Papel dos tricomas glandulares da folha do tomateiro na oviposição de Tuta absoluta

Os tricomas glandulares presentes nas folhas e ramos das plantas do gênero Lycopersicon são responsáveis pela secreção de metabólitos de diferentes naturezas. A presença de alguns desses compostos tem sido associada à resistência do tomate a diferentes insetos. A traça-do-tomateiro, Tuta absoluta (Meyrick), é uma das pragas mais nocivas da América do Sul. O adulto oviposita sobre as folhas do tomate e suas larvas abrem galerias no mesófilo das folhas, ramos, flores e frutos. As espécies silvestres do tomate conservam a capacidade de biossintetizar compostos químicos que lhes conferem resistência a esta praga. No presente trabalho, foi avaliada a preferência para oviposição desse inseto sobre folhas com e sem tricomas glandulares de L. esculentum (Mill.) cv. Uco Plata, suscetível, e de L. hirsutum f. glabratum (Mull.) PI 134417, espécie silvestre afim ao tomate, e resistente à traça. Os resultados sugerem que as fêmeas ovipositam indistintamente sobre as folhas de ambas espécies, independentemente da presença, ou não, dos tricomas glandulares. E a presença destes e de seus exsudatos não têm efeito inibidor na oviposição do inseto

Genetic Diversity Enhances Restoration Success by Augmenting Ecosystem Services

Disturbance and habitat destruction due to human activities is a pervasive problem in near-shore marine ecosystems, and restoration is often used to mitigate losses. A common metric used to evaluate the success of restoration is the return of ecosystem services. Previous research has shown that biodiversity, including genetic diversity, is positively associated with the provision of ecosystem services. We conducted a restoration experiment using sources, techniques, and sites similar to actual large-scale seagrass restoration projects and demonstrated that a small increase in genetic diversity enhanced ecosystem services (invertebrate habitat, increased primary productivity, and nutrient retention). In our experiment, plots with elevated genetic diversity had plants that survived longer, increased in density more quickly, and provided more ecosystem services (invertebrate habitat, increased primary productivity, and nutrient retention). We used the number of alleles per locus as a measure of genetic diversity, which, unlike clonal diversity used in earlier research, can be applied to any organism. Additionally, unlike previous studies where positive impacts of diversity occurred only after a large disturbance, this study assessed the importance of diversity in response to potential environmental stresses (high temperature, low light) along a water–depth gradient. We found a positive impact of diversity along the entire depth gradient. Taken together, these results suggest that ecosystem restoration will significantly benefit from obtaining sources (transplants or seeds) with high genetic diversity and from restoration techniques that can maintain that genetic diversity

Floral volatiles from Clarkia breweri and C. concinna ( Onagraceae ): Recent evolution of floral scent and moth pollination

Clarkia breweri ( Onagraceae ) is the only species known in its genus to produce strong floral fragrance and to be pollinated by moths. We used gas chromatography-mass spectrometry (GC-MS) to identify 12 abundant compounds in the floral headspace from two inbred lines of C. breweri. These volatiles are derived from two biochemical pathways, one producing acyclic monoterpenes and their oxides, the other leading from phenylalanine to benzoate and its derivatives. Linalool and linalool oxide (pyran form) were the most abundant monoterpenoids, while linalool oxide (furan form) was present at lower concentrations. Of the aromatic compounds detected, benzyl acetate was most abundant, whereas benzyl benzoate, eugenol, methyl salicylate, and vanillin were present as minor constituents in all floral samples. The two inbred C. breweri lines differed for the presence of the additional benzenoid compounds isoeugenol, methyleugenol, methylisoeugenol, and veratraldehyde. We also analyzed floral headspace from C. concinna , the likely progenitor of C. breweri , whose flowers are odorless to the human nose. Ten volatiles (mostly terpenoids) were detected at low concentrations, but only when headspace was collected from 20 or more flowers at a time. Trans-β-ocimene was the most abundant floral compound identified from this species. Our data are consistent with the hypothesized recent evolution of floral scent production and moth pollination in C. breweri.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41639/1/606_2004_Article_BF00983216.pd

Tomato stem trichomes and dispersal success ofPhytoseiulus persimilis relative to its preyTetranychus urticae

Tomato varieties used at present for commercial production in Dutch glasshouses have a high density of glandular trichomes on the stem, but a very low density on the leaves. The two-spotted spider mite, Tetranychus urticae Koch, and the predatory mite, Phytoseiulus persimilis Athias-Henriot, usually disperse from leaf to leaf via the stem, thereby incurring high risks of entrapment (and death) in the exudate of the glandular trichomes. These risks have been quantified on the tomato cv. 'Turbo' and an accession of Lycopersicon peruvianum almost free of glandular trichomes. The possible consequences for biological control are discussed and new perspectives for predator release strategies and for plant breeding are considered. © 1987 Elsevier Science Publishers B.V