CiteULike: toadfrog's pine

Plant regeneration from callus cultures derived from mature zygotic embryos in white pine (Pinus strobus L.).

W Tang — 2006-07-20T14:35:01-00:00

Plant Cell Rep, Vol. 24, No. 1. (April 2005), pp. 1-9.

Plant regeneration via adventitious shoot organogenesis from callus cultures initiated from mature embryos in white pine (Pinus strobus L.) was achieved in this study. Callus cultures were induced from mature embryos cultured on PS medium supplemented with 2,4-dichlorophenoxyacetic acid, alpha-naphthaleneacetic acid, or indole-3-acetic acid. Adventitious shoot regeneration from callus cultures was induced on medium containing 2 microM indole-3-butyric acid (IBA) and 3-12 microM N(6)-benzylaminopurine, thidiazuron (TDZ), or 6-(gamma,gamma-dimethylallylamino) purine. Sucrose was the most suitable sugar for adventitious shoot organogenesis in white pine. Shoot organogenesis was improved by treatment at 4 degrees C for 6 weeks. The frequency of adventitious shoot formation increased when 0.1 mM putrescine was added to basal medium supplemented with 6 microM TDZ and 2 microM IBA. Putrescine improved adventitious shoot organogenesis by decreasing lipid peroxidation. These findings provide useful information on adventitious shoot organogenesis and may be valuable to genetic transformation in white pine.

Influence of the embryonal-suspensor mass (ESM) sampling on development and proliferation of maritime pine somatic embryos.

A Ramarosandratana — 2006-07-20T14:28:33-00:00

Plant Sci, Vol. 160, No. 3. (5 February 2001), pp. 473-479.

Two maturation media with high and low concentration of gellan gum were used to evaluate the maturation performances of four maritime pine ESM (embryonal-suspensor mass) lines. The maturation performance is influenced by sampling modalities; the outer part of the ESM yielded more cotyledonary embryos than the inner part or the whole colony. ESM lines showing several stage 1 embryos at the periphery (spiky) were more productive than those for which stage 1 embryos were rarely visible (smooth). This latter group develop preferably stage 3 embryos on the maturation medium containing high concentration of gellan gum. Biomass production is higher on a medium containing low concentration of gellan gum. However, sampling modalities did not affect the biomass production, and no relation was found between the biomass production and the maturation performance of each line. Stage 3 embryos developed on the medium with low concentration of gellan gum (0.45%, w/v) were shorter than those developed on medium with 0.9% of gellan gum. These short embryos were not able to germinate whereas about 48% of germination was reached with the longest embryos. The ability to develop primary root is dependent on the genotype while epicotyl elongation was observed among all lines.

The role of sucrose during maturation of black spruce (Picea mariana) and white spruce (Picea glauca) somatic embryos.

Driss Iraqi — 2006-07-20T14:27:40-00:00

Physiol Plant, Vol. 111, No. 3. (March 2001), pp. 381-388.

The present study was conducted to understand the role of sucrose in the medium on the maturation of black spruce and white spruce somatic embryos. A maturation medium containing 6% sucrose, which hydrolyzed into glucose and fructose, gave significantly more embryos than a medium containing 3.16% of each glucose and fructose. Preventing the complete sucrose hydrolysis by a daily transfer of the tissues onto fresh medium significantly decreased the yield of somatic embryos compared to when sucrose was allowed to complete its hydrolysis. This reduction was not due to the manipulation of the tissues during the transfer, since a daily in situ transfer did not affect embryo production. To verify if the better embryo production observed on a medium containing 6% sucrose was due to the increasing osmotic pressure of the medium, this increasing osmotic pressure was simulated with a sequence of media containing different concentrations of glucose and fructose. Unexpectedly and for both species, this simulation did not improve somatic embryo production, which stayed similar to the one obtained on constant osmotic pressure. To understand these results, embryos produced on the different treatments were analyzed in terms of sucrose, glucose, fructose and starch levels and protein contents. The embryo carbohydrate content was independent from the carbohydrate used in the maturation medium. However, embryos matured on 6% sucrose allowed to hydrolyze during the maturation period contained significantly more soluble and insoluble proteins than embryos matured on any other treatment. Furthermore, embryos with a higher protein content also exhibited a higher epicotyl appearance frequency. The role of sucrose as a regulatory factor during the maturation of spruce somatic embryos is discussed.

Early selection improves clonal performance and reduces intraclonal variation of Norway spruce plants propagated by somatic embryogenesis.

KA Högberg — 2006-07-20T14:26:39-00:00

Tree Physiol, Vol. 23, No. 3. (February 2003), pp. 211-216.

Height growth during the first and second growth periods (i.e., the June-September period in consecutive years) and intraclonal variation were assessed in 13 Norway spruce (Picea abies (L.) Karst.) clones propagated by somatic embryogenesis. The plants were acclimatized and grown in a greenhouse until mid-July and then transferred outdoors. The clonal mean heights after the first and second growth periods were lower for somatic embryo plants than for seedlings from corresponding families sown at the time of somatic embryo plant ex vitro transfer, because a large proportion of somatic embryo plants were small. We determined whether certain selection criteria at ex vitro transfer can be used to identify somatic embryo plants with height growth characteristics comparable with those of seedlings. Epicotyl length and presence of lateral roots proved to be important parameters for selection, whereas main root length was less useful. A combined selection for somatic embryo plants with lateral roots and with an epicotyl length exceeding 8 mm resulted in taller plants and reduced intraclonal variation after the first and second growth periods. The growth of somatic embryo plants selected in this way was similar to that of seedlings from the corresponding families. We conclude that selection according to these criteria at ex vitro transfer can result in improved performance of clonal stock propagated by somatic embryogenesis.