Histodifferentiation and ultrastructure of nodular cultures from seeds of Vriesea friburgensis Mez var. paludosa (L.B. Smith) L.B. Smith and leaf explants of Vriesea reitzii Leme & A. Costa (Bromeliaceae)

Abstract

Micropropagation via induction, multiplication and development of nodular cultures (NCs) is an efficient regeneration system for Bromeliaceae, a family of endangered monocot plants with ornamental value. Therefore, the present work aimed to induce NCs from seeds and leaf explants of Vriesea in order to characterize the morphological and histochemical aspects of induction and formation of these cultures. Seeds of Vriesea friburgensis var. paludosa were sterilized and inoculated into liquid culture media supplemented with different concentrations and combinations of growth regulators. Leaf explants of Vriesea reitzii were inoculated into medium supplemented with 4 μM α-naphthalene acetic acid (NAA) and 2 μM 6-benzylaminopurine (BAP). The addition of NAA (4 μM) in the culture medium used for seeds led to an induction rate of 72% in NCs. First, the embryo began to germinate, and afterwards, nodular structures started to form. While NCs formed from seeds is associated with root and shoot meristems, the formation of NCs from leaf explants involves the intercalary meristem. Meristematic cells generate an appropriate response in the induction medium, producing NCs by the proliferation of small cells with meristematic characteristics and large vacuolated cells. These results provide a better understanding of morphogenetic responses in bromeliads and, hence, the opportunity to develop optimized micropropagation protocols.Abbreviations: BAP, 6-benzylaminopurine; 2-iP, N6 (2-isopentyl) adenine; CBB, Coomassie Brilliant Blue; CLSM, confocal laser scanning microscopy; MSB, MS basal medium; NAA, α-Naphthalene acetic acid; NCs, nodular cultures; PAS, Periodic Acid-Schiff; SEM, scanning electron microscopy; TDZ, N-phenyl-N’-1,2,3-thidiazol-5-ylurea; TB-O, Toluidine Blue O; TEM, Transmission electron microscopy.

Protuberances are organized distinct regions of long-term callus: histological and transcriptomic analyses in kiwifruit

“…The regular cell composition on the surface in comparison with regions beyond the PT, the presence of starch granules, and the shoot buds arising on the PT can be mentioned as the most relevant. These features are similar to the histology of protocorm-like bodies or the multiple meristem-like tissues observed in Orchidaceae (Zhao et al 2008 ; Chen et al 2019 ) and nodular cultures in Bromeliaceae (Corredor-Prado et al 2015 ). However, the histological organization of PT in kiwifruit also resembles PT observed in other woody vines— Passiflora edulis (Fernando et al 2007 ).…”

“…The relationship between the appearance of PTs or outgrowths and the emergence of primordia-like structures or shoot buds has been observed during tissue culturing of different species (Nakano and Maeda 1974 ; Jarret et al 1981 ; Fernando et al 2007 ; Daffalla et al 2011 ; Qiao et al 2012 ; Tekdal and Cetiner 2013 ; Manivannan et al 2015 ; Lee and Pijut 2017 ). However, morpho-histological data about organogenic calluses are focused mainly on structures referred to as protocorm-like bodies (Zhao et al 2008 ; Palama et al 2010 ; Chen et al 2019 ) or nodular structure formation (Oka et al 1982 ; Rocha et al 2012 ; Corredor-Prado et al 2015 ). Histological and ultrastructural studies describing the origin and different stages of in vitro morphogenesis have contributed significantly to the understanding and optimization of regeneration systems (Rocha et al 2012 ).…”

Dynamics of proteins, carbohydrates and global DNA methylation patterns during induction of nodular cluster cultures from seeds of Vriesea reitzii

“…In this context, NAA in the culture medium altered the seedling development for NCs induction. Other studies have reported the effect of auxins combined with cytokinins, which also caused NCs induction from Vriesea seeds but at lower percentages (Dal Vesco et al, 2014a;Corredor-Prado et al, 2015). In morphogenetic routes, such as somatic embryogenesis, several steps including dedifferentiation and somatic cells reprogramming, are necessary for the initiation and progression of development programs (Zhang & Ogas, 2009).…”

“…NCs are defined as groups or conglomerates of organogenic nodules with high regenerative efficiency Dal Vesco et al, 2011). Strategies for induction of NCs in bromeliads include nodal segments (Dal Vesco, Stefenon, Welter, Guerra, & Scherer, 2011), leaf segments (Alves, Dal Vesco, & Guerra, 2006;Scherer et al, 2013;Dal Vesco, Vieira, Corredor Prado, Guerra, & Elter, 2014b) and seeds (Dal Vesco, Pescador, Corredor Prado, Welter, & Guerra, 2014a;Corredor-Prado et al, 2015). This work has established a system of NCs induction and regeneration of shoots in response to different types and combinations of plant growth regulators (PGRs).…”

“…Other studies regarding NCs multiplication and differentiation to microshoots are related to GDM levels (Scherer, Fraga, Klabunde, Silva, & Guerra, 2015) and genetic analysis using amplified fragment length polymorphism (AFLP) markers (Dal Vesco, Stefenon, Welter, Steiner, & Guerra, 2012;Scherer et al, 2015). On the other hand, characterization of the NCs induction process has been focused on morphological and anatomical alterations (Corredor-Prado et al, 2015). Biochemical and epigenetic alterations have not been evaluated.…”