Effects of reducing sugar concentration on in vitro tuber formation and sprouting in yam (Dioscorea cayenensis–D. rotundata complex)

Abstract

The effects of reducing sucrose level on tuber formation (% of cultures with microtubers), development (length and fresh weight of microtubers) and sprouting in yam Dioscorea cayenensis-D. rotundata complex in vitro were investigated. Only 29% of the explants showed tuber formation after 3 weeks in the presence of 1% sucrose in contrast to 100% with 3%. After 120 days of culture, the length and the weight of the tubers obtained in the presence of 1% sucrose were less than with 3% sucrose. Addition of sorbitol to keep osmolarity at the same level did not restore normal rate of tuber formation. Similar results were obtained with the use of reduced fructose or glucose level. Microtuber sprouting was also affected by sucrose level incorporated into the tuberisation medium. Tubers obtained on reduced sucrose level sprouted later and the increase of osmolarity with sorbitol did not restore normal sprouting. The bigger tubers obtained on high sucrose media could contain more carbohydrate reserves that could partially explain a higher sprouting rate. These results can be used for optimising in vitro conditions for mass production of microtubers in yam and especially in Dioscorea cayenensis-D. rotundata complex, a very important species in West Africa. They specially showed the importance of tuberisation conditions on precocity of tuberisation, on tuber length and weight and on their further sprouting.

Connaissances endogènes et perceptions paysannes de l’impact des changements climatiques sur la production et la diversité du niébé (<i>Vigna unguiculata</i> (L.)Walp.) et du voandzou (<i>Vigna subterranea</i> (L) Verdc.) au Bénin

“…La sécurité alimentaire et la lutte contre la pauvreté constituent une préoccupation de la plupart des pays du monde (Ondo, 2009). Dans plusieurs pays de l'Afrique subsaharienne, l'agriculture est un secteur majeur de l'économie et son intensification et diversification restent une priorité (Eromosele et al, 2008).…”

In vitro acclimatization of <i>Curcuma longa</i> under controlled <i>iso</i>-osmotic conditions

“…Thus, the mini-rhizome and microrhizome formation in response to sugar classes and concentration in the culture medium depends on plant species. Tuber formation, size and fresh weight in acclimatized plantlets of yam under 3% sucrose was maximized after transplanting for 60-120 day (Ovono et al 2009), whereas 6% sucrose or 8% maltose was required for cocoyam (Xanthosoma sagittifolium) for mini-tuberization (Djeuani et al 2014). The secondary metabolites, BIS, DEM and CUR, in mini-rhizomes of wild turmeric plantlets acclimatized under 3% sucrose were highest, whereas micro-rhizome formation (>50%) and fresh weight (>0.025 g) were maximized in 5-9% sucrose (Wu et al 2015).…”

Seasonal Variation in Transcriptomic Profiling of Tetrastigma hemsleyanum Fully Developed Tuberous Roots Enriches Candidate Genes in Essential Metabolic Pathways and Phytohormone Signaling

“…For example, an increase in the level of AGPase has been shown to enhance biomass and yield in cassava tubers (Ihemere et al, 2006). Sucrose is not only one of the main photoassimilates but also a driving force for the formation and growth of TR (Ovono et al, 2009). It has been reported that a high sucrose level is required for in vitro induction of TR in sweetpotato (Tsubone et al, 2000).…”