Changes in the starch content during organogenesis in in vitro cultured Begonia rex stem explants

Abstract

Stem explants, excised from greenhouse‐grown Begonia rex plants, were cultured on basal medium (T. Murashige and F. Skoog, Physiol. Plant. 15: 473–497, 1962) contained in sterile Petri dishes. The medium was supplemented with benzyladenine (0.1 mg 1−1) naphthaleneacetic acid (0.01 mg 1−1) and, according to experimental requirements, with either sucrose (3%) or mannitol (3%). Histochemical and biochemical examination of the starch content of the explant was carried out over several days. There was no starch deposition or organogenesis in tissue cultured on mannitol and carbohydrate‐free growth medium. The most dramatic finding was the heavy accumulation of starch in tissue cultured on sucrose medium. This copious accumulation preceded any organ formation and was mainly in regions which ultimately gave rise to shoot primordia. The heavy build‐up of starch preceding organogenesis was also observed when explants previously cultured on mannitol medium were transferred to medium containing sucrose. During shoot primordia development there was a decrease in the starch content of the cultured tissue indicating the utilization of the polyglucan in the organogenic process.

Efficient cryopreservation of adventitious shoots of Begonia x erythrophylla using encapsulation–dehydration requires pretreatment with both ABA and proline

“…It has been suggested that mannitol can modify the physical and chemical properties of alginate beads, resulting in mechanical compression damage to shoot apices (Paul et al 2000). In addition, mannitol has been shown to inhibit adventitous shoot formation in B. Rex petiole explants cultured on a SIM (Mangat et al 1990). This inhibition was thought to be due to reduced starch synthesis during the early stages of organogenesis.…”

Chloroplast ultrastructure and hormone endogenous levels are differently affected under light and dark conditions during in vitro culture of Guadua chacoensis (Rojas) Londoño & P. M. Peterson

“…Previous studies (Mangat et al 1990;Sulpice et al 2009; Lee and Huang 2013) demonstrated the relationship between the starch granules formation in response to sucrose supplementation to different species in in vitro cultured, and in both organogenesis and somatic embryogenesis morphogenetic routes. Mangat et al (1990) related that during Begonia rex organogenesis, with 3% sucrose supplementation, starch accumulation was observed in the first days of culture, with a maximum in about 4-6 days. These starch granules decreased as the shoots were under development, thus suggesting that starch was used as energy source during in vitro morphogenesis.…”

Cytokinin, auxin, and abscisic acid affects sucrose metabolism conduce to de novo shoot organogenesis in rice (Oryza sativa L.) callus

“…Sucrose is the main carbohydrate supplemented into the culture media and prominently acts as an energy source and osmotic requirement during organogenesis (Verma and Dougall, 1977; Thorpe et al, 1986; Iraqi et al, 2005; Huang et al, 2006; Feng et al, 2010; Silva, 2010). The correlation between starch metabolism and shoot regeneration was also reported in tobacco (Thorpe et al, 1986), sugarcane (Ho and Vasil, 1983), Begonia (Mangat et al, 1990) and rice (Huang et al, 2006). However, little is known about the signals to trigger sucrose metabolism in cultured cells, especially at the gene expression level.…”