CARACTERIZAÇÃO DO MECANISMO FOTOSSINTÉTICO E

3
CHARACTERIZATION OF PHOTOSYNTHETIC MECHANISM AND THE
FLOWERING ASPECTS OF Artemisia annua L. Botucatu, 2006. 68p. Tese
(Doutorado em Agronomia/Horticultura) - Faculdade de Ciências Agronômicas,
Universidade Estadual Paulista.
Author: JOSÉ ABRAMO MARCHESE
Adviser: FERNANDO BROETTO
Co-Adviser: RITA M. MORAES
2 SUMMARY
Leaves of Artemisia annua L. are a plentiful source of artemisinin, a
drug with proven effectiveness against malaria. One of the objectives of this work was to
identify the photosynthetic type of A. annua through studies of the carbon isotope composition
(δ‰ 13 C) and the leaf anatomy. We also verified the growth and development of the CPQBA
2/39x1V accession under moist subtropical climate. Two experiments were carried out in
greenhouse using photoperiodic chambers. The plants were submitted to photoperiods of 7, 9,
11, 13, 15 and 17 h, in two natural conditions of temperature: spring/summer (maximum of
37ºC and minimum of 19ºC) and autumn/winter (maximum of 29ºC and minimum of 13ºC).
Another experiment with different planting dates at field was carried out in Pato Branco, PR
(26º11' S, 52º36' W and 760 m), Southern part of Brazil. The last experiment was the
application of artemisinin (0, 500, 5000, and 10000 mg L -1 ) in A. annua plants to verify the
role of the molecule on the flowering induction. A. annua presented a δ‰ 13 C = - 31.76 ± 0.07,
what characterizes it as typical species with a C 3 photosynthetic mechanism, with an average
of δ‰ 13 C = - 28, while C 4 species possess an average of δ‰ 13 C = - 14. The study of A. annua
leaf anatomy confirms the results of δ‰ 13 C, where, in spite of the existence of parenchymatic
cells forming a different sheath surrounding of the vascular tissue, these cells do not have
chloroplast or starch. These features do not describe the Kranz anatomy typical of C 4 species.
The application of artemisinin did not induce the flowering of A. annua at any of the
concentrations used. The results suggest that the accumulation of the artemisinin in the pre-