Differential Mechanisms to Induce Dehydration Tolerance by Abscisic Acid and Sucrose in Spathoglottis plicata (Orchidaceae) protocorms

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Wang, X-J, Loh, Chiang-Shiong, Yeoh, Hock-Hin and Sun, W. Q (2003) Differential Mechanisms to Induce Dehydration Tolerance by Abscisic Acid and Sucrose in Spathoglottis plicata (Orchidaceae) protocorms. Plant, Cell and Environment, 26. pp. 737-744. ISSN 0140-7791


Abscisic acid (ABA) and sucrose are known to induce dehydration tolerance of in vitro plant cells and tissues. The present study reports the presence of different mechanisms by which sucrose and ABA improve dehydration tolerance of Spathoglottis plicata (orchid) protocorms. Orchid protocorms were generated aseptically from seeds on Murashig and Skoog medium, and then treated for 7 d in medium containing 10 mg L−1 ABA and/or 10% (w/v) sucrose. Dehydration tolerance of protocorms was determined at ∼25 °C under various drying conditions at relative humidity from 7 to 93%. The actual rate of water loss (i.e. drying rate) was determined using the rate constant of tissue water loss during drying according to the first-order kinetics. Drying rate affected dehydration tolerance. ABA treatment reduced drying rate and increased dehydration tolerance of protocorms at all relative humidity values tested. However, when compared on the basis of actual drying rates, there was no difference in dehydration tolerance between control and ABA-treated protocorms, suggesting that ABA-induced tolerance was correlated with the drying rate reduction. Sucrose treatment was more effective than ABA treatment for the induction of dehydration tolerance. Interestingly, sucrose only slightly affected drying rate. ABA treatment significantly enhanced the synthesis of dehydrin, whereas sucrose treatment primarily resulted in sucrose accumulation. Sucrose treatment also affected protein turnover during drying, causing a significant decrease in protein content in protocorms. Slow drying promoted the degradation of high molecular weight proteins and enhanced the synthesis of low molecular weight dehydrin. The data suggest that different physiological mechanisms are probably involved in the induction of dehydration tolerance by ABA and sucrose treatment.

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Item type Article
URI https://vuir.vu.edu.au/id/eprint/2513
DOI 10.1046/j.1365-3040.2003.01010.x
Official URL http://onlinelibrary.wiley.com/doi/10.1046/j.1365-...
Subjects Historical > FOR Classification > 0903 Biomedical Engineering
Historical > FOR Classification > 1199 Other Medical and Health Sciences
Historical > Faculty/School/Research Centre/Department > School of Biomedical and Health Sciences
Keywords ResPubID18558, dehydrin, desiccation tolerance, drying rate, osmotic adjustment, water stress
Citations in Scopus 13 - View on Scopus
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