Cryopreservation of winter-dormant apple: III Bud water status and survival after cooling to -30°c and during recovery from cryopreservation

Abstract In a continuing study to improve the efficiency of dormant bud cryopreservation for tissues hardened in maritime climates, the water status of dormant buds was monitored between -4°C and recovery from liquid nitrogen (LN). Measurement of water content, simple thermal analysis and differential scanning calorimetry were employed. Buds did not lose water during cooling to, or holding at -30°C indicating that cryodehydration and/or other adaptive responses contributed during this essential step. A bud exotherm that was an artefact of warming was detected due to necessary handling at -4°C before cooling to -30°C. There were no significant differences between cultivars with respect to water status at -30°C or immediately upon rewarming from LN despite significant differences in post-LN survival. Buds rehydrated in 5 days, but up to 14 days may be needed for recovery for some cultivars. In some instances buds could be grafted without rehydration, taking up water across the early graft union

Aspects of Growth and Metabolism in a Suspension Culture of Acer pseudoplatanus (L. ) Grown on a Glycerol Carbon Source

Original article can be found at: http://jxb.oxfordjournals.org/ Copyright Society for Experimental Biology [Full text of this article is not available in the UHRA]A suspension culture of Acer pseudoplatanus cells was transferred from medium containing 2% (w/v) glucose to an identical one containing glycerol at 2% (w/v) as the sole carbon source. The patterns of cell number increase, dry weight increase, and changes in packed cell volume showed marked differences as a result of this transfer. The glucose-grown cultures contained a small proportion of cells of exceptionally large diameter, and transfer to the glycerol carbon source appeared to bring about a considerable increase in their number. These larger cells, in both glucose- and glycerol-containing cultures, exhibited considerable differences in cell wall architecture when compared with their smaller counterparts. They appeared more irregular, and had much looser cellulose microfibril arrangement in their outer layersPeer reviewe

Early stages in cell wall regeneration of tobacco mesophyll protoplasts : An electrophoretic study

The electrophoretic mobilities of isolated mesophyll protoplasts of Nicotiana tabacum var. Xanthi n.c. were measured using a whole cell electrophoresis apparatus. Changes in mobility were recorded at times during aseptic culture which related to events in the known sequence of de novo cell wall regeneration. It is proposed that these changes are a result of activity in, or at, the plasmalemma resulting in synthesis and transport to the cell surface of regenerated cell wall material. Coumarin, a compound known to affect the developmental sequence of cultured mesophyll protoplasts, was examined as a medium component during the regenerative process, differences in protoplast mobility resulting from Coumarin addition were recorded. The possible mode of action of Coumarin is discussedPeer reviewe

Cryopreservation of winter-dormant apple buds: 1 - variation in recovery with cultivar and winter conditions

The widely-adopted protocol for the cryopreservation of winter buds of fruit trees, such as Malus and Pyrus, was developed in a region with a continental climate, that provides relatively hard winters with a consequent effect on adaptive plant hardiness. In this study the protocol was evaluated in a typical maritime climate (eastern Denmark) where milder winters can be expected. The survival over two winters was evaluated, looking at variation between seasons and cultivars together with the progressive reduction in survival due to individual steps in the protocol. The study confirms that under such conditions significant variation in survival can be expected and that an extended period of imposed dehydration at -4oC is critical for bud survival. The occurrence of freezing events during this treatment suggests that cryodehydration may be involved, as well as evaporative water loss. To optimize the protocol for maritime environments, further investigation into the water status of the explants during cryopreservation is proposed. Keywords: Malus x domestica, cryopreservation, dormant bud, survival, graftin