Cover illustration: Glandular trichomes are involved in the production of allelochemicals, which are important in defence mechanisms. Leaves of jasmonic acid mutants of tomato present lower levels of allelochemicals. Conversely, Campos et al. (2009) report in this issue (page 4347) that brassinosteroid-deficient mutants produce very high amounts of these compounds. Although viable, brassinosteroid mutants are extremely reduced in size, despite its high defence capacity, which may be representative of the so-called 'plant dilemma of resource allocation to growth versus defence'. The interaction between these opposite hormonal classes on plant defence against insects is also reported. (Top) Scanning micrograph showing a lowtrichome density on the leaf of the jasmonic acid-insensitive mutant jai1-1. (Middle) High-density trichome phenotype of the brassinosteroid-deficient mutant dpy and its whole plant aspect (inset) in the Micro-Tom (MT) genetic background. Usually MT plants are ~20 cm tall, but adult dpy is only 3 cm tall. (Bottom) detail of type V (left) non-glandular trichome, and types VII (centre) and VI (right) glandular trichomes. The micrographs were prepared by Monica Rossi, the plant photograph was taken by Rogerio Carvalho, and the layout was designed by Marcelo Campos. (See Campos et al., pp. 4347-4361.)
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