Expression of CAM photosynthesis in plants of Guzmania monostachia (Bromeliaceae) in diverses ontogenetic fases and leaves in different development stages

• Grant number: 11/04963-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2011
• End date: September 30, 2012
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Helenice Mercier
• Grantee: Leonardo Hamachi
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Guzmania monostachia is a species of heteroblastic bromeliad, in other words, whereas in the juvenile phase, it assumes the atmospheric form, in the adult, it acquires a structure called a tank, by which water and nutrients can be stored in moments of sporadic drought. It is also recognized through being C3-CAM facultative, thus inducible to CAM through environmental stimuli, such as the lack of water. In the young plants of other species capable of CAM expression, there are reports of preferential C3 photosynthesis expression in young tissues, leading to CAM expression on reaching maturity. In the Laboratory of Plant Development Physiology, studies were made of CAM induction in adult plants of the species G. monostachia during the lack of water at times of drought. It was noted that this bromeliad possessed leaves with distinct functional regions: whereas the basal portion was responsible for the absorption of both water and nutrients, the apical was mainly responsible for photosynthesis. Nonetheless, there was no available information on how ontogeny and morphological changes could influence competence for CAM expression throughout the whole leaf, as well as in the different parts. In order to characterize CAM in this species throughout ontogeny, selection was concentrated on plants in the three ontogenetic phases (Atmospheric, Tank-1 and Tank-2), as well as in the Tank-1 and Tank-2 phases by separating groups of leaves representing the three stages of development in the rosette, viz., Stage1 - the seven inner-most leaves, Stage2 - the next seven, and Stage3 - the seven located more at the base. By suspending irrigation, all the plants were submitted to 7 days without water, whereupon further material was collected from Tank-2 plants. The leaves thus obtained were first divided into groups representing the same three developmental phases as used in the preceding experiment, and then separated into basal and apical portions. Morphometric measurement was applied to the characterization of each ontogenetic phase. Tissue water content in the leaves was defined, and CAM detected through PEPC enzymatic assaying, MDH, and organic acid (citric and malic) quantification. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

RODRIGUES, MARIA AURINEIDE; HAMACHI, LEONARDO; MIOTO, PAULO TAMASO; PURGATTO, EDUARDO; MERCIER, HELENICE. Implications of leaf ontogeny on drought-induced gradients of CAM expression and ABA levels in rosettes of the epiphytic tank bromeliad Guzmania monostachia. Plant Physiology and Biochemistry, v. 108, p. 400-411, NOV 2016. (11/04963-2, 11/50637-0, 13/15108-1)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

HAMACHI, Leonardo. Competence for CAM photosynthesis expression in different ontogenétic stages of plants of Guzmania monostachia (Bromeliaceae). 2013. Master's Dissertation - Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) São Paulo.