AOBPreview originally published online on June 18, 2003
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Annals of Botany 92: 239-245, 2003
© 2003 Annals of Botany Company
Effects of Benomyl and Drought on the Mycorrhizal Development and Daily Net CO2 Uptake of a Wild Platyopuntia in a Rocky Semi-arid Environment
1 Departamento de Ecología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, 45110 Zapopan, Jalisco, México and 2 Department of Organismic Biology, Ecology, and Evolution, University of California, Los Angeles, CA 90095-1606, USA
* For correspondence at: Cerrada de la Maestranza 1098, Residencial Guadalupe Jardín, 45030 Zapopan, Jalisco, México. Fax +52 (33) 37 77 11 56, e-mail epimient{at}maiz.cucba.udg.mx
Received: 18 December 2002; Returned for revision: 28 April 2003; Accepted: 1 May 2003 Published electronically: 18 June 2003
The effects of drought and the fungicide benomyl on a wild platyopuntia, Opuntia robusta Wendl., growing in a rocky semi-arid environment were assessed. Cladode phosphorus content, cladode water potential and daily net CO2 uptake were measured monthly in 2000 and 2001 before, during and after the summer rainy period. During 2000, the formation of new roots and new cladodes was severely suppressed in response to a prolonged drought, impairing the development of the symbiotic relationship between the arbuscular mycorrhizal (AM) fungi and the roots. Hence no effect of benomyl application was observed on daily carbon assimilation by this Crassulacean acid metabolism plant. During 2001, drought was interrupted, and new cladodes and roots were formed in response to rainfall. Benomyl was highly effective in suppressing root colonization by AM-fungi; however, daily C assimilation was reduced by benomyl application only in October. Thus, the inhibition of AM-fungal colonization by benomyl did not affect photosynthesis, water uptake and P uptake under prolonged drought.
Key words: Arbuscular mycorrhizae, benomyl, CO2 uptake, drought, Opuntia robusta Wendl., phosphorus, rocky environment.