Embryogenic cell suspension cultures of Pinus caribaea var. hondurensis have been cryopreserved in liquid nitrogen for up to four months, using sucrose and dimethylsulfoxide as cryoprotectants. Post-thaw growth was obtained after a short lag phase. Removal of the remaining liquid around the cells using a filter disc favoured subsequent regrowth of the cells. These reestablished cultures maintained an embryogenic potential similar to non-frozen cultures. The embryos produced were able to regenerate into plants, which are now growing in a greenhouse.
The effects of photoperiod on the development of in vitro grown plantlets of yam (Dioscorea alata L.), were investigated. Plantlets were transplanted into pots, acclimatizated until they reached vegetative stages V 1 (3 leaves) or V 2 (8 leaves), and then grown under 12-h or 16-h photoperiod. The formation and development of underground tubers was only induced under 12-h photoperiod. Tuber initiation was not related to the initial vegetative stage of plants, and the tubers were visible at about 18 -24 d. On the contrary, a 16-h photoperiod inhibited tuber formation and stimulated vine and leaf growth. The total dry matter production and the number of leaves per plant of V 1 stage plants were 50 and 30 % lower respectively, after 44 d under 12-h compared to 16-h photoperiod. These parameters were not influenced by photoperiod in V 2 stage plants. Consequently, the effect of 12-h photoperiod on dry matter of V 1 plants was attributed to a source limitation related to the early initiation of tuberization. The transfer of plants grown under 12-h to 16-h photoperiod stopped tuber growth and starch accumulation. On the other hand, it stimulated the shoots and the roots to grow.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.