The special conditions during in vitro culture result in the formation of plantlets of abnormal morphology, anatomy and physiology. After ex vitro transfer, these plantlets might easily be impaired by sudden changes in environmental conditions, and so need a period of acclimatization to correct the abnormalities. This review is focused upon contemporary information on the changes in leaf structure, water relations and photosynthesis during acclimatization of plantlets to ex vitro conditions. It also describes some ways of improving plant survival and for the speeding up of acclimatization.

Acclimatization of Micropropagated Plants to Ex Vitro Conditions

Morpho-physiological disorders in in vitro culture of plants

A substantial number of micropropagated plants do not survive transfer from in vitro conditions to greenhouse or field environment. The greenhouse and field have substantially lower relative humidity, higher light level and septic environment that are stressful to micropropagated plants compared to in vitro conditions. The benefit of any micropropagation system can, however, only be fully realized by the successful transfer of plantlets from tissue-culture vessels to the ambient conditions found ex vitro. Most species grown in vitro require an acclimatization process in order to ensure that sufficient number of plants survive and grow vigorously when transferred to soil. This article reviews current and developing methods for the acclimatization of micropropagated plantlets.

Acclimatization of tissue cultured plants

Substantial numbers of micropropagated plants do not survive transfer from in vitro conditions to greenhouse or field environments. The greenhouse and field have substantially lower relative humidities, higher light levels, and septic environments that are stressful to micropropagated plants compared to in vitro conditions. Most species grown in vitro require an acclimatization process in order to insure that sufficient numbers of plants survive and grow vigorously when transferred to soil.

Acclimatization of micropropagated plants to the greenhouse and field

The literature has been reviewed and 160 references are presented to provide an overview of organosilicones as adjuvants for agrochemicals. Early studies (1973-1981) elucidated the special properties of these compounds, notably their extreme spreading and, by virtue of the exceptionally low surface tensions of their aqueous solutions, the ability to induce infiltration of spray formulations into foliage via stomata. Subsequent research at the New Zealand Forest Research Institute explored these and other properties in-depth, and demonstrated that they enabled the herbicide glyphosate to be used as a cost-effective alternative to 2,4,5-T for the control of forest scrubweeds. As a result, in 198S, «Silwet» L-77 was the first organosilicone adjuvant to be commercialised, and various other products have subsequently been introduced

Michelle Hutzell

Papers

Use of humidity tents and antitranspirants in the acclimatization of tissue-cultured plants to the greenhouse