A Protocol for ExVitro Acclimation in Hydroculture in Liquid Substrate short description Alexandru Fira
[email protected] Doina Clapa
[email protected] The Fruit Research Station of Cluj Str. Horticultorilor no. 5, ClujNapoca, jud. Cluj, ROMANIA Email address:
[email protected] Website: http://www.scdpcluj.ro Introduction Ex vitro acclimation is an essential phase in the process of micropropagation, as it allows in vitrocultured plants to survive in normal, natural conditions. Ex vitro acclimation is the gradual adaptation of in vitrocultured plants to the normal, natural environment. The usual, classical methods used for ex vitro acclimation involve the use of various types of trays or pots containing a solid substrate (peat, perlite, bark, vermiculite, soil etc. or various mixtures of these solid components) and a more or less closed environment (greenhouse, tunnel, wet tent, acclimation chamber) where humidity is provided artificially in order to prevent plants from drying out, either by using special installations that provide artificial fog (e.g. in greenhouses) or simply by the evaporation of water and retention of humidity around the plantlets in a relatively closed environment (in plastic tunnels or in trays covered with transparent lids or foil or in wet tents). Our ex vitro acclimation method involves the use of open, uncovered (uncapped), glass or plastic vessels with no solid substrate, where the roots of the ex vitrotransferred plants are inserted into a layer of liquid consisting of ordinary tap water with natural or modified pH, according to the requirements of each species. We began research on this method in August 2008 and now we are exclusively and routinely using it for smallscale production and we are further experimenting with this method. This file was written on the 27th of July 2009. Brief description of the method The wellrooted plantlets are carefully taken out of the vessels used for in vitro culture and the roots are washed with warm water in order to melt away the remnants of the agargelled nutritive media . Then the plantlets are inserted into open, uncapped glass vessels (e.g. jars) or plastic vessels (e.g. plastic trays or cups) containing a layer of ordinary tap water 13 cm thick which should cover the roots but should not exceed root level in a great extent, only a few milimetres. Thus, the plantlets are in direct contact with the surrounding air, which ensures continuous and enhanced gas exchange and humidity is provided continuously by the continuous availability of water, while air humidity around the plantlets is provided by evaporation from the vessels. The acclimation vessels should be kept at artificial or natural light but not in direct sun and close to room temperature (1825 ºC), indoors, in a growth chamber, room or greenhouse. The plants are cultured for one month on the liquid substrate, then planted to soil or potting mix. If the water gets browned during the acclimation phase, it should be replaced with fresh tap water and if
the amount of water in the acclimation vessels decreases due to consumption by the plants and evaporation it should be resupplied. Occasional dead leaves from the base of the plants should be removed, as well as occasional rotted plantlets. Examples Our ex vitro acclimation method proved to be suitable for many horticultural species as well as some rare and protected wild species. It was a surprising success for blackberry cultivar Thornless Evergreen as well as a nonhomologated new blackberry hybrid, Romanian black currant cultivars Perla Neagra and Amurg, red raspberry cultivars Citria and Cuthbert, selfrooted plantlets of plum cultivar Iulia, Chrysanthemum sp., ornamental tomato (Lycopersicon esculentum), Cymbidium and Drosera rotundifolia, in unsuitable conditions. Photographs of plants acclimated in hydroculture
Acclimated blackberry plantlets, cv. Thornless Evergreen
Acclimated blackberry plantlets: an important hybrid
Acclimated raspberry plantlets
Plum cultivar Iulia
Acclimated Drosera rotundifolia
Acclimated Chrysanthemum Acclimated ornamental tomato
Acclimated Cymbidium plantlets Acclimated black currant
Photographs of potted plants which were acclimated in hydroculture according to the method described in the present file
Potted plum plants, cv. Iulia Potted blackberry cv. Thornless Evergreen
Potted raspberry Potted Drosera rotundifolia
Potted Cymbidium plants Potted tomato
Note. It is strictly forbidden to patent the ex vitro acclimation technique described in the present file. Anybody has the right to experiment with the technique described in the present file and everybody has the right to use it for practical purposes.