Effects of the High Concentration of Atmospheric CO2 on Growth and Development of Sugar Cane (Saccharum Officinarum)
Marília
Gaspar, Instituto de Botânica de SP, gasparmarilia@yahoo.com.br
(Presenting)
Amanda
Pereira
Souza, Universidade Metodista, amandita_ps@uol.com.br
Mauro
Marabesi, Instituto de Botânica de SP, mauromarabesi@bol.com.br
João
R.L.
Godoy, Instituto de Botânica de SP, jrlgodoy@usp.br
Marcos
P.M.
Aidar, Instituto de Botânica de SP, maidar@uol.com.br
Marcos
Silveira
Buckeridge, Instituto de Botânica de SP, msbuck@usp.br
Some studies have been performed to evaluate the effects of the raising [CO2] on important commercial crops such as maize, soybeans and Pinus, but there is no previous account on sugar cane. Sugar cane is currently among the most important crops in Brazilian agribusiness, being responsible for more than 30% of the sugar produced in the world. A considerable amount of “medium-term” carbon sequestration in Brazil is accounted for by sugarcane which occupies very large areas in Northeast and Southeast regions. Native forests and savannahs have previously occupied most of these lands and it is important to evaluate the potential for carbon sequestration after their conversion to croplands. In the present work, we grew sugar cane plants in open top chambers in order to evaluate its photosynthetic and growth capacity in the atmosphere of 720ppm in comparison with 360ppm. Plants growing in elevated [CO2] displayed an increase of about 12% in plant height and a significant increase in the rate of leaf production. An increase of as much as 30% in CO2 assimilation was observed on the basis of curves A x Ci, followed by a raise in fresh and dry masses of the whole plant. Preliminary results show that there is no significant differences in the levels of soluble sugars in leaves suggesting that the higher assimilation of carbon by sugar cane plants is stored as biomass rather than sucrose. This is an indication of a longer-term carbon sequestration potential for the sugar cane as the stored carbon might be accumulated mainly as cellulose. FAPESP
Submetido por Marilia Gaspar em 18-MAR-2004
Tema Científico do LBA: CD (Armazenamento e Trocas de Carbono)