Tissue culture of ornamental cacti

Abstract

Cacti species are plants that are well adapted to growing in arid and semiarid regions where the main problem is water availability. Cacti have developed a series of adaptations to cope with water scarcity, such as reduced leaf surface via morphological modifications including spines, cereous cuticles, extended root systems and stem tissue modifications to increase water storage, and crassulacean acid metabolism to reduce transpiration and water loss. Furthermore, seeds of these plants very often exhibit dormancy, a phenomenon that helps to prevent germination when the availability of water is reduced. In general, cactus species exhibit a low growth rate that makes their rapid propagation difficult. Cacti are much appreciated as ornamental plants due to their great variety and diversity of forms and their beautiful short-life flowers; however, due to difficulties in propagating them rapidly to meet market demand, they are very often over-collected in their natural habitats, which leads to numerous species being threatened, endangered or becoming extinct. Therefore, plant tissue culture techniques may facilitate their propagation over a shorter time period than conventional techniques used for commercial purposes; or may help to recover populations of endangered or threatened species for their re-introduction in the wild; or may also be of value to the preservation and conservation of the genetic resources of this important family. Herein we present the state-of-the-art of tissue culture techniques used for ornamental cacti and selected suggestions for solving a number of the problems faced by members of the Cactaceae family.

Micropropagation of two species of Micranthocereus (Cactaceae) with ornamental potential native to Bahia, Brazil

“…The latter, thus, reached greater lengths than those of M. flaviflorus (Figure 3), which were, in turn, smaller and more numerous in comparisons at the end of the evaluated period (Figure 4). Apical dominance break through apex removal is still the most efficient and widely used mode of achieving areolar activation and cactus in vitro multiplication (Rubluo et al, 2002;Pérez-Molphe-Balch et al, 2015). The usage of plant growth regulators, however, must be accommodated to each cactus species, varying according to specific genotypes (Lema-Rumińska and Kulus, 2014).…”

“…The family Cactaceae encompasses 100 genera and 1500 to 2000 species distributed in the American continent, with the exception of genus Rhipsalis, which occurs also in tropical Africa, Madagascar, islands in the Indian Ocean and Sri Lanka (Rojas-Aréchiga and Vázquez-Yanes, 2000;Pérez-Molphe-Balch et al, 2015). Its species possess great ecological and economic importance, and are under several threats of anthropic origin such as habitat destruction, predatory collection and illegal trading (Oldfield, 1997;Machado, 1999;Taylor and Zappi, 2004;Pérez-Molphe-Balch et al, 2015).…”

“…With the advent of plant tissue culture, the problems of traditional cultivation like low germination rates or difficulty in obtaining seeds, can be evaded and cacti can be multiplied in large scale and/or conserved in vitro (Lema-Rumińska and Kulus, 2014;Pérez-Molphe-Balch et al, 2015). One of the approaches provided by tissue culture is the in vitro multiplication of plants previously established in laboratory, meeting the demand of the ornamental market and indirectly protecting the integrity of natural populations (Malda et al, 1999;Pence, 2010).…”

Anatomy, Flow Cytometry, and X-Ray Tomography Reveal Tissue Organization and Ploidy Distribution in Long-Term In Vitro Cultures of Melocactus Species

“…The specialized stems play an important role in their taxonomy as their colors and shapes often provide the characteristics that distinguish subfamilies and genera within Cactaceae ( Anderson, 2001 ). Moreover, the stem is used extensively in vegetative propagation, by either removing branches or using sectioned parts as explants in tissue culture ( Lema-Rumińska and Kulus, 2014 ; Pérez-Molphe-Balch et al, 2015 ).…”

“…Some species of Cactaceae such as species of the genus Melocactus do not branch ( Machado, 2009 ). This limits opportunities for vegetative propagation, making them particularly susceptible to overharvesting during the removal of whole specimens from their natural populations for commercialization as ornamental plants ( Goettsch et al, 2015 ; Pérez-Molphe-Balch et al, 2015 ). This has led to the development of conservation strategies that rely on in vitro propagation of Melocactus species ( Resende et al, 2010 ; Torres-Silva et al, 2018 ; Santos et al, 2020 ).…”