The global abundance of tree palms

Aim: Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location: Tropical and subtropical moist forests. Time period: Current. Major taxa studied: Palms (Arecaceae). Methods: We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results: On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions: Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

Sinergism among auxins, gibberellins and cytokinins in tomato cv. Micro-Tom

The aim of this study was to evaluate the effect of isolated and combined applications of gibberellic acid (gibberellin), indolbutyric acid (auxin) and kinetin (cytokinin) on vegetative and reproductive development of tomato test plants (Solanum lycopersicum cv. Micro-Tom), to better elucidate the interactions among these hormonal classes. The following treatments were accomplished through foliar application: GA3 (5 mg L-1); IBA (5 mg L-1); KIN (9 mg L-1); GA3 + IBA (5 mg L-1 + 5 mg L-1); GA3 + KIN (5 mg L-1 + 9 mg L-1); IBA + KIN (5 mg L-1 + 9 mg L-1); GA3 + IBA + KIN (5 mg L-1 + 5 mg L-1 + 9 mg L-1) and Stimulate® (100 mL L-1). Plants from the control were sprayed with water. Stimulate®, is a commercial liquid formulation containing KIN (90 mg L-1), GA3 (50 mg L-1) and IBA (50 mg L-1). We analyzed the shoot dry matter (g), root dry matter (g); fruit fresh matter (g); fruit dry matter (g) and fruit size (cm). The experimental design was completely randomized with nine treatments and fifteen replications. The treatment means were compared by Tukey's test. Some combined applications of GA3, IBA and KIN or Stimulate® promoted significant increases in the dry matter accumulation of roots and fresh and dry matter of fruit compared to the control. Besides the perspective to extend such results for commercial tomato production, the relevance of known hormonal interactions for the results obtained is discussed