The physiology of ex vitro pineapple (Ananas comosus L.Merr. var MD-2) as CAM or C3 is regulated by the environmental conditions
2012
Aragón, C. | Carvalho, L. | Gonzalez, J. | Escalona, M. | Amâncio, Sara
Many plant species grown under in vitro con- trolled conditions can be used as models for the study of physiological processes. Adult pineapple can display CAM physiology while in vitro it functions as a C3 plant. Ex vitro Ananas comosus has plastic morphology and physi- ology, both easy to modify from C3 to CAM by changing the environmental conditions. The yield of survival for a rentable propagation protocol of pineapple is closely rela- ted with the C3/CAM shift and the associated physiological characteristics. In the present work, ex vitro pineapple plants were divided in two sets and subjected to C3 and CAM-inducing environmental conditions, determined by light intensity and relative humidity, respectively, 40 lmol m-2 s-1/85% and 260 lmol m-2 s-1/50%. The results demonstrated that the stress imposed by the envi- ronmental conditions switched pineapple plants from C3 to CAM behavior. Comparing to CAM induced, C3-induced pineapple plants showed substandard growth parameters and morphological leaf characteristics but a better rooting process and a higher ABA production, a phenotype closer to adult plants, which are expected to produce fruits in a normal production cycle. We conclude that the upholding of these characteristics is conditioned by low light intensity plus high relative humidity, especially during the first 8 weeks of ex vitro growth. It is expected that the better understanding of pineapple acclimatization will contribute to the design of a protocol to apply as a rentable tool in the pineapple agronomic industry.
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