigantum and Skyhawk), Hostas (Abiqua drinking gourd, Lakeside shore master and Dancing queen), and Ferns (Lady fern, Western sword fern, and

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

Christmas fern). Over the years, numerous researchers have tried to manipulate bamboo flowering and seed sets under *in vivo* and *in vitro* conditions [11]. Two different polyploidy groups were found to be present in woody bamboo. Tropical bamboo is hexaploid, whereas temperate bamboo is tetraploid. Likewise, different molecular markers have been employed to explore genetic diversity. Using these markers, it has been elucidated that lowland *bamboo* is associated with distinct geographic regions. Genetic diversity among the ornamental palm accessions helped to explore their origin, genetic identification, and conservation [12]. Some other prominent indoor plants, i.e., spider plants, African violet, baby rubber plant, and weeping fig had also been worked out to overcome existing bottlenecks in propagation.
