Coconut Callus Initiation for Cell Suspension Culture

Abstract

The development of a cell suspension culture system for the scaling up of coconut embryogenic callus (EC) production would drastically improve efforts to achieve the large-scale production of high-quality clonal plantlets. To date, the hard nature of coconut EC appeared to be the main constraint for developing cell suspension cultures. Hence, this study attempted to acquire friable EC through the following approaches: The manipulation of (1) medium type and subculture frequency, (2) a reduced 2,4-dichlorophenoxy acetic acid concentration during subculture, (3) the nitrate level and the ammonium-to-nitrate ratio, and the addition of amino acid mixture, (4) the addition of L-proline, and (5) the reduction of medium nutrients. Unfortunately, none of these culture conditions produced friable coconut EC. Even though friable EC was not achieved via these approaches, some of the conditions were found to influence the formation of compact EC, therefore these results are important for further studies focused on somatic embryogenesis in coconut and other species.

Effects of Amino Acids on Callus Proliferation and Somatic Embryogenesis in Litchi chinensis cv. ‘Feizixiao’

“…Pintos et al [35] found that a mixture of three AAs (Gln, Arg, and Asn) or GABA alone could promote embryonic development, while these three AAs alone did not significantly promote embryo induction. Kong et al [36] found that a mixture of AAs (685 µM Gln, 574 µM Arg, and 667 µM Asn) promoted coconut callus formation. Maruyama et al [37] found that the AAs mixture (Major AA: 2 g•L −1 Glu, 1 g•L −1 Asp, and 0.5 g•L −1 Arg; Minor AA: 0.158 g•L −1 citrulline (Cit), 0.152 g•L −1 Orn, 0.11 g•L −1 Lys, 0.08 g•L −1 Ala, 1 g•L −1 Asp, and 0.5 g•L −1 Arg) significantly promoted embryo maturation and increased the number of mature cotyledon embryos by more than 27 times.…”

The Influence of Maturity, Storage, and Embryo Size on Coconut Callus Induction Success

“…Embryogenic callus (Figure 3a) has the capacity of generating somatic embryos, which are distinguished by their smooth, translucent, and clearly defined somatic structure. On the other hand, the non-embryogenic callus (Figure 3c) exhibits a rough, yellowish, and sponge-like appearance [14]. Non-embryogenic callus refers to a type of callus in plant tissue culture that does not possess the ability to develop into embryos.…”

“…In vitro methods (micropropagation, embryo culture, and protoplast-based approaches [13]) were created to address this issue. The induction of calluses during the micropropagation process is one of the most important stages in somatic embryogenesis, directly linked to the final multiplication rate [2,14]. The micropropagation of the coconut palm is influenced by various factors, including the composition of the culture medium, the type of explants used [15], the presence of plant growth regulators, heterogeneous responses, and the acclimatization procedure [16].…”

Phytosulfokine contributes to suspension culture of Cunninghamia lanceolata through its impact on redox homeostasis

“…However, embryogenic calli are normally induced to form somatic embryos and develop into whole regenerated plants on a solid medium during indirect SE, which cannot be used for large-scale propagation due to the insufficient regeneration efficiency and the poor synchrony of somatic embryo development [ 6 ]. An alternative method is to culture and propagate embryogenic calli in liquid medium, namely, with an embryogenic cell suspension culture system that has been well established for mass proliferation in many plant species, such as Euonymus alatus , coconut, and date palm [ 7 – 9 ]. In addition, embryogenic cell suspension culture together with successive plant regeneration systems via SE has provided an ideal platform for genetic transformation in multiple species, such as in citrus, Coffea arabica , and Liridoendron [ 10 – 12 ].…”